v2.2.0

.gitea/workflows/default_nottags.yaml

@@ -0,0 +1,66 @@
+name: Default (not tags)
+
+on:
+  push:
+    tags-ignore:
+      - '**'
+
+env:
+  IMAGE: code.foss.global/host.today/ht-docker-node:npmci
+  NPMCI_COMPUTED_REPOURL: https://${{gitea.repository_owner}}:${{secrets.GITEA_TOKEN}}@/${{gitea.repository}}.git
+  NPMCI_TOKEN_NPM: ${{secrets.NPMCI_TOKEN_NPM}}
+  NPMCI_TOKEN_NPM2: ${{secrets.NPMCI_TOKEN_NPM2}}
+  NPMCI_GIT_GITHUBTOKEN: ${{secrets.NPMCI_GIT_GITHUBTOKEN}}
+  NPMCI_URL_CLOUDLY: ${{secrets.NPMCI_URL_CLOUDLY}}
+
+jobs:
+  security:
+    runs-on: ubuntu-latest
+    continue-on-error: true
+    container:
+      image: ${{ env.IMAGE }}
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Install pnpm and npmci
+        run: |
+          pnpm install -g pnpm
+          pnpm install -g @ship.zone/npmci
+
+      - name: Run npm prepare
+        run: npmci npm prepare
+
+      - name: Audit production dependencies
+        run: |
+          npmci command npm config set registry https://registry.npmjs.org
+          npmci command pnpm audit --audit-level=high --prod
+        continue-on-error: true
+
+      - name: Audit development dependencies
+        run: |
+          npmci command npm config set registry https://registry.npmjs.org
+          npmci command pnpm audit --audit-level=high --dev
+        continue-on-error: true
+
+  test:
+    if: ${{ always() }}
+    needs: security
+    runs-on: ubuntu-latest
+    container:
+      image: ${{ env.IMAGE }}
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Test stable
+        run: |
+          npmci node install stable
+          npmci npm install
+          npmci npm test
+
+      - name: Test build
+        run: |
+          npmci node install stable
+          npmci npm install
+          npmci npm build

.gitea/workflows/default_tags.yaml

@@ -0,0 +1,124 @@
+name: Default (tags)
+
+on:
+  push:
+    tags:
+      - '*'
+
+env:
+  IMAGE: code.foss.global/host.today/ht-docker-node:npmci
+  NPMCI_COMPUTED_REPOURL: https://${{gitea.repository_owner}}:${{secrets.GITEA_TOKEN}}@/${{gitea.repository}}.git
+  NPMCI_TOKEN_NPM: ${{secrets.NPMCI_TOKEN_NPM}}
+  NPMCI_TOKEN_NPM2: ${{secrets.NPMCI_TOKEN_NPM2}}
+  NPMCI_GIT_GITHUBTOKEN: ${{secrets.NPMCI_GIT_GITHUBTOKEN}}
+  NPMCI_URL_CLOUDLY: ${{secrets.NPMCI_URL_CLOUDLY}}
+
+jobs:
+  security:
+    runs-on: ubuntu-latest
+    continue-on-error: true
+    container:
+      image: ${{ env.IMAGE }}
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Prepare
+        run: |
+          pnpm install -g pnpm
+          pnpm install -g @ship.zone/npmci
+          npmci npm prepare
+
+      - name: Audit production dependencies
+        run: |
+          npmci command npm config set registry https://registry.npmjs.org
+          npmci command pnpm audit --audit-level=high --prod
+        continue-on-error: true
+
+      - name: Audit development dependencies
+        run: |
+          npmci command npm config set registry https://registry.npmjs.org
+          npmci command pnpm audit --audit-level=high --dev
+        continue-on-error: true
+
+  test:
+    if: ${{ always() }}
+    needs: security
+    runs-on: ubuntu-latest
+    container:
+      image: ${{ env.IMAGE }}
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Prepare
+        run: |
+          pnpm install -g pnpm
+          pnpm install -g @ship.zone/npmci
+          npmci npm prepare
+
+      - name: Test stable
+        run: |
+          npmci node install stable
+          npmci npm install
+          npmci npm test
+
+      - name: Test build
+        run: |
+          npmci node install stable
+          npmci npm install
+          npmci npm build
+
+  release:
+    needs: test
+    if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/')
+    runs-on: ubuntu-latest
+    container:
+      image: ${{ env.IMAGE }}
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Prepare
+        run: |
+          pnpm install -g pnpm
+          pnpm install -g @ship.zone/npmci
+          npmci npm prepare
+
+      - name: Release
+        run: |
+          npmci node install stable
+          npmci npm publish
+
+  metadata:
+    needs: test
+    if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/')
+    runs-on: ubuntu-latest
+    container:
+      image: ${{ env.IMAGE }}
+    continue-on-error: true
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Prepare
+        run: |
+          pnpm install -g pnpm
+          pnpm install -g @ship.zone/npmci
+          npmci npm prepare
+
+      - name: Code quality
+        run: |
+          npmci command npm install -g typescript
+          npmci npm install
+
+      - name: Trigger
+        run: npmci trigger
+
+      - name: Build docs and upload artifacts
+        run: |
+          npmci node install stable
+          npmci npm install
+          pnpm install -g @git.zone/tsdoc
+          npmci command tsdoc
+        continue-on-error: true

.gitignore

@@ -3,7 +3,6 @@
 # artifacts
 coverage/
 public/
-pages/
 
 # installs
 node_modules/
@@ -17,4 +16,4 @@ node_modules/
 dist/
 dist_*/
 
-# custom
+#------# custom

.gitlab-ci.yml

@@ -1,141 +0,0 @@
-# gitzone ci_default
-image: registry.gitlab.com/hosttoday/ht-docker-node:npmci
-
-cache:
-  paths:
-    - .npmci_cache/
-  key: '$CI_BUILD_STAGE'
-
-stages:
-  - security
-  - test
-  - release
-  - metadata
-
-before_script:
-  - npm install -g @shipzone/npmci
-
-# ====================
-# security stage
-# ====================
-mirror:
-  stage: security
-  script:
-    - npmci git mirror
-  only:
-    - tags
-  tags:
-    - lossless
-    - docker
-    - notpriv
-
-auditProductionDependencies:
-  image: registry.gitlab.com/hosttoday/ht-docker-node:npmci
-  stage: security
-  script:
-    - npmci npm prepare
-    - npmci command npm install --production --ignore-scripts
-    - npmci command npm config set registry https://registry.npmjs.org
-    - npmci command npm audit --audit-level=high --only=prod --production
-  tags:
-    - docker
-  allow_failure: true
-
-auditDevDependencies:
-  image: registry.gitlab.com/hosttoday/ht-docker-node:npmci
-  stage: security
-  script:
-    - npmci npm prepare
-    - npmci command npm install --ignore-scripts
-    - npmci command npm config set registry https://registry.npmjs.org
-    - npmci command npm audit --audit-level=high --only=dev
-  tags:
-    - docker
-  allow_failure: true
-
-# ====================
-# test stage
-# ====================
-
-testStable:
-  stage: test
-  script:
-    - npmci npm prepare
-    - npmci node install stable
-    - npmci npm install
-    - npmci npm test
-  coverage: /\d+.?\d+?\%\s*coverage/
-  tags:
-    - docker
-
-testBuild:
-  stage: test
-  script:
-    - npmci npm prepare
-    - npmci node install stable
-    - npmci npm install
-    - npmci command npm run build
-  coverage: /\d+.?\d+?\%\s*coverage/
-  tags:
-    - docker
-
-release:
-  stage: release
-  script:
-    - npmci node install stable
-    - npmci npm publish
-  only:
-    - tags
-  tags:
-    - lossless
-    - docker
-    - notpriv
-
-# ====================
-# metadata stage
-# ====================
-codequality:
-  stage: metadata
-  allow_failure: true
-  only:
-    - tags
-  script:
-    - npmci command npm install -g tslint typescript
-    - npmci npm prepare
-    - npmci npm install
-    - npmci command "tslint -c tslint.json ./ts/**/*.ts"
-  tags:
-    - lossless
-    - docker
-    - priv
-
-trigger:
-  stage: metadata
-  script:
-    - npmci trigger
-  only:
-    - tags
-  tags:
-    - lossless
-    - docker
-    - notpriv
-
-pages:
-  stage: metadata
-  script:
-    - npmci node install lts
-    - npmci command npm install -g @gitzone/tsdoc
-    - npmci npm prepare
-    - npmci npm install
-    - npmci command tsdoc
-  tags:
-    - lossless
-    - docker
-    - notpriv
-  only:
-    - tags
-  artifacts:
-    expire_in: 1 week
-    paths:
-      - public
-  allow_failure: true

changelog.md

@@ -0,0 +1,152 @@
+# Changelog
+
+## 2026-01-31 - 2.2.0 - feat(readme)
+update README with expanded documentation covering CongoDB and SmartMongo, installation, quick start examples, architecture, usage examples, and legal/company information
+
+- Completely expanded README: added detailed overview for SmartMongo and new CongoDB (wire-protocol server)
+- Added Quick Start examples for both SmartMongo and CongoDB (TypeScript/ESM snippets)
+- Included installation instructions for npm and pnpm and issue reporting/security guidance
+- Added architecture diagram, example tests, and storage/engine descriptions
+- Clarified license, trademark, and company contact information
+- Large non-functional documentation-only change (+398 -44)
+
+## 2026-01-31 - 2.1.0 - feat(congodb)
+implement CongoDB MongoDB wire-protocol compatible in-memory server and APIs
+
+- Add full congodb module: CongoServer, WireProtocol, CommandRouter and handlers (Hello, Insert, Find, Update, Delete, Aggregate, Index, Admin).
+- Implement query/update/aggregation/index/transaction engines (QueryEngine, UpdateEngine, AggregationEngine, IndexEngine, TransactionEngine) and OpLog for change stream support.
+- Add storage adapters: in-memory (MemoryStorageAdapter) and file-backed (FileStorageAdapter) with persistence and oplog support.
+- Introduce types/interfaces and rich error classes (CongoErrors) plus congodb.plugins re-exports (bson, mingo, smartfs, smartpath, smartrx).
+- Add many server-side utilities: IndexEngine, Aggregation helpers ($lookup, $graphLookup, $merge, $facet, $unionWith), cursor management and command routing.
+- Add integration tests for CongoDB using official mongodb MongoClient (test/test.congodb.ts) and update unit test entry (test/test.ts) to use tstest tapbundle.
+- Export congodb from ts/index.ts and update package.json: bump devDependencies, add runtime deps (mongodb, bson, mingo, mingo), add new @push.rocks/* deps and dev tool versions.
+- Update readme.hints.md with CongoDB architecture, usage examples and supported commands.
+- Update npmextra.json metadata and release/registry config and reorganize tsdoc mappings.
+
+## 2025-11-17 - 2.0.14 - fix(smartmongo.plugins)
+Use default import for mongodb-memory-server (Deno compatibility), update hints and bump package version to 2.0.13
+
+- Replace namespace import with default import for mongodb-memory-server to ensure compatibility with Deno (ts/smartmongo.plugins.ts).
+- Add readme.hints.md documenting the Deno compatibility change and the reason for using a default import.
+- Bump package.json version to 2.0.13.
+- Note: ts/00_commitinfo_data.ts still lists version 2.0.12 and may need to be updated to match package.json.
+
+## 2025-04-06 - 2.0.12 - fix(ci/config)
+Update CI workflow environment variables, refine package metadata, and improve configuration settings
+
+- Updated workflow YAML files to use new IMAGE and npmci package names
+- Adjusted package.json homepage, added bugs field and pnpm overrides
+- Minor formatting improvements in readme.md and .gitignore
+- Enhanced tsconfig with baseUrl and paths for improved module resolution
+
+## 2025-04-06 - 2.0.11 - fix(dependencies)
+Update dependency names and versions in CI workflows and package configuration
+
+- Rename devDependency packages from '@gitzone/*' to '@git.zone/*' for consistency
+- Bump '@types/node' from '^20.4.8' to '^22.14.0'
+- Upgrade 'mongodb-memory-server' from '^8.14.0' to '^10.1.4'
+- Add 'packageManager' field in package.json
+- Introduce pnpm-workspace.yaml with 'onlyBuiltDependencies' configuration
+
+## 2024-05-29 - 2.0.10 - misc  
+Various updates to project configuration and documentation.
+
+- update description  
+- update tsconfig  
+- update npmextra.json: githost (applied on three occasions)
+
+## 2023-08-08 - 2.0.9 - core  
+Core fix.
+
+- fix(core): update
+
+## 2023-08-08 - 2.0.8 - core  
+Core fix.
+
+- fix(core): update
+
+## 2023-08-08 - 2.0.7 - core & org  
+Combined changes for core stability and organization improvements.
+
+- fix(core): update  
+- switch to new org scheme (recorded twice)
+
+## 2022-06-08 - 2.0.6 - core  
+Core fix.
+
+- fix(core): update
+
+## 2022-06-08 - 2.0.5 - core  
+Core fix.
+
+- fix(core): update
+
+## 2022-06-06 - 2.0.4 - core  
+Core fix.
+
+- fix(core): update
+
+## 2022-06-06 - 2.0.3 - core  
+Core fix.
+
+- fix(core): update
+
+## 2022-06-03 - 2.0.2 - core  
+Core fix.
+
+- fix(core): update
+
+## 2022-05-19 - 2.0.1 - core  
+Core fix.
+
+- fix(core): update
+
+## 2022-05-18 - 2.0.0 - core  
+Core fix.
+
+- fix(core): update
+
+## 2022-05-17 - 1.0.9 - core  
+Breaking change for module format.
+
+- BREAKING CHANGE(core): switch to esm
+
+## 2022-05-17 - 1.0.8 - core  
+Core fix.
+
+- fix(core): update
+
+## 2021-12-21 - 1.0.7 - core  
+Core fix.
+
+- fix(core): update
+
+## 2021-12-20 - 1.0.6 - core  
+Core fix.
+
+- fix(core): update
+
+## 2021-12-20 - 1.0.5 - core  
+Core fix.
+
+- fix(core): update
+
+## 2021-12-20 - 1.0.4 - core  
+Core fix.
+
+- fix(core): update
+
+## 2021-12-20 - 1.0.3 - core  
+Core fix.
+
+- fix(core): update
+
+## 2021-12-20 - 1.0.2 - no notable changes  
+These version bumps did not include additional modifications.
+
+- version update only
+
+## 2021-12-20 - 1.0.1 - core  
+Core fix.
+
+- fix(core): update

npmextra.json

@@ -1,18 +1,40 @@
 {
-  "gitzone": {
+  "@git.zone/cli": {
     "projectType": "npm",
     "module": {
-      "githost": "gitlab.com",
+      "githost": "code.foss.global",
-      "gitscope": "pushrocks",
+      "gitscope": "push.rocks",
       "gitrepo": "smartmongo",
-      "shortDescription": "create a local mongodb for testing",
+      "description": "A module for creating and managing a local MongoDB instance for testing purposes.",
-      "npmPackagename": "@pushrocks/smartmongo",
+      "npmPackagename": "@push.rocks/smartmongo",
       "license": "MIT",
-      "projectDomain": "push.rocks"
+      "projectDomain": "push.rocks",
-    }
+      "keywords": [
+        "mongodb",
+        "testing",
+        "local database",
+        "replica set",
+        "memory server",
+        "database management",
+        "typescript"
+      ]
     },
-  "npmci": {
+    "release": {
-    "npmGlobalTools": [],
+      "registries": [
-    "npmAccessLevel": "public"
+        "https://verdaccio.lossless.digital",
+        "https://registry.npmjs.org"
+      ],
+      "accessLevel": "public"
+    },
+    "services": [
+      "mongodb",
+      "minio"
+    ]
+  },
+  "@git.zone/tsdoc": {
+    "legal": "\n## License and Legal Information\n\nThis repository contains open-source code that is licensed under the MIT License. A copy of the MIT License can be found in the [license](license) file within this repository. \n\n**Please note:** The MIT License does not grant permission to use the trade names, trademarks, service marks, or product names of the project, except as required for reasonable and customary use in describing the origin of the work and reproducing the content of the NOTICE file.\n\n### Trademarks\n\nThis project is owned and maintained by Task Venture Capital GmbH. The names and logos associated with Task Venture Capital GmbH and any related products or services are trademarks of Task Venture Capital GmbH and are not included within the scope of the MIT license granted herein. Use of these trademarks must comply with Task Venture Capital GmbH's Trademark Guidelines, and any usage must be approved in writing by Task Venture Capital GmbH.\n\n### Company Information\n\nTask Venture Capital GmbH  \nRegistered at District court Bremen HRB 35230 HB, Germany\n\nFor any legal inquiries or if you require further information, please contact us via email at hello@task.vc.\n\nBy using this repository, you acknowledge that you have read this section, agree to comply with its terms, and understand that the licensing of the code does not imply endorsement by Task Venture Capital GmbH of any derivative works.\n"
+  },
+  "@ship.zone/szci": {
+    "npmGlobalTools": []
   }
 }

package.json

@@ -1,29 +1,36 @@
 {
-  "name": "@pushrocks/smartmongo",
+  "name": "@push.rocks/smartmongo",
-  "version": "1.0.9",
+  "version": "2.2.0",
   "private": false,
-  "description": "create a local mongodb for testing",
+  "description": "A module for creating and managing a local MongoDB instance for testing purposes.",
   "main": "dist_ts/index.js",
   "typings": "dist_ts/index.d.ts",
+  "type": "module",
   "author": "Lossless GmbH",
   "license": "MIT",
   "scripts": {
-    "test": "(tstest test/ --web)",
+    "test": "(tstest test/)",
-    "build": "(tsbuild --web)"
+    "build": "(tsbuild --web)",
+    "buildDocs": "tsdoc"
   },
   "devDependencies": {
-    "@gitzone/tsbuild": "^2.1.25",
+    "@git.zone/tsbuild": "^4.1.2",
-    "@gitzone/tsbundle": "^1.0.78",
+    "@git.zone/tsbundle": "^2.8.3",
-    "@gitzone/tstest": "^1.0.44",
+    "@git.zone/tsrun": "^2.0.1",
-    "@pushrocks/tapbundle": "^3.2.9",
+    "@git.zone/tstest": "^3.1.8",
-    "@types/node": "^14.11.2",
+    "@types/node": "^25.1.0",
-    "tslint": "^6.1.3",
+    "mongodb": "^7.0.0"
-    "tslint-config-prettier": "^1.15.0"
   },
   "dependencies": {
-    "@pushrocks/smartdata": "^4.0.27",
+    "@push.rocks/mongodump": "^1.0.7",
-    "@pushrocks/smartpromise": "^3.1.6",
+    "@push.rocks/smartdata": "^5.0.23",
-    "mongodb-memory-server": "^8.0.4"
+    "@push.rocks/smartfs": "^1.3.1",
+    "@push.rocks/smartpath": "^5.0.11",
+    "@push.rocks/smartpromise": "^4.0.3",
+    "@push.rocks/smartrx": "^3.0.0",
+    "bson": "^6.10.0",
+    "mingo": "^7.2.0",
+    "mongodb-memory-server": "^10.1.4"
   },
   "browserslist": [
     "last 1 chrome versions"
@@ -39,5 +46,26 @@
     "cli.js",
     "npmextra.json",
     "readme.md"
-  ]
+  ],
+  "keywords": [
+    "mongodb",
+    "testing",
+    "local database",
+    "replica set",
+    "memory server",
+    "database management",
+    "typescript"
+  ],
+  "homepage": "https://code.foss.global/push.rocks/smartmongo#readme",
+  "repository": {
+    "type": "git",
+    "url": "https://code.foss.global/push.rocks/smartmongo.git"
+  },
+  "packageManager": "pnpm@10.7.0+sha512.6b865ad4b62a1d9842b61d674a393903b871d9244954f652b8842c2b553c72176b278f64c463e52d40fff8aba385c235c8c9ecf5cc7de4fd78b8bb6d49633ab6",
+  "bugs": {
+    "url": "https://code.foss.global/push.rocks/smartmongo/issues"
+  },
+  "pnpm": {
+    "overrides": {}
+  }
 }

readme.hints.md

@@ -0,0 +1,89 @@
+# Project Hints
+
+## Deno Compatibility
+
+### mongodb-memory-server Import
+- The package uses a **default import** for `mongodb-memory-server` in `ts/smartmongo.plugins.ts`
+- Syntax: `import mongoPlugin from 'mongodb-memory-server';`
+- This works in both Node.js and Deno environments
+- **Why:** Deno wraps CommonJS exports in a `default` property, so default imports are required
+- Fixed in version 2.0.13 (changed from `import * as mongoPlugin`)
+
+## CongoDB - MongoDB Wire Protocol Server
+
+### Architecture
+CongoDB implements the MongoDB binary wire protocol (OP_MSG, OP_QUERY) allowing official MongoDB drivers to connect directly.
+
+```
+Official MongoClient  →  TCP (wire protocol)  →  CongoServer  →  Engines  →  Storage
+     (mongodb npm)           OP_MSG/BSON            (port)
+```
+
+### Module Structure
+```
+ts/congodb/
+├── server/                   # Wire protocol server
+│   ├── CongoServer.ts        # TCP server, connection handling
+│   ├── WireProtocol.ts       # OP_MSG/OP_QUERY parsing & encoding
+│   ├── CommandRouter.ts      # Route commands to handlers
+│   └── handlers/             # Command implementations
+│       ├── HelloHandler.ts   # hello/isMaster handshake
+│       ├── FindHandler.ts    # find, getMore, killCursors, count, distinct
+│       ├── InsertHandler.ts  # insert
+│       ├── UpdateHandler.ts  # update, findAndModify
+│       ├── DeleteHandler.ts  # delete
+│       ├── AggregateHandler.ts # aggregate
+│       ├── IndexHandler.ts   # createIndexes, dropIndexes, listIndexes
+│       └── AdminHandler.ts   # ping, listDatabases, listCollections, etc.
+│
+├── engine/                   # Core logic (reused)
+│   ├── QueryEngine.ts        # Query filtering with mingo
+│   ├── UpdateEngine.ts       # Update operations
+│   ├── AggregationEngine.ts  # Aggregation pipelines
+│   ├── IndexEngine.ts        # Index management
+│   └── TransactionEngine.ts  # Transaction support
+│
+├── storage/                  # Storage layer
+│   ├── IStorageAdapter.ts    # Interface
+│   ├── MemoryStorageAdapter.ts
+│   └── FileStorageAdapter.ts
+│
+└── types/interfaces.ts       # Type definitions
+```
+
+### Usage Example
+```typescript
+import { CongoServer } from '@push.rocks/smartmongo/congodb';
+import { MongoClient } from 'mongodb';
+
+// Start server
+const server = new CongoServer({ port: 27117 });
+await server.start();
+
+// Connect with official MongoDB driver
+const client = new MongoClient('mongodb://127.0.0.1:27117', {
+  directConnection: true
+});
+await client.connect();
+
+// Use like any MongoDB instance
+const db = client.db('mydb');
+await db.collection('users').insertOne({ name: 'John' });
+const user = await db.collection('users').findOne({ name: 'John' });
+
+// Cleanup
+await client.close();
+await server.stop();
+```
+
+### Supported Commands
+- **Handshake**: hello, isMaster
+- **CRUD**: find, insert, update, delete, findAndModify, getMore, killCursors
+- **Aggregation**: aggregate, count, distinct
+- **Indexes**: createIndexes, dropIndexes, listIndexes
+- **Admin**: ping, listDatabases, listCollections, drop, dropDatabase, create, serverStatus, buildInfo
+
+### Notes
+- The old CongoClient/CongoDb/CongoCollection classes have been removed
+- Use the official `mongodb` npm package's MongoClient instead
+- Server supports MongoDB wire protocol versions 0-21 (MongoDB 3.6 through 7.0 compatible)

readme.md

@@ -1,39 +1,458 @@
-# @pushrocks/smartmongo
+# @push.rocks/smartmongo
-create a local mongodb for testing
 
-## Availabililty and Links
+A powerful MongoDB toolkit for testing and development — featuring both a real MongoDB memory server (**SmartMongo**) and an ultra-fast, lightweight wire-protocol-compatible in-memory database server (**CongoDB**). 🚀
-* [npmjs.org (npm package)](https://www.npmjs.com/package/@pushrocks/smartmongo)
-* [gitlab.com (source)](https://gitlab.com/pushrocks/smartmongo)
-* [github.com (source mirror)](https://github.com/pushrocks/smartmongo)
-* [docs (typedoc)](https://pushrocks.gitlab.io/smartmongo/)
 
-## Status for master
+## Install
 
-Status Category | Status Badge
+```bash
--- | --
+npm install @push.rocks/smartmongo --save-dev
-GitLab Pipelines | [![pipeline status](https://gitlab.com/pushrocks/smartmongo/badges/master/pipeline.svg)](https://lossless.cloud)
+# or
-GitLab Pipline Test Coverage | [![coverage report](https://gitlab.com/pushrocks/smartmongo/badges/master/coverage.svg)](https://lossless.cloud)
+pnpm add -D @push.rocks/smartmongo
-npm | [![npm downloads per month](https://badgen.net/npm/dy/@pushrocks/smartmongo)](https://lossless.cloud)
+```
-Snyk | [![Known Vulnerabilities](https://badgen.net/snyk/pushrocks/smartmongo)](https://lossless.cloud)
-TypeScript Support | [![TypeScript](https://badgen.net/badge/TypeScript/>=%203.x/blue?icon=typescript)](https://lossless.cloud)
-node Support | [![node](https://img.shields.io/badge/node->=%2010.x.x-blue.svg)](https://nodejs.org/dist/latest-v10.x/docs/api/)
-Code Style | [![Code Style](https://badgen.net/badge/style/prettier/purple)](https://lossless.cloud)
-PackagePhobia (total standalone install weight) | [![PackagePhobia](https://badgen.net/packagephobia/install/@pushrocks/smartmongo)](https://lossless.cloud)
-PackagePhobia (package size on registry) | [![PackagePhobia](https://badgen.net/packagephobia/publish/@pushrocks/smartmongo)](https://lossless.cloud)
-BundlePhobia (total size when bundled) | [![BundlePhobia](https://badgen.net/bundlephobia/minzip/@pushrocks/smartmongo)](https://lossless.cloud)
-Platform support | [![Supports Windows 10](https://badgen.net/badge/supports%20Windows%2010/yes/green?icon=windows)](https://lossless.cloud) [![Supports Mac OS X](https://badgen.net/badge/supports%20Mac%20OS%20X/yes/green?icon=apple)](https://lossless.cloud)
 
-## Usage
+## Issue Reporting and Security
 
-Use TypeScript for best in class intellisense
+For reporting bugs, issues, or security vulnerabilities, please visit [community.foss.global/](https://community.foss.global/). This is the central community hub for all issue reporting. Developers who sign and comply with our contribution agreement and go through identification can also get a [code.foss.global/](https://code.foss.global/) account to submit Pull Requests directly.
 
-## Contribution
+## Overview
 
-We are always happy for code contributions. If you are not the code contributing type that is ok. Still, maintaining Open Source repositories takes considerable time and thought. If you like the quality of what we do and our modules are useful to you we would appreciate a little monthly contribution: You can [contribute one time](https://lossless.link/contribute-onetime) or [contribute monthly](https://lossless.link/contribute). :)
+`@push.rocks/smartmongo` provides two powerful approaches for MongoDB in testing and development:
 
-For further information read the linked docs at the top of this readme.
+| Feature | SmartMongo | CongoDB |
+|---------|------------|---------|
+| **Type** | Real MongoDB (memory server) | Pure TypeScript wire protocol server |
+| **Speed** | ~2-5s startup | ⚡ Instant startup (~5ms) |
+| **Compatibility** | 100% MongoDB | MongoDB driver compatible |
+| **Dependencies** | Downloads MongoDB binary | Zero external dependencies |
+| **Replication** | ✅ Full replica set support | Single node emulation |
+| **Use Case** | Integration testing | Unit testing, CI/CD |
+| **Persistence** | Dump to directory | Optional file/memory persistence |
 
-> MIT licensed | **©** [Lossless GmbH](https://lossless.gmbh)
+## 🚀 Quick Start
-| By using this npm module you agree to our [privacy policy](https://lossless.gmbH/privacy)
 
-[![repo-footer](https://lossless.gitlab.io/publicrelations/repofooter.svg)](https://maintainedby.lossless.com)
+### Option 1: SmartMongo (Real MongoDB)
+
+Spin up a real MongoDB replica set in memory — perfect for integration tests that need full MongoDB compatibility.
+
+```typescript
+import { SmartMongo } from '@push.rocks/smartmongo';
+
+// Start a MongoDB replica set
+const mongo = await SmartMongo.createAndStart();
+
+// Get connection details
+const descriptor = await mongo.getMongoDescriptor();
+console.log(descriptor.mongoDbUrl); // mongodb://127.0.0.1:xxxxx/...
+
+// Use with your MongoDB client or ORM
+// ... run your tests ...
+
+// Clean up
+await mongo.stop();
+```
+
+### Option 2: CongoDB (Wire Protocol Server)
+
+A lightweight, pure TypeScript MongoDB-compatible server that speaks the wire protocol — use the official `mongodb` driver directly!
+
+```typescript
+import { congodb } from '@push.rocks/smartmongo';
+import { MongoClient } from 'mongodb';
+
+// Start CongoDB server
+const server = new congodb.CongoServer({ port: 27017 });
+await server.start();
+
+// Connect with the official MongoDB driver!
+const client = new MongoClient('mongodb://127.0.0.1:27017');
+await client.connect();
+
+// Use exactly like real MongoDB
+const db = client.db('myapp');
+await db.collection('users').insertOne({ name: 'Alice', age: 30 });
+
+const user = await db.collection('users').findOne({ name: 'Alice' });
+console.log(user); // { _id: ObjectId(...), name: 'Alice', age: 30 }
+
+// Clean up
+await client.close();
+await server.stop();
+```
+
+## 📖 SmartMongo API
+
+### Creating an Instance
+
+```typescript
+import { SmartMongo } from '@push.rocks/smartmongo';
+
+// Default: single replica
+const mongo = await SmartMongo.createAndStart();
+
+// Multiple replicas for testing replication
+const mongo = await SmartMongo.createAndStart(3);
+```
+
+### Getting Connection Details
+
+```typescript
+const descriptor = await mongo.getMongoDescriptor();
+// {
+//   mongoDbName: 'smartmongo_testdatabase',
+//   mongoDbUrl: 'mongodb://127.0.0.1:xxxxx/?replicaSet=testset'
+// }
+```
+
+### Stopping & Cleanup
+
+```typescript
+// Simple stop (data discarded)
+await mongo.stop();
+
+// Stop and dump data to disk for inspection
+await mongo.stopAndDumpToDir('./test-data');
+
+// With custom file naming
+await mongo.stopAndDumpToDir('./test-data', (doc) => `${doc.collection}-${doc._id}.bson`);
+```
+
+## 🔧 CongoDB API
+
+### Server Configuration
+
+```typescript
+import { congodb } from '@push.rocks/smartmongo';
+
+const server = new congodb.CongoServer({
+  port: 27017,           // Default MongoDB port
+  host: '127.0.0.1',     // Bind address
+  storage: 'memory',     // 'memory' or 'file'
+  storagePath: './data', // For file-based storage
+});
+
+await server.start();
+console.log(server.getConnectionUri()); // mongodb://127.0.0.1:27017
+
+// Server properties
+console.log(server.running);           // true
+console.log(server.getUptime());       // seconds
+console.log(server.getConnectionCount()); // active connections
+
+await server.stop();
+```
+
+### Supported MongoDB Operations
+
+CongoDB supports the core MongoDB operations via the wire protocol:
+
+#### 🔹 CRUD Operations
+```typescript
+// Insert
+await collection.insertOne({ name: 'Bob' });
+await collection.insertMany([{ a: 1 }, { a: 2 }]);
+
+// Find
+const doc = await collection.findOne({ name: 'Bob' });
+const docs = await collection.find({ age: { $gte: 18 } }).toArray();
+
+// Update
+await collection.updateOne({ name: 'Bob' }, { $set: { age: 25 } });
+await collection.updateMany({ active: false }, { $set: { archived: true } });
+
+// Delete
+await collection.deleteOne({ name: 'Bob' });
+await collection.deleteMany({ archived: true });
+
+// Replace
+await collection.replaceOne({ _id: id }, { name: 'New Bob', age: 30 });
+
+// Find and Modify
+const result = await collection.findOneAndUpdate(
+  { name: 'Bob' },
+  { $inc: { visits: 1 } },
+  { returnDocument: 'after' }
+);
+```
+
+#### 🔹 Query Operators
+```typescript
+// Comparison
+{ age: { $eq: 25 } }
+{ age: { $ne: 25 } }
+{ age: { $gt: 18, $lt: 65 } }
+{ age: { $gte: 18, $lte: 65 } }
+{ status: { $in: ['active', 'pending'] } }
+{ status: { $nin: ['deleted'] } }
+
+// Logical
+{ $and: [{ age: { $gte: 18 } }, { active: true }] }
+{ $or: [{ status: 'active' }, { admin: true }] }
+{ $not: { status: 'deleted' } }
+
+// Element
+{ email: { $exists: true } }
+{ type: { $type: 'string' } }
+
+// Array
+{ tags: { $all: ['mongodb', 'database'] } }
+{ scores: { $elemMatch: { $gte: 80, $lt: 90 } } }
+{ tags: { $size: 3 } }
+```
+
+#### 🔹 Update Operators
+```typescript
+{ $set: { name: 'New Name' } }
+{ $unset: { tempField: '' } }
+{ $inc: { count: 1 } }
+{ $mul: { price: 1.1 } }
+{ $min: { lowScore: 50 } }
+{ $max: { highScore: 100 } }
+{ $push: { tags: 'new-tag' } }
+{ $pull: { tags: 'old-tag' } }
+{ $addToSet: { tags: 'unique-tag' } }
+{ $pop: { queue: 1 } }  // Remove last
+{ $pop: { queue: -1 } } // Remove first
+```
+
+#### 🔹 Aggregation Pipeline
+```typescript
+const results = await collection.aggregate([
+  { $match: { status: 'active' } },
+  { $group: { _id: '$category', total: { $sum: '$amount' } } },
+  { $sort: { total: -1 } },
+  { $limit: 10 },
+  { $project: { category: '$_id', total: 1, _id: 0 } }
+]).toArray();
+```
+
+Supported stages: `$match`, `$project`, `$group`, `$sort`, `$limit`, `$skip`, `$unwind`, `$lookup`, `$addFields`, `$count`, `$facet`, and more.
+
+#### 🔹 Index Operations
+```typescript
+await collection.createIndex({ email: 1 }, { unique: true });
+await collection.createIndex({ name: 1, age: -1 });
+const indexes = await collection.listIndexes().toArray();
+await collection.dropIndex('email_1');
+```
+
+#### 🔹 Database Operations
+```typescript
+// List databases
+const dbs = await client.db().admin().listDatabases();
+
+// List collections
+const collections = await db.listCollections().toArray();
+
+// Create/drop collections
+await db.createCollection('newcollection');
+await db.dropCollection('oldcollection');
+
+// Drop database
+await db.dropDatabase();
+```
+
+#### 🔹 Count & Distinct
+```typescript
+// Count documents
+const total = await collection.countDocuments({});
+const active = await collection.countDocuments({ status: 'active' });
+const estimated = await collection.estimatedDocumentCount();
+
+// Distinct values
+const departments = await collection.distinct('department');
+const activeDepts = await collection.distinct('department', { status: 'active' });
+```
+
+#### 🔹 Bulk Operations
+```typescript
+const result = await collection.bulkWrite([
+  { insertOne: { document: { name: 'Bulk1' } } },
+  { updateOne: { filter: { name: 'John' }, update: { $set: { bulk: true } } } },
+  { deleteOne: { filter: { name: 'Expired' } } },
+  { replaceOne: { filter: { _id: id }, replacement: { name: 'Replaced' } } }
+]);
+
+console.log(result.insertedCount);  // 1
+console.log(result.modifiedCount);  // 1
+console.log(result.deletedCount);   // 1
+```
+
+### Storage Adapters
+
+CongoDB supports pluggable storage:
+
+```typescript
+// In-memory (default) - fast, data lost on stop
+const server = new congodb.CongoServer({ storage: 'memory' });
+
+// In-memory with persistence - periodic snapshots to disk
+const server = new congodb.CongoServer({
+  storage: 'memory',
+  persistPath: './data/snapshot.json',
+  persistIntervalMs: 30000  // Save every 30 seconds
+});
+
+// File-based - persistent storage
+const server = new congodb.CongoServer({
+  storage: 'file',
+  storagePath: './data/congodb'
+});
+```
+
+### 📋 Supported Wire Protocol Commands
+
+| Category | Commands |
+|----------|----------|
+| **Handshake** | `hello`, `isMaster` |
+| **CRUD** | `find`, `insert`, `update`, `delete`, `findAndModify`, `getMore`, `killCursors` |
+| **Aggregation** | `aggregate`, `count`, `distinct` |
+| **Indexes** | `createIndexes`, `dropIndexes`, `listIndexes` |
+| **Admin** | `ping`, `listDatabases`, `listCollections`, `drop`, `dropDatabase`, `create`, `serverStatus`, `buildInfo` |
+
+CongoDB supports MongoDB wire protocol versions 0-21, compatible with MongoDB 3.6 through 7.0 drivers.
+
+## 🧪 Testing Examples
+
+### Jest/Mocha with CongoDB
+
+```typescript
+import { congodb } from '@push.rocks/smartmongo';
+import { MongoClient } from 'mongodb';
+
+let server: congodb.CongoServer;
+let client: MongoClient;
+let db: Db;
+
+beforeAll(async () => {
+  server = new congodb.CongoServer({ port: 27117 });
+  await server.start();
+
+  client = new MongoClient('mongodb://127.0.0.1:27117');
+  await client.connect();
+  db = client.db('test');
+});
+
+afterAll(async () => {
+  await client.close();
+  await server.stop();
+});
+
+beforeEach(async () => {
+  // Clean slate for each test
+  await db.dropDatabase();
+});
+
+test('should insert and find user', async () => {
+  const users = db.collection('users');
+  await users.insertOne({ name: 'Alice', email: 'alice@example.com' });
+
+  const user = await users.findOne({ name: 'Alice' });
+  expect(user?.email).toBe('alice@example.com');
+});
+```
+
+### With @push.rocks/tapbundle
+
+```typescript
+import { expect, tap } from '@git.zone/tstest/tapbundle';
+import { congodb } from '@push.rocks/smartmongo';
+import { MongoClient } from 'mongodb';
+
+let server: congodb.CongoServer;
+let client: MongoClient;
+
+tap.test('setup', async () => {
+  server = new congodb.CongoServer({ port: 27117 });
+  await server.start();
+  client = new MongoClient('mongodb://127.0.0.1:27117');
+  await client.connect();
+});
+
+tap.test('should perform CRUD operations', async () => {
+  const db = client.db('test');
+  const col = db.collection('items');
+
+  // Create
+  const result = await col.insertOne({ name: 'Widget', price: 9.99 });
+  expect(result.insertedId).toBeTruthy();
+
+  // Read
+  const item = await col.findOne({ name: 'Widget' });
+  expect(item?.price).toEqual(9.99);
+
+  // Update
+  await col.updateOne({ name: 'Widget' }, { $set: { price: 12.99 } });
+  const updated = await col.findOne({ name: 'Widget' });
+  expect(updated?.price).toEqual(12.99);
+
+  // Delete
+  await col.deleteOne({ name: 'Widget' });
+  const deleted = await col.findOne({ name: 'Widget' });
+  expect(deleted).toBeNull();
+});
+
+tap.test('teardown', async () => {
+  await client.close();
+  await server.stop();
+});
+
+export default tap.start();
+```
+
+## 🏗️ Architecture
+
+### CongoDB Wire Protocol Stack
+
+```
+┌─────────────────────────────────────────────────────────────┐
+│                   Official MongoDB Driver                    │
+│                      (mongodb npm)                          │
+└─────────────────────────┬───────────────────────────────────┘
+                          │ TCP + OP_MSG/BSON
+                          ▼
+┌─────────────────────────────────────────────────────────────┐
+│                      CongoServer                            │
+│  ┌──────────────┐  ┌──────────────┐  ┌──────────────────┐  │
+│  │ WireProtocol │→ │CommandRouter │→ │     Handlers     │  │
+│  │  (OP_MSG)    │  │              │  │ (Find, Insert..) │  │
+│  └──────────────┘  └──────────────┘  └──────────────────┘  │
+└─────────────────────────┬───────────────────────────────────┘
+                          │
+                          ▼
+┌─────────────────────────────────────────────────────────────┐
+│                       Engines                               │
+│  ┌───────────┐ ┌────────────┐ ┌────────────┐ ┌───────────┐ │
+│  │  Query    │ │   Update   │ │Aggregation │ │   Index   │ │
+│  │  Engine   │ │   Engine   │ │  Engine    │ │  Engine   │ │
+│  └───────────┘ └────────────┘ └────────────┘ └───────────┘ │
+└─────────────────────────┬───────────────────────────────────┘
+                          │
+                          ▼
+┌─────────────────────────────────────────────────────────────┐
+│                   Storage Adapters                          │
+│       ┌──────────────────┐  ┌──────────────────┐           │
+│       │  MemoryStorage   │  │   FileStorage    │           │
+│       └──────────────────┘  └──────────────────┘           │
+└─────────────────────────────────────────────────────────────┘
+```
+
+## License and Legal Information
+
+This repository contains open-source code licensed under the MIT License. A copy of the license can be found in the [LICENSE](./LICENSE) file.
+
+**Please note:** The MIT License does not grant permission to use the trade names, trademarks, service marks, or product names of the project, except as required for reasonable and customary use in describing the origin of the work and reproducing the content of the NOTICE file.
+
+### Trademarks
+
+This project is owned and maintained by Task Venture Capital GmbH. The names and logos associated with Task Venture Capital GmbH and any related products or services are trademarks of Task Venture Capital GmbH or third parties, and are not included within the scope of the MIT license granted herein.
+
+Use of these trademarks must comply with Task Venture Capital GmbH's Trademark Guidelines or the guidelines of the respective third-party owners, and any usage must be approved in writing. Third-party trademarks used herein are the property of their respective owners and used only in a descriptive manner, e.g. for an implementation of an API or similar.
+
+### Company Information
+
+Task Venture Capital GmbH
+Registered at District Court Bremen HRB 35230 HB, Germany
+
+For any legal inquiries or further information, please contact us via email at hello@task.vc.
+
+By using this repository, you acknowledge that you have read this section, agree to comply with its terms, and understand that the licensing of the code does not imply endorsement by Task Venture Capital GmbH of any derivative works.

test/test.congodb.ts

@@ -0,0 +1,572 @@
+import { expect, tap } from '@git.zone/tstest/tapbundle';
+import * as smartmongo from '../ts/index.js';
+import { MongoClient, Db, Collection } from 'mongodb';
+
+const { congodb } = smartmongo;
+
+let server: smartmongo.congodb.CongoServer;
+let client: MongoClient;
+let db: Db;
+
+// ============================================================================
+// Server Startup
+// ============================================================================
+
+tap.test('congodb: should start the server', async () => {
+  server = new congodb.CongoServer({ port: 27117 }); // Use non-standard port for tests
+  await server.start();
+  expect(server.running).toBeTrue();
+});
+
+tap.test('congodb: should connect with official MongoClient', async () => {
+  client = new MongoClient('mongodb://127.0.0.1:27117', {
+    directConnection: true,
+    serverSelectionTimeoutMS: 5000,
+  });
+  await client.connect();
+  expect(client).toBeTruthy();
+});
+
+tap.test('congodb: should get a database instance', async () => {
+  db = client.db('testdb');
+  expect(db).toBeTruthy();
+  expect(db.databaseName).toEqual('testdb');
+});
+
+// ============================================================================
+// Basic CRUD Tests
+// ============================================================================
+
+tap.test('congodb: insertOne - should insert a document', async () => {
+  const collection = db.collection('users');
+  const result = await collection.insertOne({
+    name: 'John Doe',
+    email: 'john@example.com',
+    age: 30,
+  });
+
+  expect(result.acknowledged).toBeTrue();
+  expect(result.insertedId).toBeTruthy();
+});
+
+tap.test('congodb: insertMany - should insert multiple documents', async () => {
+  const collection = db.collection('users');
+  const result = await collection.insertMany([
+    { name: 'Jane Doe', email: 'jane@example.com', age: 25 },
+    { name: 'Bob Smith', email: 'bob@example.com', age: 35 },
+    { name: 'Alice Johnson', email: 'alice@example.com', age: 28 },
+  ]);
+
+  expect(result.acknowledged).toBeTrue();
+  expect(result.insertedCount).toEqual(3);
+  expect(Object.keys(result.insertedIds).length).toEqual(3);
+});
+
+tap.test('congodb: findOne - should find a single document', async () => {
+  const collection = db.collection('users');
+  const doc = await collection.findOne({ name: 'John Doe' });
+
+  expect(doc).toBeTruthy();
+  expect(doc!.name).toEqual('John Doe');
+  expect(doc!.email).toEqual('john@example.com');
+});
+
+tap.test('congodb: find - should find multiple documents', async () => {
+  const collection = db.collection('users');
+  const docs = await collection.find({ age: { $gte: 28 } }).toArray();
+
+  expect(docs.length).toEqual(3);
+});
+
+tap.test('congodb: updateOne - should update a single document', async () => {
+  const collection = db.collection('users');
+  const result = await collection.updateOne(
+    { name: 'John Doe' },
+    { $set: { age: 31 } }
+  );
+
+  expect(result.acknowledged).toBeTrue();
+  expect(result.matchedCount).toEqual(1);
+  expect(result.modifiedCount).toEqual(1);
+
+  const updated = await collection.findOne({ name: 'John Doe' });
+  expect(updated!.age).toEqual(31);
+});
+
+tap.test('congodb: updateMany - should update multiple documents', async () => {
+  const collection = db.collection('users');
+  const result = await collection.updateMany(
+    { age: { $gte: 30 } },
+    { $set: { senior: true } }
+  );
+
+  expect(result.acknowledged).toBeTrue();
+  expect(result.matchedCount).toEqual(2);
+  expect(result.modifiedCount).toEqual(2);
+});
+
+tap.test('congodb: deleteOne - should delete a single document', async () => {
+  const collection = db.collection('users');
+  const result = await collection.deleteOne({ name: 'Bob Smith' });
+
+  expect(result.acknowledged).toBeTrue();
+  expect(result.deletedCount).toEqual(1);
+});
+
+tap.test('congodb: deleteMany - should delete multiple documents', async () => {
+  const collection = db.collection('users');
+
+  // First add some test docs to delete
+  await collection.insertMany([
+    { name: 'Delete1', toDelete: true },
+    { name: 'Delete2', toDelete: true },
+  ]);
+
+  const result = await collection.deleteMany({ toDelete: true });
+
+  expect(result.acknowledged).toBeTrue();
+  expect(result.deletedCount).toEqual(2);
+});
+
+// ============================================================================
+// Query Operator Tests
+// ============================================================================
+
+tap.test('congodb: query - $eq operator', async () => {
+  const collection = db.collection('users');
+  const docs = await collection.find({ name: { $eq: 'Jane Doe' } }).toArray();
+  expect(docs.length).toEqual(1);
+  expect(docs[0].name).toEqual('Jane Doe');
+});
+
+tap.test('congodb: query - $ne operator', async () => {
+  const collection = db.collection('users');
+  const docs = await collection.find({ name: { $ne: 'Jane Doe' } }).toArray();
+  expect(docs.every(d => d.name !== 'Jane Doe')).toBeTrue();
+});
+
+tap.test('congodb: query - $gt and $lt operators', async () => {
+  const collection = db.collection('users');
+  const docs = await collection.find({ age: { $gt: 25, $lt: 35 } }).toArray();
+  expect(docs.every(d => d.age > 25 && d.age < 35)).toBeTrue();
+});
+
+tap.test('congodb: query - $in operator', async () => {
+  const collection = db.collection('users');
+  const docs = await collection.find({ name: { $in: ['Jane Doe', 'Alice Johnson'] } }).toArray();
+  expect(docs.length).toEqual(2);
+});
+
+tap.test('congodb: query - $or operator', async () => {
+  const collection = db.collection('users');
+  const docs = await collection.find({
+    $or: [
+      { name: 'Jane Doe' },
+      { age: 31 }
+    ]
+  }).toArray();
+  expect(docs.length).toBeGreaterThanOrEqual(1);
+});
+
+tap.test('congodb: query - $and operator', async () => {
+  const collection = db.collection('users');
+  const docs = await collection.find({
+    $and: [
+      { age: { $gte: 25 } },
+      { age: { $lte: 30 } }
+    ]
+  }).toArray();
+  expect(docs.every(d => d.age >= 25 && d.age <= 30)).toBeTrue();
+});
+
+tap.test('congodb: query - $exists operator', async () => {
+  const collection = db.collection('users');
+  const docs = await collection.find({ senior: { $exists: true } }).toArray();
+  expect(docs.every(d => 'senior' in d)).toBeTrue();
+});
+
+// ============================================================================
+// Update Operator Tests
+// ============================================================================
+
+tap.test('congodb: update - $inc operator', async () => {
+  const collection = db.collection('users');
+  await collection.updateOne(
+    { name: 'Jane Doe' },
+    { $inc: { age: 1 } }
+  );
+
+  const updated = await collection.findOne({ name: 'Jane Doe' });
+  expect(updated!.age).toEqual(26);
+});
+
+tap.test('congodb: update - $unset operator', async () => {
+  const collection = db.collection('users');
+  await collection.updateOne(
+    { name: 'Jane Doe' },
+    { $unset: { senior: '' } }
+  );
+
+  const updated = await collection.findOne({ name: 'Jane Doe' });
+  expect('senior' in updated!).toBeFalse();
+});
+
+tap.test('congodb: update - $push operator', async () => {
+  const collection = db.collection('users');
+  await collection.updateOne(
+    { name: 'Jane Doe' },
+    { $set: { tags: ['developer'] } }
+  );
+  await collection.updateOne(
+    { name: 'Jane Doe' },
+    { $push: { tags: 'tester' } }
+  );
+
+  const updated = await collection.findOne({ name: 'Jane Doe' });
+  expect(updated!.tags).toContain('developer');
+  expect(updated!.tags).toContain('tester');
+});
+
+tap.test('congodb: update - $pull operator', async () => {
+  const collection = db.collection('users');
+  await collection.updateOne(
+    { name: 'Jane Doe' },
+    { $pull: { tags: 'tester' } }
+  );
+
+  const updated = await collection.findOne({ name: 'Jane Doe' });
+  expect(updated!.tags).not.toContain('tester');
+});
+
+tap.test('congodb: update - upsert creates new document', async () => {
+  const collection = db.collection('users');
+  const result = await collection.updateOne(
+    { name: 'New User' },
+    { $set: { email: 'new@example.com', age: 40 } },
+    { upsert: true }
+  );
+
+  expect(result.upsertedCount).toEqual(1);
+  expect(result.upsertedId).toBeTruthy();
+
+  const inserted = await collection.findOne({ name: 'New User' });
+  expect(inserted).toBeTruthy();
+  expect(inserted!.email).toEqual('new@example.com');
+});
+
+// ============================================================================
+// Cursor Tests
+// ============================================================================
+
+tap.test('congodb: cursor - sort', async () => {
+  const collection = db.collection('users');
+  const docs = await collection.find({}).sort({ age: -1 }).toArray();
+
+  for (let i = 1; i < docs.length; i++) {
+    if (docs[i-1].age !== undefined && docs[i].age !== undefined) {
+      expect(docs[i-1].age).toBeGreaterThanOrEqual(docs[i].age);
+    }
+  }
+});
+
+tap.test('congodb: cursor - limit', async () => {
+  const collection = db.collection('users');
+  const docs = await collection.find({}).limit(2).toArray();
+  expect(docs.length).toBeLessThanOrEqual(2);
+});
+
+tap.test('congodb: cursor - skip', async () => {
+  const collection = db.collection('users');
+  const allDocs = await collection.find({}).toArray();
+  const skippedDocs = await collection.find({}).skip(1).toArray();
+
+  expect(skippedDocs.length).toEqual(Math.max(0, allDocs.length - 1));
+});
+
+tap.test('congodb: cursor - project', async () => {
+  const collection = db.collection('users');
+  const docs = await collection.find({}).project({ name: 1, _id: 0 }).toArray();
+
+  expect(docs.length).toBeGreaterThan(0);
+  expect(docs[0].name).toBeTruthy();
+  expect(docs[0].email).toBeUndefined();
+});
+
+// ============================================================================
+// FindOneAnd* Tests
+// ============================================================================
+
+tap.test('congodb: findOneAndUpdate - returns updated document', async () => {
+  const collection = db.collection('users');
+  const result = await collection.findOneAndUpdate(
+    { name: 'Jane Doe' },
+    { $set: { status: 'active' } },
+    { returnDocument: 'after' }
+  );
+
+  expect(result).toBeTruthy();
+  expect(result!.status).toEqual('active');
+});
+
+tap.test('congodb: findOneAndDelete - returns deleted document', async () => {
+  const collection = db.collection('users');
+
+  // Insert a temp doc to delete
+  await collection.insertOne({ name: 'TempUser', temp: true });
+
+  const result = await collection.findOneAndDelete({ name: 'TempUser' });
+
+  expect(result).toBeTruthy();
+  expect(result!.name).toEqual('TempUser');
+
+  // Verify deleted
+  const found = await collection.findOne({ name: 'TempUser' });
+  expect(found).toBeNull();
+});
+
+// ============================================================================
+// Count and Distinct Tests
+// ============================================================================
+
+tap.test('congodb: countDocuments - counts matching documents', async () => {
+  const collection = db.collection('users');
+  const count = await collection.countDocuments({ age: { $gte: 25 } });
+  expect(count).toBeGreaterThan(0);
+});
+
+tap.test('congodb: estimatedDocumentCount - returns total count', async () => {
+  const collection = db.collection('users');
+  const count = await collection.estimatedDocumentCount();
+  expect(count).toBeGreaterThan(0);
+});
+
+tap.test('congodb: distinct - returns unique values', async () => {
+  const collection = db.collection('users');
+  const names = await collection.distinct('name');
+
+  expect(names.length).toBeGreaterThan(0);
+  // All names should be unique
+  expect(new Set(names).size).toEqual(names.length);
+});
+
+// ============================================================================
+// Index Tests
+// ============================================================================
+
+tap.test('congodb: createIndex - creates a single index', async () => {
+  const collection = db.collection('users');
+  const indexName = await collection.createIndex({ email: 1 });
+
+  expect(indexName).toBeTruthy();
+  expect(indexName).toContain('email');
+});
+
+tap.test('congodb: createIndex - creates compound index', async () => {
+  const collection = db.collection('users');
+  const indexName = await collection.createIndex({ name: 1, age: -1 });
+
+  expect(indexName).toBeTruthy();
+});
+
+tap.test('congodb: listIndexes - lists all indexes', async () => {
+  const collection = db.collection('users');
+  const indexes = await collection.listIndexes().toArray();
+
+  expect(indexes.length).toBeGreaterThanOrEqual(1); // At least _id index
+  expect(indexes.some(i => i.name === '_id_')).toBeTrue();
+});
+
+tap.test('congodb: dropIndex - drops an index', async () => {
+  const collection = db.collection('users');
+  const indexName = await collection.createIndex({ toDropField: 1 });
+
+  await collection.dropIndex(indexName);
+
+  const indexes = await collection.listIndexes().toArray();
+  expect(indexes.some(i => i.name === indexName)).toBeFalse();
+});
+
+// ============================================================================
+// Aggregation Tests
+// ============================================================================
+
+tap.test('congodb: aggregate - $match stage', async () => {
+  const collection = db.collection('users');
+  const results = await collection.aggregate([
+    { $match: { age: { $gte: 25 } } }
+  ]).toArray();
+
+  expect(results.length).toBeGreaterThan(0);
+  expect(results.every(d => d.age >= 25)).toBeTrue();
+});
+
+tap.test('congodb: aggregate - $project stage', async () => {
+  const collection = db.collection('users');
+  const results = await collection.aggregate([
+    { $project: { name: 1, _id: 0 } }
+  ]).toArray();
+
+  expect(results.length).toBeGreaterThan(0);
+  expect(results[0].name).toBeTruthy();
+  expect(results[0].email).toBeUndefined();
+});
+
+tap.test('congodb: aggregate - $sort stage', async () => {
+  const collection = db.collection('users');
+  const results = await collection.aggregate([
+    { $match: { age: { $exists: true } } },
+    { $sort: { age: 1 } }
+  ]).toArray();
+
+  for (let i = 1; i < results.length; i++) {
+    expect(results[i].age).toBeGreaterThanOrEqual(results[i-1].age);
+  }
+});
+
+tap.test('congodb: aggregate - $group stage', async () => {
+  const collection = db.collection('users');
+
+  // Add some categorized data
+  await collection.insertMany([
+    { name: 'GroupTest1', category: 'A', value: 10 },
+    { name: 'GroupTest2', category: 'A', value: 20 },
+    { name: 'GroupTest3', category: 'B', value: 30 },
+  ]);
+
+  const results = await collection.aggregate([
+    { $match: { category: { $exists: true } } },
+    { $group: { _id: '$category', total: { $sum: '$value' } } }
+  ]).toArray();
+
+  expect(results.length).toEqual(2);
+  const groupA = results.find(r => r._id === 'A');
+  const groupB = results.find(r => r._id === 'B');
+  expect(groupA!.total).toEqual(30);
+  expect(groupB!.total).toEqual(30);
+});
+
+tap.test('congodb: aggregate - $limit and $skip stages', async () => {
+  const collection = db.collection('users');
+  const results = await collection.aggregate([
+    { $skip: 1 },
+    { $limit: 2 }
+  ]).toArray();
+
+  expect(results.length).toBeLessThanOrEqual(2);
+});
+
+// ============================================================================
+// Bulk Operations Tests
+// ============================================================================
+
+tap.test('congodb: bulkWrite - executes multiple operations', async () => {
+  const collection = db.collection('bulktest');
+
+  const result = await collection.bulkWrite([
+    { insertOne: { document: { name: 'Bulk1', value: 1 } } },
+    { insertOne: { document: { name: 'Bulk2', value: 2 } } },
+    { updateOne: { filter: { name: 'Bulk1' }, update: { $set: { updated: true } } } },
+  ]);
+
+  expect(result.insertedCount).toEqual(2);
+  expect(result.modifiedCount).toEqual(1);
+});
+
+// ============================================================================
+// Database Operations Tests
+// ============================================================================
+
+tap.test('congodb: listCollections - lists all collections', async () => {
+  const collections = await db.listCollections().toArray();
+  expect(collections.length).toBeGreaterThan(0);
+});
+
+tap.test('congodb: createCollection - creates a new collection', async () => {
+  await db.createCollection('newcollection');
+  const collections = await db.listCollections().toArray();
+  expect(collections.some(c => c.name === 'newcollection')).toBeTrue();
+});
+
+tap.test('congodb: dropCollection - drops a collection', async () => {
+  await db.createCollection('todrop');
+  await db.dropCollection('todrop');
+  const collections = await db.listCollections().toArray();
+  expect(collections.some(c => c.name === 'todrop')).toBeFalse();
+});
+
+// ============================================================================
+// Admin Tests
+// ============================================================================
+
+tap.test('congodb: admin - listDatabases', async () => {
+  const admin = client.db().admin();
+  const result = await admin.listDatabases();
+  expect(result.ok).toEqual(1);
+  expect(result.databases).toBeArray();
+});
+
+tap.test('congodb: admin - serverStatus', async () => {
+  const admin = client.db().admin();
+  const status = await admin.serverStatus();
+  expect(status.ok).toEqual(1);
+});
+
+tap.test('congodb: admin - ping', async () => {
+  const admin = client.db().admin();
+  const result = await admin.ping();
+  expect(result.ok).toEqual(1);
+});
+
+// ============================================================================
+// Replace Operations Tests
+// ============================================================================
+
+tap.test('congodb: replaceOne - replaces entire document', async () => {
+  const collection = db.collection('replacetest');
+  await collection.insertOne({ name: 'Original', field1: 'value1', field2: 'value2' });
+
+  const result = await collection.replaceOne(
+    { name: 'Original' },
+    { name: 'Replaced', newField: 'newValue' }
+  );
+
+  expect(result.matchedCount).toEqual(1);
+  expect(result.modifiedCount).toEqual(1);
+
+  const replaced = await collection.findOne({ name: 'Replaced' });
+  expect(replaced).toBeTruthy();
+  expect(replaced!.newField).toEqual('newValue');
+  expect(replaced!.field1).toBeUndefined();
+  expect(replaced!.field2).toBeUndefined();
+});
+
+tap.test('congodb: findOneAndReplace - returns replaced document', async () => {
+  const collection = db.collection('replacetest');
+  await collection.insertOne({ name: 'ToReplace', data: 'old' });
+
+  const result = await collection.findOneAndReplace(
+    { name: 'ToReplace' },
+    { name: 'Replaced', data: 'new' },
+    { returnDocument: 'after' }
+  );
+
+  expect(result).toBeTruthy();
+  expect(result!.data).toEqual('new');
+});
+
+// ============================================================================
+// Cleanup
+// ============================================================================
+
+tap.test('congodb: cleanup - drop database', async () => {
+  const result = await db.dropDatabase();
+  expect(result).toBeTrue();
+});
+
+tap.test('congodb: cleanup - close client and server', async () => {
+  await client.close();
+  await server.stop();
+  expect(server.running).toBeFalse();
+});
+
+export default tap.start();

test/test.ts

@@ -1,5 +1,5 @@
-import { expect, tap } from '@pushrocks/tapbundle';
+import { tap } from '@git.zone/tstest/tapbundle';
-import * as smartmongo from '../ts/index';
+import * as smartmongo from '../ts/index.js';
 
 let smartmongoInstance: smartmongo.SmartMongo;
 
@@ -8,7 +8,7 @@ tap.test('should create a mongo instance', async () => {
 });
 
 tap.test('should stop the instance', async () => {
-  await smartmongoInstance.stop();
+  await smartmongoInstance.stopAndDumpToDir('.nogit/');
-})
+});
 
-tap.start();
+export default tap.start();

ts/00_commitinfo_data.ts

@@ -1,8 +1,8 @@
 /**
- * autocreated commitinfo by @pushrocks/commitinfo
+ * autocreated commitinfo by @push.rocks/commitinfo
  */
 export const commitinfo = {
-  name: '@pushrocks/smartmongo',
+  name: '@push.rocks/smartmongo',
-  version: '1.0.9',
+  version: '2.2.0',
-  description: 'create a local mongodb for testing'
+  description: 'A module for creating and managing a local MongoDB instance for testing purposes.'
 }

ts/congodb/congodb.plugins.ts

@@ -0,0 +1,17 @@
+// @push.rocks scope
+import * as smartfs from '@push.rocks/smartfs';
+import * as smartpath from '@push.rocks/smartpath';
+import * as smartpromise from '@push.rocks/smartpromise';
+import * as smartrx from '@push.rocks/smartrx';
+
+export { smartfs, smartpath, smartpromise, smartrx };
+
+// thirdparty
+import * as bson from 'bson';
+import * as mingo from 'mingo';
+
+export { bson, mingo };
+
+// Re-export commonly used mingo classes
+export { Query } from 'mingo';
+export { Aggregator } from 'mingo';

ts/congodb/engine/AggregationEngine.ts

@@ -0,0 +1,283 @@
+import * as plugins from '../congodb.plugins.js';
+import type { Document, IStoredDocument, IAggregateOptions } from '../types/interfaces.js';
+
+// Import mingo Aggregator
+import { Aggregator } from 'mingo';
+
+/**
+ * Aggregation engine using mingo for MongoDB-compatible aggregation pipeline execution
+ */
+export class AggregationEngine {
+  /**
+   * Execute an aggregation pipeline on a collection of documents
+   */
+  static aggregate(
+    documents: IStoredDocument[],
+    pipeline: Document[],
+    options?: IAggregateOptions
+  ): Document[] {
+    if (!pipeline || pipeline.length === 0) {
+      return documents;
+    }
+
+    // Create mingo aggregator with the pipeline
+    const aggregator = new Aggregator(pipeline, {
+      collation: options?.collation as any,
+    });
+
+    // Run the aggregation
+    const result = aggregator.run(documents);
+
+    return Array.isArray(result) ? result : [];
+  }
+
+  /**
+   * Execute aggregation and return an iterator for lazy evaluation
+   */
+  static *aggregateIterator(
+    documents: IStoredDocument[],
+    pipeline: Document[],
+    options?: IAggregateOptions
+  ): Generator<Document> {
+    const aggregator = new Aggregator(pipeline, {
+      collation: options?.collation as any,
+    });
+
+    // Get the cursor from mingo
+    const cursor = aggregator.stream(documents);
+
+    for (const doc of cursor) {
+      yield doc;
+    }
+  }
+
+  /**
+   * Execute a $lookup stage manually (for cross-collection lookups)
+   * This is used when the lookup references another collection in the same database
+   */
+  static executeLookup(
+    documents: IStoredDocument[],
+    lookupSpec: {
+      from: string;
+      localField: string;
+      foreignField: string;
+      as: string;
+    },
+    foreignCollection: IStoredDocument[]
+  ): Document[] {
+    const { localField, foreignField, as } = lookupSpec;
+
+    return documents.map(doc => {
+      const localValue = this.getNestedValue(doc, localField);
+      const matches = foreignCollection.filter(foreignDoc => {
+        const foreignValue = this.getNestedValue(foreignDoc, foreignField);
+        return this.valuesMatch(localValue, foreignValue);
+      });
+
+      return {
+        ...doc,
+        [as]: matches,
+      };
+    });
+  }
+
+  /**
+   * Execute a $graphLookup stage manually
+   */
+  static executeGraphLookup(
+    documents: IStoredDocument[],
+    graphLookupSpec: {
+      from: string;
+      startWith: string | Document;
+      connectFromField: string;
+      connectToField: string;
+      as: string;
+      maxDepth?: number;
+      depthField?: string;
+      restrictSearchWithMatch?: Document;
+    },
+    foreignCollection: IStoredDocument[]
+  ): Document[] {
+    const {
+      startWith,
+      connectFromField,
+      connectToField,
+      as,
+      maxDepth = 10,
+      depthField,
+      restrictSearchWithMatch,
+    } = graphLookupSpec;
+
+    return documents.map(doc => {
+      const startValue = typeof startWith === 'string' && startWith.startsWith('$')
+        ? this.getNestedValue(doc, startWith.slice(1))
+        : startWith;
+
+      const results: Document[] = [];
+      const visited = new Set<string>();
+      const queue: Array<{ value: any; depth: number }> = [];
+
+      // Initialize with start value(s)
+      const startValues = Array.isArray(startValue) ? startValue : [startValue];
+      for (const val of startValues) {
+        queue.push({ value: val, depth: 0 });
+      }
+
+      while (queue.length > 0) {
+        const { value, depth } = queue.shift()!;
+        if (depth > maxDepth) continue;
+
+        const valueKey = JSON.stringify(value);
+        if (visited.has(valueKey)) continue;
+        visited.add(valueKey);
+
+        // Find matching documents
+        for (const foreignDoc of foreignCollection) {
+          const foreignValue = this.getNestedValue(foreignDoc, connectToField);
+
+          if (this.valuesMatch(value, foreignValue)) {
+            // Check restrictSearchWithMatch
+            if (restrictSearchWithMatch) {
+              const matchQuery = new plugins.mingo.Query(restrictSearchWithMatch);
+              if (!matchQuery.test(foreignDoc)) continue;
+            }
+
+            const resultDoc = depthField
+              ? { ...foreignDoc, [depthField]: depth }
+              : { ...foreignDoc };
+
+            // Avoid duplicates in results
+            const docKey = foreignDoc._id.toHexString();
+            if (!results.some(r => r._id?.toHexString?.() === docKey)) {
+              results.push(resultDoc);
+
+              // Add connected values to queue
+              const nextValue = this.getNestedValue(foreignDoc, connectFromField);
+              if (nextValue !== undefined) {
+                const nextValues = Array.isArray(nextValue) ? nextValue : [nextValue];
+                for (const nv of nextValues) {
+                  queue.push({ value: nv, depth: depth + 1 });
+                }
+              }
+            }
+          }
+        }
+      }
+
+      return {
+        ...doc,
+        [as]: results,
+      };
+    });
+  }
+
+  /**
+   * Execute a $facet stage manually
+   */
+  static executeFacet(
+    documents: IStoredDocument[],
+    facetSpec: Record<string, Document[]>
+  ): Document {
+    const result: Document = {};
+
+    for (const [facetName, pipeline] of Object.entries(facetSpec)) {
+      result[facetName] = this.aggregate(documents, pipeline);
+    }
+
+    return result;
+  }
+
+  /**
+   * Execute a $unionWith stage
+   */
+  static executeUnionWith(
+    documents: IStoredDocument[],
+    otherDocuments: IStoredDocument[],
+    pipeline?: Document[]
+  ): Document[] {
+    let unionDocs: Document[] = otherDocuments;
+    if (pipeline && pipeline.length > 0) {
+      unionDocs = this.aggregate(otherDocuments, pipeline);
+    }
+    return [...documents, ...unionDocs];
+  }
+
+  /**
+   * Execute a $merge stage (output to another collection)
+   * Returns the documents that would be inserted/updated
+   */
+  static prepareMerge(
+    documents: Document[],
+    mergeSpec: {
+      into: string;
+      on?: string | string[];
+      whenMatched?: 'replace' | 'keepExisting' | 'merge' | 'fail' | Document[];
+      whenNotMatched?: 'insert' | 'discard' | 'fail';
+    }
+  ): {
+    toInsert: Document[];
+    toUpdate: Array<{ filter: Document; update: Document }>;
+    onField: string | string[];
+    whenMatched: string | Document[];
+    whenNotMatched: string;
+  } {
+    const onField = mergeSpec.on || '_id';
+    const whenMatched = mergeSpec.whenMatched || 'merge';
+    const whenNotMatched = mergeSpec.whenNotMatched || 'insert';
+
+    return {
+      toInsert: [],
+      toUpdate: [],
+      onField,
+      whenMatched,
+      whenNotMatched,
+    };
+  }
+
+  // ============================================================================
+  // Helper Methods
+  // ============================================================================
+
+  private static getNestedValue(obj: any, path: string): any {
+    const parts = path.split('.');
+    let current = obj;
+
+    for (const part of parts) {
+      if (current === null || current === undefined) {
+        return undefined;
+      }
+      current = current[part];
+    }
+
+    return current;
+  }
+
+  private static valuesMatch(a: any, b: any): boolean {
+    if (a === b) return true;
+
+    // Handle ObjectId comparison
+    if (a instanceof plugins.bson.ObjectId && b instanceof plugins.bson.ObjectId) {
+      return a.equals(b);
+    }
+
+    // Handle array contains check
+    if (Array.isArray(a)) {
+      return a.some(item => this.valuesMatch(item, b));
+    }
+    if (Array.isArray(b)) {
+      return b.some(item => this.valuesMatch(a, item));
+    }
+
+    // Handle Date comparison
+    if (a instanceof Date && b instanceof Date) {
+      return a.getTime() === b.getTime();
+    }
+
+    // Handle object comparison
+    if (typeof a === 'object' && typeof b === 'object' && a !== null && b !== null) {
+      return JSON.stringify(a) === JSON.stringify(b);
+    }
+
+    return false;
+  }
+}

ts/congodb/engine/IndexEngine.ts

@@ -0,0 +1,479 @@
+import * as plugins from '../congodb.plugins.js';
+import type { IStorageAdapter } from '../storage/IStorageAdapter.js';
+import type {
+  Document,
+  IStoredDocument,
+  IIndexSpecification,
+  IIndexInfo,
+  ICreateIndexOptions,
+} from '../types/interfaces.js';
+import { CongoDuplicateKeyError, CongoIndexError } from '../errors/CongoErrors.js';
+import { QueryEngine } from './QueryEngine.js';
+
+/**
+ * Index data structure for fast lookups
+ */
+interface IIndexData {
+  name: string;
+  key: Record<string, 1 | -1 | string>;
+  unique: boolean;
+  sparse: boolean;
+  expireAfterSeconds?: number;
+  // Map from index key value to document _id(s)
+  entries: Map<string, Set<string>>;
+}
+
+/**
+ * Index engine for managing indexes and query optimization
+ */
+export class IndexEngine {
+  private dbName: string;
+  private collName: string;
+  private storage: IStorageAdapter;
+  private indexes: Map<string, IIndexData> = new Map();
+  private initialized = false;
+
+  constructor(dbName: string, collName: string, storage: IStorageAdapter) {
+    this.dbName = dbName;
+    this.collName = collName;
+    this.storage = storage;
+  }
+
+  /**
+   * Initialize indexes from storage
+   */
+  async initialize(): Promise<void> {
+    if (this.initialized) return;
+
+    const storedIndexes = await this.storage.getIndexes(this.dbName, this.collName);
+    const documents = await this.storage.findAll(this.dbName, this.collName);
+
+    for (const indexSpec of storedIndexes) {
+      const indexData: IIndexData = {
+        name: indexSpec.name,
+        key: indexSpec.key,
+        unique: indexSpec.unique || false,
+        sparse: indexSpec.sparse || false,
+        expireAfterSeconds: indexSpec.expireAfterSeconds,
+        entries: new Map(),
+      };
+
+      // Build index entries
+      for (const doc of documents) {
+        const keyValue = this.extractKeyValue(doc, indexSpec.key);
+        if (keyValue !== null || !indexData.sparse) {
+          const keyStr = JSON.stringify(keyValue);
+          if (!indexData.entries.has(keyStr)) {
+            indexData.entries.set(keyStr, new Set());
+          }
+          indexData.entries.get(keyStr)!.add(doc._id.toHexString());
+        }
+      }
+
+      this.indexes.set(indexSpec.name, indexData);
+    }
+
+    this.initialized = true;
+  }
+
+  /**
+   * Create a new index
+   */
+  async createIndex(
+    key: Record<string, 1 | -1 | 'text' | '2dsphere'>,
+    options?: ICreateIndexOptions
+  ): Promise<string> {
+    await this.initialize();
+
+    // Generate index name if not provided
+    const name = options?.name || this.generateIndexName(key);
+
+    // Check if index already exists
+    if (this.indexes.has(name)) {
+      return name;
+    }
+
+    // Create index data structure
+    const indexData: IIndexData = {
+      name,
+      key: key as Record<string, 1 | -1 | string>,
+      unique: options?.unique || false,
+      sparse: options?.sparse || false,
+      expireAfterSeconds: options?.expireAfterSeconds,
+      entries: new Map(),
+    };
+
+    // Build index from existing documents
+    const documents = await this.storage.findAll(this.dbName, this.collName);
+
+    for (const doc of documents) {
+      const keyValue = this.extractKeyValue(doc, key);
+
+      if (keyValue === null && indexData.sparse) {
+        continue;
+      }
+
+      const keyStr = JSON.stringify(keyValue);
+
+      if (indexData.unique && indexData.entries.has(keyStr)) {
+        throw new CongoDuplicateKeyError(
+          `E11000 duplicate key error index: ${this.dbName}.${this.collName}.$${name}`,
+          key as Record<string, 1>,
+          keyValue
+        );
+      }
+
+      if (!indexData.entries.has(keyStr)) {
+        indexData.entries.set(keyStr, new Set());
+      }
+      indexData.entries.get(keyStr)!.add(doc._id.toHexString());
+    }
+
+    // Store index
+    this.indexes.set(name, indexData);
+    await this.storage.saveIndex(this.dbName, this.collName, name, {
+      key,
+      unique: options?.unique,
+      sparse: options?.sparse,
+      expireAfterSeconds: options?.expireAfterSeconds,
+    });
+
+    return name;
+  }
+
+  /**
+   * Drop an index
+   */
+  async dropIndex(name: string): Promise<void> {
+    await this.initialize();
+
+    if (name === '_id_') {
+      throw new CongoIndexError('cannot drop _id index');
+    }
+
+    if (!this.indexes.has(name)) {
+      throw new CongoIndexError(`index not found: ${name}`);
+    }
+
+    this.indexes.delete(name);
+    await this.storage.dropIndex(this.dbName, this.collName, name);
+  }
+
+  /**
+   * Drop all indexes except _id
+   */
+  async dropAllIndexes(): Promise<void> {
+    await this.initialize();
+
+    const names = Array.from(this.indexes.keys()).filter(n => n !== '_id_');
+    for (const name of names) {
+      this.indexes.delete(name);
+      await this.storage.dropIndex(this.dbName, this.collName, name);
+    }
+  }
+
+  /**
+   * List all indexes
+   */
+  async listIndexes(): Promise<IIndexInfo[]> {
+    await this.initialize();
+
+    return Array.from(this.indexes.values()).map(idx => ({
+      v: 2,
+      key: idx.key,
+      name: idx.name,
+      unique: idx.unique || undefined,
+      sparse: idx.sparse || undefined,
+      expireAfterSeconds: idx.expireAfterSeconds,
+    }));
+  }
+
+  /**
+   * Check if an index exists
+   */
+  async indexExists(name: string): Promise<boolean> {
+    await this.initialize();
+    return this.indexes.has(name);
+  }
+
+  /**
+   * Update index entries after document insert
+   */
+  async onInsert(doc: IStoredDocument): Promise<void> {
+    await this.initialize();
+
+    for (const [name, indexData] of this.indexes) {
+      const keyValue = this.extractKeyValue(doc, indexData.key);
+
+      if (keyValue === null && indexData.sparse) {
+        continue;
+      }
+
+      const keyStr = JSON.stringify(keyValue);
+
+      // Check unique constraint
+      if (indexData.unique) {
+        const existing = indexData.entries.get(keyStr);
+        if (existing && existing.size > 0) {
+          throw new CongoDuplicateKeyError(
+            `E11000 duplicate key error collection: ${this.dbName}.${this.collName} index: ${name}`,
+            indexData.key as Record<string, 1>,
+            keyValue
+          );
+        }
+      }
+
+      if (!indexData.entries.has(keyStr)) {
+        indexData.entries.set(keyStr, new Set());
+      }
+      indexData.entries.get(keyStr)!.add(doc._id.toHexString());
+    }
+  }
+
+  /**
+   * Update index entries after document update
+   */
+  async onUpdate(oldDoc: IStoredDocument, newDoc: IStoredDocument): Promise<void> {
+    await this.initialize();
+
+    for (const [name, indexData] of this.indexes) {
+      const oldKeyValue = this.extractKeyValue(oldDoc, indexData.key);
+      const newKeyValue = this.extractKeyValue(newDoc, indexData.key);
+      const oldKeyStr = JSON.stringify(oldKeyValue);
+      const newKeyStr = JSON.stringify(newKeyValue);
+
+      // Remove old entry if key changed
+      if (oldKeyStr !== newKeyStr) {
+        if (oldKeyValue !== null || !indexData.sparse) {
+          const oldSet = indexData.entries.get(oldKeyStr);
+          if (oldSet) {
+            oldSet.delete(oldDoc._id.toHexString());
+            if (oldSet.size === 0) {
+              indexData.entries.delete(oldKeyStr);
+            }
+          }
+        }
+
+        // Add new entry
+        if (newKeyValue !== null || !indexData.sparse) {
+          // Check unique constraint
+          if (indexData.unique) {
+            const existing = indexData.entries.get(newKeyStr);
+            if (existing && existing.size > 0) {
+              throw new CongoDuplicateKeyError(
+                `E11000 duplicate key error collection: ${this.dbName}.${this.collName} index: ${name}`,
+                indexData.key as Record<string, 1>,
+                newKeyValue
+              );
+            }
+          }
+
+          if (!indexData.entries.has(newKeyStr)) {
+            indexData.entries.set(newKeyStr, new Set());
+          }
+          indexData.entries.get(newKeyStr)!.add(newDoc._id.toHexString());
+        }
+      }
+    }
+  }
+
+  /**
+   * Update index entries after document delete
+   */
+  async onDelete(doc: IStoredDocument): Promise<void> {
+    await this.initialize();
+
+    for (const indexData of this.indexes.values()) {
+      const keyValue = this.extractKeyValue(doc, indexData.key);
+
+      if (keyValue === null && indexData.sparse) {
+        continue;
+      }
+
+      const keyStr = JSON.stringify(keyValue);
+      const set = indexData.entries.get(keyStr);
+      if (set) {
+        set.delete(doc._id.toHexString());
+        if (set.size === 0) {
+          indexData.entries.delete(keyStr);
+        }
+      }
+    }
+  }
+
+  /**
+   * Find the best index for a query
+   */
+  selectIndex(filter: Document): { name: string; data: IIndexData } | null {
+    if (!filter || Object.keys(filter).length === 0) {
+      return null;
+    }
+
+    // Get filter fields
+    const filterFields = new Set(this.getFilterFields(filter));
+
+    // Score each index
+    let bestIndex: { name: string; data: IIndexData } | null = null;
+    let bestScore = 0;
+
+    for (const [name, indexData] of this.indexes) {
+      const indexFields = Object.keys(indexData.key);
+      let score = 0;
+
+      // Count how many index fields are in the filter
+      for (const field of indexFields) {
+        if (filterFields.has(field)) {
+          score++;
+        } else {
+          break; // Index fields must be contiguous
+        }
+      }
+
+      // Prefer unique indexes
+      if (indexData.unique && score > 0) {
+        score += 0.5;
+      }
+
+      if (score > bestScore) {
+        bestScore = score;
+        bestIndex = { name, data: indexData };
+      }
+    }
+
+    return bestIndex;
+  }
+
+  /**
+   * Use index to find candidate document IDs
+   */
+  async findCandidateIds(filter: Document): Promise<Set<string> | null> {
+    await this.initialize();
+
+    const index = this.selectIndex(filter);
+    if (!index) return null;
+
+    // Try to use the index for equality matches
+    const indexFields = Object.keys(index.data.key);
+    const equalityValues: Record<string, any> = {};
+
+    for (const field of indexFields) {
+      const filterValue = this.getFilterValue(filter, field);
+      if (filterValue === undefined) break;
+
+      // Only use equality matches for index lookup
+      if (typeof filterValue === 'object' && filterValue !== null) {
+        if (filterValue.$eq !== undefined) {
+          equalityValues[field] = filterValue.$eq;
+        } else if (filterValue.$in !== undefined) {
+          // Handle $in with multiple lookups
+          const results = new Set<string>();
+          for (const val of filterValue.$in) {
+            equalityValues[field] = val;
+            const keyStr = JSON.stringify(this.buildKeyValue(equalityValues, index.data.key));
+            const ids = index.data.entries.get(keyStr);
+            if (ids) {
+              for (const id of ids) {
+                results.add(id);
+              }
+            }
+          }
+          return results;
+        } else {
+          break; // Non-equality operator, stop here
+        }
+      } else {
+        equalityValues[field] = filterValue;
+      }
+    }
+
+    if (Object.keys(equalityValues).length === 0) {
+      return null;
+    }
+
+    const keyStr = JSON.stringify(this.buildKeyValue(equalityValues, index.data.key));
+    return index.data.entries.get(keyStr) || new Set();
+  }
+
+  // ============================================================================
+  // Helper Methods
+  // ============================================================================
+
+  private generateIndexName(key: Record<string, any>): string {
+    return Object.entries(key)
+      .map(([field, dir]) => `${field}_${dir}`)
+      .join('_');
+  }
+
+  private extractKeyValue(doc: Document, key: Record<string, any>): any {
+    const values: any[] = [];
+
+    for (const field of Object.keys(key)) {
+      const value = QueryEngine.getNestedValue(doc, field);
+      values.push(value === undefined ? null : value);
+    }
+
+    // For single-field index, return the value directly
+    if (values.length === 1) {
+      return values[0];
+    }
+
+    return values;
+  }
+
+  private buildKeyValue(values: Record<string, any>, key: Record<string, any>): any {
+    const result: any[] = [];
+
+    for (const field of Object.keys(key)) {
+      result.push(values[field] !== undefined ? values[field] : null);
+    }
+
+    if (result.length === 1) {
+      return result[0];
+    }
+
+    return result;
+  }
+
+  private getFilterFields(filter: Document, prefix = ''): string[] {
+    const fields: string[] = [];
+
+    for (const [key, value] of Object.entries(filter)) {
+      if (key.startsWith('$')) {
+        // Logical operator
+        if (key === '$and' || key === '$or' || key === '$nor') {
+          for (const subFilter of value as Document[]) {
+            fields.push(...this.getFilterFields(subFilter, prefix));
+          }
+        }
+      } else {
+        const fullKey = prefix ? `${prefix}.${key}` : key;
+        fields.push(fullKey);
+
+        // Check for nested filters
+        if (typeof value === 'object' && value !== null && !Array.isArray(value)) {
+          const subKeys = Object.keys(value);
+          if (subKeys.length > 0 && !subKeys[0].startsWith('$')) {
+            fields.push(...this.getFilterFields(value, fullKey));
+          }
+        }
+      }
+    }
+
+    return fields;
+  }
+
+  private getFilterValue(filter: Document, field: string): any {
+    // Handle dot notation
+    const parts = field.split('.');
+    let current: any = filter;
+
+    for (const part of parts) {
+      if (current === null || current === undefined) {
+        return undefined;
+      }
+      current = current[part];
+    }
+
+    return current;
+  }
+}

ts/congodb/engine/QueryEngine.ts

@@ -0,0 +1,301 @@
+import * as plugins from '../congodb.plugins.js';
+import type { Document, IStoredDocument, ISortSpecification, ISortDirection } from '../types/interfaces.js';
+
+// Import mingo Query class
+import { Query } from 'mingo';
+
+/**
+ * Query engine using mingo for MongoDB-compatible query matching
+ */
+export class QueryEngine {
+  /**
+   * Filter documents by a MongoDB query filter
+   */
+  static filter(documents: IStoredDocument[], filter: Document): IStoredDocument[] {
+    if (!filter || Object.keys(filter).length === 0) {
+      return documents;
+    }
+
+    const query = new Query(filter);
+    return documents.filter(doc => query.test(doc));
+  }
+
+  /**
+   * Test if a single document matches a filter
+   */
+  static matches(document: Document, filter: Document): boolean {
+    if (!filter || Object.keys(filter).length === 0) {
+      return true;
+    }
+
+    const query = new Query(filter);
+    return query.test(document);
+  }
+
+  /**
+   * Find a single document matching the filter
+   */
+  static findOne(documents: IStoredDocument[], filter: Document): IStoredDocument | null {
+    if (!filter || Object.keys(filter).length === 0) {
+      return documents[0] || null;
+    }
+
+    const query = new Query(filter);
+    for (const doc of documents) {
+      if (query.test(doc)) {
+        return doc;
+      }
+    }
+    return null;
+  }
+
+  /**
+   * Sort documents by a sort specification
+   */
+  static sort(documents: IStoredDocument[], sort: ISortSpecification): IStoredDocument[] {
+    if (!sort) {
+      return documents;
+    }
+
+    // Normalize sort specification to array of [field, direction] pairs
+    const sortFields: Array<[string, number]> = [];
+
+    if (Array.isArray(sort)) {
+      for (const [field, direction] of sort) {
+        sortFields.push([field, this.normalizeDirection(direction)]);
+      }
+    } else {
+      for (const [field, direction] of Object.entries(sort)) {
+        sortFields.push([field, this.normalizeDirection(direction)]);
+      }
+    }
+
+    return [...documents].sort((a, b) => {
+      for (const [field, direction] of sortFields) {
+        const aVal = this.getNestedValue(a, field);
+        const bVal = this.getNestedValue(b, field);
+
+        const comparison = this.compareValues(aVal, bVal);
+        if (comparison !== 0) {
+          return comparison * direction;
+        }
+      }
+      return 0;
+    });
+  }
+
+  /**
+   * Apply projection to documents
+   */
+  static project(documents: IStoredDocument[], projection: Document): Document[] {
+    if (!projection || Object.keys(projection).length === 0) {
+      return documents;
+    }
+
+    // Determine if this is inclusion or exclusion projection
+    const keys = Object.keys(projection);
+    const hasInclusion = keys.some(k => k !== '_id' && projection[k] === 1);
+    const hasExclusion = keys.some(k => k !== '_id' && projection[k] === 0);
+
+    // Can't mix inclusion and exclusion (except for _id)
+    if (hasInclusion && hasExclusion) {
+      throw new Error('Cannot mix inclusion and exclusion in projection');
+    }
+
+    return documents.map(doc => {
+      if (hasInclusion) {
+        // Inclusion projection
+        const result: Document = {};
+
+        // Handle _id
+        if (projection._id !== 0 && projection._id !== false) {
+          result._id = doc._id;
+        }
+
+        for (const key of keys) {
+          if (key === '_id') continue;
+          if (projection[key] === 1 || projection[key] === true) {
+            const value = this.getNestedValue(doc, key);
+            if (value !== undefined) {
+              this.setNestedValue(result, key, value);
+            }
+          }
+        }
+
+        return result;
+      } else {
+        // Exclusion projection - start with copy and remove fields
+        const result = { ...doc };
+
+        for (const key of keys) {
+          if (projection[key] === 0 || projection[key] === false) {
+            this.deleteNestedValue(result, key);
+          }
+        }
+
+        return result;
+      }
+    });
+  }
+
+  /**
+   * Get distinct values for a field
+   */
+  static distinct(documents: IStoredDocument[], field: string, filter?: Document): any[] {
+    let docs = documents;
+    if (filter && Object.keys(filter).length > 0) {
+      docs = this.filter(documents, filter);
+    }
+
+    const values = new Set<any>();
+    for (const doc of docs) {
+      const value = this.getNestedValue(doc, field);
+      if (value !== undefined) {
+        if (Array.isArray(value)) {
+          // For arrays, add each element
+          for (const v of value) {
+            values.add(this.toComparable(v));
+          }
+        } else {
+          values.add(this.toComparable(value));
+        }
+      }
+    }
+
+    return Array.from(values);
+  }
+
+  /**
+   * Normalize sort direction to 1 or -1
+   */
+  private static normalizeDirection(direction: ISortDirection): number {
+    if (typeof direction === 'number') {
+      return direction > 0 ? 1 : -1;
+    }
+    if (direction === 'asc' || direction === 'ascending') {
+      return 1;
+    }
+    return -1;
+  }
+
+  /**
+   * Get a nested value from an object using dot notation
+   */
+  static getNestedValue(obj: any, path: string): any {
+    const parts = path.split('.');
+    let current = obj;
+
+    for (const part of parts) {
+      if (current === null || current === undefined) {
+        return undefined;
+      }
+      if (Array.isArray(current)) {
+        // Handle array access
+        const index = parseInt(part, 10);
+        if (!isNaN(index)) {
+          current = current[index];
+        } else {
+          // Get the field from all array elements
+          return current.map(item => this.getNestedValue(item, part)).flat();
+        }
+      } else {
+        current = current[part];
+      }
+    }
+
+    return current;
+  }
+
+  /**
+   * Set a nested value in an object using dot notation
+   */
+  private static setNestedValue(obj: any, path: string, value: any): void {
+    const parts = path.split('.');
+    let current = obj;
+
+    for (let i = 0; i < parts.length - 1; i++) {
+      const part = parts[i];
+      if (!(part in current)) {
+        current[part] = {};
+      }
+      current = current[part];
+    }
+
+    current[parts[parts.length - 1]] = value;
+  }
+
+  /**
+   * Delete a nested value from an object using dot notation
+   */
+  private static deleteNestedValue(obj: any, path: string): void {
+    const parts = path.split('.');
+    let current = obj;
+
+    for (let i = 0; i < parts.length - 1; i++) {
+      const part = parts[i];
+      if (!(part in current)) {
+        return;
+      }
+      current = current[part];
+    }
+
+    delete current[parts[parts.length - 1]];
+  }
+
+  /**
+   * Compare two values for sorting
+   */
+  private static compareValues(a: any, b: any): number {
+    // Handle undefined/null
+    if (a === undefined && b === undefined) return 0;
+    if (a === undefined) return -1;
+    if (b === undefined) return 1;
+    if (a === null && b === null) return 0;
+    if (a === null) return -1;
+    if (b === null) return 1;
+
+    // Handle ObjectId
+    if (a instanceof plugins.bson.ObjectId && b instanceof plugins.bson.ObjectId) {
+      return a.toHexString().localeCompare(b.toHexString());
+    }
+
+    // Handle dates
+    if (a instanceof Date && b instanceof Date) {
+      return a.getTime() - b.getTime();
+    }
+
+    // Handle numbers
+    if (typeof a === 'number' && typeof b === 'number') {
+      return a - b;
+    }
+
+    // Handle strings
+    if (typeof a === 'string' && typeof b === 'string') {
+      return a.localeCompare(b);
+    }
+
+    // Handle booleans
+    if (typeof a === 'boolean' && typeof b === 'boolean') {
+      return (a ? 1 : 0) - (b ? 1 : 0);
+    }
+
+    // Fall back to string comparison
+    return String(a).localeCompare(String(b));
+  }
+
+  /**
+   * Convert a value to a comparable form (for distinct)
+   */
+  private static toComparable(value: any): any {
+    if (value instanceof plugins.bson.ObjectId) {
+      return value.toHexString();
+    }
+    if (value instanceof Date) {
+      return value.toISOString();
+    }
+    if (typeof value === 'object' && value !== null) {
+      return JSON.stringify(value);
+    }
+    return value;
+  }
+}

ts/congodb/engine/TransactionEngine.ts

@@ -0,0 +1,351 @@
+import * as plugins from '../congodb.plugins.js';
+import type { IStorageAdapter } from '../storage/IStorageAdapter.js';
+import type { Document, IStoredDocument, ITransactionOptions } from '../types/interfaces.js';
+import { CongoTransactionError, CongoWriteConflictError } from '../errors/CongoErrors.js';
+
+/**
+ * Transaction state
+ */
+export interface ITransactionState {
+  id: string;
+  sessionId: string;
+  startTime: plugins.bson.Timestamp;
+  status: 'active' | 'committed' | 'aborted';
+  readSet: Map<string, Set<string>>; // ns -> document _ids read
+  writeSet: Map<string, Map<string, { op: 'insert' | 'update' | 'delete'; doc?: IStoredDocument; originalDoc?: IStoredDocument }>>; // ns -> _id -> operation
+  snapshots: Map<string, IStoredDocument[]>; // ns -> snapshot of documents
+}
+
+/**
+ * Transaction engine for ACID transaction support
+ */
+export class TransactionEngine {
+  private storage: IStorageAdapter;
+  private transactions: Map<string, ITransactionState> = new Map();
+  private txnCounter = 0;
+
+  constructor(storage: IStorageAdapter) {
+    this.storage = storage;
+  }
+
+  /**
+   * Start a new transaction
+   */
+  startTransaction(sessionId: string, options?: ITransactionOptions): string {
+    this.txnCounter++;
+    const txnId = `txn_${sessionId}_${this.txnCounter}`;
+
+    const transaction: ITransactionState = {
+      id: txnId,
+      sessionId,
+      startTime: new plugins.bson.Timestamp({ t: Math.floor(Date.now() / 1000), i: this.txnCounter }),
+      status: 'active',
+      readSet: new Map(),
+      writeSet: new Map(),
+      snapshots: new Map(),
+    };
+
+    this.transactions.set(txnId, transaction);
+    return txnId;
+  }
+
+  /**
+   * Get a transaction by ID
+   */
+  getTransaction(txnId: string): ITransactionState | undefined {
+    return this.transactions.get(txnId);
+  }
+
+  /**
+   * Check if a transaction is active
+   */
+  isActive(txnId: string): boolean {
+    const txn = this.transactions.get(txnId);
+    return txn?.status === 'active';
+  }
+
+  /**
+   * Get or create a snapshot for a namespace
+   */
+  async getSnapshot(txnId: string, dbName: string, collName: string): Promise<IStoredDocument[]> {
+    const txn = this.transactions.get(txnId);
+    if (!txn || txn.status !== 'active') {
+      throw new CongoTransactionError('Transaction is not active');
+    }
+
+    const ns = `${dbName}.${collName}`;
+    if (!txn.snapshots.has(ns)) {
+      const snapshot = await this.storage.createSnapshot(dbName, collName);
+      txn.snapshots.set(ns, snapshot);
+    }
+
+    // Apply transaction writes to snapshot
+    const snapshot = txn.snapshots.get(ns)!;
+    const writes = txn.writeSet.get(ns);
+
+    if (!writes) {
+      return snapshot;
+    }
+
+    // Create a modified view of the snapshot
+    const result: IStoredDocument[] = [];
+    const deletedIds = new Set<string>();
+    const modifiedDocs = new Map<string, IStoredDocument>();
+
+    for (const [idStr, write] of writes) {
+      if (write.op === 'delete') {
+        deletedIds.add(idStr);
+      } else if (write.op === 'update' || write.op === 'insert') {
+        if (write.doc) {
+          modifiedDocs.set(idStr, write.doc);
+        }
+      }
+    }
+
+    // Add existing documents (not deleted, possibly modified)
+    for (const doc of snapshot) {
+      const idStr = doc._id.toHexString();
+      if (deletedIds.has(idStr)) {
+        continue;
+      }
+      if (modifiedDocs.has(idStr)) {
+        result.push(modifiedDocs.get(idStr)!);
+        modifiedDocs.delete(idStr);
+      } else {
+        result.push(doc);
+      }
+    }
+
+    // Add new documents (inserts)
+    for (const doc of modifiedDocs.values()) {
+      result.push(doc);
+    }
+
+    return result;
+  }
+
+  /**
+   * Record a read operation
+   */
+  recordRead(txnId: string, dbName: string, collName: string, docIds: string[]): void {
+    const txn = this.transactions.get(txnId);
+    if (!txn || txn.status !== 'active') return;
+
+    const ns = `${dbName}.${collName}`;
+    if (!txn.readSet.has(ns)) {
+      txn.readSet.set(ns, new Set());
+    }
+
+    const readSet = txn.readSet.get(ns)!;
+    for (const id of docIds) {
+      readSet.add(id);
+    }
+  }
+
+  /**
+   * Record a write operation (insert)
+   */
+  recordInsert(txnId: string, dbName: string, collName: string, doc: IStoredDocument): void {
+    const txn = this.transactions.get(txnId);
+    if (!txn || txn.status !== 'active') {
+      throw new CongoTransactionError('Transaction is not active');
+    }
+
+    const ns = `${dbName}.${collName}`;
+    if (!txn.writeSet.has(ns)) {
+      txn.writeSet.set(ns, new Map());
+    }
+
+    txn.writeSet.get(ns)!.set(doc._id.toHexString(), {
+      op: 'insert',
+      doc,
+    });
+  }
+
+  /**
+   * Record a write operation (update)
+   */
+  recordUpdate(
+    txnId: string,
+    dbName: string,
+    collName: string,
+    originalDoc: IStoredDocument,
+    updatedDoc: IStoredDocument
+  ): void {
+    const txn = this.transactions.get(txnId);
+    if (!txn || txn.status !== 'active') {
+      throw new CongoTransactionError('Transaction is not active');
+    }
+
+    const ns = `${dbName}.${collName}`;
+    if (!txn.writeSet.has(ns)) {
+      txn.writeSet.set(ns, new Map());
+    }
+
+    const idStr = originalDoc._id.toHexString();
+    const existing = txn.writeSet.get(ns)!.get(idStr);
+
+    // If we already have a write for this document, update it
+    if (existing) {
+      existing.doc = updatedDoc;
+    } else {
+      txn.writeSet.get(ns)!.set(idStr, {
+        op: 'update',
+        doc: updatedDoc,
+        originalDoc,
+      });
+    }
+  }
+
+  /**
+   * Record a write operation (delete)
+   */
+  recordDelete(txnId: string, dbName: string, collName: string, doc: IStoredDocument): void {
+    const txn = this.transactions.get(txnId);
+    if (!txn || txn.status !== 'active') {
+      throw new CongoTransactionError('Transaction is not active');
+    }
+
+    const ns = `${dbName}.${collName}`;
+    if (!txn.writeSet.has(ns)) {
+      txn.writeSet.set(ns, new Map());
+    }
+
+    const idStr = doc._id.toHexString();
+    const existing = txn.writeSet.get(ns)!.get(idStr);
+
+    if (existing && existing.op === 'insert') {
+      // If we inserted and then deleted, just remove the write
+      txn.writeSet.get(ns)!.delete(idStr);
+    } else {
+      txn.writeSet.get(ns)!.set(idStr, {
+        op: 'delete',
+        originalDoc: doc,
+      });
+    }
+  }
+
+  /**
+   * Commit a transaction
+   */
+  async commitTransaction(txnId: string): Promise<void> {
+    const txn = this.transactions.get(txnId);
+    if (!txn) {
+      throw new CongoTransactionError('Transaction not found');
+    }
+    if (txn.status !== 'active') {
+      throw new CongoTransactionError(`Cannot commit transaction in state: ${txn.status}`);
+    }
+
+    // Check for write conflicts
+    for (const [ns, writes] of txn.writeSet) {
+      const [dbName, collName] = ns.split('.');
+      const ids = Array.from(writes.keys()).map(id => new plugins.bson.ObjectId(id));
+
+      const hasConflicts = await this.storage.hasConflicts(dbName, collName, ids, txn.startTime);
+      if (hasConflicts) {
+        txn.status = 'aborted';
+        throw new CongoWriteConflictError();
+      }
+    }
+
+    // Apply all writes
+    for (const [ns, writes] of txn.writeSet) {
+      const [dbName, collName] = ns.split('.');
+
+      for (const [idStr, write] of writes) {
+        switch (write.op) {
+          case 'insert':
+            if (write.doc) {
+              await this.storage.insertOne(dbName, collName, write.doc);
+            }
+            break;
+          case 'update':
+            if (write.doc) {
+              await this.storage.updateById(dbName, collName, new plugins.bson.ObjectId(idStr), write.doc);
+            }
+            break;
+          case 'delete':
+            await this.storage.deleteById(dbName, collName, new plugins.bson.ObjectId(idStr));
+            break;
+        }
+      }
+    }
+
+    txn.status = 'committed';
+  }
+
+  /**
+   * Abort a transaction
+   */
+  async abortTransaction(txnId: string): Promise<void> {
+    const txn = this.transactions.get(txnId);
+    if (!txn) {
+      throw new CongoTransactionError('Transaction not found');
+    }
+    if (txn.status !== 'active') {
+      // Already committed or aborted, just return
+      return;
+    }
+
+    // Simply discard all buffered writes
+    txn.writeSet.clear();
+    txn.readSet.clear();
+    txn.snapshots.clear();
+    txn.status = 'aborted';
+  }
+
+  /**
+   * End a transaction (cleanup)
+   */
+  endTransaction(txnId: string): void {
+    this.transactions.delete(txnId);
+  }
+
+  /**
+   * Get all pending writes for a namespace
+   */
+  getPendingWrites(txnId: string, dbName: string, collName: string): Map<string, { op: 'insert' | 'update' | 'delete'; doc?: IStoredDocument }> | undefined {
+    const txn = this.transactions.get(txnId);
+    if (!txn) return undefined;
+
+    const ns = `${dbName}.${collName}`;
+    return txn.writeSet.get(ns);
+  }
+
+  /**
+   * Execute a callback within a transaction, with automatic retry on conflict
+   */
+  async withTransaction<T>(
+    sessionId: string,
+    callback: (txnId: string) => Promise<T>,
+    options?: ITransactionOptions & { maxRetries?: number }
+  ): Promise<T> {
+    const maxRetries = options?.maxRetries ?? 3;
+    let lastError: Error | undefined;
+
+    for (let attempt = 0; attempt < maxRetries; attempt++) {
+      const txnId = this.startTransaction(sessionId, options);
+
+      try {
+        const result = await callback(txnId);
+        await this.commitTransaction(txnId);
+        this.endTransaction(txnId);
+        return result;
+      } catch (error: any) {
+        await this.abortTransaction(txnId);
+        this.endTransaction(txnId);
+
+        if (error instanceof CongoWriteConflictError && attempt < maxRetries - 1) {
+          // Retry on write conflict
+          lastError = error;
+          continue;
+        }
+
+        throw error;
+      }
+    }
+
+    throw lastError || new CongoTransactionError('Transaction failed after max retries');
+  }
+}

ts/congodb/engine/UpdateEngine.ts

@@ -0,0 +1,506 @@
+import * as plugins from '../congodb.plugins.js';
+import type { Document, IStoredDocument } from '../types/interfaces.js';
+import { QueryEngine } from './QueryEngine.js';
+
+/**
+ * Update engine for MongoDB-compatible update operations
+ */
+export class UpdateEngine {
+  /**
+   * Apply an update specification to a document
+   * Returns the updated document or null if no update was applied
+   */
+  static applyUpdate(document: IStoredDocument, update: Document, arrayFilters?: Document[]): IStoredDocument {
+    // Check if this is an aggregation pipeline update
+    if (Array.isArray(update)) {
+      // Aggregation pipeline updates are not yet supported
+      throw new Error('Aggregation pipeline updates are not yet supported');
+    }
+
+    // Check if this is a replacement (no $ operators at top level)
+    const hasOperators = Object.keys(update).some(k => k.startsWith('$'));
+
+    if (!hasOperators) {
+      // This is a replacement - preserve _id
+      return {
+        _id: document._id,
+        ...update,
+      };
+    }
+
+    // Apply update operators
+    const result = this.deepClone(document);
+
+    for (const [operator, operand] of Object.entries(update)) {
+      switch (operator) {
+        case '$set':
+          this.applySet(result, operand);
+          break;
+        case '$unset':
+          this.applyUnset(result, operand);
+          break;
+        case '$inc':
+          this.applyInc(result, operand);
+          break;
+        case '$mul':
+          this.applyMul(result, operand);
+          break;
+        case '$min':
+          this.applyMin(result, operand);
+          break;
+        case '$max':
+          this.applyMax(result, operand);
+          break;
+        case '$rename':
+          this.applyRename(result, operand);
+          break;
+        case '$currentDate':
+          this.applyCurrentDate(result, operand);
+          break;
+        case '$setOnInsert':
+          // Only applied during upsert insert, handled elsewhere
+          break;
+        case '$push':
+          this.applyPush(result, operand, arrayFilters);
+          break;
+        case '$pop':
+          this.applyPop(result, operand);
+          break;
+        case '$pull':
+          this.applyPull(result, operand, arrayFilters);
+          break;
+        case '$pullAll':
+          this.applyPullAll(result, operand);
+          break;
+        case '$addToSet':
+          this.applyAddToSet(result, operand);
+          break;
+        case '$bit':
+          this.applyBit(result, operand);
+          break;
+        default:
+          throw new Error(`Unknown update operator: ${operator}`);
+      }
+    }
+
+    return result;
+  }
+
+  /**
+   * Apply $setOnInsert for upsert operations
+   */
+  static applySetOnInsert(document: IStoredDocument, setOnInsert: Document): IStoredDocument {
+    const result = this.deepClone(document);
+    this.applySet(result, setOnInsert);
+    return result;
+  }
+
+  /**
+   * Deep clone a document
+   */
+  private static deepClone(obj: any): any {
+    if (obj === null || typeof obj !== 'object') {
+      return obj;
+    }
+
+    if (obj instanceof plugins.bson.ObjectId) {
+      return new plugins.bson.ObjectId(obj.toHexString());
+    }
+
+    if (obj instanceof Date) {
+      return new Date(obj.getTime());
+    }
+
+    if (obj instanceof plugins.bson.Timestamp) {
+      return new plugins.bson.Timestamp({ t: obj.high, i: obj.low });
+    }
+
+    if (Array.isArray(obj)) {
+      return obj.map(item => this.deepClone(item));
+    }
+
+    const cloned: any = {};
+    for (const key of Object.keys(obj)) {
+      cloned[key] = this.deepClone(obj[key]);
+    }
+    return cloned;
+  }
+
+  /**
+   * Set a nested value
+   */
+  private static setNestedValue(obj: any, path: string, value: any): void {
+    const parts = path.split('.');
+    let current = obj;
+
+    for (let i = 0; i < parts.length - 1; i++) {
+      const part = parts[i];
+
+      // Handle array index notation
+      const arrayMatch = part.match(/^(\w+)\[(\d+)\]$/);
+      if (arrayMatch) {
+        const [, fieldName, indexStr] = arrayMatch;
+        const index = parseInt(indexStr, 10);
+        if (!(fieldName in current)) {
+          current[fieldName] = [];
+        }
+        if (!current[fieldName][index]) {
+          current[fieldName][index] = {};
+        }
+        current = current[fieldName][index];
+        continue;
+      }
+
+      // Handle numeric index (array positional)
+      const numIndex = parseInt(part, 10);
+      if (!isNaN(numIndex) && Array.isArray(current)) {
+        if (!current[numIndex]) {
+          current[numIndex] = {};
+        }
+        current = current[numIndex];
+        continue;
+      }
+
+      if (!(part in current) || current[part] === null) {
+        current[part] = {};
+      }
+      current = current[part];
+    }
+
+    const lastPart = parts[parts.length - 1];
+    const numIndex = parseInt(lastPart, 10);
+    if (!isNaN(numIndex) && Array.isArray(current)) {
+      current[numIndex] = value;
+    } else {
+      current[lastPart] = value;
+    }
+  }
+
+  /**
+   * Get a nested value
+   */
+  private static getNestedValue(obj: any, path: string): any {
+    return QueryEngine.getNestedValue(obj, path);
+  }
+
+  /**
+   * Delete a nested value
+   */
+  private static deleteNestedValue(obj: any, path: string): void {
+    const parts = path.split('.');
+    let current = obj;
+
+    for (let i = 0; i < parts.length - 1; i++) {
+      const part = parts[i];
+      if (!(part in current)) {
+        return;
+      }
+      current = current[part];
+    }
+
+    delete current[parts[parts.length - 1]];
+  }
+
+  // ============================================================================
+  // Field Update Operators
+  // ============================================================================
+
+  private static applySet(doc: any, fields: Document): void {
+    for (const [path, value] of Object.entries(fields)) {
+      this.setNestedValue(doc, path, this.deepClone(value));
+    }
+  }
+
+  private static applyUnset(doc: any, fields: Document): void {
+    for (const path of Object.keys(fields)) {
+      this.deleteNestedValue(doc, path);
+    }
+  }
+
+  private static applyInc(doc: any, fields: Document): void {
+    for (const [path, value] of Object.entries(fields)) {
+      const current = this.getNestedValue(doc, path) || 0;
+      if (typeof current !== 'number') {
+        throw new Error(`Cannot apply $inc to non-numeric field: ${path}`);
+      }
+      this.setNestedValue(doc, path, current + (value as number));
+    }
+  }
+
+  private static applyMul(doc: any, fields: Document): void {
+    for (const [path, value] of Object.entries(fields)) {
+      const current = this.getNestedValue(doc, path) || 0;
+      if (typeof current !== 'number') {
+        throw new Error(`Cannot apply $mul to non-numeric field: ${path}`);
+      }
+      this.setNestedValue(doc, path, current * (value as number));
+    }
+  }
+
+  private static applyMin(doc: any, fields: Document): void {
+    for (const [path, value] of Object.entries(fields)) {
+      const current = this.getNestedValue(doc, path);
+      if (current === undefined || this.compareValues(value, current) < 0) {
+        this.setNestedValue(doc, path, this.deepClone(value));
+      }
+    }
+  }
+
+  private static applyMax(doc: any, fields: Document): void {
+    for (const [path, value] of Object.entries(fields)) {
+      const current = this.getNestedValue(doc, path);
+      if (current === undefined || this.compareValues(value, current) > 0) {
+        this.setNestedValue(doc, path, this.deepClone(value));
+      }
+    }
+  }
+
+  private static applyRename(doc: any, fields: Document): void {
+    for (const [oldPath, newPath] of Object.entries(fields)) {
+      const value = this.getNestedValue(doc, oldPath);
+      if (value !== undefined) {
+        this.deleteNestedValue(doc, oldPath);
+        this.setNestedValue(doc, newPath as string, value);
+      }
+    }
+  }
+
+  private static applyCurrentDate(doc: any, fields: Document): void {
+    for (const [path, spec] of Object.entries(fields)) {
+      if (spec === true) {
+        this.setNestedValue(doc, path, new Date());
+      } else if (typeof spec === 'object' && spec.$type === 'date') {
+        this.setNestedValue(doc, path, new Date());
+      } else if (typeof spec === 'object' && spec.$type === 'timestamp') {
+        this.setNestedValue(doc, path, new plugins.bson.Timestamp({ t: Math.floor(Date.now() / 1000), i: 0 }));
+      }
+    }
+  }
+
+  // ============================================================================
+  // Array Update Operators
+  // ============================================================================
+
+  private static applyPush(doc: any, fields: Document, arrayFilters?: Document[]): void {
+    for (const [path, spec] of Object.entries(fields)) {
+      let arr = this.getNestedValue(doc, path);
+      if (arr === undefined) {
+        arr = [];
+        this.setNestedValue(doc, path, arr);
+      }
+      if (!Array.isArray(arr)) {
+        throw new Error(`Cannot apply $push to non-array field: ${path}`);
+      }
+
+      if (spec && typeof spec === 'object' && '$each' in spec) {
+        // $push with modifiers
+        let elements = (spec.$each as any[]).map(e => this.deepClone(e));
+        const position = spec.$position as number | undefined;
+        const slice = spec.$slice as number | undefined;
+        const sortSpec = spec.$sort;
+
+        if (position !== undefined) {
+          arr.splice(position, 0, ...elements);
+        } else {
+          arr.push(...elements);
+        }
+
+        if (sortSpec !== undefined) {
+          if (typeof sortSpec === 'number') {
+            arr.sort((a, b) => (a - b) * sortSpec);
+          } else {
+            // Sort by field(s)
+            const entries = Object.entries(sortSpec as Document);
+            arr.sort((a, b) => {
+              for (const [field, dir] of entries) {
+                const av = this.getNestedValue(a, field);
+                const bv = this.getNestedValue(b, field);
+                const cmp = this.compareValues(av, bv) * (dir as number);
+                if (cmp !== 0) return cmp;
+              }
+              return 0;
+            });
+          }
+        }
+
+        if (slice !== undefined) {
+          if (slice >= 0) {
+            arr.splice(slice);
+          } else {
+            arr.splice(0, arr.length + slice);
+          }
+        }
+      } else {
+        // Simple push
+        arr.push(this.deepClone(spec));
+      }
+    }
+  }
+
+  private static applyPop(doc: any, fields: Document): void {
+    for (const [path, direction] of Object.entries(fields)) {
+      const arr = this.getNestedValue(doc, path);
+      if (!Array.isArray(arr)) {
+        throw new Error(`Cannot apply $pop to non-array field: ${path}`);
+      }
+
+      if ((direction as number) === 1) {
+        arr.pop();
+      } else {
+        arr.shift();
+      }
+    }
+  }
+
+  private static applyPull(doc: any, fields: Document, arrayFilters?: Document[]): void {
+    for (const [path, condition] of Object.entries(fields)) {
+      const arr = this.getNestedValue(doc, path);
+      if (!Array.isArray(arr)) {
+        continue; // Skip if not an array
+      }
+
+      if (typeof condition === 'object' && condition !== null && !Array.isArray(condition)) {
+        // Condition is a query filter
+        const hasOperators = Object.keys(condition).some(k => k.startsWith('$'));
+        if (hasOperators) {
+          // Filter using query operators
+          const remaining = arr.filter(item => !QueryEngine.matches(item, condition));
+          arr.length = 0;
+          arr.push(...remaining);
+        } else {
+          // Match documents with all specified fields
+          const remaining = arr.filter(item => {
+            if (typeof item !== 'object' || item === null) {
+              return true;
+            }
+            return !Object.entries(condition).every(([k, v]) => {
+              const itemVal = this.getNestedValue(item, k);
+              return this.valuesEqual(itemVal, v);
+            });
+          });
+          arr.length = 0;
+          arr.push(...remaining);
+        }
+      } else {
+        // Direct value match
+        const remaining = arr.filter(item => !this.valuesEqual(item, condition));
+        arr.length = 0;
+        arr.push(...remaining);
+      }
+    }
+  }
+
+  private static applyPullAll(doc: any, fields: Document): void {
+    for (const [path, values] of Object.entries(fields)) {
+      const arr = this.getNestedValue(doc, path);
+      if (!Array.isArray(arr)) {
+        continue;
+      }
+      if (!Array.isArray(values)) {
+        throw new Error(`$pullAll requires an array argument`);
+      }
+
+      const valueSet = new Set(values.map(v => JSON.stringify(v)));
+      const remaining = arr.filter(item => !valueSet.has(JSON.stringify(item)));
+      arr.length = 0;
+      arr.push(...remaining);
+    }
+  }
+
+  private static applyAddToSet(doc: any, fields: Document): void {
+    for (const [path, spec] of Object.entries(fields)) {
+      let arr = this.getNestedValue(doc, path);
+      if (arr === undefined) {
+        arr = [];
+        this.setNestedValue(doc, path, arr);
+      }
+      if (!Array.isArray(arr)) {
+        throw new Error(`Cannot apply $addToSet to non-array field: ${path}`);
+      }
+
+      const existingSet = new Set(arr.map(v => JSON.stringify(v)));
+
+      if (spec && typeof spec === 'object' && '$each' in spec) {
+        for (const item of spec.$each as any[]) {
+          const key = JSON.stringify(item);
+          if (!existingSet.has(key)) {
+            arr.push(this.deepClone(item));
+            existingSet.add(key);
+          }
+        }
+      } else {
+        const key = JSON.stringify(spec);
+        if (!existingSet.has(key)) {
+          arr.push(this.deepClone(spec));
+        }
+      }
+    }
+  }
+
+  private static applyBit(doc: any, fields: Document): void {
+    for (const [path, operations] of Object.entries(fields)) {
+      let current = this.getNestedValue(doc, path) || 0;
+      if (typeof current !== 'number') {
+        throw new Error(`Cannot apply $bit to non-numeric field: ${path}`);
+      }
+
+      for (const [op, value] of Object.entries(operations as Document)) {
+        switch (op) {
+          case 'and':
+            current = current & (value as number);
+            break;
+          case 'or':
+            current = current | (value as number);
+            break;
+          case 'xor':
+            current = current ^ (value as number);
+            break;
+        }
+      }
+
+      this.setNestedValue(doc, path, current);
+    }
+  }
+
+  // ============================================================================
+  // Helper Methods
+  // ============================================================================
+
+  private static compareValues(a: any, b: any): number {
+    if (a === b) return 0;
+    if (a === null || a === undefined) return -1;
+    if (b === null || b === undefined) return 1;
+
+    if (typeof a === 'number' && typeof b === 'number') {
+      return a - b;
+    }
+
+    if (a instanceof Date && b instanceof Date) {
+      return a.getTime() - b.getTime();
+    }
+
+    if (typeof a === 'string' && typeof b === 'string') {
+      return a.localeCompare(b);
+    }
+
+    return String(a).localeCompare(String(b));
+  }
+
+  private static valuesEqual(a: any, b: any): boolean {
+    if (a === b) return true;
+
+    if (a instanceof plugins.bson.ObjectId && b instanceof plugins.bson.ObjectId) {
+      return a.equals(b);
+    }
+
+    if (a instanceof Date && b instanceof Date) {
+      return a.getTime() === b.getTime();
+    }
+
+    if (typeof a === 'object' && typeof b === 'object' && a !== null && b !== null) {
+      return JSON.stringify(a) === JSON.stringify(b);
+    }
+
+    return false;
+  }
+}

ts/congodb/errors/CongoErrors.ts

@@ -0,0 +1,181 @@
+/**
+ * Base error class for all CongoDB errors
+ * Mirrors MongoDB driver error hierarchy
+ */
+export class CongoError extends Error {
+  public code?: number;
+  public codeName?: string;
+
+  constructor(message: string, code?: number, codeName?: string) {
+    super(message);
+    this.name = 'CongoError';
+    this.code = code;
+    this.codeName = codeName;
+    Object.setPrototypeOf(this, new.target.prototype);
+  }
+}
+
+/**
+ * Error thrown during connection issues
+ */
+export class CongoConnectionError extends CongoError {
+  constructor(message: string) {
+    super(message);
+    this.name = 'CongoConnectionError';
+  }
+}
+
+/**
+ * Error thrown when an operation times out
+ */
+export class CongoTimeoutError extends CongoError {
+  constructor(message: string) {
+    super(message, 50, 'MaxTimeMSExpired');
+    this.name = 'CongoTimeoutError';
+  }
+}
+
+/**
+ * Error thrown during write operations
+ */
+export class CongoWriteError extends CongoError {
+  public writeErrors?: IWriteError[];
+  public result?: any;
+
+  constructor(message: string, code?: number, writeErrors?: IWriteError[]) {
+    super(message, code);
+    this.name = 'CongoWriteError';
+    this.writeErrors = writeErrors;
+  }
+}
+
+/**
+ * Error thrown for duplicate key violations
+ */
+export class CongoDuplicateKeyError extends CongoWriteError {
+  public keyPattern?: Record<string, 1>;
+  public keyValue?: Record<string, any>;
+
+  constructor(message: string, keyPattern?: Record<string, 1>, keyValue?: Record<string, any>) {
+    super(message, 11000);
+    this.name = 'CongoDuplicateKeyError';
+    this.codeName = 'DuplicateKey';
+    this.keyPattern = keyPattern;
+    this.keyValue = keyValue;
+  }
+}
+
+/**
+ * Error thrown for bulk write failures
+ */
+export class CongoBulkWriteError extends CongoError {
+  public writeErrors: IWriteError[];
+  public result: any;
+
+  constructor(message: string, writeErrors: IWriteError[], result: any) {
+    super(message, 65);
+    this.name = 'CongoBulkWriteError';
+    this.writeErrors = writeErrors;
+    this.result = result;
+  }
+}
+
+/**
+ * Error thrown during transaction operations
+ */
+export class CongoTransactionError extends CongoError {
+  constructor(message: string, code?: number) {
+    super(message, code);
+    this.name = 'CongoTransactionError';
+  }
+}
+
+/**
+ * Error thrown when a transaction is aborted due to conflict
+ */
+export class CongoWriteConflictError extends CongoTransactionError {
+  constructor(message: string = 'Write conflict during transaction') {
+    super(message, 112);
+    this.name = 'CongoWriteConflictError';
+    this.codeName = 'WriteConflict';
+  }
+}
+
+/**
+ * Error thrown for invalid arguments
+ */
+export class CongoArgumentError extends CongoError {
+  constructor(message: string) {
+    super(message);
+    this.name = 'CongoArgumentError';
+  }
+}
+
+/**
+ * Error thrown when an operation is not supported
+ */
+export class CongoNotSupportedError extends CongoError {
+  constructor(message: string) {
+    super(message, 115);
+    this.name = 'CongoNotSupportedError';
+    this.codeName = 'CommandNotSupported';
+  }
+}
+
+/**
+ * Error thrown when cursor is exhausted or closed
+ */
+export class CongoCursorError extends CongoError {
+  constructor(message: string) {
+    super(message);
+    this.name = 'CongoCursorError';
+  }
+}
+
+/**
+ * Error thrown when a namespace (database.collection) is invalid
+ */
+export class CongoNamespaceError extends CongoError {
+  constructor(message: string) {
+    super(message, 73);
+    this.name = 'CongoNamespaceError';
+    this.codeName = 'InvalidNamespace';
+  }
+}
+
+/**
+ * Error thrown when an index operation fails
+ */
+export class CongoIndexError extends CongoError {
+  constructor(message: string, code?: number) {
+    super(message, code || 86);
+    this.name = 'CongoIndexError';
+  }
+}
+
+/**
+ * Write error detail for bulk operations
+ */
+export interface IWriteError {
+  index: number;
+  code: number;
+  errmsg: string;
+  op: any;
+}
+
+/**
+ * Convert any error to a CongoError
+ */
+export function toCongoError(error: any): CongoError {
+  if (error instanceof CongoError) {
+    return error;
+  }
+  const congoError = new CongoError(error.message || String(error));
+  if (error.code) {
+    congoError.code = error.code;
+  }
+  if (error.codeName) {
+    congoError.codeName = error.codeName;
+  }
+  return congoError;
+}

ts/congodb/index.ts

@@ -0,0 +1,37 @@
+// CongoDB - MongoDB Wire Protocol compatible in-memory database server
+// Use the official MongoDB driver to connect to CongoServer
+
+// Re-export plugins for external use
+import * as plugins from './congodb.plugins.js';
+export { plugins };
+
+// Export BSON types for convenience
+export { ObjectId, Binary, Timestamp, Long, Decimal128, UUID } from 'bson';
+
+// Export all types
+export * from './types/interfaces.js';
+
+// Export errors
+export * from './errors/CongoErrors.js';
+
+// Export storage adapters
+export type { IStorageAdapter } from './storage/IStorageAdapter.js';
+export { MemoryStorageAdapter } from './storage/MemoryStorageAdapter.js';
+export { FileStorageAdapter } from './storage/FileStorageAdapter.js';
+export { OpLog } from './storage/OpLog.js';
+
+// Export engines
+export { QueryEngine } from './engine/QueryEngine.js';
+export { UpdateEngine } from './engine/UpdateEngine.js';
+export { AggregationEngine } from './engine/AggregationEngine.js';
+export { IndexEngine } from './engine/IndexEngine.js';
+export { TransactionEngine } from './engine/TransactionEngine.js';
+
+// Export server (the main entry point for using CongoDB)
+export { CongoServer } from './server/CongoServer.js';
+export type { ICongoServerOptions } from './server/CongoServer.js';
+
+// Export wire protocol utilities (for advanced usage)
+export { WireProtocol } from './server/WireProtocol.js';
+export { CommandRouter } from './server/CommandRouter.js';
+export type { ICommandHandler, IHandlerContext, ICursorState } from './server/CommandRouter.js';

ts/congodb/server/CommandRouter.ts

@@ -0,0 +1,180 @@
+import * as plugins from '../congodb.plugins.js';
+import type { IStorageAdapter } from '../storage/IStorageAdapter.js';
+import type { IParsedCommand } from './WireProtocol.js';
+import type { CongoServer } from './CongoServer.js';
+
+// Import handlers
+import { HelloHandler } from './handlers/HelloHandler.js';
+import { InsertHandler } from './handlers/InsertHandler.js';
+import { FindHandler } from './handlers/FindHandler.js';
+import { UpdateHandler } from './handlers/UpdateHandler.js';
+import { DeleteHandler } from './handlers/DeleteHandler.js';
+import { AggregateHandler } from './handlers/AggregateHandler.js';
+import { IndexHandler } from './handlers/IndexHandler.js';
+import { AdminHandler } from './handlers/AdminHandler.js';
+
+/**
+ * Handler context passed to command handlers
+ */
+export interface IHandlerContext {
+  storage: IStorageAdapter;
+  server: CongoServer;
+  database: string;
+  command: plugins.bson.Document;
+  documentSequences?: Map<string, plugins.bson.Document[]>;
+}
+
+/**
+ * Command handler interface
+ */
+export interface ICommandHandler {
+  handle(context: IHandlerContext): Promise<plugins.bson.Document>;
+}
+
+/**
+ * CommandRouter - Routes incoming commands to appropriate handlers
+ */
+export class CommandRouter {
+  private storage: IStorageAdapter;
+  private server: CongoServer;
+  private handlers: Map<string, ICommandHandler> = new Map();
+
+  // Cursor state for getMore operations
+  private cursors: Map<bigint, ICursorState> = new Map();
+  private cursorIdCounter: bigint = BigInt(1);
+
+  constructor(storage: IStorageAdapter, server: CongoServer) {
+    this.storage = storage;
+    this.server = server;
+    this.registerHandlers();
+  }
+
+  /**
+   * Register all command handlers
+   */
+  private registerHandlers(): void {
+    // Create handler instances with shared state
+    const helloHandler = new HelloHandler();
+    const findHandler = new FindHandler(this.cursors, () => this.cursorIdCounter++);
+    const insertHandler = new InsertHandler();
+    const updateHandler = new UpdateHandler();
+    const deleteHandler = new DeleteHandler();
+    const aggregateHandler = new AggregateHandler(this.cursors, () => this.cursorIdCounter++);
+    const indexHandler = new IndexHandler();
+    const adminHandler = new AdminHandler();
+
+    // Handshake commands
+    this.handlers.set('hello', helloHandler);
+    this.handlers.set('ismaster', helloHandler);
+    this.handlers.set('isMaster', helloHandler);
+
+    // CRUD commands
+    this.handlers.set('find', findHandler);
+    this.handlers.set('insert', insertHandler);
+    this.handlers.set('update', updateHandler);
+    this.handlers.set('delete', deleteHandler);
+    this.handlers.set('findAndModify', updateHandler);
+    this.handlers.set('getMore', findHandler);
+    this.handlers.set('killCursors', findHandler);
+
+    // Aggregation
+    this.handlers.set('aggregate', aggregateHandler);
+    this.handlers.set('count', findHandler);
+    this.handlers.set('distinct', findHandler);
+
+    // Index operations
+    this.handlers.set('createIndexes', indexHandler);
+    this.handlers.set('dropIndexes', indexHandler);
+    this.handlers.set('listIndexes', indexHandler);
+
+    // Admin/Database operations
+    this.handlers.set('ping', adminHandler);
+    this.handlers.set('listDatabases', adminHandler);
+    this.handlers.set('listCollections', adminHandler);
+    this.handlers.set('drop', adminHandler);
+    this.handlers.set('dropDatabase', adminHandler);
+    this.handlers.set('create', adminHandler);
+    this.handlers.set('serverStatus', adminHandler);
+    this.handlers.set('buildInfo', adminHandler);
+    this.handlers.set('whatsmyuri', adminHandler);
+    this.handlers.set('getLog', adminHandler);
+    this.handlers.set('hostInfo', adminHandler);
+    this.handlers.set('replSetGetStatus', adminHandler);
+    this.handlers.set('isMaster', helloHandler);
+    this.handlers.set('saslStart', adminHandler);
+    this.handlers.set('saslContinue', adminHandler);
+    this.handlers.set('endSessions', adminHandler);
+    this.handlers.set('abortTransaction', adminHandler);
+    this.handlers.set('commitTransaction', adminHandler);
+    this.handlers.set('collStats', adminHandler);
+    this.handlers.set('dbStats', adminHandler);
+    this.handlers.set('connectionStatus', adminHandler);
+    this.handlers.set('currentOp', adminHandler);
+    this.handlers.set('collMod', adminHandler);
+    this.handlers.set('renameCollection', adminHandler);
+  }
+
+  /**
+   * Route a command to its handler
+   */
+  async route(parsedCommand: IParsedCommand): Promise<plugins.bson.Document> {
+    const { commandName, command, database, documentSequences } = parsedCommand;
+
+    // Create handler context
+    const context: IHandlerContext = {
+      storage: this.storage,
+      server: this.server,
+      database,
+      command,
+      documentSequences,
+    };
+
+    // Find handler
+    const handler = this.handlers.get(commandName);
+
+    if (!handler) {
+      // Unknown command
+      return {
+        ok: 0,
+        errmsg: `no such command: '${commandName}'`,
+        code: 59,
+        codeName: 'CommandNotFound',
+      };
+    }
+
+    try {
+      return await handler.handle(context);
+    } catch (error: any) {
+      // Handle known error types
+      if (error.code) {
+        return {
+          ok: 0,
+          errmsg: error.message,
+          code: error.code,
+          codeName: error.codeName || 'UnknownError',
+        };
+      }
+
+      // Generic error
+      return {
+        ok: 0,
+        errmsg: error.message || 'Internal error',
+        code: 1,
+        codeName: 'InternalError',
+      };
+    }
+  }
+}
+
+/**
+ * Cursor state for multi-batch queries
+ */
+export interface ICursorState {
+  id: bigint;
+  database: string;
+  collection: string;
+  documents: plugins.bson.Document[];
+  position: number;
+  batchSize: number;
+  createdAt: Date;
+}

ts/congodb/server/CongoServer.ts

@@ -0,0 +1,298 @@
+import * as net from 'net';
+import * as plugins from '../congodb.plugins.js';
+import { WireProtocol, OP_QUERY } from './WireProtocol.js';
+import { CommandRouter } from './CommandRouter.js';
+import { MemoryStorageAdapter } from '../storage/MemoryStorageAdapter.js';
+import { FileStorageAdapter } from '../storage/FileStorageAdapter.js';
+import type { IStorageAdapter } from '../storage/IStorageAdapter.js';
+
+/**
+ * Server configuration options
+ */
+export interface ICongoServerOptions {
+  /** Port to listen on (default: 27017) */
+  port?: number;
+  /** Host to bind to (default: 127.0.0.1) */
+  host?: string;
+  /** Storage type: 'memory' or 'file' (default: 'memory') */
+  storage?: 'memory' | 'file';
+  /** Path for file storage (required if storage is 'file') */
+  storagePath?: string;
+  /** Enable persistence for memory storage */
+  persistPath?: string;
+  /** Persistence interval in ms (default: 60000) */
+  persistIntervalMs?: number;
+}
+
+/**
+ * Connection state for each client
+ */
+interface IConnectionState {
+  id: number;
+  socket: net.Socket;
+  buffer: Buffer;
+  authenticated: boolean;
+  database: string;
+}
+
+/**
+ * CongoServer - MongoDB Wire Protocol compatible server
+ *
+ * This server implements the MongoDB wire protocol (OP_MSG) to allow
+ * official MongoDB drivers to connect and perform operations.
+ *
+ * @example
+ * ```typescript
+ * import { CongoServer } from '@push.rocks/smartmongo/congodb';
+ * import { MongoClient } from 'mongodb';
+ *
+ * const server = new CongoServer({ port: 27017 });
+ * await server.start();
+ *
+ * const client = new MongoClient('mongodb://127.0.0.1:27017');
+ * await client.connect();
+ * ```
+ */
+export class CongoServer {
+  private options: Required<ICongoServerOptions>;
+  private server: net.Server | null = null;
+  private storage: IStorageAdapter;
+  private commandRouter: CommandRouter;
+  private connections: Map<number, IConnectionState> = new Map();
+  private connectionIdCounter = 0;
+  private isRunning = false;
+  private startTime: Date = new Date();
+
+  constructor(options: ICongoServerOptions = {}) {
+    this.options = {
+      port: options.port ?? 27017,
+      host: options.host ?? '127.0.0.1',
+      storage: options.storage ?? 'memory',
+      storagePath: options.storagePath ?? './data',
+      persistPath: options.persistPath ?? '',
+      persistIntervalMs: options.persistIntervalMs ?? 60000,
+    };
+
+    // Create storage adapter
+    if (this.options.storage === 'file') {
+      this.storage = new FileStorageAdapter(this.options.storagePath);
+    } else {
+      this.storage = new MemoryStorageAdapter({
+        persistPath: this.options.persistPath || undefined,
+        persistIntervalMs: this.options.persistPath ? this.options.persistIntervalMs : undefined,
+      });
+    }
+
+    // Create command router
+    this.commandRouter = new CommandRouter(this.storage, this);
+  }
+
+  /**
+   * Get the storage adapter (for testing/debugging)
+   */
+  getStorage(): IStorageAdapter {
+    return this.storage;
+  }
+
+  /**
+   * Get server uptime in seconds
+   */
+  getUptime(): number {
+    return Math.floor((Date.now() - this.startTime.getTime()) / 1000);
+  }
+
+  /**
+   * Get current connection count
+   */
+  getConnectionCount(): number {
+    return this.connections.size;
+  }
+
+  /**
+   * Start the server
+   */
+  async start(): Promise<void> {
+    if (this.isRunning) {
+      throw new Error('Server is already running');
+    }
+
+    // Initialize storage
+    await this.storage.initialize();
+
+    return new Promise((resolve, reject) => {
+      this.server = net.createServer((socket) => {
+        this.handleConnection(socket);
+      });
+
+      this.server.on('error', (err) => {
+        if (!this.isRunning) {
+          reject(err);
+        } else {
+          console.error('Server error:', err);
+        }
+      });
+
+      this.server.listen(this.options.port, this.options.host, () => {
+        this.isRunning = true;
+        this.startTime = new Date();
+        resolve();
+      });
+    });
+  }
+
+  /**
+   * Stop the server
+   */
+  async stop(): Promise<void> {
+    if (!this.isRunning || !this.server) {
+      return;
+    }
+
+    // Close all connections
+    for (const conn of this.connections.values()) {
+      conn.socket.destroy();
+    }
+    this.connections.clear();
+
+    // Close storage
+    await this.storage.close();
+
+    return new Promise((resolve) => {
+      this.server!.close(() => {
+        this.isRunning = false;
+        this.server = null;
+        resolve();
+      });
+    });
+  }
+
+  /**
+   * Handle a new client connection
+   */
+  private handleConnection(socket: net.Socket): void {
+    const connectionId = ++this.connectionIdCounter;
+
+    const state: IConnectionState = {
+      id: connectionId,
+      socket,
+      buffer: Buffer.alloc(0),
+      authenticated: true, // No auth required for now
+      database: 'test',
+    };
+
+    this.connections.set(connectionId, state);
+
+    socket.on('data', (data) => {
+      this.handleData(state, Buffer.isBuffer(data) ? data : Buffer.from(data));
+    });
+
+    socket.on('close', () => {
+      this.connections.delete(connectionId);
+    });
+
+    socket.on('error', (err) => {
+      // Connection errors are expected when clients disconnect
+      this.connections.delete(connectionId);
+    });
+  }
+
+  /**
+   * Handle incoming data from a client
+   */
+  private handleData(state: IConnectionState, data: Buffer): void {
+    // Append new data to buffer
+    state.buffer = Buffer.concat([state.buffer, data]);
+
+    // Process messages from buffer
+    this.processMessages(state);
+  }
+
+  /**
+   * Process complete messages from the buffer
+   */
+  private async processMessages(state: IConnectionState): Promise<void> {
+    while (state.buffer.length >= 16) {
+      try {
+        const result = WireProtocol.parseMessage(state.buffer);
+
+        if (!result) {
+          // Not enough data for a complete message
+          break;
+        }
+
+        const { command, bytesConsumed } = result;
+
+        // Remove processed bytes from buffer
+        state.buffer = state.buffer.subarray(bytesConsumed);
+
+        // Process the command
+        const response = await this.commandRouter.route(command);
+
+        // Encode and send response
+        let responseBuffer: Buffer;
+        if (command.opCode === OP_QUERY) {
+          // Legacy OP_QUERY gets OP_REPLY response
+          responseBuffer = WireProtocol.encodeOpReplyResponse(
+            command.requestID,
+            [response]
+          );
+        } else {
+          // OP_MSG gets OP_MSG response
+          responseBuffer = WireProtocol.encodeOpMsgResponse(
+            command.requestID,
+            response
+          );
+        }
+
+        if (!state.socket.destroyed) {
+          state.socket.write(responseBuffer);
+        }
+      } catch (error: any) {
+        // Send error response
+        const errorResponse = WireProtocol.encodeErrorResponse(
+          0, // We don't have the requestID at this point
+          1,
+          error.message || 'Internal error'
+        );
+
+        if (!state.socket.destroyed) {
+          state.socket.write(errorResponse);
+        }
+
+        // Clear buffer on parse errors to avoid infinite loops
+        if (error.message?.includes('opCode') || error.message?.includes('section')) {
+          state.buffer = Buffer.alloc(0);
+        }
+        break;
+      }
+    }
+  }
+
+  /**
+   * Get the connection URI for this server
+   */
+  getConnectionUri(): string {
+    return `mongodb://${this.options.host}:${this.options.port}`;
+  }
+
+  /**
+   * Check if the server is running
+   */
+  get running(): boolean {
+    return this.isRunning;
+  }
+
+  /**
+   * Get the port the server is listening on
+   */
+  get port(): number {
+    return this.options.port;
+  }
+
+  /**
+   * Get the host the server is bound to
+   */
+  get host(): string {
+    return this.options.host;
+  }
+}

ts/congodb/server/WireProtocol.ts

@@ -0,0 +1,416 @@
+import * as plugins from '../congodb.plugins.js';
+
+/**
+ * MongoDB Wire Protocol Implementation
+ * Handles parsing and encoding of MongoDB wire protocol messages (OP_MSG primarily)
+ *
+ * Wire Protocol Message Format:
+ * - Header (16 bytes): messageLength (4), requestID (4), responseTo (4), opCode (4)
+ * - OP_MSG: flagBits (4), sections[], optional checksum (4)
+ *
+ * References:
+ * - https://www.mongodb.com/docs/manual/reference/mongodb-wire-protocol/
+ */
+
+// OpCodes
+export const OP_REPLY = 1;        // Legacy reply
+export const OP_UPDATE = 2001;    // Legacy update
+export const OP_INSERT = 2002;    // Legacy insert
+export const OP_QUERY = 2004;     // Legacy query (still used for initial handshake)
+export const OP_GET_MORE = 2005;  // Legacy getMore
+export const OP_DELETE = 2006;    // Legacy delete
+export const OP_KILL_CURSORS = 2007; // Legacy kill cursors
+export const OP_COMPRESSED = 2012;   // Compressed message
+export const OP_MSG = 2013;       // Modern protocol (MongoDB 3.6+)
+
+// OP_MSG Section Types
+export const SECTION_BODY = 0;           // Single BSON document
+export const SECTION_DOCUMENT_SEQUENCE = 1; // Document sequence for bulk operations
+
+// OP_MSG Flag Bits
+export const MSG_FLAG_CHECKSUM_PRESENT = 1 << 0;
+export const MSG_FLAG_MORE_TO_COME = 1 << 1;
+export const MSG_FLAG_EXHAUST_ALLOWED = 1 << 16;
+
+/**
+ * Parsed message header
+ */
+export interface IMessageHeader {
+  messageLength: number;
+  requestID: number;
+  responseTo: number;
+  opCode: number;
+}
+
+/**
+ * Parsed OP_MSG message
+ */
+export interface IOpMsgMessage {
+  header: IMessageHeader;
+  flagBits: number;
+  sections: IOpMsgSection[];
+  checksum?: number;
+}
+
+/**
+ * OP_MSG section (either body or document sequence)
+ */
+export interface IOpMsgSection {
+  type: number;
+  payload: plugins.bson.Document;
+  sequenceIdentifier?: string;
+  documents?: plugins.bson.Document[];
+}
+
+/**
+ * Parsed OP_QUERY message (legacy, but used for initial handshake)
+ */
+export interface IOpQueryMessage {
+  header: IMessageHeader;
+  flags: number;
+  fullCollectionName: string;
+  numberToSkip: number;
+  numberToReturn: number;
+  query: plugins.bson.Document;
+  returnFieldsSelector?: plugins.bson.Document;
+}
+
+/**
+ * Parsed command from any message type
+ */
+export interface IParsedCommand {
+  commandName: string;
+  command: plugins.bson.Document;
+  database: string;
+  requestID: number;
+  opCode: number;
+  documentSequences?: Map<string, plugins.bson.Document[]>;
+}
+
+/**
+ * Wire Protocol parser and encoder
+ */
+export class WireProtocol {
+  /**
+   * Parse a complete message from a buffer
+   * Returns the parsed command and the number of bytes consumed
+   */
+  static parseMessage(buffer: Buffer): { command: IParsedCommand; bytesConsumed: number } | null {
+    if (buffer.length < 16) {
+      return null; // Not enough data for header
+    }
+
+    const header = this.parseHeader(buffer);
+
+    if (buffer.length < header.messageLength) {
+      return null; // Not enough data for complete message
+    }
+
+    const messageBuffer = buffer.subarray(0, header.messageLength);
+
+    switch (header.opCode) {
+      case OP_MSG:
+        return this.parseOpMsg(messageBuffer, header);
+      case OP_QUERY:
+        return this.parseOpQuery(messageBuffer, header);
+      default:
+        throw new Error(`Unsupported opCode: ${header.opCode}`);
+    }
+  }
+
+  /**
+   * Parse message header (16 bytes)
+   */
+  private static parseHeader(buffer: Buffer): IMessageHeader {
+    return {
+      messageLength: buffer.readInt32LE(0),
+      requestID: buffer.readInt32LE(4),
+      responseTo: buffer.readInt32LE(8),
+      opCode: buffer.readInt32LE(12),
+    };
+  }
+
+  /**
+   * Parse OP_MSG message
+   */
+  private static parseOpMsg(buffer: Buffer, header: IMessageHeader): { command: IParsedCommand; bytesConsumed: number } {
+    let offset = 16; // Skip header
+
+    const flagBits = buffer.readUInt32LE(offset);
+    offset += 4;
+
+    const sections: IOpMsgSection[] = [];
+    const documentSequences = new Map<string, plugins.bson.Document[]>();
+
+    // Parse sections until we reach the end (or checksum)
+    const messageEnd = (flagBits & MSG_FLAG_CHECKSUM_PRESENT)
+      ? header.messageLength - 4
+      : header.messageLength;
+
+    while (offset < messageEnd) {
+      const sectionType = buffer.readUInt8(offset);
+      offset += 1;
+
+      if (sectionType === SECTION_BODY) {
+        // Single BSON document
+        const docSize = buffer.readInt32LE(offset);
+        const docBuffer = buffer.subarray(offset, offset + docSize);
+        const doc = plugins.bson.deserialize(docBuffer);
+        sections.push({ type: SECTION_BODY, payload: doc });
+        offset += docSize;
+      } else if (sectionType === SECTION_DOCUMENT_SEQUENCE) {
+        // Document sequence
+        const sectionSize = buffer.readInt32LE(offset);
+        const sectionEnd = offset + sectionSize;
+        offset += 4;
+
+        // Read sequence identifier (C string)
+        let identifierEnd = offset;
+        while (buffer[identifierEnd] !== 0 && identifierEnd < sectionEnd) {
+          identifierEnd++;
+        }
+        const identifier = buffer.subarray(offset, identifierEnd).toString('utf8');
+        offset = identifierEnd + 1; // Skip null terminator
+
+        // Read documents
+        const documents: plugins.bson.Document[] = [];
+        while (offset < sectionEnd) {
+          const docSize = buffer.readInt32LE(offset);
+          const docBuffer = buffer.subarray(offset, offset + docSize);
+          documents.push(plugins.bson.deserialize(docBuffer));
+          offset += docSize;
+        }
+
+        sections.push({
+          type: SECTION_DOCUMENT_SEQUENCE,
+          payload: {},
+          sequenceIdentifier: identifier,
+          documents
+        });
+        documentSequences.set(identifier, documents);
+      } else {
+        throw new Error(`Unknown section type: ${sectionType}`);
+      }
+    }
+
+    // The first section body contains the command
+    const commandSection = sections.find(s => s.type === SECTION_BODY);
+    if (!commandSection) {
+      throw new Error('OP_MSG missing command body section');
+    }
+
+    const command = commandSection.payload;
+    const commandName = Object.keys(command)[0];
+    const database = command.$db || 'admin';
+
+    return {
+      command: {
+        commandName,
+        command,
+        database,
+        requestID: header.requestID,
+        opCode: header.opCode,
+        documentSequences: documentSequences.size > 0 ? documentSequences : undefined,
+      },
+      bytesConsumed: header.messageLength,
+    };
+  }
+
+  /**
+   * Parse OP_QUERY message (legacy, used for initial handshake)
+   */
+  private static parseOpQuery(buffer: Buffer, header: IMessageHeader): { command: IParsedCommand; bytesConsumed: number } {
+    let offset = 16; // Skip header
+
+    const flags = buffer.readInt32LE(offset);
+    offset += 4;
+
+    // Read full collection name (C string)
+    let nameEnd = offset;
+    while (buffer[nameEnd] !== 0 && nameEnd < buffer.length) {
+      nameEnd++;
+    }
+    const fullCollectionName = buffer.subarray(offset, nameEnd).toString('utf8');
+    offset = nameEnd + 1;
+
+    const numberToSkip = buffer.readInt32LE(offset);
+    offset += 4;
+
+    const numberToReturn = buffer.readInt32LE(offset);
+    offset += 4;
+
+    // Read query document
+    const querySize = buffer.readInt32LE(offset);
+    const queryBuffer = buffer.subarray(offset, offset + querySize);
+    const query = plugins.bson.deserialize(queryBuffer);
+    offset += querySize;
+
+    // Extract database from collection name (format: "dbname.$cmd" or "dbname.collection")
+    const parts = fullCollectionName.split('.');
+    const database = parts[0];
+
+    // For OP_QUERY to .$cmd, the query IS the command
+    let commandName = 'find';
+    let command = query;
+
+    if (parts[1] === '$cmd') {
+      // This is a command
+      commandName = Object.keys(query)[0];
+      // Handle special commands like isMaster, hello
+      if (commandName === 'isMaster' || commandName === 'ismaster') {
+        commandName = 'hello';
+      }
+    }
+
+    return {
+      command: {
+        commandName,
+        command,
+        database,
+        requestID: header.requestID,
+        opCode: header.opCode,
+      },
+      bytesConsumed: header.messageLength,
+    };
+  }
+
+  /**
+   * Encode a response as OP_MSG
+   */
+  static encodeOpMsgResponse(
+    responseTo: number,
+    response: plugins.bson.Document,
+    requestID: number = Math.floor(Math.random() * 0x7FFFFFFF)
+  ): Buffer {
+    // Add $db if not present (optional in response)
+    const responseDoc = { ...response };
+
+    // Serialize the response document
+    const bodyBson = plugins.bson.serialize(responseDoc);
+
+    // Calculate message length
+    // Header (16) + flagBits (4) + section type (1) + body BSON
+    const messageLength = 16 + 4 + 1 + bodyBson.length;
+
+    const buffer = Buffer.alloc(messageLength);
+    let offset = 0;
+
+    // Write header
+    buffer.writeInt32LE(messageLength, offset);     // messageLength
+    offset += 4;
+    buffer.writeInt32LE(requestID, offset);         // requestID
+    offset += 4;
+    buffer.writeInt32LE(responseTo, offset);        // responseTo
+    offset += 4;
+    buffer.writeInt32LE(OP_MSG, offset);            // opCode
+    offset += 4;
+
+    // Write flagBits (0 = no flags)
+    buffer.writeUInt32LE(0, offset);
+    offset += 4;
+
+    // Write section type 0 (body)
+    buffer.writeUInt8(SECTION_BODY, offset);
+    offset += 1;
+
+    // Write body BSON
+    Buffer.from(bodyBson).copy(buffer, offset);
+
+    return buffer;
+  }
+
+  /**
+   * Encode a response as OP_REPLY (legacy, for OP_QUERY responses)
+   */
+  static encodeOpReplyResponse(
+    responseTo: number,
+    documents: plugins.bson.Document[],
+    requestID: number = Math.floor(Math.random() * 0x7FFFFFFF),
+    cursorId: bigint = BigInt(0)
+  ): Buffer {
+    // Serialize all documents
+    const docBuffers = documents.map(doc => plugins.bson.serialize(doc));
+    const totalDocsSize = docBuffers.reduce((sum, buf) => sum + buf.length, 0);
+
+    // Message format:
+    // Header (16) + responseFlags (4) + cursorID (8) + startingFrom (4) + numberReturned (4) + documents
+    const messageLength = 16 + 4 + 8 + 4 + 4 + totalDocsSize;
+
+    const buffer = Buffer.alloc(messageLength);
+    let offset = 0;
+
+    // Write header
+    buffer.writeInt32LE(messageLength, offset);     // messageLength
+    offset += 4;
+    buffer.writeInt32LE(requestID, offset);         // requestID
+    offset += 4;
+    buffer.writeInt32LE(responseTo, offset);        // responseTo
+    offset += 4;
+    buffer.writeInt32LE(OP_REPLY, offset);          // opCode
+    offset += 4;
+
+    // Write OP_REPLY fields
+    buffer.writeInt32LE(0, offset);                 // responseFlags (0 = no errors)
+    offset += 4;
+    buffer.writeBigInt64LE(cursorId, offset);       // cursorID
+    offset += 8;
+    buffer.writeInt32LE(0, offset);                 // startingFrom
+    offset += 4;
+    buffer.writeInt32LE(documents.length, offset);  // numberReturned
+    offset += 4;
+
+    // Write documents
+    for (const docBuffer of docBuffers) {
+      Buffer.from(docBuffer).copy(buffer, offset);
+      offset += docBuffer.length;
+    }
+
+    return buffer;
+  }
+
+  /**
+   * Encode an error response
+   */
+  static encodeErrorResponse(
+    responseTo: number,
+    errorCode: number,
+    errorMessage: string,
+    commandName?: string
+  ): Buffer {
+    const response: plugins.bson.Document = {
+      ok: 0,
+      errmsg: errorMessage,
+      code: errorCode,
+      codeName: this.getErrorCodeName(errorCode),
+    };
+
+    return this.encodeOpMsgResponse(responseTo, response);
+  }
+
+  /**
+   * Get error code name from error code
+   */
+  private static getErrorCodeName(code: number): string {
+    const errorNames: Record<number, string> = {
+      0: 'OK',
+      1: 'InternalError',
+      2: 'BadValue',
+      11000: 'DuplicateKey',
+      11001: 'DuplicateKeyValue',
+      13: 'Unauthorized',
+      26: 'NamespaceNotFound',
+      27: 'IndexNotFound',
+      48: 'NamespaceExists',
+      59: 'CommandNotFound',
+      66: 'ImmutableField',
+      73: 'InvalidNamespace',
+      85: 'IndexOptionsConflict',
+      112: 'WriteConflict',
+      121: 'DocumentValidationFailure',
+      211: 'KeyNotFound',
+      251: 'NoSuchTransaction',
+    };
+
+    return errorNames[code] || 'UnknownError';
+  }
+}

ts/congodb/server/handlers/AdminHandler.ts

@@ -0,0 +1,614 @@
+import * as plugins from '../../congodb.plugins.js';
+import type { ICommandHandler, IHandlerContext } from '../CommandRouter.js';
+
+/**
+ * AdminHandler - Handles administrative commands
+ */
+export class AdminHandler implements ICommandHandler {
+  async handle(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { command } = context;
+
+    // Determine which command to handle
+    if (command.ping !== undefined) {
+      return this.handlePing(context);
+    } else if (command.listDatabases !== undefined) {
+      return this.handleListDatabases(context);
+    } else if (command.listCollections !== undefined) {
+      return this.handleListCollections(context);
+    } else if (command.drop !== undefined) {
+      return this.handleDrop(context);
+    } else if (command.dropDatabase !== undefined) {
+      return this.handleDropDatabase(context);
+    } else if (command.create !== undefined) {
+      return this.handleCreate(context);
+    } else if (command.serverStatus !== undefined) {
+      return this.handleServerStatus(context);
+    } else if (command.buildInfo !== undefined) {
+      return this.handleBuildInfo(context);
+    } else if (command.whatsmyuri !== undefined) {
+      return this.handleWhatsMyUri(context);
+    } else if (command.getLog !== undefined) {
+      return this.handleGetLog(context);
+    } else if (command.hostInfo !== undefined) {
+      return this.handleHostInfo(context);
+    } else if (command.replSetGetStatus !== undefined) {
+      return this.handleReplSetGetStatus(context);
+    } else if (command.saslStart !== undefined) {
+      return this.handleSaslStart(context);
+    } else if (command.saslContinue !== undefined) {
+      return this.handleSaslContinue(context);
+    } else if (command.endSessions !== undefined) {
+      return this.handleEndSessions(context);
+    } else if (command.abortTransaction !== undefined) {
+      return this.handleAbortTransaction(context);
+    } else if (command.commitTransaction !== undefined) {
+      return this.handleCommitTransaction(context);
+    } else if (command.collStats !== undefined) {
+      return this.handleCollStats(context);
+    } else if (command.dbStats !== undefined) {
+      return this.handleDbStats(context);
+    } else if (command.connectionStatus !== undefined) {
+      return this.handleConnectionStatus(context);
+    } else if (command.currentOp !== undefined) {
+      return this.handleCurrentOp(context);
+    } else if (command.collMod !== undefined) {
+      return this.handleCollMod(context);
+    } else if (command.renameCollection !== undefined) {
+      return this.handleRenameCollection(context);
+    }
+
+    return {
+      ok: 0,
+      errmsg: 'Unknown admin command',
+      code: 59,
+      codeName: 'CommandNotFound',
+    };
+  }
+
+  /**
+   * Handle ping command
+   */
+  private async handlePing(context: IHandlerContext): Promise<plugins.bson.Document> {
+    return { ok: 1 };
+  }
+
+  /**
+   * Handle listDatabases command
+   */
+  private async handleListDatabases(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, command } = context;
+
+    const dbNames = await storage.listDatabases();
+    const nameOnly = command.nameOnly || false;
+
+    if (nameOnly) {
+      return {
+        ok: 1,
+        databases: dbNames.map(name => ({ name })),
+      };
+    }
+
+    // Build database list with sizes
+    const databases: plugins.bson.Document[] = [];
+    let totalSize = 0;
+
+    for (const name of dbNames) {
+      const collections = await storage.listCollections(name);
+      let dbSize = 0;
+
+      for (const collName of collections) {
+        const docs = await storage.findAll(name, collName);
+        // Estimate size (rough approximation)
+        dbSize += docs.reduce((sum, doc) => sum + JSON.stringify(doc).length, 0);
+      }
+
+      totalSize += dbSize;
+
+      databases.push({
+        name,
+        sizeOnDisk: dbSize,
+        empty: dbSize === 0,
+      });
+    }
+
+    return {
+      ok: 1,
+      databases,
+      totalSize,
+      totalSizeMb: totalSize / (1024 * 1024),
+    };
+  }
+
+  /**
+   * Handle listCollections command
+   */
+  private async handleListCollections(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command } = context;
+
+    const filter = command.filter || {};
+    const nameOnly = command.nameOnly || false;
+    const cursor = command.cursor || {};
+    const batchSize = cursor.batchSize || 101;
+
+    const collNames = await storage.listCollections(database);
+
+    let collections: plugins.bson.Document[] = [];
+
+    for (const name of collNames) {
+      // Apply name filter
+      if (filter.name && filter.name !== name) {
+        // Check regex
+        if (filter.name.$regex) {
+          const regex = new RegExp(filter.name.$regex, filter.name.$options);
+          if (!regex.test(name)) continue;
+        } else {
+          continue;
+        }
+      }
+
+      if (nameOnly) {
+        collections.push({ name });
+      } else {
+        collections.push({
+          name,
+          type: 'collection',
+          options: {},
+          info: {
+            readOnly: false,
+            uuid: new plugins.bson.UUID(),
+          },
+          idIndex: {
+            v: 2,
+            key: { _id: 1 },
+            name: '_id_',
+          },
+        });
+      }
+    }
+
+    return {
+      ok: 1,
+      cursor: {
+        id: plugins.bson.Long.fromNumber(0),
+        ns: `${database}.$cmd.listCollections`,
+        firstBatch: collections,
+      },
+    };
+  }
+
+  /**
+   * Handle drop command (drop collection)
+   */
+  private async handleDrop(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command } = context;
+
+    const collection = command.drop;
+
+    const existed = await storage.dropCollection(database, collection);
+
+    if (!existed) {
+      return {
+        ok: 0,
+        errmsg: `ns not found ${database}.${collection}`,
+        code: 26,
+        codeName: 'NamespaceNotFound',
+      };
+    }
+
+    return { ok: 1, ns: `${database}.${collection}` };
+  }
+
+  /**
+   * Handle dropDatabase command
+   */
+  private async handleDropDatabase(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database } = context;
+
+    await storage.dropDatabase(database);
+
+    return { ok: 1, dropped: database };
+  }
+
+  /**
+   * Handle create command (create collection)
+   */
+  private async handleCreate(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command } = context;
+
+    const collection = command.create;
+
+    // Check if already exists
+    const exists = await storage.collectionExists(database, collection);
+    if (exists) {
+      return {
+        ok: 0,
+        errmsg: `Collection ${database}.${collection} already exists.`,
+        code: 48,
+        codeName: 'NamespaceExists',
+      };
+    }
+
+    await storage.createCollection(database, collection);
+
+    return { ok: 1 };
+  }
+
+  /**
+   * Handle serverStatus command
+   */
+  private async handleServerStatus(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { server } = context;
+
+    const uptime = server.getUptime();
+    const connections = server.getConnectionCount();
+
+    return {
+      ok: 1,
+      host: `${server.host}:${server.port}`,
+      version: '7.0.0',
+      process: 'congodb',
+      pid: process.pid,
+      uptime,
+      uptimeMillis: uptime * 1000,
+      uptimeEstimate: uptime,
+      localTime: new Date(),
+      mem: {
+        resident: Math.floor(process.memoryUsage().rss / (1024 * 1024)),
+        virtual: Math.floor(process.memoryUsage().heapTotal / (1024 * 1024)),
+        supported: true,
+      },
+      connections: {
+        current: connections,
+        available: 1000 - connections,
+        totalCreated: connections,
+        active: connections,
+      },
+      network: {
+        bytesIn: 0,
+        bytesOut: 0,
+        numRequests: 0,
+      },
+      storageEngine: {
+        name: 'congodb',
+        supportsCommittedReads: true,
+        persistent: false,
+      },
+    };
+  }
+
+  /**
+   * Handle buildInfo command
+   */
+  private async handleBuildInfo(context: IHandlerContext): Promise<plugins.bson.Document> {
+    return {
+      ok: 1,
+      version: '7.0.0',
+      gitVersion: 'congodb',
+      modules: [],
+      allocator: 'system',
+      javascriptEngine: 'none',
+      sysInfo: 'deprecated',
+      versionArray: [7, 0, 0, 0],
+      openssl: {
+        running: 'disabled',
+        compiled: 'disabled',
+      },
+      buildEnvironment: {
+        distmod: 'congodb',
+        distarch: process.arch,
+        cc: '',
+        ccflags: '',
+        cxx: '',
+        cxxflags: '',
+        linkflags: '',
+        target_arch: process.arch,
+        target_os: process.platform,
+      },
+      bits: 64,
+      debug: false,
+      maxBsonObjectSize: 16777216,
+      storageEngines: ['congodb'],
+    };
+  }
+
+  /**
+   * Handle whatsmyuri command
+   */
+  private async handleWhatsMyUri(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { server } = context;
+    return {
+      ok: 1,
+      you: `127.0.0.1:${server.port}`,
+    };
+  }
+
+  /**
+   * Handle getLog command
+   */
+  private async handleGetLog(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { command } = context;
+
+    if (command.getLog === '*') {
+      return {
+        ok: 1,
+        names: ['global', 'startupWarnings'],
+      };
+    }
+
+    return {
+      ok: 1,
+      totalLinesWritten: 0,
+      log: [],
+    };
+  }
+
+  /**
+   * Handle hostInfo command
+   */
+  private async handleHostInfo(context: IHandlerContext): Promise<plugins.bson.Document> {
+    return {
+      ok: 1,
+      system: {
+        currentTime: new Date(),
+        hostname: 'localhost',
+        cpuAddrSize: 64,
+        memSizeMB: Math.floor(process.memoryUsage().heapTotal / (1024 * 1024)),
+        numCores: 1,
+        cpuArch: process.arch,
+        numaEnabled: false,
+      },
+      os: {
+        type: process.platform,
+        name: process.platform,
+        version: process.version,
+      },
+      extra: {},
+    };
+  }
+
+  /**
+   * Handle replSetGetStatus command
+   */
+  private async handleReplSetGetStatus(context: IHandlerContext): Promise<plugins.bson.Document> {
+    // We're standalone, not a replica set
+    return {
+      ok: 0,
+      errmsg: 'not running with --replSet',
+      code: 76,
+      codeName: 'NoReplicationEnabled',
+    };
+  }
+
+  /**
+   * Handle saslStart command (authentication)
+   */
+  private async handleSaslStart(context: IHandlerContext): Promise<plugins.bson.Document> {
+    // We don't require authentication, but we need to respond properly
+    // to let drivers know auth is "successful"
+    return {
+      ok: 1,
+      conversationId: 1,
+      done: true,
+      payload: Buffer.from([]),
+    };
+  }
+
+  /**
+   * Handle saslContinue command
+   */
+  private async handleSaslContinue(context: IHandlerContext): Promise<plugins.bson.Document> {
+    return {
+      ok: 1,
+      conversationId: 1,
+      done: true,
+      payload: Buffer.from([]),
+    };
+  }
+
+  /**
+   * Handle endSessions command
+   */
+  private async handleEndSessions(context: IHandlerContext): Promise<plugins.bson.Document> {
+    return { ok: 1 };
+  }
+
+  /**
+   * Handle abortTransaction command
+   */
+  private async handleAbortTransaction(context: IHandlerContext): Promise<plugins.bson.Document> {
+    // Transactions are not fully supported, but acknowledge the command
+    return { ok: 1 };
+  }
+
+  /**
+   * Handle commitTransaction command
+   */
+  private async handleCommitTransaction(context: IHandlerContext): Promise<plugins.bson.Document> {
+    // Transactions are not fully supported, but acknowledge the command
+    return { ok: 1 };
+  }
+
+  /**
+   * Handle collStats command
+   */
+  private async handleCollStats(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command } = context;
+
+    const collection = command.collStats;
+
+    const exists = await storage.collectionExists(database, collection);
+    if (!exists) {
+      return {
+        ok: 0,
+        errmsg: `ns not found ${database}.${collection}`,
+        code: 26,
+        codeName: 'NamespaceNotFound',
+      };
+    }
+
+    const docs = await storage.findAll(database, collection);
+    const size = docs.reduce((sum, doc) => sum + JSON.stringify(doc).length, 0);
+    const count = docs.length;
+    const avgObjSize = count > 0 ? size / count : 0;
+
+    const indexes = await storage.getIndexes(database, collection);
+
+    return {
+      ok: 1,
+      ns: `${database}.${collection}`,
+      count,
+      size,
+      avgObjSize,
+      storageSize: size,
+      totalIndexSize: 0,
+      indexSizes: indexes.reduce((acc: any, idx: any) => {
+        acc[idx.name] = 0;
+        return acc;
+      }, {}),
+      nindexes: indexes.length,
+    };
+  }
+
+  /**
+   * Handle dbStats command
+   */
+  private async handleDbStats(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database } = context;
+
+    const collections = await storage.listCollections(database);
+    let totalSize = 0;
+    let totalObjects = 0;
+
+    for (const collName of collections) {
+      const docs = await storage.findAll(database, collName);
+      totalObjects += docs.length;
+      totalSize += docs.reduce((sum, doc) => sum + JSON.stringify(doc).length, 0);
+    }
+
+    return {
+      ok: 1,
+      db: database,
+      collections: collections.length,
+      views: 0,
+      objects: totalObjects,
+      avgObjSize: totalObjects > 0 ? totalSize / totalObjects : 0,
+      dataSize: totalSize,
+      storageSize: totalSize,
+      indexes: collections.length, // At least _id index per collection
+      indexSize: 0,
+      totalSize,
+    };
+  }
+
+  /**
+   * Handle connectionStatus command
+   */
+  private async handleConnectionStatus(context: IHandlerContext): Promise<plugins.bson.Document> {
+    return {
+      ok: 1,
+      authInfo: {
+        authenticatedUsers: [],
+        authenticatedUserRoles: [],
+      },
+    };
+  }
+
+  /**
+   * Handle currentOp command
+   */
+  private async handleCurrentOp(context: IHandlerContext): Promise<plugins.bson.Document> {
+    return {
+      ok: 1,
+      inprog: [],
+    };
+  }
+
+  /**
+   * Handle collMod command
+   */
+  private async handleCollMod(context: IHandlerContext): Promise<plugins.bson.Document> {
+    // We don't support modifying collection options, but acknowledge the command
+    return { ok: 1 };
+  }
+
+  /**
+   * Handle renameCollection command
+   */
+  private async handleRenameCollection(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, command } = context;
+
+    const from = command.renameCollection;
+    const to = command.to;
+    const dropTarget = command.dropTarget || false;
+
+    if (!from || !to) {
+      return {
+        ok: 0,
+        errmsg: 'renameCollection requires both source and target',
+        code: 2,
+        codeName: 'BadValue',
+      };
+    }
+
+    // Parse namespace (format: "db.collection")
+    const fromParts = from.split('.');
+    const toParts = to.split('.');
+
+    if (fromParts.length < 2 || toParts.length < 2) {
+      return {
+        ok: 0,
+        errmsg: 'Invalid namespace format',
+        code: 73,
+        codeName: 'InvalidNamespace',
+      };
+    }
+
+    const fromDb = fromParts[0];
+    const fromColl = fromParts.slice(1).join('.');
+    const toDb = toParts[0];
+    const toColl = toParts.slice(1).join('.');
+
+    // Check if source exists
+    const sourceExists = await storage.collectionExists(fromDb, fromColl);
+    if (!sourceExists) {
+      return {
+        ok: 0,
+        errmsg: `source namespace ${from} does not exist`,
+        code: 26,
+        codeName: 'NamespaceNotFound',
+      };
+    }
+
+    // Check if target exists
+    const targetExists = await storage.collectionExists(toDb, toColl);
+    if (targetExists) {
+      if (dropTarget) {
+        await storage.dropCollection(toDb, toColl);
+      } else {
+        return {
+          ok: 0,
+          errmsg: `target namespace ${to} already exists`,
+          code: 48,
+          codeName: 'NamespaceExists',
+        };
+      }
+    }
+
+    // Same database rename
+    if (fromDb === toDb) {
+      await storage.renameCollection(fromDb, fromColl, toColl);
+    } else {
+      // Cross-database rename: copy documents then drop source
+      await storage.createCollection(toDb, toColl);
+      const docs = await storage.findAll(fromDb, fromColl);
+
+      for (const doc of docs) {
+        await storage.insertOne(toDb, toColl, doc);
+      }
+
+      await storage.dropCollection(fromDb, fromColl);
+    }
+
+    return { ok: 1 };
+  }
+}

ts/congodb/server/handlers/AggregateHandler.ts

@@ -0,0 +1,342 @@
+import * as plugins from '../../congodb.plugins.js';
+import type { ICommandHandler, IHandlerContext, ICursorState } from '../CommandRouter.js';
+import { AggregationEngine } from '../../engine/AggregationEngine.js';
+
+/**
+ * AggregateHandler - Handles aggregate command
+ */
+export class AggregateHandler implements ICommandHandler {
+  private cursors: Map<bigint, ICursorState>;
+  private nextCursorId: () => bigint;
+
+  constructor(
+    cursors: Map<bigint, ICursorState>,
+    nextCursorId: () => bigint
+  ) {
+    this.cursors = cursors;
+    this.nextCursorId = nextCursorId;
+  }
+
+  async handle(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command } = context;
+
+    const collection = command.aggregate;
+    const pipeline = command.pipeline || [];
+    const cursor = command.cursor || {};
+    const batchSize = cursor.batchSize || 101;
+
+    // Validate
+    if (typeof collection !== 'string' && collection !== 1) {
+      return {
+        ok: 0,
+        errmsg: 'aggregate command requires a collection name or 1',
+        code: 2,
+        codeName: 'BadValue',
+      };
+    }
+
+    if (!Array.isArray(pipeline)) {
+      return {
+        ok: 0,
+        errmsg: 'pipeline must be an array',
+        code: 2,
+        codeName: 'BadValue',
+      };
+    }
+
+    try {
+      // Get source documents
+      let documents: plugins.bson.Document[] = [];
+
+      if (collection === 1 || collection === '1') {
+        // Database-level aggregation (e.g., $listLocalSessions)
+        documents = [];
+      } else {
+        // Collection-level aggregation
+        const exists = await storage.collectionExists(database, collection);
+        if (exists) {
+          documents = await storage.findAll(database, collection);
+        }
+      }
+
+      // Handle $lookup and $graphLookup stages that reference other collections
+      const processedPipeline = await this.preprocessPipeline(
+        storage,
+        database,
+        pipeline,
+        documents
+      );
+
+      // Run aggregation
+      let results: plugins.bson.Document[];
+
+      // Check for special stages that we handle manually
+      if (this.hasSpecialStages(pipeline)) {
+        results = await this.executeWithSpecialStages(
+          storage,
+          database,
+          documents,
+          pipeline
+        );
+      } else {
+        results = AggregationEngine.aggregate(documents as any, processedPipeline);
+      }
+
+      // Handle $out and $merge stages
+      const lastStage = pipeline[pipeline.length - 1];
+      if (lastStage && lastStage.$out) {
+        await this.handleOut(storage, database, results, lastStage.$out);
+        return { ok: 1, cursor: { id: plugins.bson.Long.fromNumber(0), ns: `${database}.${collection}`, firstBatch: [] } };
+      }
+
+      if (lastStage && lastStage.$merge) {
+        await this.handleMerge(storage, database, results, lastStage.$merge);
+        return { ok: 1, cursor: { id: plugins.bson.Long.fromNumber(0), ns: `${database}.${collection}`, firstBatch: [] } };
+      }
+
+      // Build cursor response
+      const effectiveBatchSize = Math.min(batchSize, results.length);
+      const firstBatch = results.slice(0, effectiveBatchSize);
+      const remaining = results.slice(effectiveBatchSize);
+
+      let cursorId = BigInt(0);
+      if (remaining.length > 0) {
+        cursorId = this.nextCursorId();
+        this.cursors.set(cursorId, {
+          id: cursorId,
+          database,
+          collection: typeof collection === 'string' ? collection : '$cmd.aggregate',
+          documents: remaining,
+          position: 0,
+          batchSize,
+          createdAt: new Date(),
+        });
+      }
+
+      return {
+        ok: 1,
+        cursor: {
+          id: plugins.bson.Long.fromBigInt(cursorId),
+          ns: `${database}.${typeof collection === 'string' ? collection : '$cmd.aggregate'}`,
+          firstBatch,
+        },
+      };
+    } catch (error: any) {
+      return {
+        ok: 0,
+        errmsg: error.message || 'Aggregation failed',
+        code: 1,
+        codeName: 'InternalError',
+      };
+    }
+  }
+
+  /**
+   * Preprocess pipeline to handle cross-collection lookups
+   */
+  private async preprocessPipeline(
+    storage: any,
+    database: string,
+    pipeline: plugins.bson.Document[],
+    documents: plugins.bson.Document[]
+  ): Promise<plugins.bson.Document[]> {
+    // For now, return the pipeline as-is
+    // Cross-collection lookups are handled in executeWithSpecialStages
+    return pipeline;
+  }
+
+  /**
+   * Check if pipeline has stages that need special handling
+   */
+  private hasSpecialStages(pipeline: plugins.bson.Document[]): boolean {
+    return pipeline.some(stage =>
+      stage.$lookup ||
+      stage.$graphLookup ||
+      stage.$unionWith
+    );
+  }
+
+  /**
+   * Execute pipeline with special stage handling
+   */
+  private async executeWithSpecialStages(
+    storage: any,
+    database: string,
+    documents: plugins.bson.Document[],
+    pipeline: plugins.bson.Document[]
+  ): Promise<plugins.bson.Document[]> {
+    let results: plugins.bson.Document[] = [...documents];
+
+    for (const stage of pipeline) {
+      if (stage.$lookup) {
+        const lookupSpec = stage.$lookup;
+        const fromCollection = lookupSpec.from;
+
+        // Get foreign collection documents
+        const foreignExists = await storage.collectionExists(database, fromCollection);
+        const foreignDocs = foreignExists
+          ? await storage.findAll(database, fromCollection)
+          : [];
+
+        results = AggregationEngine.executeLookup(results as any, lookupSpec, foreignDocs);
+      } else if (stage.$graphLookup) {
+        const graphLookupSpec = stage.$graphLookup;
+        const fromCollection = graphLookupSpec.from;
+
+        const foreignExists = await storage.collectionExists(database, fromCollection);
+        const foreignDocs = foreignExists
+          ? await storage.findAll(database, fromCollection)
+          : [];
+
+        results = AggregationEngine.executeGraphLookup(results as any, graphLookupSpec, foreignDocs);
+      } else if (stage.$unionWith) {
+        let unionSpec = stage.$unionWith;
+        let unionColl: string;
+        let unionPipeline: plugins.bson.Document[] | undefined;
+
+        if (typeof unionSpec === 'string') {
+          unionColl = unionSpec;
+        } else {
+          unionColl = unionSpec.coll;
+          unionPipeline = unionSpec.pipeline;
+        }
+
+        const unionExists = await storage.collectionExists(database, unionColl);
+        const unionDocs = unionExists
+          ? await storage.findAll(database, unionColl)
+          : [];
+
+        results = AggregationEngine.executeUnionWith(results as any, unionDocs, unionPipeline);
+      } else if (stage.$facet) {
+        // Execute each facet pipeline separately
+        const facetResults: plugins.bson.Document = {};
+
+        for (const [facetName, facetPipeline] of Object.entries(stage.$facet)) {
+          const facetDocs = await this.executeWithSpecialStages(
+            storage,
+            database,
+            results,
+            facetPipeline as plugins.bson.Document[]
+          );
+          facetResults[facetName] = facetDocs;
+        }
+
+        results = [facetResults];
+      } else {
+        // Regular stage - pass to mingo
+        results = AggregationEngine.aggregate(results as any, [stage]);
+      }
+    }
+
+    return results;
+  }
+
+  /**
+   * Handle $out stage - write results to a collection
+   */
+  private async handleOut(
+    storage: any,
+    database: string,
+    results: plugins.bson.Document[],
+    outSpec: string | { db?: string; coll: string }
+  ): Promise<void> {
+    let targetDb = database;
+    let targetColl: string;
+
+    if (typeof outSpec === 'string') {
+      targetColl = outSpec;
+    } else {
+      targetDb = outSpec.db || database;
+      targetColl = outSpec.coll;
+    }
+
+    // Drop existing collection
+    await storage.dropCollection(targetDb, targetColl);
+
+    // Create new collection and insert results
+    await storage.createCollection(targetDb, targetColl);
+
+    for (const doc of results) {
+      if (!doc._id) {
+        doc._id = new plugins.bson.ObjectId();
+      }
+      await storage.insertOne(targetDb, targetColl, doc);
+    }
+  }
+
+  /**
+   * Handle $merge stage - merge results into a collection
+   */
+  private async handleMerge(
+    storage: any,
+    database: string,
+    results: plugins.bson.Document[],
+    mergeSpec: any
+  ): Promise<void> {
+    let targetDb = database;
+    let targetColl: string;
+
+    if (typeof mergeSpec === 'string') {
+      targetColl = mergeSpec;
+    } else if (typeof mergeSpec.into === 'string') {
+      targetColl = mergeSpec.into;
+    } else {
+      targetDb = mergeSpec.into.db || database;
+      targetColl = mergeSpec.into.coll;
+    }
+
+    const on = mergeSpec.on || '_id';
+    const whenMatched = mergeSpec.whenMatched || 'merge';
+    const whenNotMatched = mergeSpec.whenNotMatched || 'insert';
+
+    // Ensure target collection exists
+    await storage.createCollection(targetDb, targetColl);
+
+    for (const doc of results) {
+      // Find matching document
+      const existingDocs = await storage.findAll(targetDb, targetColl);
+      const onFields = Array.isArray(on) ? on : [on];
+
+      let matchingDoc = null;
+      for (const existing of existingDocs) {
+        let matches = true;
+        for (const field of onFields) {
+          if (JSON.stringify(existing[field]) !== JSON.stringify(doc[field])) {
+            matches = false;
+            break;
+          }
+        }
+        if (matches) {
+          matchingDoc = existing;
+          break;
+        }
+      }
+
+      if (matchingDoc) {
+        // Handle whenMatched
+        if (whenMatched === 'replace') {
+          await storage.updateById(targetDb, targetColl, matchingDoc._id, doc);
+        } else if (whenMatched === 'keepExisting') {
+          // Do nothing
+        } else if (whenMatched === 'merge') {
+          const merged = { ...matchingDoc, ...doc };
+          await storage.updateById(targetDb, targetColl, matchingDoc._id, merged);
+        } else if (whenMatched === 'fail') {
+          throw new Error('Document matched but whenMatched is fail');
+        }
+      } else {
+        // Handle whenNotMatched
+        if (whenNotMatched === 'insert') {
+          if (!doc._id) {
+            doc._id = new plugins.bson.ObjectId();
+          }
+          await storage.insertOne(targetDb, targetColl, doc);
+        } else if (whenNotMatched === 'discard') {
+          // Do nothing
+        } else if (whenNotMatched === 'fail') {
+          throw new Error('Document not matched but whenNotMatched is fail');
+        }
+      }
+    }
+  }
+}

ts/congodb/server/handlers/DeleteHandler.ts

@@ -0,0 +1,100 @@
+import * as plugins from '../../congodb.plugins.js';
+import type { ICommandHandler, IHandlerContext } from '../CommandRouter.js';
+import { QueryEngine } from '../../engine/QueryEngine.js';
+
+/**
+ * DeleteHandler - Handles delete commands
+ */
+export class DeleteHandler implements ICommandHandler {
+  async handle(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command, documentSequences } = context;
+
+    const collection = command.delete;
+    if (typeof collection !== 'string') {
+      return {
+        ok: 0,
+        errmsg: 'delete command requires a collection name',
+        code: 2,
+        codeName: 'BadValue',
+      };
+    }
+
+    // Get deletes from command or document sequences
+    let deletes: plugins.bson.Document[] = command.deletes || [];
+
+    // Check for OP_MSG document sequences
+    if (documentSequences && documentSequences.has('deletes')) {
+      deletes = documentSequences.get('deletes')!;
+    }
+
+    if (!Array.isArray(deletes) || deletes.length === 0) {
+      return {
+        ok: 0,
+        errmsg: 'delete command requires deletes array',
+        code: 2,
+        codeName: 'BadValue',
+      };
+    }
+
+    const ordered = command.ordered !== false;
+    const writeErrors: plugins.bson.Document[] = [];
+    let totalDeleted = 0;
+
+    // Check if collection exists
+    const exists = await storage.collectionExists(database, collection);
+    if (!exists) {
+      // Collection doesn't exist, return success with 0 deleted
+      return { ok: 1, n: 0 };
+    }
+
+    for (let i = 0; i < deletes.length; i++) {
+      const deleteSpec = deletes[i];
+      const filter = deleteSpec.q || deleteSpec.filter || {};
+      const limit = deleteSpec.limit;
+
+      // limit: 0 means delete all matching, limit: 1 means delete one
+      const deleteAll = limit === 0;
+
+      try {
+        // Get all documents
+        const documents = await storage.findAll(database, collection);
+
+        // Apply filter
+        const matchingDocs = QueryEngine.filter(documents, filter);
+
+        if (matchingDocs.length === 0) {
+          continue;
+        }
+
+        // Determine which documents to delete
+        const docsToDelete = deleteAll ? matchingDocs : matchingDocs.slice(0, 1);
+
+        // Delete the documents
+        const idsToDelete = docsToDelete.map(doc => doc._id);
+        const deleted = await storage.deleteByIds(database, collection, idsToDelete);
+        totalDeleted += deleted;
+      } catch (error: any) {
+        writeErrors.push({
+          index: i,
+          code: error.code || 1,
+          errmsg: error.message || 'Delete failed',
+        });
+
+        if (ordered) {
+          break;
+        }
+      }
+    }
+
+    const response: plugins.bson.Document = {
+      ok: 1,
+      n: totalDeleted,
+    };
+
+    if (writeErrors.length > 0) {
+      response.writeErrors = writeErrors;
+    }
+
+    return response;
+  }
+}

ts/congodb/server/handlers/FindHandler.ts

@@ -0,0 +1,301 @@
+import * as plugins from '../../congodb.plugins.js';
+import type { ICommandHandler, IHandlerContext, ICursorState } from '../CommandRouter.js';
+import { QueryEngine } from '../../engine/QueryEngine.js';
+
+/**
+ * FindHandler - Handles find, getMore, killCursors, count, distinct commands
+ */
+export class FindHandler implements ICommandHandler {
+  private cursors: Map<bigint, ICursorState>;
+  private nextCursorId: () => bigint;
+
+  constructor(
+    cursors: Map<bigint, ICursorState>,
+    nextCursorId: () => bigint
+  ) {
+    this.cursors = cursors;
+    this.nextCursorId = nextCursorId;
+  }
+
+  async handle(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { command } = context;
+
+    // Determine which operation to perform
+    if (command.find) {
+      return this.handleFind(context);
+    } else if (command.getMore !== undefined) {
+      return this.handleGetMore(context);
+    } else if (command.killCursors) {
+      return this.handleKillCursors(context);
+    } else if (command.count) {
+      return this.handleCount(context);
+    } else if (command.distinct) {
+      return this.handleDistinct(context);
+    }
+
+    return {
+      ok: 0,
+      errmsg: 'Unknown find-related command',
+      code: 59,
+      codeName: 'CommandNotFound',
+    };
+  }
+
+  /**
+   * Handle find command
+   */
+  private async handleFind(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command } = context;
+
+    const collection = command.find;
+    const filter = command.filter || {};
+    const projection = command.projection;
+    const sort = command.sort;
+    const skip = command.skip || 0;
+    const limit = command.limit || 0;
+    const batchSize = command.batchSize || 101;
+    const singleBatch = command.singleBatch || false;
+
+    // Ensure collection exists
+    const exists = await storage.collectionExists(database, collection);
+    if (!exists) {
+      // Return empty cursor for non-existent collection
+      return {
+        ok: 1,
+        cursor: {
+          id: plugins.bson.Long.fromNumber(0),
+          ns: `${database}.${collection}`,
+          firstBatch: [],
+        },
+      };
+    }
+
+    // Get all documents
+    let documents = await storage.findAll(database, collection);
+
+    // Apply filter
+    documents = QueryEngine.filter(documents, filter);
+
+    // Apply sort
+    if (sort) {
+      documents = QueryEngine.sort(documents, sort);
+    }
+
+    // Apply skip
+    if (skip > 0) {
+      documents = documents.slice(skip);
+    }
+
+    // Apply limit
+    if (limit > 0) {
+      documents = documents.slice(0, limit);
+    }
+
+    // Apply projection
+    if (projection) {
+      documents = QueryEngine.project(documents, projection) as any[];
+    }
+
+    // Determine how many documents to return in first batch
+    const effectiveBatchSize = Math.min(batchSize, documents.length);
+    const firstBatch = documents.slice(0, effectiveBatchSize);
+    const remaining = documents.slice(effectiveBatchSize);
+
+    // Create cursor if there are more documents
+    let cursorId = BigInt(0);
+    if (remaining.length > 0 && !singleBatch) {
+      cursorId = this.nextCursorId();
+      this.cursors.set(cursorId, {
+        id: cursorId,
+        database,
+        collection,
+        documents: remaining,
+        position: 0,
+        batchSize,
+        createdAt: new Date(),
+      });
+    }
+
+    return {
+      ok: 1,
+      cursor: {
+        id: plugins.bson.Long.fromBigInt(cursorId),
+        ns: `${database}.${collection}`,
+        firstBatch,
+      },
+    };
+  }
+
+  /**
+   * Handle getMore command
+   */
+  private async handleGetMore(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { database, command } = context;
+
+    const cursorIdInput = command.getMore;
+    const collection = command.collection;
+    const batchSize = command.batchSize || 101;
+
+    // Convert cursorId to bigint
+    let cursorId: bigint;
+    if (typeof cursorIdInput === 'bigint') {
+      cursorId = cursorIdInput;
+    } else if (cursorIdInput instanceof plugins.bson.Long) {
+      cursorId = cursorIdInput.toBigInt();
+    } else {
+      cursorId = BigInt(cursorIdInput);
+    }
+
+    const cursor = this.cursors.get(cursorId);
+    if (!cursor) {
+      return {
+        ok: 0,
+        errmsg: `cursor id ${cursorId} not found`,
+        code: 43,
+        codeName: 'CursorNotFound',
+      };
+    }
+
+    // Verify namespace
+    if (cursor.database !== database || cursor.collection !== collection) {
+      return {
+        ok: 0,
+        errmsg: 'cursor namespace mismatch',
+        code: 43,
+        codeName: 'CursorNotFound',
+      };
+    }
+
+    // Get next batch
+    const start = cursor.position;
+    const end = Math.min(start + batchSize, cursor.documents.length);
+    const nextBatch = cursor.documents.slice(start, end);
+    cursor.position = end;
+
+    // Check if cursor is exhausted
+    let returnCursorId = cursorId;
+    if (cursor.position >= cursor.documents.length) {
+      this.cursors.delete(cursorId);
+      returnCursorId = BigInt(0);
+    }
+
+    return {
+      ok: 1,
+      cursor: {
+        id: plugins.bson.Long.fromBigInt(returnCursorId),
+        ns: `${database}.${collection}`,
+        nextBatch,
+      },
+    };
+  }
+
+  /**
+   * Handle killCursors command
+   */
+  private async handleKillCursors(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { command } = context;
+
+    const collection = command.killCursors;
+    const cursorIds = command.cursors || [];
+
+    const cursorsKilled: plugins.bson.Long[] = [];
+    const cursorsNotFound: plugins.bson.Long[] = [];
+    const cursorsUnknown: plugins.bson.Long[] = [];
+
+    for (const idInput of cursorIds) {
+      let cursorId: bigint;
+      if (typeof idInput === 'bigint') {
+        cursorId = idInput;
+      } else if (idInput instanceof plugins.bson.Long) {
+        cursorId = idInput.toBigInt();
+      } else {
+        cursorId = BigInt(idInput);
+      }
+
+      if (this.cursors.has(cursorId)) {
+        this.cursors.delete(cursorId);
+        cursorsKilled.push(plugins.bson.Long.fromBigInt(cursorId));
+      } else {
+        cursorsNotFound.push(plugins.bson.Long.fromBigInt(cursorId));
+      }
+    }
+
+    return {
+      ok: 1,
+      cursorsKilled,
+      cursorsNotFound,
+      cursorsUnknown,
+      cursorsAlive: [],
+    };
+  }
+
+  /**
+   * Handle count command
+   */
+  private async handleCount(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command } = context;
+
+    const collection = command.count;
+    const query = command.query || {};
+    const skip = command.skip || 0;
+    const limit = command.limit || 0;
+
+    // Check if collection exists
+    const exists = await storage.collectionExists(database, collection);
+    if (!exists) {
+      return { ok: 1, n: 0 };
+    }
+
+    // Get all documents
+    let documents = await storage.findAll(database, collection);
+
+    // Apply filter
+    documents = QueryEngine.filter(documents, query);
+
+    // Apply skip
+    if (skip > 0) {
+      documents = documents.slice(skip);
+    }
+
+    // Apply limit
+    if (limit > 0) {
+      documents = documents.slice(0, limit);
+    }
+
+    return { ok: 1, n: documents.length };
+  }
+
+  /**
+   * Handle distinct command
+   */
+  private async handleDistinct(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command } = context;
+
+    const collection = command.distinct;
+    const key = command.key;
+    const query = command.query || {};
+
+    if (!key) {
+      return {
+        ok: 0,
+        errmsg: 'distinct requires a key',
+        code: 2,
+        codeName: 'BadValue',
+      };
+    }
+
+    // Check if collection exists
+    const exists = await storage.collectionExists(database, collection);
+    if (!exists) {
+      return { ok: 1, values: [] };
+    }
+
+    // Get all documents
+    const documents = await storage.findAll(database, collection);
+
+    // Get distinct values
+    const values = QueryEngine.distinct(documents, key, query);
+
+    return { ok: 1, values };
+  }
+}

ts/congodb/server/handlers/HelloHandler.ts

@@ -0,0 +1,78 @@
+import * as plugins from '../../congodb.plugins.js';
+import type { ICommandHandler, IHandlerContext } from '../CommandRouter.js';
+
+/**
+ * HelloHandler - Handles hello/isMaster handshake commands
+ *
+ * This is the first command sent by MongoDB drivers to establish a connection.
+ * It returns server capabilities and configuration.
+ */
+export class HelloHandler implements ICommandHandler {
+  async handle(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { command, server } = context;
+
+    // Build response with server capabilities
+    const response: plugins.bson.Document = {
+      ismaster: true,
+      ok: 1,
+
+      // Maximum sizes
+      maxBsonObjectSize: 16777216,           // 16 MB
+      maxMessageSizeBytes: 48000000,         // 48 MB
+      maxWriteBatchSize: 100000,             // 100k documents per batch
+
+      // Timestamps
+      localTime: new Date(),
+
+      // Session support
+      logicalSessionTimeoutMinutes: 30,
+
+      // Connection info
+      connectionId: 1,
+
+      // Wire protocol versions (support MongoDB 3.6 through 7.0)
+      minWireVersion: 0,
+      maxWireVersion: 21,
+
+      // Server mode
+      readOnly: false,
+
+      // Topology info (standalone mode)
+      isWritablePrimary: true,
+
+      // Additional info
+      topologyVersion: {
+        processId: new plugins.bson.ObjectId(),
+        counter: plugins.bson.Long.fromNumber(0),
+      },
+    };
+
+    // Handle hello-specific fields
+    if (command.hello || command.hello === 1) {
+      response.helloOk = true;
+    }
+
+    // Handle client metadata
+    if (command.client) {
+      // Client is providing metadata about itself
+      // We just acknowledge it - no need to do anything special
+    }
+
+    // Handle SASL mechanisms query
+    if (command.saslSupportedMechs) {
+      response.saslSupportedMechs = [
+        // We don't actually support auth, but the driver needs to see this
+      ];
+    }
+
+    // Compression support (none for now)
+    if (command.compression) {
+      response.compression = [];
+    }
+
+    // Server version info
+    response.version = '7.0.0';
+
+    return response;
+  }
+}

ts/congodb/server/handlers/IndexHandler.ts

@@ -0,0 +1,207 @@
+import * as plugins from '../../congodb.plugins.js';
+import type { ICommandHandler, IHandlerContext } from '../CommandRouter.js';
+import { IndexEngine } from '../../engine/IndexEngine.js';
+
+// Cache of index engines per collection
+const indexEngines: Map<string, IndexEngine> = new Map();
+
+/**
+ * Get or create an IndexEngine for a collection
+ */
+function getIndexEngine(storage: any, database: string, collection: string): IndexEngine {
+  const key = `${database}.${collection}`;
+  let engine = indexEngines.get(key);
+
+  if (!engine) {
+    engine = new IndexEngine(database, collection, storage);
+    indexEngines.set(key, engine);
+  }
+
+  return engine;
+}
+
+/**
+ * IndexHandler - Handles createIndexes, dropIndexes, listIndexes commands
+ */
+export class IndexHandler implements ICommandHandler {
+  async handle(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { command } = context;
+
+    if (command.createIndexes) {
+      return this.handleCreateIndexes(context);
+    } else if (command.dropIndexes) {
+      return this.handleDropIndexes(context);
+    } else if (command.listIndexes) {
+      return this.handleListIndexes(context);
+    }
+
+    return {
+      ok: 0,
+      errmsg: 'Unknown index command',
+      code: 59,
+      codeName: 'CommandNotFound',
+    };
+  }
+
+  /**
+   * Handle createIndexes command
+   */
+  private async handleCreateIndexes(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command } = context;
+
+    const collection = command.createIndexes;
+    const indexes = command.indexes || [];
+
+    if (!Array.isArray(indexes)) {
+      return {
+        ok: 0,
+        errmsg: 'indexes must be an array',
+        code: 2,
+        codeName: 'BadValue',
+      };
+    }
+
+    // Ensure collection exists
+    await storage.createCollection(database, collection);
+
+    const indexEngine = getIndexEngine(storage, database, collection);
+    const createdNames: string[] = [];
+    let numIndexesBefore = 0;
+    let numIndexesAfter = 0;
+
+    try {
+      const existingIndexes = await indexEngine.listIndexes();
+      numIndexesBefore = existingIndexes.length;
+
+      for (const indexSpec of indexes) {
+        const key = indexSpec.key;
+        const options = {
+          name: indexSpec.name,
+          unique: indexSpec.unique,
+          sparse: indexSpec.sparse,
+          expireAfterSeconds: indexSpec.expireAfterSeconds,
+          background: indexSpec.background,
+          partialFilterExpression: indexSpec.partialFilterExpression,
+        };
+
+        const name = await indexEngine.createIndex(key, options);
+        createdNames.push(name);
+      }
+
+      const finalIndexes = await indexEngine.listIndexes();
+      numIndexesAfter = finalIndexes.length;
+    } catch (error: any) {
+      return {
+        ok: 0,
+        errmsg: error.message || 'Failed to create index',
+        code: error.code || 1,
+        codeName: error.codeName || 'InternalError',
+      };
+    }
+
+    return {
+      ok: 1,
+      numIndexesBefore,
+      numIndexesAfter,
+      createdCollectionAutomatically: false,
+      commitQuorum: 'votingMembers',
+    };
+  }
+
+  /**
+   * Handle dropIndexes command
+   */
+  private async handleDropIndexes(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command } = context;
+
+    const collection = command.dropIndexes;
+    const indexName = command.index;
+
+    // Check if collection exists
+    const exists = await storage.collectionExists(database, collection);
+    if (!exists) {
+      return {
+        ok: 0,
+        errmsg: `ns not found ${database}.${collection}`,
+        code: 26,
+        codeName: 'NamespaceNotFound',
+      };
+    }
+
+    const indexEngine = getIndexEngine(storage, database, collection);
+
+    try {
+      if (indexName === '*') {
+        // Drop all indexes except _id
+        await indexEngine.dropAllIndexes();
+      } else if (typeof indexName === 'string') {
+        // Drop specific index by name
+        await indexEngine.dropIndex(indexName);
+      } else if (typeof indexName === 'object') {
+        // Drop index by key specification
+        const indexes = await indexEngine.listIndexes();
+        const keyStr = JSON.stringify(indexName);
+
+        for (const idx of indexes) {
+          if (JSON.stringify(idx.key) === keyStr) {
+            await indexEngine.dropIndex(idx.name);
+            break;
+          }
+        }
+      }
+
+      return { ok: 1, nIndexesWas: 1 };
+    } catch (error: any) {
+      return {
+        ok: 0,
+        errmsg: error.message || 'Failed to drop index',
+        code: error.code || 27,
+        codeName: error.codeName || 'IndexNotFound',
+      };
+    }
+  }
+
+  /**
+   * Handle listIndexes command
+   */
+  private async handleListIndexes(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command } = context;
+
+    const collection = command.listIndexes;
+    const cursor = command.cursor || {};
+    const batchSize = cursor.batchSize || 101;
+
+    // Check if collection exists
+    const exists = await storage.collectionExists(database, collection);
+    if (!exists) {
+      return {
+        ok: 0,
+        errmsg: `ns not found ${database}.${collection}`,
+        code: 26,
+        codeName: 'NamespaceNotFound',
+      };
+    }
+
+    const indexEngine = getIndexEngine(storage, database, collection);
+    const indexes = await indexEngine.listIndexes();
+
+    // Format indexes for response
+    const indexDocs = indexes.map(idx => ({
+      v: idx.v || 2,
+      key: idx.key,
+      name: idx.name,
+      ...(idx.unique ? { unique: idx.unique } : {}),
+      ...(idx.sparse ? { sparse: idx.sparse } : {}),
+      ...(idx.expireAfterSeconds !== undefined ? { expireAfterSeconds: idx.expireAfterSeconds } : {}),
+    }));
+
+    return {
+      ok: 1,
+      cursor: {
+        id: plugins.bson.Long.fromNumber(0),
+        ns: `${database}.${collection}`,
+        firstBatch: indexDocs,
+      },
+    };
+  }
+}

ts/congodb/server/handlers/InsertHandler.ts

@@ -0,0 +1,91 @@
+import * as plugins from '../../congodb.plugins.js';
+import type { ICommandHandler, IHandlerContext } from '../CommandRouter.js';
+
+/**
+ * InsertHandler - Handles insert commands
+ */
+export class InsertHandler implements ICommandHandler {
+  async handle(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command, documentSequences } = context;
+
+    const collection = command.insert;
+    if (typeof collection !== 'string') {
+      return {
+        ok: 0,
+        errmsg: 'insert command requires a collection name',
+        code: 2,
+        codeName: 'BadValue',
+      };
+    }
+
+    // Get documents from command or document sequences
+    let documents: plugins.bson.Document[] = command.documents || [];
+
+    // Check for OP_MSG document sequences (for bulk inserts)
+    if (documentSequences && documentSequences.has('documents')) {
+      documents = documentSequences.get('documents')!;
+    }
+
+    if (!Array.isArray(documents) || documents.length === 0) {
+      return {
+        ok: 0,
+        errmsg: 'insert command requires documents array',
+        code: 2,
+        codeName: 'BadValue',
+      };
+    }
+
+    const ordered = command.ordered !== false;
+    const writeErrors: plugins.bson.Document[] = [];
+    let insertedCount = 0;
+
+    // Ensure collection exists
+    await storage.createCollection(database, collection);
+
+    // Insert documents
+    for (let i = 0; i < documents.length; i++) {
+      const doc = documents[i];
+
+      try {
+        // Ensure _id exists
+        if (!doc._id) {
+          doc._id = new plugins.bson.ObjectId();
+        }
+
+        await storage.insertOne(database, collection, doc);
+        insertedCount++;
+      } catch (error: any) {
+        const writeError: plugins.bson.Document = {
+          index: i,
+          code: error.code || 11000,
+          errmsg: error.message || 'Insert failed',
+        };
+
+        // Check for duplicate key error
+        if (error.message?.includes('Duplicate key')) {
+          writeError.code = 11000;
+          writeError.keyPattern = { _id: 1 };
+          writeError.keyValue = { _id: doc._id };
+        }
+
+        writeErrors.push(writeError);
+
+        if (ordered) {
+          // Stop on first error for ordered inserts
+          break;
+        }
+      }
+    }
+
+    const response: plugins.bson.Document = {
+      ok: 1,
+      n: insertedCount,
+    };
+
+    if (writeErrors.length > 0) {
+      response.writeErrors = writeErrors;
+    }
+
+    return response;
+  }
+}

ts/congodb/server/handlers/UpdateHandler.ts

@@ -0,0 +1,315 @@
+import * as plugins from '../../congodb.plugins.js';
+import type { ICommandHandler, IHandlerContext } from '../CommandRouter.js';
+import { QueryEngine } from '../../engine/QueryEngine.js';
+import { UpdateEngine } from '../../engine/UpdateEngine.js';
+
+/**
+ * UpdateHandler - Handles update, findAndModify commands
+ */
+export class UpdateHandler implements ICommandHandler {
+  async handle(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { command } = context;
+
+    // Check findAndModify first since it also has an 'update' field
+    if (command.findAndModify) {
+      return this.handleFindAndModify(context);
+    } else if (command.update && typeof command.update === 'string') {
+      // 'update' command has collection name as the value
+      return this.handleUpdate(context);
+    }
+
+    return {
+      ok: 0,
+      errmsg: 'Unknown update-related command',
+      code: 59,
+      codeName: 'CommandNotFound',
+    };
+  }
+
+  /**
+   * Handle update command
+   */
+  private async handleUpdate(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command, documentSequences } = context;
+
+    const collection = command.update;
+    if (typeof collection !== 'string') {
+      return {
+        ok: 0,
+        errmsg: 'update command requires a collection name',
+        code: 2,
+        codeName: 'BadValue',
+      };
+    }
+
+    // Get updates from command or document sequences
+    let updates: plugins.bson.Document[] = command.updates || [];
+
+    // Check for OP_MSG document sequences
+    if (documentSequences && documentSequences.has('updates')) {
+      updates = documentSequences.get('updates')!;
+    }
+
+    if (!Array.isArray(updates) || updates.length === 0) {
+      return {
+        ok: 0,
+        errmsg: 'update command requires updates array',
+        code: 2,
+        codeName: 'BadValue',
+      };
+    }
+
+    const ordered = command.ordered !== false;
+    const writeErrors: plugins.bson.Document[] = [];
+    let totalMatched = 0;
+    let totalModified = 0;
+    let totalUpserted = 0;
+    const upserted: plugins.bson.Document[] = [];
+
+    // Ensure collection exists
+    await storage.createCollection(database, collection);
+
+    for (let i = 0; i < updates.length; i++) {
+      const updateSpec = updates[i];
+      const filter = updateSpec.q || updateSpec.filter || {};
+      const update = updateSpec.u || updateSpec.update || {};
+      const multi = updateSpec.multi || false;
+      const upsert = updateSpec.upsert || false;
+      const arrayFilters = updateSpec.arrayFilters;
+
+      try {
+        // Get all documents
+        let documents = await storage.findAll(database, collection);
+
+        // Apply filter
+        let matchingDocs = QueryEngine.filter(documents, filter);
+
+        if (matchingDocs.length === 0 && upsert) {
+          // Upsert: create new document
+          const newDoc: plugins.bson.Document = { _id: new plugins.bson.ObjectId() };
+
+          // Apply filter fields to the new document
+          this.applyFilterToDoc(newDoc, filter);
+
+          // Apply update
+          const updatedDoc = UpdateEngine.applyUpdate(newDoc as any, update, arrayFilters);
+
+          // Handle $setOnInsert
+          if (update.$setOnInsert) {
+            Object.assign(updatedDoc, update.$setOnInsert);
+          }
+
+          await storage.insertOne(database, collection, updatedDoc);
+          totalUpserted++;
+          upserted.push({ index: i, _id: updatedDoc._id });
+        } else {
+          // Update existing documents
+          const docsToUpdate = multi ? matchingDocs : matchingDocs.slice(0, 1);
+          totalMatched += docsToUpdate.length;
+
+          for (const doc of docsToUpdate) {
+            const updatedDoc = UpdateEngine.applyUpdate(doc, update, arrayFilters);
+
+            // Check if document actually changed
+            const changed = JSON.stringify(doc) !== JSON.stringify(updatedDoc);
+            if (changed) {
+              await storage.updateById(database, collection, doc._id, updatedDoc);
+              totalModified++;
+            }
+          }
+        }
+      } catch (error: any) {
+        writeErrors.push({
+          index: i,
+          code: error.code || 1,
+          errmsg: error.message || 'Update failed',
+        });
+
+        if (ordered) {
+          break;
+        }
+      }
+    }
+
+    const response: plugins.bson.Document = {
+      ok: 1,
+      n: totalMatched + totalUpserted,
+      nModified: totalModified,
+    };
+
+    if (upserted.length > 0) {
+      response.upserted = upserted;
+    }
+
+    if (writeErrors.length > 0) {
+      response.writeErrors = writeErrors;
+    }
+
+    return response;
+  }
+
+  /**
+   * Handle findAndModify command
+   */
+  private async handleFindAndModify(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { storage, database, command } = context;
+
+    const collection = command.findAndModify;
+    const query = command.query || {};
+    const update = command.update;
+    const remove = command.remove || false;
+    const returnNew = command.new || false;
+    const upsert = command.upsert || false;
+    const sort = command.sort;
+    const fields = command.fields;
+    const arrayFilters = command.arrayFilters;
+
+    // Validate - either update or remove, not both
+    if (update && remove) {
+      return {
+        ok: 0,
+        errmsg: 'cannot specify both update and remove',
+        code: 2,
+        codeName: 'BadValue',
+      };
+    }
+
+    if (!update && !remove) {
+      return {
+        ok: 0,
+        errmsg: 'either update or remove is required',
+        code: 2,
+        codeName: 'BadValue',
+      };
+    }
+
+    // Ensure collection exists
+    await storage.createCollection(database, collection);
+
+    // Get matching documents
+    let documents = await storage.findAll(database, collection);
+    let matchingDocs = QueryEngine.filter(documents, query);
+
+    // Apply sort if specified
+    if (sort) {
+      matchingDocs = QueryEngine.sort(matchingDocs, sort);
+    }
+
+    const doc = matchingDocs[0];
+
+    if (remove) {
+      // Delete operation
+      if (!doc) {
+        return { ok: 1, value: null };
+      }
+
+      await storage.deleteById(database, collection, doc._id);
+
+      let result = doc;
+      if (fields) {
+        result = QueryEngine.project([doc], fields)[0] as any;
+      }
+
+      return {
+        ok: 1,
+        value: result,
+        lastErrorObject: {
+          n: 1,
+        },
+      };
+    } else {
+      // Update operation
+      if (!doc && !upsert) {
+        return { ok: 1, value: null };
+      }
+
+      let resultDoc: plugins.bson.Document;
+      let originalDoc: plugins.bson.Document | null = null;
+      let isUpsert = false;
+
+      if (doc) {
+        // Update existing
+        originalDoc = { ...doc };
+        resultDoc = UpdateEngine.applyUpdate(doc, update, arrayFilters);
+        await storage.updateById(database, collection, doc._id, resultDoc as any);
+      } else {
+        // Upsert
+        isUpsert = true;
+        const newDoc: plugins.bson.Document = { _id: new plugins.bson.ObjectId() };
+        this.applyFilterToDoc(newDoc, query);
+        resultDoc = UpdateEngine.applyUpdate(newDoc as any, update, arrayFilters);
+
+        if (update.$setOnInsert) {
+          Object.assign(resultDoc, update.$setOnInsert);
+        }
+
+        await storage.insertOne(database, collection, resultDoc);
+      }
+
+      // Apply projection
+      let returnValue = returnNew ? resultDoc : (originalDoc || null);
+      if (returnValue && fields) {
+        returnValue = QueryEngine.project([returnValue as any], fields)[0];
+      }
+
+      const response: plugins.bson.Document = {
+        ok: 1,
+        value: returnValue,
+        lastErrorObject: {
+          n: 1,
+          updatedExisting: !isUpsert && doc !== undefined,
+        },
+      };
+
+      if (isUpsert) {
+        response.lastErrorObject.upserted = resultDoc._id;
+      }
+
+      return response;
+    }
+  }
+
+  /**
+   * Apply filter equality conditions to a new document (for upsert)
+   */
+  private applyFilterToDoc(doc: plugins.bson.Document, filter: plugins.bson.Document): void {
+    for (const [key, value] of Object.entries(filter)) {
+      // Skip operators
+      if (key.startsWith('$')) continue;
+
+      // Handle nested paths
+      if (typeof value === 'object' && value !== null) {
+        // Check if it's an operator
+        const valueKeys = Object.keys(value);
+        if (valueKeys.some(k => k.startsWith('$'))) {
+          // Extract equality value from $eq if present
+          if ('$eq' in value) {
+            this.setNestedValue(doc, key, value.$eq);
+          }
+          continue;
+        }
+      }
+
+      // Direct value assignment
+      this.setNestedValue(doc, key, value);
+    }
+  }
+
+  /**
+   * Set a nested value using dot notation
+   */
+  private setNestedValue(obj: plugins.bson.Document, path: string, value: any): void {
+    const parts = path.split('.');
+    let current = obj;
+
+    for (let i = 0; i < parts.length - 1; i++) {
+      const part = parts[i];
+      if (!(part in current)) {
+        current[part] = {};
+      }
+      current = current[part];
+    }
+
+    current[parts[parts.length - 1]] = value;
+  }
+}

ts/congodb/server/handlers/index.ts

@@ -0,0 +1,10 @@
+// Export all command handlers
+
+export { HelloHandler } from './HelloHandler.js';
+export { InsertHandler } from './InsertHandler.js';
+export { FindHandler } from './FindHandler.js';
+export { UpdateHandler } from './UpdateHandler.js';
+export { DeleteHandler } from './DeleteHandler.js';
+export { AggregateHandler } from './AggregateHandler.js';
+export { IndexHandler } from './IndexHandler.js';
+export { AdminHandler } from './AdminHandler.js';

ts/congodb/server/index.ts

@@ -0,0 +1,10 @@
+// Server module exports
+
+export { CongoServer } from './CongoServer.js';
+export type { ICongoServerOptions } from './CongoServer.js';
+export { WireProtocol } from './WireProtocol.js';
+export { CommandRouter } from './CommandRouter.js';
+export type { ICommandHandler, IHandlerContext, ICursorState } from './CommandRouter.js';
+
+// Export handlers
+export * from './handlers/index.js';

ts/congodb/storage/FileStorageAdapter.ts

@@ -0,0 +1,479 @@
+import * as plugins from '../congodb.plugins.js';
+import type { IStorageAdapter } from './IStorageAdapter.js';
+import type { IStoredDocument, IOpLogEntry, Document } from '../types/interfaces.js';
+
+/**
+ * File-based storage adapter for CongoDB
+ * Stores data in JSON files on disk for persistence
+ */
+export class FileStorageAdapter implements IStorageAdapter {
+  private basePath: string;
+  private opLogCounter = 0;
+  private initialized = false;
+  private fs = new plugins.smartfs.SmartFs(new plugins.smartfs.SmartFsProviderNode());
+
+  constructor(basePath: string) {
+    this.basePath = basePath;
+  }
+
+  // ============================================================================
+  // Helper Methods
+  // ============================================================================
+
+  private getDbPath(dbName: string): string {
+    return plugins.smartpath.join(this.basePath, dbName);
+  }
+
+  private getCollectionPath(dbName: string, collName: string): string {
+    return plugins.smartpath.join(this.basePath, dbName, `${collName}.json`);
+  }
+
+  private getIndexPath(dbName: string, collName: string): string {
+    return plugins.smartpath.join(this.basePath, dbName, `${collName}.indexes.json`);
+  }
+
+  private getOpLogPath(): string {
+    return plugins.smartpath.join(this.basePath, '_oplog.json');
+  }
+
+  private getMetaPath(): string {
+    return plugins.smartpath.join(this.basePath, '_meta.json');
+  }
+
+  private async readJsonFile<T>(filePath: string, defaultValue: T): Promise<T> {
+    try {
+      const exists = await this.fs.file(filePath).exists();
+      if (!exists) return defaultValue;
+      const content = await this.fs.file(filePath).encoding('utf8').read();
+      return JSON.parse(content as string);
+    } catch {
+      return defaultValue;
+    }
+  }
+
+  private async writeJsonFile(filePath: string, data: any): Promise<void> {
+    const dir = filePath.substring(0, filePath.lastIndexOf('/'));
+    await this.fs.directory(dir).recursive().create();
+    await this.fs.file(filePath).encoding('utf8').write(JSON.stringify(data, null, 2));
+  }
+
+  private restoreObjectIds(doc: any): IStoredDocument {
+    if (doc._id) {
+      if (typeof doc._id === 'string') {
+        doc._id = new plugins.bson.ObjectId(doc._id);
+      } else if (typeof doc._id === 'object' && doc._id.$oid) {
+        doc._id = new plugins.bson.ObjectId(doc._id.$oid);
+      }
+    }
+    return doc;
+  }
+
+  // ============================================================================
+  // Initialization
+  // ============================================================================
+
+  async initialize(): Promise<void> {
+    if (this.initialized) return;
+
+    await this.fs.directory(this.basePath).recursive().create();
+
+    // Load metadata
+    const meta = await this.readJsonFile(this.getMetaPath(), { opLogCounter: 0 });
+    this.opLogCounter = meta.opLogCounter || 0;
+
+    this.initialized = true;
+  }
+
+  async close(): Promise<void> {
+    // Save metadata
+    await this.writeJsonFile(this.getMetaPath(), { opLogCounter: this.opLogCounter });
+    this.initialized = false;
+  }
+
+  // ============================================================================
+  // Database Operations
+  // ============================================================================
+
+  async listDatabases(): Promise<string[]> {
+    await this.initialize();
+    try {
+      const entries = await this.fs.directory(this.basePath).list();
+      return entries
+        .filter(entry => entry.isDirectory && !entry.name.startsWith('_'))
+        .map(entry => entry.name);
+    } catch {
+      return [];
+    }
+  }
+
+  async createDatabase(dbName: string): Promise<void> {
+    await this.initialize();
+    const dbPath = this.getDbPath(dbName);
+    await this.fs.directory(dbPath).recursive().create();
+  }
+
+  async dropDatabase(dbName: string): Promise<boolean> {
+    await this.initialize();
+    const dbPath = this.getDbPath(dbName);
+    try {
+      const exists = await this.fs.directory(dbPath).exists();
+      if (exists) {
+        await this.fs.directory(dbPath).recursive().delete();
+        return true;
+      }
+      return false;
+    } catch {
+      return false;
+    }
+  }
+
+  async databaseExists(dbName: string): Promise<boolean> {
+    await this.initialize();
+    const dbPath = this.getDbPath(dbName);
+    return this.fs.directory(dbPath).exists();
+  }
+
+  // ============================================================================
+  // Collection Operations
+  // ============================================================================
+
+  async listCollections(dbName: string): Promise<string[]> {
+    await this.initialize();
+    const dbPath = this.getDbPath(dbName);
+    try {
+      const entries = await this.fs.directory(dbPath).list();
+      return entries
+        .filter(entry => entry.isFile && entry.name.endsWith('.json') && !entry.name.endsWith('.indexes.json'))
+        .map(entry => entry.name.replace('.json', ''));
+    } catch {
+      return [];
+    }
+  }
+
+  async createCollection(dbName: string, collName: string): Promise<void> {
+    await this.createDatabase(dbName);
+    const collPath = this.getCollectionPath(dbName, collName);
+    const exists = await this.fs.file(collPath).exists();
+    if (!exists) {
+      await this.writeJsonFile(collPath, []);
+      // Create default _id index
+      await this.writeJsonFile(this.getIndexPath(dbName, collName), [
+        { name: '_id_', key: { _id: 1 }, unique: true }
+      ]);
+    }
+  }
+
+  async dropCollection(dbName: string, collName: string): Promise<boolean> {
+    await this.initialize();
+    const collPath = this.getCollectionPath(dbName, collName);
+    const indexPath = this.getIndexPath(dbName, collName);
+    try {
+      const exists = await this.fs.file(collPath).exists();
+      if (exists) {
+        await this.fs.file(collPath).delete();
+        try {
+          await this.fs.file(indexPath).delete();
+        } catch {}
+        return true;
+      }
+      return false;
+    } catch {
+      return false;
+    }
+  }
+
+  async collectionExists(dbName: string, collName: string): Promise<boolean> {
+    await this.initialize();
+    const collPath = this.getCollectionPath(dbName, collName);
+    return this.fs.file(collPath).exists();
+  }
+
+  async renameCollection(dbName: string, oldName: string, newName: string): Promise<void> {
+    await this.initialize();
+    const oldPath = this.getCollectionPath(dbName, oldName);
+    const newPath = this.getCollectionPath(dbName, newName);
+    const oldIndexPath = this.getIndexPath(dbName, oldName);
+    const newIndexPath = this.getIndexPath(dbName, newName);
+
+    const exists = await this.fs.file(oldPath).exists();
+    if (!exists) {
+      throw new Error(`Collection ${oldName} not found`);
+    }
+
+    // Read, write to new, delete old
+    const docs = await this.readJsonFile<any[]>(oldPath, []);
+    await this.writeJsonFile(newPath, docs);
+    await this.fs.file(oldPath).delete();
+
+    // Handle indexes
+    const indexes = await this.readJsonFile<any[]>(oldIndexPath, []);
+    await this.writeJsonFile(newIndexPath, indexes);
+    try {
+      await this.fs.file(oldIndexPath).delete();
+    } catch {}
+  }
+
+  // ============================================================================
+  // Document Operations
+  // ============================================================================
+
+  async insertOne(dbName: string, collName: string, doc: Document): Promise<IStoredDocument> {
+    await this.createCollection(dbName, collName);
+    const collPath = this.getCollectionPath(dbName, collName);
+    const docs = await this.readJsonFile<any[]>(collPath, []);
+
+    const storedDoc: IStoredDocument = {
+      ...doc,
+      _id: doc._id ? (doc._id instanceof plugins.bson.ObjectId ? doc._id : new plugins.bson.ObjectId(doc._id)) : new plugins.bson.ObjectId(),
+    };
+
+    // Check for duplicate
+    const idStr = storedDoc._id.toHexString();
+    if (docs.some(d => d._id === idStr || (d._id && d._id.toString() === idStr))) {
+      throw new Error(`Duplicate key error: _id ${idStr}`);
+    }
+
+    docs.push(storedDoc);
+    await this.writeJsonFile(collPath, docs);
+    return storedDoc;
+  }
+
+  async insertMany(dbName: string, collName: string, docsToInsert: Document[]): Promise<IStoredDocument[]> {
+    await this.createCollection(dbName, collName);
+    const collPath = this.getCollectionPath(dbName, collName);
+    const docs = await this.readJsonFile<any[]>(collPath, []);
+
+    const results: IStoredDocument[] = [];
+    const existingIds = new Set(docs.map(d => d._id?.toString?.() || d._id));
+
+    for (const doc of docsToInsert) {
+      const storedDoc: IStoredDocument = {
+        ...doc,
+        _id: doc._id ? (doc._id instanceof plugins.bson.ObjectId ? doc._id : new plugins.bson.ObjectId(doc._id)) : new plugins.bson.ObjectId(),
+      };
+
+      const idStr = storedDoc._id.toHexString();
+      if (existingIds.has(idStr)) {
+        throw new Error(`Duplicate key error: _id ${idStr}`);
+      }
+
+      existingIds.add(idStr);
+      docs.push(storedDoc);
+      results.push(storedDoc);
+    }
+
+    await this.writeJsonFile(collPath, docs);
+    return results;
+  }
+
+  async findAll(dbName: string, collName: string): Promise<IStoredDocument[]> {
+    await this.createCollection(dbName, collName);
+    const collPath = this.getCollectionPath(dbName, collName);
+    const docs = await this.readJsonFile<any[]>(collPath, []);
+    return docs.map(doc => this.restoreObjectIds(doc));
+  }
+
+  async findById(dbName: string, collName: string, id: plugins.bson.ObjectId): Promise<IStoredDocument | null> {
+    const docs = await this.findAll(dbName, collName);
+    const idStr = id.toHexString();
+    return docs.find(d => d._id.toHexString() === idStr) || null;
+  }
+
+  async updateById(dbName: string, collName: string, id: plugins.bson.ObjectId, doc: IStoredDocument): Promise<boolean> {
+    const collPath = this.getCollectionPath(dbName, collName);
+    const docs = await this.readJsonFile<any[]>(collPath, []);
+    const idStr = id.toHexString();
+
+    const idx = docs.findIndex(d => {
+      const docId = d._id?.toHexString?.() || d._id?.toString?.() || d._id;
+      return docId === idStr;
+    });
+
+    if (idx === -1) return false;
+
+    docs[idx] = doc;
+    await this.writeJsonFile(collPath, docs);
+    return true;
+  }
+
+  async deleteById(dbName: string, collName: string, id: plugins.bson.ObjectId): Promise<boolean> {
+    const collPath = this.getCollectionPath(dbName, collName);
+    const docs = await this.readJsonFile<any[]>(collPath, []);
+    const idStr = id.toHexString();
+
+    const idx = docs.findIndex(d => {
+      const docId = d._id?.toHexString?.() || d._id?.toString?.() || d._id;
+      return docId === idStr;
+    });
+
+    if (idx === -1) return false;
+
+    docs.splice(idx, 1);
+    await this.writeJsonFile(collPath, docs);
+    return true;
+  }
+
+  async deleteByIds(dbName: string, collName: string, ids: plugins.bson.ObjectId[]): Promise<number> {
+    const collPath = this.getCollectionPath(dbName, collName);
+    const docs = await this.readJsonFile<any[]>(collPath, []);
+    const idStrs = new Set(ids.map(id => id.toHexString()));
+
+    const originalLength = docs.length;
+    const filtered = docs.filter(d => {
+      const docId = d._id?.toHexString?.() || d._id?.toString?.() || d._id;
+      return !idStrs.has(docId);
+    });
+
+    await this.writeJsonFile(collPath, filtered);
+    return originalLength - filtered.length;
+  }
+
+  async count(dbName: string, collName: string): Promise<number> {
+    const collPath = this.getCollectionPath(dbName, collName);
+    const docs = await this.readJsonFile<any[]>(collPath, []);
+    return docs.length;
+  }
+
+  // ============================================================================
+  // Index Operations
+  // ============================================================================
+
+  async saveIndex(
+    dbName: string,
+    collName: string,
+    indexName: string,
+    indexSpec: { key: Record<string, any>; unique?: boolean; sparse?: boolean; expireAfterSeconds?: number }
+  ): Promise<void> {
+    await this.createCollection(dbName, collName);
+    const indexPath = this.getIndexPath(dbName, collName);
+    const indexes = await this.readJsonFile<any[]>(indexPath, [
+      { name: '_id_', key: { _id: 1 }, unique: true }
+    ]);
+
+    const existingIdx = indexes.findIndex(i => i.name === indexName);
+    if (existingIdx >= 0) {
+      indexes[existingIdx] = { name: indexName, ...indexSpec };
+    } else {
+      indexes.push({ name: indexName, ...indexSpec });
+    }
+
+    await this.writeJsonFile(indexPath, indexes);
+  }
+
+  async getIndexes(dbName: string, collName: string): Promise<Array<{
+    name: string;
+    key: Record<string, any>;
+    unique?: boolean;
+    sparse?: boolean;
+    expireAfterSeconds?: number;
+  }>> {
+    const indexPath = this.getIndexPath(dbName, collName);
+    return this.readJsonFile(indexPath, [{ name: '_id_', key: { _id: 1 }, unique: true }]);
+  }
+
+  async dropIndex(dbName: string, collName: string, indexName: string): Promise<boolean> {
+    if (indexName === '_id_') {
+      throw new Error('Cannot drop _id index');
+    }
+
+    const indexPath = this.getIndexPath(dbName, collName);
+    const indexes = await this.readJsonFile<any[]>(indexPath, []);
+
+    const idx = indexes.findIndex(i => i.name === indexName);
+    if (idx >= 0) {
+      indexes.splice(idx, 1);
+      await this.writeJsonFile(indexPath, indexes);
+      return true;
+    }
+    return false;
+  }
+
+  // ============================================================================
+  // OpLog Operations
+  // ============================================================================
+
+  async appendOpLog(entry: IOpLogEntry): Promise<void> {
+    const opLogPath = this.getOpLogPath();
+    const opLog = await this.readJsonFile<IOpLogEntry[]>(opLogPath, []);
+    opLog.push(entry);
+
+    // Trim oplog if it gets too large
+    if (opLog.length > 10000) {
+      opLog.splice(0, opLog.length - 10000);
+    }
+
+    await this.writeJsonFile(opLogPath, opLog);
+  }
+
+  async getOpLogAfter(ts: plugins.bson.Timestamp, limit: number = 1000): Promise<IOpLogEntry[]> {
+    const opLogPath = this.getOpLogPath();
+    const opLog = await this.readJsonFile<any[]>(opLogPath, []);
+    const tsValue = ts.toNumber();
+
+    const entries = opLog.filter(e => {
+      const entryTs = e.ts.toNumber ? e.ts.toNumber() : (e.ts.t * 4294967296 + e.ts.i);
+      return entryTs > tsValue;
+    });
+
+    return entries.slice(0, limit);
+  }
+
+  async getLatestOpLogTimestamp(): Promise<plugins.bson.Timestamp | null> {
+    const opLogPath = this.getOpLogPath();
+    const opLog = await this.readJsonFile<any[]>(opLogPath, []);
+    if (opLog.length === 0) return null;
+
+    const last = opLog[opLog.length - 1];
+    if (last.ts instanceof plugins.bson.Timestamp) {
+      return last.ts;
+    }
+    return new plugins.bson.Timestamp({ t: last.ts.t, i: last.ts.i });
+  }
+
+  generateTimestamp(): plugins.bson.Timestamp {
+    this.opLogCounter++;
+    return new plugins.bson.Timestamp({ t: Math.floor(Date.now() / 1000), i: this.opLogCounter });
+  }
+
+  // ============================================================================
+  // Transaction Support
+  // ============================================================================
+
+  async createSnapshot(dbName: string, collName: string): Promise<IStoredDocument[]> {
+    const docs = await this.findAll(dbName, collName);
+    return docs.map(doc => JSON.parse(JSON.stringify(doc)));
+  }
+
+  async hasConflicts(
+    dbName: string,
+    collName: string,
+    ids: plugins.bson.ObjectId[],
+    snapshotTime: plugins.bson.Timestamp
+  ): Promise<boolean> {
+    const opLogPath = this.getOpLogPath();
+    const opLog = await this.readJsonFile<any[]>(opLogPath, []);
+    const ns = `${dbName}.${collName}`;
+    const snapshotTs = snapshotTime.toNumber();
+    const modifiedIds = new Set<string>();
+
+    for (const entry of opLog) {
+      const entryTs = entry.ts.toNumber ? entry.ts.toNumber() : (entry.ts.t * 4294967296 + entry.ts.i);
+      if (entryTs > snapshotTs && entry.ns === ns) {
+        if (entry.o._id) {
+          modifiedIds.add(entry.o._id.toString());
+        }
+        if (entry.o2?._id) {
+          modifiedIds.add(entry.o2._id.toString());
+        }
+      }
+    }
+
+    for (const id of ids) {
+      if (modifiedIds.has(id.toString())) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+}

ts/congodb/storage/IStorageAdapter.ts

@@ -0,0 +1,202 @@
+import type * as plugins from '../congodb.plugins.js';
+import type { IStoredDocument, IOpLogEntry, Document } from '../types/interfaces.js';
+
+/**
+ * Storage adapter interface for CongoDB
+ * Implementations can provide different storage backends (memory, file, etc.)
+ */
+export interface IStorageAdapter {
+  /**
+   * Initialize the storage adapter
+   */
+  initialize(): Promise<void>;
+
+  /**
+   * Close the storage adapter and release resources
+   */
+  close(): Promise<void>;
+
+  // ============================================================================
+  // Database Operations
+  // ============================================================================
+
+  /**
+   * List all database names
+   */
+  listDatabases(): Promise<string[]>;
+
+  /**
+   * Create a database (typically lazy - just marks it as existing)
+   */
+  createDatabase(dbName: string): Promise<void>;
+
+  /**
+   * Drop a database and all its collections
+   */
+  dropDatabase(dbName: string): Promise<boolean>;
+
+  /**
+   * Check if a database exists
+   */
+  databaseExists(dbName: string): Promise<boolean>;
+
+  // ============================================================================
+  // Collection Operations
+  // ============================================================================
+
+  /**
+   * List all collection names in a database
+   */
+  listCollections(dbName: string): Promise<string[]>;
+
+  /**
+   * Create a collection
+   */
+  createCollection(dbName: string, collName: string): Promise<void>;
+
+  /**
+   * Drop a collection
+   */
+  dropCollection(dbName: string, collName: string): Promise<boolean>;
+
+  /**
+   * Check if a collection exists
+   */
+  collectionExists(dbName: string, collName: string): Promise<boolean>;
+
+  /**
+   * Rename a collection
+   */
+  renameCollection(dbName: string, oldName: string, newName: string): Promise<void>;
+
+  // ============================================================================
+  // Document Operations
+  // ============================================================================
+
+  /**
+   * Insert a single document
+   * @returns The inserted document with _id
+   */
+  insertOne(dbName: string, collName: string, doc: Document): Promise<IStoredDocument>;
+
+  /**
+   * Insert multiple documents
+   * @returns Array of inserted documents with _ids
+   */
+  insertMany(dbName: string, collName: string, docs: Document[]): Promise<IStoredDocument[]>;
+
+  /**
+   * Find all documents in a collection
+   */
+  findAll(dbName: string, collName: string): Promise<IStoredDocument[]>;
+
+  /**
+   * Find a document by _id
+   */
+  findById(dbName: string, collName: string, id: plugins.bson.ObjectId): Promise<IStoredDocument | null>;
+
+  /**
+   * Update a document by _id
+   * @returns true if document was updated
+   */
+  updateById(dbName: string, collName: string, id: plugins.bson.ObjectId, doc: IStoredDocument): Promise<boolean>;
+
+  /**
+   * Delete a document by _id
+   * @returns true if document was deleted
+   */
+  deleteById(dbName: string, collName: string, id: plugins.bson.ObjectId): Promise<boolean>;
+
+  /**
+   * Delete multiple documents by _id
+   * @returns Number of deleted documents
+   */
+  deleteByIds(dbName: string, collName: string, ids: plugins.bson.ObjectId[]): Promise<number>;
+
+  /**
+   * Get the count of documents in a collection
+   */
+  count(dbName: string, collName: string): Promise<number>;
+
+  // ============================================================================
+  // Index Operations
+  // ============================================================================
+
+  /**
+   * Store index metadata
+   */
+  saveIndex(
+    dbName: string,
+    collName: string,
+    indexName: string,
+    indexSpec: { key: Record<string, any>; unique?: boolean; sparse?: boolean; expireAfterSeconds?: number }
+  ): Promise<void>;
+
+  /**
+   * Get all index metadata for a collection
+   */
+  getIndexes(dbName: string, collName: string): Promise<Array<{
+    name: string;
+    key: Record<string, any>;
+    unique?: boolean;
+    sparse?: boolean;
+    expireAfterSeconds?: number;
+  }>>;
+
+  /**
+   * Drop an index
+   */
+  dropIndex(dbName: string, collName: string, indexName: string): Promise<boolean>;
+
+  // ============================================================================
+  // OpLog Operations (for change streams)
+  // ============================================================================
+
+  /**
+   * Append an operation to the oplog
+   */
+  appendOpLog(entry: IOpLogEntry): Promise<void>;
+
+  /**
+   * Get oplog entries after a timestamp
+   */
+  getOpLogAfter(ts: plugins.bson.Timestamp, limit?: number): Promise<IOpLogEntry[]>;
+
+  /**
+   * Get the latest oplog timestamp
+   */
+  getLatestOpLogTimestamp(): Promise<plugins.bson.Timestamp | null>;
+
+  // ============================================================================
+  // Transaction Support
+  // ============================================================================
+
+  /**
+   * Create a snapshot of current data for transaction isolation
+   */
+  createSnapshot(dbName: string, collName: string): Promise<IStoredDocument[]>;
+
+  /**
+   * Check if any documents have been modified since the snapshot
+   */
+  hasConflicts(
+    dbName: string,
+    collName: string,
+    ids: plugins.bson.ObjectId[],
+    snapshotTime: plugins.bson.Timestamp
+  ): Promise<boolean>;
+
+  // ============================================================================
+  // Persistence (optional, for MemoryStorageAdapter with file backup)
+  // ============================================================================
+
+  /**
+   * Persist current state to disk (if supported)
+   */
+  persist?(): Promise<void>;
+
+  /**
+   * Load state from disk (if supported)
+   */
+  restore?(): Promise<void>;
+}

ts/congodb/storage/MemoryStorageAdapter.ts

@@ -0,0 +1,443 @@
+import * as plugins from '../congodb.plugins.js';
+import type { IStorageAdapter } from './IStorageAdapter.js';
+import type { IStoredDocument, IOpLogEntry, Document } from '../types/interfaces.js';
+
+/**
+ * In-memory storage adapter for CongoDB
+ * Optionally supports persistence to a file
+ */
+export class MemoryStorageAdapter implements IStorageAdapter {
+  // Database -> Collection -> Documents
+  private databases: Map<string, Map<string, Map<string, IStoredDocument>>> = new Map();
+
+  // Database -> Collection -> Indexes
+  private indexes: Map<string, Map<string, Array<{
+    name: string;
+    key: Record<string, any>;
+    unique?: boolean;
+    sparse?: boolean;
+    expireAfterSeconds?: number;
+  }>>> = new Map();
+
+  // OpLog entries
+  private opLog: IOpLogEntry[] = [];
+  private opLogCounter = 0;
+
+  // Persistence settings
+  private persistPath?: string;
+  private persistInterval?: ReturnType<typeof setInterval>;
+  private fs = new plugins.smartfs.SmartFs(new plugins.smartfs.SmartFsProviderNode());
+
+  constructor(options?: { persistPath?: string; persistIntervalMs?: number }) {
+    this.persistPath = options?.persistPath;
+    if (this.persistPath && options?.persistIntervalMs) {
+      this.persistInterval = setInterval(() => {
+        this.persist().catch(console.error);
+      }, options.persistIntervalMs);
+    }
+  }
+
+  async initialize(): Promise<void> {
+    if (this.persistPath) {
+      await this.restore();
+    }
+  }
+
+  async close(): Promise<void> {
+    if (this.persistInterval) {
+      clearInterval(this.persistInterval);
+    }
+    if (this.persistPath) {
+      await this.persist();
+    }
+  }
+
+  // ============================================================================
+  // Database Operations
+  // ============================================================================
+
+  async listDatabases(): Promise<string[]> {
+    return Array.from(this.databases.keys());
+  }
+
+  async createDatabase(dbName: string): Promise<void> {
+    if (!this.databases.has(dbName)) {
+      this.databases.set(dbName, new Map());
+      this.indexes.set(dbName, new Map());
+    }
+  }
+
+  async dropDatabase(dbName: string): Promise<boolean> {
+    const existed = this.databases.has(dbName);
+    this.databases.delete(dbName);
+    this.indexes.delete(dbName);
+    return existed;
+  }
+
+  async databaseExists(dbName: string): Promise<boolean> {
+    return this.databases.has(dbName);
+  }
+
+  // ============================================================================
+  // Collection Operations
+  // ============================================================================
+
+  async listCollections(dbName: string): Promise<string[]> {
+    const db = this.databases.get(dbName);
+    return db ? Array.from(db.keys()) : [];
+  }
+
+  async createCollection(dbName: string, collName: string): Promise<void> {
+    await this.createDatabase(dbName);
+    const db = this.databases.get(dbName)!;
+    if (!db.has(collName)) {
+      db.set(collName, new Map());
+      // Initialize default _id index
+      const dbIndexes = this.indexes.get(dbName)!;
+      dbIndexes.set(collName, [{ name: '_id_', key: { _id: 1 }, unique: true }]);
+    }
+  }
+
+  async dropCollection(dbName: string, collName: string): Promise<boolean> {
+    const db = this.databases.get(dbName);
+    if (!db) return false;
+    const existed = db.has(collName);
+    db.delete(collName);
+    const dbIndexes = this.indexes.get(dbName);
+    if (dbIndexes) {
+      dbIndexes.delete(collName);
+    }
+    return existed;
+  }
+
+  async collectionExists(dbName: string, collName: string): Promise<boolean> {
+    const db = this.databases.get(dbName);
+    return db ? db.has(collName) : false;
+  }
+
+  async renameCollection(dbName: string, oldName: string, newName: string): Promise<void> {
+    const db = this.databases.get(dbName);
+    if (!db || !db.has(oldName)) {
+      throw new Error(`Collection ${oldName} not found`);
+    }
+    const collection = db.get(oldName)!;
+    db.set(newName, collection);
+    db.delete(oldName);
+
+    // Also rename indexes
+    const dbIndexes = this.indexes.get(dbName);
+    if (dbIndexes && dbIndexes.has(oldName)) {
+      const collIndexes = dbIndexes.get(oldName)!;
+      dbIndexes.set(newName, collIndexes);
+      dbIndexes.delete(oldName);
+    }
+  }
+
+  // ============================================================================
+  // Document Operations
+  // ============================================================================
+
+  private getCollection(dbName: string, collName: string): Map<string, IStoredDocument> {
+    const db = this.databases.get(dbName);
+    if (!db) {
+      throw new Error(`Database ${dbName} not found`);
+    }
+    const collection = db.get(collName);
+    if (!collection) {
+      throw new Error(`Collection ${collName} not found`);
+    }
+    return collection;
+  }
+
+  private ensureCollection(dbName: string, collName: string): Map<string, IStoredDocument> {
+    if (!this.databases.has(dbName)) {
+      this.databases.set(dbName, new Map());
+      this.indexes.set(dbName, new Map());
+    }
+    const db = this.databases.get(dbName)!;
+    if (!db.has(collName)) {
+      db.set(collName, new Map());
+      const dbIndexes = this.indexes.get(dbName)!;
+      dbIndexes.set(collName, [{ name: '_id_', key: { _id: 1 }, unique: true }]);
+    }
+    return db.get(collName)!;
+  }
+
+  async insertOne(dbName: string, collName: string, doc: Document): Promise<IStoredDocument> {
+    const collection = this.ensureCollection(dbName, collName);
+    const storedDoc: IStoredDocument = {
+      ...doc,
+      _id: doc._id instanceof plugins.bson.ObjectId ? doc._id : new plugins.bson.ObjectId(doc._id),
+    };
+
+    if (!storedDoc._id) {
+      storedDoc._id = new plugins.bson.ObjectId();
+    }
+
+    const idStr = storedDoc._id.toHexString();
+    if (collection.has(idStr)) {
+      throw new Error(`Duplicate key error: _id ${idStr}`);
+    }
+
+    collection.set(idStr, storedDoc);
+    return storedDoc;
+  }
+
+  async insertMany(dbName: string, collName: string, docs: Document[]): Promise<IStoredDocument[]> {
+    const results: IStoredDocument[] = [];
+    for (const doc of docs) {
+      results.push(await this.insertOne(dbName, collName, doc));
+    }
+    return results;
+  }
+
+  async findAll(dbName: string, collName: string): Promise<IStoredDocument[]> {
+    const collection = this.ensureCollection(dbName, collName);
+    return Array.from(collection.values());
+  }
+
+  async findById(dbName: string, collName: string, id: plugins.bson.ObjectId): Promise<IStoredDocument | null> {
+    const collection = this.ensureCollection(dbName, collName);
+    return collection.get(id.toHexString()) || null;
+  }
+
+  async updateById(dbName: string, collName: string, id: plugins.bson.ObjectId, doc: IStoredDocument): Promise<boolean> {
+    const collection = this.ensureCollection(dbName, collName);
+    const idStr = id.toHexString();
+    if (!collection.has(idStr)) {
+      return false;
+    }
+    collection.set(idStr, doc);
+    return true;
+  }
+
+  async deleteById(dbName: string, collName: string, id: plugins.bson.ObjectId): Promise<boolean> {
+    const collection = this.ensureCollection(dbName, collName);
+    return collection.delete(id.toHexString());
+  }
+
+  async deleteByIds(dbName: string, collName: string, ids: plugins.bson.ObjectId[]): Promise<number> {
+    let count = 0;
+    for (const id of ids) {
+      if (await this.deleteById(dbName, collName, id)) {
+        count++;
+      }
+    }
+    return count;
+  }
+
+  async count(dbName: string, collName: string): Promise<number> {
+    const collection = this.ensureCollection(dbName, collName);
+    return collection.size;
+  }
+
+  // ============================================================================
+  // Index Operations
+  // ============================================================================
+
+  async saveIndex(
+    dbName: string,
+    collName: string,
+    indexName: string,
+    indexSpec: { key: Record<string, any>; unique?: boolean; sparse?: boolean; expireAfterSeconds?: number }
+  ): Promise<void> {
+    await this.createCollection(dbName, collName);
+    const dbIndexes = this.indexes.get(dbName)!;
+    let collIndexes = dbIndexes.get(collName);
+    if (!collIndexes) {
+      collIndexes = [{ name: '_id_', key: { _id: 1 }, unique: true }];
+      dbIndexes.set(collName, collIndexes);
+    }
+
+    // Check if index already exists
+    const existingIndex = collIndexes.findIndex(i => i.name === indexName);
+    if (existingIndex >= 0) {
+      collIndexes[existingIndex] = { name: indexName, ...indexSpec };
+    } else {
+      collIndexes.push({ name: indexName, ...indexSpec });
+    }
+  }
+
+  async getIndexes(dbName: string, collName: string): Promise<Array<{
+    name: string;
+    key: Record<string, any>;
+    unique?: boolean;
+    sparse?: boolean;
+    expireAfterSeconds?: number;
+  }>> {
+    const dbIndexes = this.indexes.get(dbName);
+    if (!dbIndexes) return [{ name: '_id_', key: { _id: 1 }, unique: true }];
+    const collIndexes = dbIndexes.get(collName);
+    return collIndexes || [{ name: '_id_', key: { _id: 1 }, unique: true }];
+  }
+
+  async dropIndex(dbName: string, collName: string, indexName: string): Promise<boolean> {
+    if (indexName === '_id_') {
+      throw new Error('Cannot drop _id index');
+    }
+    const dbIndexes = this.indexes.get(dbName);
+    if (!dbIndexes) return false;
+    const collIndexes = dbIndexes.get(collName);
+    if (!collIndexes) return false;
+
+    const idx = collIndexes.findIndex(i => i.name === indexName);
+    if (idx >= 0) {
+      collIndexes.splice(idx, 1);
+      return true;
+    }
+    return false;
+  }
+
+  // ============================================================================
+  // OpLog Operations
+  // ============================================================================
+
+  async appendOpLog(entry: IOpLogEntry): Promise<void> {
+    this.opLog.push(entry);
+    // Trim oplog if it gets too large (keep last 10000 entries)
+    if (this.opLog.length > 10000) {
+      this.opLog = this.opLog.slice(-10000);
+    }
+  }
+
+  async getOpLogAfter(ts: plugins.bson.Timestamp, limit: number = 1000): Promise<IOpLogEntry[]> {
+    const tsValue = ts.toNumber();
+    const entries = this.opLog.filter(e => e.ts.toNumber() > tsValue);
+    return entries.slice(0, limit);
+  }
+
+  async getLatestOpLogTimestamp(): Promise<plugins.bson.Timestamp | null> {
+    if (this.opLog.length === 0) return null;
+    return this.opLog[this.opLog.length - 1].ts;
+  }
+
+  /**
+   * Generate a new timestamp for oplog entries
+   */
+  generateTimestamp(): plugins.bson.Timestamp {
+    this.opLogCounter++;
+    return new plugins.bson.Timestamp({ t: Math.floor(Date.now() / 1000), i: this.opLogCounter });
+  }
+
+  // ============================================================================
+  // Transaction Support
+  // ============================================================================
+
+  async createSnapshot(dbName: string, collName: string): Promise<IStoredDocument[]> {
+    const docs = await this.findAll(dbName, collName);
+    // Deep clone the documents for snapshot isolation
+    return docs.map(doc => JSON.parse(JSON.stringify(doc)));
+  }
+
+  async hasConflicts(
+    dbName: string,
+    collName: string,
+    ids: plugins.bson.ObjectId[],
+    snapshotTime: plugins.bson.Timestamp
+  ): Promise<boolean> {
+    // Check if any of the given document IDs have been modified after snapshotTime
+    const ns = `${dbName}.${collName}`;
+    const modifiedIds = new Set<string>();
+
+    for (const entry of this.opLog) {
+      if (entry.ts.greaterThan(snapshotTime) && entry.ns === ns) {
+        if (entry.o._id) {
+          modifiedIds.add(entry.o._id.toString());
+        }
+        if (entry.o2?._id) {
+          modifiedIds.add(entry.o2._id.toString());
+        }
+      }
+    }
+
+    for (const id of ids) {
+      if (modifiedIds.has(id.toString())) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  // ============================================================================
+  // Persistence
+  // ============================================================================
+
+  async persist(): Promise<void> {
+    if (!this.persistPath) return;
+
+    const data = {
+      databases: {} as Record<string, Record<string, IStoredDocument[]>>,
+      indexes: {} as Record<string, Record<string, any[]>>,
+      opLogCounter: this.opLogCounter,
+    };
+
+    for (const [dbName, collections] of this.databases) {
+      data.databases[dbName] = {};
+      for (const [collName, docs] of collections) {
+        data.databases[dbName][collName] = Array.from(docs.values());
+      }
+    }
+
+    for (const [dbName, collIndexes] of this.indexes) {
+      data.indexes[dbName] = {};
+      for (const [collName, indexes] of collIndexes) {
+        data.indexes[dbName][collName] = indexes;
+      }
+    }
+
+    // Ensure parent directory exists
+    const dir = this.persistPath.substring(0, this.persistPath.lastIndexOf('/'));
+    if (dir) {
+      await this.fs.directory(dir).recursive().create();
+    }
+    await this.fs.file(this.persistPath).encoding('utf8').write(JSON.stringify(data, null, 2));
+  }
+
+  async restore(): Promise<void> {
+    if (!this.persistPath) return;
+
+    try {
+      const exists = await this.fs.file(this.persistPath).exists();
+      if (!exists) return;
+
+      const content = await this.fs.file(this.persistPath).encoding('utf8').read();
+      const data = JSON.parse(content as string);
+
+      this.databases.clear();
+      this.indexes.clear();
+
+      for (const [dbName, collections] of Object.entries(data.databases || {})) {
+        const dbMap = new Map<string, Map<string, IStoredDocument>>();
+        this.databases.set(dbName, dbMap);
+
+        for (const [collName, docs] of Object.entries(collections as Record<string, any[]>)) {
+          const collMap = new Map<string, IStoredDocument>();
+          for (const doc of docs) {
+            // Restore ObjectId
+            if (doc._id && typeof doc._id === 'string') {
+              doc._id = new plugins.bson.ObjectId(doc._id);
+            } else if (doc._id && typeof doc._id === 'object' && doc._id.$oid) {
+              doc._id = new plugins.bson.ObjectId(doc._id.$oid);
+            }
+            collMap.set(doc._id.toHexString(), doc);
+          }
+          dbMap.set(collName, collMap);
+        }
+      }
+
+      for (const [dbName, collIndexes] of Object.entries(data.indexes || {})) {
+        const indexMap = new Map<string, any[]>();
+        this.indexes.set(dbName, indexMap);
+        for (const [collName, indexes] of Object.entries(collIndexes as Record<string, any[]>)) {
+          indexMap.set(collName, indexes);
+        }
+      }
+
+      this.opLogCounter = data.opLogCounter || 0;
+    } catch (error) {
+      // If restore fails, start fresh
+      console.warn('Failed to restore from persistence:', error);
+    }
+  }
+}

ts/congodb/storage/OpLog.ts

@@ -0,0 +1,282 @@
+import * as plugins from '../congodb.plugins.js';
+import type { IStorageAdapter } from './IStorageAdapter.js';
+import type { IOpLogEntry, Document, IResumeToken, ChangeStreamOperationType } from '../types/interfaces.js';
+
+/**
+ * Operation Log for tracking all mutations
+ * Used primarily for change stream support
+ */
+export class OpLog {
+  private storage: IStorageAdapter;
+  private counter = 0;
+  private listeners: Array<(entry: IOpLogEntry) => void> = [];
+
+  constructor(storage: IStorageAdapter) {
+    this.storage = storage;
+  }
+
+  /**
+   * Generate a new timestamp for oplog entries
+   */
+  generateTimestamp(): plugins.bson.Timestamp {
+    this.counter++;
+    return new plugins.bson.Timestamp({ t: Math.floor(Date.now() / 1000), i: this.counter });
+  }
+
+  /**
+   * Generate a resume token from a timestamp
+   */
+  generateResumeToken(ts: plugins.bson.Timestamp): IResumeToken {
+    // Create a resume token similar to MongoDB's format
+    // It's a base64-encoded BSON document containing the timestamp
+    const tokenData = {
+      _data: Buffer.from(JSON.stringify({
+        ts: { t: ts.high, i: ts.low },
+        version: 1,
+      })).toString('base64'),
+    };
+    return tokenData;
+  }
+
+  /**
+   * Parse a resume token to get the timestamp
+   */
+  parseResumeToken(token: IResumeToken): plugins.bson.Timestamp {
+    try {
+      const data = JSON.parse(Buffer.from(token._data, 'base64').toString('utf-8'));
+      return new plugins.bson.Timestamp({ t: data.ts.t, i: data.ts.i });
+    } catch {
+      throw new Error('Invalid resume token');
+    }
+  }
+
+  /**
+   * Record an insert operation
+   */
+  async recordInsert(
+    dbName: string,
+    collName: string,
+    document: Document,
+    txnInfo?: { txnNumber?: number; lsid?: { id: plugins.bson.Binary } }
+  ): Promise<IOpLogEntry> {
+    const entry: IOpLogEntry = {
+      ts: this.generateTimestamp(),
+      op: 'i',
+      ns: `${dbName}.${collName}`,
+      o: document,
+      ...txnInfo,
+    };
+
+    await this.storage.appendOpLog(entry);
+    this.notifyListeners(entry);
+    return entry;
+  }
+
+  /**
+   * Record an update operation
+   */
+  async recordUpdate(
+    dbName: string,
+    collName: string,
+    filter: Document,
+    update: Document,
+    txnInfo?: { txnNumber?: number; lsid?: { id: plugins.bson.Binary } }
+  ): Promise<IOpLogEntry> {
+    const entry: IOpLogEntry = {
+      ts: this.generateTimestamp(),
+      op: 'u',
+      ns: `${dbName}.${collName}`,
+      o: update,
+      o2: filter,
+      ...txnInfo,
+    };
+
+    await this.storage.appendOpLog(entry);
+    this.notifyListeners(entry);
+    return entry;
+  }
+
+  /**
+   * Record a delete operation
+   */
+  async recordDelete(
+    dbName: string,
+    collName: string,
+    filter: Document,
+    txnInfo?: { txnNumber?: number; lsid?: { id: plugins.bson.Binary } }
+  ): Promise<IOpLogEntry> {
+    const entry: IOpLogEntry = {
+      ts: this.generateTimestamp(),
+      op: 'd',
+      ns: `${dbName}.${collName}`,
+      o: filter,
+      ...txnInfo,
+    };
+
+    await this.storage.appendOpLog(entry);
+    this.notifyListeners(entry);
+    return entry;
+  }
+
+  /**
+   * Record a command (drop, rename, etc.)
+   */
+  async recordCommand(
+    dbName: string,
+    command: Document
+  ): Promise<IOpLogEntry> {
+    const entry: IOpLogEntry = {
+      ts: this.generateTimestamp(),
+      op: 'c',
+      ns: `${dbName}.$cmd`,
+      o: command,
+    };
+
+    await this.storage.appendOpLog(entry);
+    this.notifyListeners(entry);
+    return entry;
+  }
+
+  /**
+   * Get oplog entries after a timestamp
+   */
+  async getEntriesAfter(ts: plugins.bson.Timestamp, limit?: number): Promise<IOpLogEntry[]> {
+    return this.storage.getOpLogAfter(ts, limit);
+  }
+
+  /**
+   * Get the latest timestamp
+   */
+  async getLatestTimestamp(): Promise<plugins.bson.Timestamp | null> {
+    return this.storage.getLatestOpLogTimestamp();
+  }
+
+  /**
+   * Subscribe to oplog changes (for change streams)
+   */
+  subscribe(listener: (entry: IOpLogEntry) => void): () => void {
+    this.listeners.push(listener);
+    return () => {
+      const idx = this.listeners.indexOf(listener);
+      if (idx >= 0) {
+        this.listeners.splice(idx, 1);
+      }
+    };
+  }
+
+  /**
+   * Notify all listeners of a new entry
+   */
+  private notifyListeners(entry: IOpLogEntry): void {
+    for (const listener of this.listeners) {
+      try {
+        listener(entry);
+      } catch (error) {
+        console.error('Error in oplog listener:', error);
+      }
+    }
+  }
+
+  /**
+   * Convert an oplog entry to a change stream document
+   */
+  opLogEntryToChangeEvent(
+    entry: IOpLogEntry,
+    fullDocument?: Document,
+    fullDocumentBeforeChange?: Document
+  ): {
+    _id: IResumeToken;
+    operationType: ChangeStreamOperationType;
+    fullDocument?: Document;
+    fullDocumentBeforeChange?: Document;
+    ns: { db: string; coll?: string };
+    documentKey?: { _id: plugins.bson.ObjectId };
+    updateDescription?: {
+      updatedFields?: Document;
+      removedFields?: string[];
+    };
+    clusterTime: plugins.bson.Timestamp;
+  } {
+    const [db, coll] = entry.ns.split('.');
+    const resumeToken = this.generateResumeToken(entry.ts);
+
+    const baseEvent = {
+      _id: resumeToken,
+      ns: { db, coll: coll === '$cmd' ? undefined : coll },
+      clusterTime: entry.ts,
+    };
+
+    switch (entry.op) {
+      case 'i':
+        return {
+          ...baseEvent,
+          operationType: 'insert' as ChangeStreamOperationType,
+          fullDocument: fullDocument || entry.o,
+          documentKey: entry.o._id ? { _id: entry.o._id } : undefined,
+        };
+
+      case 'u':
+        const updateEvent: any = {
+          ...baseEvent,
+          operationType: 'update' as ChangeStreamOperationType,
+          documentKey: entry.o2?._id ? { _id: entry.o2._id } : undefined,
+        };
+
+        if (fullDocument) {
+          updateEvent.fullDocument = fullDocument;
+        }
+        if (fullDocumentBeforeChange) {
+          updateEvent.fullDocumentBeforeChange = fullDocumentBeforeChange;
+        }
+
+        // Parse update description
+        if (entry.o.$set || entry.o.$unset) {
+          updateEvent.updateDescription = {
+            updatedFields: entry.o.$set || {},
+            removedFields: entry.o.$unset ? Object.keys(entry.o.$unset) : [],
+          };
+        }
+
+        return updateEvent;
+
+      case 'd':
+        return {
+          ...baseEvent,
+          operationType: 'delete' as ChangeStreamOperationType,
+          documentKey: entry.o._id ? { _id: entry.o._id } : undefined,
+          fullDocumentBeforeChange,
+        };
+
+      case 'c':
+        if (entry.o.drop) {
+          return {
+            ...baseEvent,
+            operationType: 'drop' as ChangeStreamOperationType,
+            ns: { db, coll: entry.o.drop },
+          };
+        }
+        if (entry.o.dropDatabase) {
+          return {
+            ...baseEvent,
+            operationType: 'dropDatabase' as ChangeStreamOperationType,
+          };
+        }
+        if (entry.o.renameCollection) {
+          return {
+            ...baseEvent,
+            operationType: 'rename' as ChangeStreamOperationType,
+          };
+        }
+        return {
+          ...baseEvent,
+          operationType: 'invalidate' as ChangeStreamOperationType,
+        };
+
+      default:
+        return {
+          ...baseEvent,
+          operationType: 'invalidate' as ChangeStreamOperationType,
+        };
+    }
+  }
+}

ts/congodb/types/interfaces.ts

@@ -0,0 +1,433 @@
+import type * as plugins from '../congodb.plugins.js';
+
+// ============================================================================
+// Document Types
+// ============================================================================
+
+export type Document = Record<string, any>;
+
+export interface WithId<TSchema> {
+  _id: plugins.bson.ObjectId;
+}
+
+// ============================================================================
+// Client Options
+// ============================================================================
+
+export interface ICongoClientOptions {
+  /** Storage adapter type: 'memory' or 'file' */
+  storageType?: 'memory' | 'file';
+  /** Path for file-based storage */
+  storagePath?: string;
+  /** Enable persistence for memory adapter */
+  persist?: boolean;
+  /** Path for persistence file when using memory adapter */
+  persistPath?: string;
+}
+
+// ============================================================================
+// Connection String Parsing
+// ============================================================================
+
+export interface IParsedConnectionString {
+  protocol: 'congo';
+  storageType: 'memory' | 'file';
+  options: {
+    persist?: string;
+    path?: string;
+  };
+}
+
+// ============================================================================
+// CRUD Operation Options
+// ============================================================================
+
+export interface IInsertOneOptions {
+  /** Session for transaction support */
+  session?: IClientSession;
+  /** Custom write concern */
+  writeConcern?: IWriteConcern;
+}
+
+export interface IInsertManyOptions extends IInsertOneOptions {
+  /** If true, inserts are ordered and stop on first error */
+  ordered?: boolean;
+}
+
+export interface IFindOptions<TSchema = Document> {
+  /** Projection to apply */
+  projection?: Partial<Record<keyof TSchema | string, 0 | 1 | boolean>>;
+  /** Sort specification */
+  sort?: ISortSpecification;
+  /** Number of documents to skip */
+  skip?: number;
+  /** Maximum number of documents to return */
+  limit?: number;
+  /** Session for transaction support */
+  session?: IClientSession;
+  /** Hint for index usage */
+  hint?: string | Document;
+}
+
+export interface IUpdateOptions {
+  /** Create document if it doesn't exist */
+  upsert?: boolean;
+  /** Session for transaction support */
+  session?: IClientSession;
+  /** Array filters for positional updates */
+  arrayFilters?: Document[];
+  /** Custom write concern */
+  writeConcern?: IWriteConcern;
+  /** Hint for index usage */
+  hint?: string | Document;
+}
+
+export interface IReplaceOptions extends IUpdateOptions {}
+
+export interface IDeleteOptions {
+  /** Session for transaction support */
+  session?: IClientSession;
+  /** Custom write concern */
+  writeConcern?: IWriteConcern;
+  /** Hint for index usage */
+  hint?: string | Document;
+}
+
+export interface IFindOneAndUpdateOptions extends IUpdateOptions {
+  /** Return the document before or after the update */
+  returnDocument?: 'before' | 'after';
+  /** Projection to apply */
+  projection?: Document;
+  /** Sort specification to determine which document to modify */
+  sort?: ISortSpecification;
+}
+
+export interface IFindOneAndReplaceOptions extends IFindOneAndUpdateOptions {}
+
+export interface IFindOneAndDeleteOptions {
+  /** Projection to apply */
+  projection?: Document;
+  /** Sort specification to determine which document to delete */
+  sort?: ISortSpecification;
+  /** Session for transaction support */
+  session?: IClientSession;
+}
+
+// ============================================================================
+// CRUD Results
+// ============================================================================
+
+export interface IInsertOneResult {
+  acknowledged: boolean;
+  insertedId: plugins.bson.ObjectId;
+}
+
+export interface IInsertManyResult {
+  acknowledged: boolean;
+  insertedCount: number;
+  insertedIds: Record<number, plugins.bson.ObjectId>;
+}
+
+export interface IUpdateResult {
+  acknowledged: boolean;
+  matchedCount: number;
+  modifiedCount: number;
+  upsertedCount: number;
+  upsertedId: plugins.bson.ObjectId | null;
+}
+
+export interface IDeleteResult {
+  acknowledged: boolean;
+  deletedCount: number;
+}
+
+export interface IModifyResult<TSchema> {
+  value: TSchema | null;
+  ok: 1 | 0;
+  lastErrorObject?: {
+    n: number;
+    updatedExisting?: boolean;
+    upserted?: plugins.bson.ObjectId;
+  };
+}
+
+// ============================================================================
+// Sort and Index Types
+// ============================================================================
+
+export type ISortDirection = 1 | -1 | 'asc' | 'desc' | 'ascending' | 'descending';
+
+export type ISortSpecification = Record<string, ISortDirection> | [string, ISortDirection][];
+
+export interface IIndexSpecification {
+  key: Record<string, 1 | -1 | 'text' | '2dsphere'>;
+  name?: string;
+  unique?: boolean;
+  sparse?: boolean;
+  expireAfterSeconds?: number;
+  background?: boolean;
+  partialFilterExpression?: Document;
+}
+
+export interface IIndexInfo {
+  v: number;
+  key: Record<string, 1 | -1 | string>;
+  name: string;
+  unique?: boolean;
+  sparse?: boolean;
+  expireAfterSeconds?: number;
+}
+
+export interface ICreateIndexOptions {
+  unique?: boolean;
+  sparse?: boolean;
+  expireAfterSeconds?: number;
+  name?: string;
+  background?: boolean;
+  partialFilterExpression?: Document;
+}
+
+// ============================================================================
+// Write Concern
+// ============================================================================
+
+export interface IWriteConcern {
+  w?: number | 'majority';
+  j?: boolean;
+  wtimeout?: number;
+}
+
+// ============================================================================
+// Aggregation Types
+// ============================================================================
+
+export interface IAggregateOptions {
+  /** Allow disk use for large aggregations */
+  allowDiskUse?: boolean;
+  /** Maximum time in ms */
+  maxTimeMS?: number;
+  /** Session for transaction support */
+  session?: IClientSession;
+  /** Batch size for cursor */
+  batchSize?: number;
+  /** Collation settings */
+  collation?: ICollation;
+  /** Hint for index usage */
+  hint?: string | Document;
+  /** Comment for profiling */
+  comment?: string;
+}
+
+export interface ICollation {
+  locale: string;
+  caseLevel?: boolean;
+  caseFirst?: string;
+  strength?: number;
+  numericOrdering?: boolean;
+  alternate?: string;
+  maxVariable?: string;
+  backwards?: boolean;
+}
+
+// ============================================================================
+// Change Stream Types
+// ============================================================================
+
+export interface IChangeStreamOptions {
+  /** Resume after this token */
+  resumeAfter?: IResumeToken;
+  /** Start at this operation time */
+  startAtOperationTime?: plugins.bson.Timestamp;
+  /** Start after this token */
+  startAfter?: IResumeToken;
+  /** Full document lookup mode */
+  fullDocument?: 'default' | 'updateLookup' | 'whenAvailable' | 'required';
+  /** Full document before change */
+  fullDocumentBeforeChange?: 'off' | 'whenAvailable' | 'required';
+  /** Batch size */
+  batchSize?: number;
+  /** Maximum await time in ms */
+  maxAwaitTimeMS?: number;
+}
+
+export interface IResumeToken {
+  _data: string;
+}
+
+export type ChangeStreamOperationType =
+  | 'insert'
+  | 'update'
+  | 'replace'
+  | 'delete'
+  | 'drop'
+  | 'rename'
+  | 'dropDatabase'
+  | 'invalidate';
+
+export interface IChangeStreamDocument<TSchema = Document> {
+  _id: IResumeToken;
+  operationType: ChangeStreamOperationType;
+  fullDocument?: TSchema;
+  fullDocumentBeforeChange?: TSchema;
+  ns: {
+    db: string;
+    coll?: string;
+  };
+  documentKey?: { _id: plugins.bson.ObjectId };
+  updateDescription?: {
+    updatedFields?: Document;
+    removedFields?: string[];
+    truncatedArrays?: Array<{ field: string; newSize: number }>;
+  };
+  clusterTime?: plugins.bson.Timestamp;
+  txnNumber?: number;
+  lsid?: { id: plugins.bson.Binary; uid: plugins.bson.Binary };
+}
+
+// ============================================================================
+// Transaction Types
+// ============================================================================
+
+export interface IClientSession {
+  id: { id: plugins.bson.Binary };
+  inTransaction(): boolean;
+  startTransaction(options?: ITransactionOptions): void;
+  commitTransaction(): Promise<void>;
+  abortTransaction(): Promise<void>;
+  withTransaction<T>(fn: () => Promise<T>, options?: ITransactionOptions): Promise<T>;
+  endSession(): Promise<void>;
+}
+
+export interface ITransactionOptions {
+  readConcern?: IReadConcern;
+  writeConcern?: IWriteConcern;
+  readPreference?: string;
+  maxCommitTimeMS?: number;
+}
+
+export interface IReadConcern {
+  level: 'local' | 'available' | 'majority' | 'linearizable' | 'snapshot';
+}
+
+// ============================================================================
+// Bulk Operation Types
+// ============================================================================
+
+export interface IBulkWriteOptions {
+  ordered?: boolean;
+  session?: IClientSession;
+  writeConcern?: IWriteConcern;
+}
+
+export interface IBulkWriteOperation<TSchema = Document> {
+  insertOne?: { document: TSchema };
+  updateOne?: { filter: Document; update: Document; upsert?: boolean; arrayFilters?: Document[]; hint?: Document | string };
+  updateMany?: { filter: Document; update: Document; upsert?: boolean; arrayFilters?: Document[]; hint?: Document | string };
+  replaceOne?: { filter: Document; replacement: TSchema; upsert?: boolean; hint?: Document | string };
+  deleteOne?: { filter: Document; hint?: Document | string };
+  deleteMany?: { filter: Document; hint?: Document | string };
+}
+
+export interface IBulkWriteResult {
+  acknowledged: boolean;
+  insertedCount: number;
+  matchedCount: number;
+  modifiedCount: number;
+  deletedCount: number;
+  upsertedCount: number;
+  insertedIds: Record<number, plugins.bson.ObjectId>;
+  upsertedIds: Record<number, plugins.bson.ObjectId>;
+}
+
+// ============================================================================
+// Storage Types
+// ============================================================================
+
+export interface IStoredDocument extends Document {
+  _id: plugins.bson.ObjectId;
+}
+
+export interface IOpLogEntry {
+  ts: plugins.bson.Timestamp;
+  op: 'i' | 'u' | 'd' | 'c' | 'n';
+  ns: string;
+  o: Document;
+  o2?: Document;
+  txnNumber?: number;
+  lsid?: { id: plugins.bson.Binary };
+}
+
+// ============================================================================
+// Admin Types
+// ============================================================================
+
+export interface IDatabaseInfo {
+  name: string;
+  sizeOnDisk: number;
+  empty: boolean;
+}
+
+export interface ICollectionInfo {
+  name: string;
+  type: 'collection' | 'view';
+  options: Document;
+  info: {
+    readOnly: boolean;
+    uuid?: plugins.bson.Binary;
+  };
+  idIndex?: IIndexInfo;
+}
+
+export interface IServerStatus {
+  host: string;
+  version: string;
+  process: string;
+  pid: number;
+  uptime: number;
+  uptimeMillis: number;
+  uptimeEstimate: number;
+  localTime: Date;
+  mem: {
+    resident: number;
+    virtual: number;
+  };
+  connections: {
+    current: number;
+    available: number;
+    totalCreated: number;
+  };
+  ok: 1;
+}
+
+export interface ICollectionStats {
+  ns: string;
+  count: number;
+  size: number;
+  avgObjSize: number;
+  storageSize: number;
+  totalIndexSize: number;
+  indexSizes: Record<string, number>;
+  nindexes: number;
+  ok: 1;
+}
+
+// ============================================================================
+// Count Types
+// ============================================================================
+
+export interface ICountDocumentsOptions {
+  skip?: number;
+  limit?: number;
+  session?: IClientSession;
+  hint?: string | Document;
+  maxTimeMS?: number;
+}
+
+export interface IEstimatedDocumentCountOptions {
+  maxTimeMS?: number;
+}
+
+export interface IDistinctOptions {
+  session?: IClientSession;
+  maxTimeMS?: number;
+}

ts/index.ts

@@ -1,10 +1,14 @@
-import * as plugins from './smartmongo.plugins';
+import { commitinfo } from './00_commitinfo_data.js';
+import * as plugins from './smartmongo.plugins.js';
+
+// Export CongoDB module
+export * as congodb from './congodb/index.js';
 
 export class SmartMongo {
   // STATIC
-  public static async createAndStart() {
+  public static async createAndStart(replCountArg: number = 1) {
     const smartMongoInstance = new SmartMongo();
-    await smartMongoInstance.start();
+    await smartMongoInstance.start(replCountArg);
     return smartMongoInstance;
   }
 
@@ -13,23 +17,58 @@ export class SmartMongo {
   public readyPromise = this._readyDeferred.promise;
   public mongoReplicaSet: plugins.mongoPlugin.MongoMemoryReplSet;
 
-  constructor() {
+  constructor() {}
-  }
 
-  public async start(countArg: number = 4) {
+  public async start(countArg: number = 1) {
-    this.mongoReplicaSet = await plugins.mongoPlugin.MongoMemoryReplSet.create({ replSet: { count: countArg } });
+    this.mongoReplicaSet = await plugins.mongoPlugin.MongoMemoryReplSet.create({
+      replSet: { count: countArg },
+      instanceOpts: [
+        {
+          storageEngine: 'wiredTiger',
+        },
+      ],
+    });
     this._readyDeferred.resolve();
     console.log(`mongoReplicaSet with ${countArg} replicas started.`);
+    console.log(`@pushrocks/smartmongo version ${commitinfo.version}`);
   }
 
+  /**
+   * returns a mongo descriptor for modules like
+   * @pushrocks/smartfile.
+   */
   public async getMongoDescriptor(): Promise<plugins.smartdata.IMongoDescriptor> {
     await this.readyPromise;
     return {
+      mongoDbName: `smartmongo_testdatabase`,
       mongoDbUrl: this.mongoReplicaSet.getUri(),
-    }
+    };
   }
 
+  /**
+   * stops the smartmongo instance
+   * and cleans up after itself
+   */
   public async stop() {
-    await this.mongoReplicaSet.stop(true);
+    await this.mongoReplicaSet.stop();
+    await this.mongoReplicaSet.cleanup();
+  }
+
+  /**
+   * like stop() but allows you to actually store
+   * the database on disk
+   */
+  public async stopAndDumpToDir(
+    dirArg: string,
+    nameFunctionArg?: (doc: any) => string,
+    emptyDirArg = true,
+  ) {
+    const mongodumpInstance = new plugins.mongodump.MongoDump();
+    const mongodumpTarget = await mongodumpInstance.addMongoTargetByMongoDescriptor(
+      await this.getMongoDescriptor(),
+    );
+    await mongodumpTarget.dumpAllCollectionsToDir(dirArg, nameFunctionArg, emptyDirArg);
+    await mongodumpInstance.stop();
+    await this.stop();
   }
 }

ts/smartmongo.plugins.ts

@@ -1,13 +1,12 @@
 // @pushrocks scope
-import * as smartdata from '@pushrocks/smartdata';
+import * as mongodump from '@push.rocks/mongodump';
-import * as smartpromise from '@pushrocks/smartpromise';
+import * as smartdata from '@push.rocks/smartdata';
+import * as smartpath from '@push.rocks/smartpath';
+import * as smartpromise from '@push.rocks/smartpromise';
 
-export {
+export { mongodump, smartdata, smartpath, smartpromise };
-  smartdata,
-  smartpromise,
-}
 
 // thirdparty
-import * as mongoPlugin from 'mongodb-memory-server';
+import mongoPlugin from 'mongodb-memory-server';
 
 export { mongoPlugin };

tsconfig.json

@@ -0,0 +1,12 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "esModuleInterop": true,
+    "verbatimModuleSyntax": true
+  },
+  "exclude": [
+    "dist_*/**/*.d.ts"
+  ]
+}

tslint.json

@@ -1,17 +0,0 @@
-{
-  "extends": ["tslint:latest", "tslint-config-prettier"],
-  "rules": {
-    "semicolon": [true, "always"],
-    "no-console": false,
-    "ordered-imports": false,
-    "object-literal-sort-keys": false,
-    "member-ordering": {
-      "options":{
-        "order": [
-          "static-method"
-        ]
-      }
-    }
-  },
-  "defaultSeverity": "warning"
-}