feat(congodb): implement CongoDB MongoDB wire-protocol compatible in-memory server and APIs

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;
+  }
+}