import { expect, tap } from '@git.zone/tstest/tapbundle';
import * as smartdb from '../ts/index.js';
import { MongoClient, Db } from 'mongodb';
import * as fs from 'fs';
import * as path from 'path';
import * as os from 'os';

// ---------------------------------------------------------------------------
// Test: Deletes persist across restart (tombstone + hint staleness detection)
// Covers: append_tombstone to data.rdb, hint file data_file_size tracking,
//         stale hint detection on restart
// ---------------------------------------------------------------------------

let tmpDir: string;
let localDb: smartdb.LocalSmartDb;
let client: MongoClient;
let db: Db;

function makeTmpDir(): string {
  return fs.mkdtempSync(path.join(os.tmpdir(), 'smartdb-delete-test-'));
}

function cleanTmpDir(dir: string): void {
  if (fs.existsSync(dir)) {
    fs.rmSync(dir, { recursive: true, force: true });
  }
}

// ============================================================================
// Setup
// ============================================================================

tap.test('setup: start local db and insert documents', async () => {
  tmpDir = makeTmpDir();
  localDb = new smartdb.LocalSmartDb({ folderPath: tmpDir });
  const info = await localDb.start();
  client = new MongoClient(info.connectionUri, {
    directConnection: true,
    serverSelectionTimeoutMS: 5000,
  });
  await client.connect();
  db = client.db('deletetest');

  const coll = db.collection('items');
  await coll.insertMany([
    { name: 'keep-1', value: 100 },
    { name: 'keep-2', value: 200 },
    { name: 'delete-me', value: 999 },
    { name: 'keep-3', value: 300 },
  ]);
  const count = await coll.countDocuments();
  expect(count).toEqual(4);
});

// ============================================================================
// Delete and verify
// ============================================================================

tap.test('delete-persistence: delete a document', async () => {
  const coll = db.collection('items');
  const result = await coll.deleteOne({ name: 'delete-me' });
  expect(result.deletedCount).toEqual(1);

  const remaining = await coll.countDocuments();
  expect(remaining).toEqual(3);

  const deleted = await coll.findOne({ name: 'delete-me' });
  expect(deleted).toBeNull();
});

// ============================================================================
// Graceful restart: delete survives
// ============================================================================

tap.test('delete-persistence: graceful stop and restart', async () => {
  await client.close();
  await localDb.stop(); // graceful — writes hint file

  localDb = new smartdb.LocalSmartDb({ folderPath: tmpDir });
  const info = await localDb.start();
  client = new MongoClient(info.connectionUri, {
    directConnection: true,
    serverSelectionTimeoutMS: 5000,
  });
  await client.connect();
  db = client.db('deletetest');
});

tap.test('delete-persistence: deleted doc stays deleted after graceful restart', async () => {
  const coll = db.collection('items');
  const count = await coll.countDocuments();
  expect(count).toEqual(3);

  const deleted = await coll.findOne({ name: 'delete-me' });
  expect(deleted).toBeNull();

  // The remaining docs are intact
  const keep1 = await coll.findOne({ name: 'keep-1' });
  expect(keep1).toBeTruthy();
  expect(keep1!.value).toEqual(100);
});

// ============================================================================
// Simulate ungraceful restart: delete after hint write, then restart
// The hint file data_file_size check should detect the stale hint
// ============================================================================

tap.test('delete-persistence: insert and delete more docs, then restart', async () => {
  const coll = db.collection('items');

  // Insert a new doc
  await coll.insertOne({ name: 'temporary', value: 777 });
  expect(await coll.countDocuments()).toEqual(4);

  // Delete it
  await coll.deleteOne({ name: 'temporary' });
  expect(await coll.countDocuments()).toEqual(3);

  const gone = await coll.findOne({ name: 'temporary' });
  expect(gone).toBeNull();
});

tap.test('delete-persistence: stop and restart again', async () => {
  await client.close();
  await localDb.stop();

  localDb = new smartdb.LocalSmartDb({ folderPath: tmpDir });
  const info = await localDb.start();
  client = new MongoClient(info.connectionUri, {
    directConnection: true,
    serverSelectionTimeoutMS: 5000,
  });
  await client.connect();
  db = client.db('deletetest');
});

tap.test('delete-persistence: all deletes survived second restart', async () => {
  const coll = db.collection('items');
  const count = await coll.countDocuments();
  expect(count).toEqual(3);

  // Both deletes are permanent
  expect(await coll.findOne({ name: 'delete-me' })).toBeNull();
  expect(await coll.findOne({ name: 'temporary' })).toBeNull();

  // Survivors intact
  const names = (await coll.find({}).toArray()).map(d => d.name).sort();
  expect(names).toEqual(['keep-1', 'keep-2', 'keep-3']);
});

// ============================================================================
// Delete all docs and verify empty after restart
// ============================================================================

tap.test('delete-persistence: delete all remaining docs', async () => {
  const coll = db.collection('items');
  await coll.deleteMany({});
  expect(await coll.countDocuments()).toEqual(0);
});

tap.test('delete-persistence: restart with empty collection', async () => {
  await client.close();
  await localDb.stop();

  localDb = new smartdb.LocalSmartDb({ folderPath: tmpDir });
  const info = await localDb.start();
  client = new MongoClient(info.connectionUri, {
    directConnection: true,
    serverSelectionTimeoutMS: 5000,
  });
  await client.connect();
  db = client.db('deletetest');
});

tap.test('delete-persistence: collection is empty after restart', async () => {
  const coll = db.collection('items');
  const count = await coll.countDocuments();
  expect(count).toEqual(0);
});

// ============================================================================
// Cleanup
// ============================================================================

tap.test('delete-persistence: cleanup', async () => {
  await client.close();
  await localDb.stop();
  cleanTmpDir(tmpDir);
});

export default tap.start();