// End-to-end test: official MongoDB Node.js driver against multiforadb.
const { MongoClient, ObjectId } = require('mongodb');

const URL = 'mongodb://127.0.0.1:27020';
const results = [];
function check(name, cond, detail = '') {
  results.push({ name, ok: !!cond, detail: String(detail) });
  if (!cond) console.error(`  ✗ ${name} ${detail}`);
}
async function main() {
  const client = new MongoClient(URL, { serverSelectionTimeoutMS: 5000 });
  await client.connect();
  const db = client.db('e2e');
  const users = db.collection('users');
  await users.drop().catch(() => {});

  // --- insert ---
  await users.insertOne({ name: 'alice', age: 30, tags: ['a', 'b'] });
  const many = await users.insertMany([
    { name: 'bob', age: 25, tags: ['b'] },
    { name: 'carol', age: 35, tags: ['c', 'a'] },
    { name: 'dave', age: 40, tags: [] },
  ]);
  check('insertMany acknowledged', many.acknowledged === true, many);
  check('auto _id assigned', ObjectId.isValid(many.insertedIds[0]));

  // --- find: filters, operators, sort, skip, limit, projection ---
  const gt = await users.find({ age: { $gt: 28 } }).sort({ age: -1 }).toArray();
  check('find $gt + sort desc', gt.map((d) => d.name).join(',') === 'dave,carol,alice', gt.map((d) => d.name));

  const inq = await users.find({ name: { $in: ['alice', 'bob'] } }).count();
  check('find $in count', inq === 2, inq);

  const rgx = await users.find({ name: /^[bc]/ }).toArray();
  check('find $regex', rgx.length === 2, rgx.map((d) => d.name));

  const exists = await users.find({ tags: { $exists: true } }).count();
  check('find $exists', exists === 4, exists);

  const lim = await users.find({}).sort({ age: 1 }).skip(1).limit(2).toArray();
  check('find skip+limit+sort', lim.map((d) => d.name).join(',') === 'alice,carol', lim.map((d) => d.name));

  const proj = await users.findOne({ name: 'alice' }, { projection: { _id: 0, name: 1 } });
  check('projection', proj.name === 'alice' && proj.age === undefined, JSON.stringify(proj));

  const dot = await users.findOne({ 'tags.0': 'c' });
  check('dot path + array', dot?.name === 'carol');

  // --- count ---
  check('countDocuments', (await users.countDocuments({})) === 4);
  check('countDocuments with filter', (await users.countDocuments({ age: { $gte: 30 } })) === 3);
  check('estimatedDocumentCount', (await users.estimatedDocumentCount()) === 4);

  // --- update ---
  const u1 = await users.updateOne({ name: 'alice' }, { $set: { vip: true }, $inc: { age: 1 } });
  check('updateOne nModified', u1.modifiedCount === 1, u1);
  const alice = await users.findOne({ name: 'alice' });
  check('updateOne $set+$inc applied', alice.vip === true && alice.age === 31, JSON.stringify(alice));

  const um = await users.updateMany({}, { $set: { seen: true } });
  check('updateMany', um.modifiedCount === 4, um);

  const push = await users.updateOne({ name: 'dave' }, { $push: { tags: 'x' } });
  check('$push', push.modifiedCount === 1);
  check('$push visible', (await users.findOne({ name: 'dave' })).tags.length === 1);

  const ups = await users.updateOne({ name: 'erin' }, { $set: { age: 28 } }, { upsert: true });
  check('upsert', ups.upsertedCount === 1 && ups.matchedCount === 0, ups);
  check('upsert doc exists', (await users.findOne({ name: 'erin' }))?.age === 28);

  // --- findOneAndUpdate (findAndModify) ---
  const fam = await users.findOneAndUpdate(
    { name: 'bob' },
    { $set: { lucky: true } },
    { returnDocument: 'after' },
  );
  const famDoc = fam.value ?? fam;
  check('findOneAndUpdate returns new', famDoc.lucky === true, JSON.stringify(fam));
  const famRemove = await users.findOneAndDelete({ name: 'erin' });
  const famDelDoc = famRemove.value ?? famRemove;
  check('findOneAndDelete', famDelDoc?.name === 'erin', JSON.stringify(famRemove));

  // --- aggregate ---
  const grp = await users
    .aggregate([
      { $match: { age: { $gte: 25 } } },
      { $group: { _id: '$tags.length', total: { $sum: '$age' } } },
      { $sort: { _id: 1 } },
    ])
    .toArray();
  check('aggregate $match+$group+$sum+$sort', grp.length >= 1 && grp.some((g) => g.total > 0), JSON.stringify(grp));

  const cnt = await users.aggregate([{ $match: {} }, { $count: 'n' }]).toArray();
  check('aggregate $count', cnt[0]?.n === 4, JSON.stringify(cnt));

  // $sort with NO preceding $group. This shape used to kill the server: the
  // stage materialized its document list from the reply arena and it was then
  // freed with the general allocator. Every aggregate case above happens to
  // sort after a $group, which leaves the stream already materialized and the
  // guilty branch unreached -- so the bug survived the whole suite. The second
  // aggregate is the part that actually proves recovery: if the server died,
  // this connection is gone.
  const sorted = await users.aggregate([{ $sort: { age: -1 } }]).toArray();
  const ages = sorted.map((d) => d.age);
  check(
    'aggregate bare $sort (no $group) returns sorted docs',
    ages.length === 4 && ages.every((a, i) => i === 0 || ages[i - 1] >= a),
    JSON.stringify(ages),
  );
  const stillAlive = await users.aggregate([{ $match: {} }, { $count: 'n' }]).toArray();
  check('server survives a bare $sort pipeline', stillAlive[0]?.n === 4, JSON.stringify(stillAlive));

  // --- a database-level command must not leak the catalog lock ---
  // db.aggregate() sends {aggregate: 1}, which names no collection. dispatch
  // used to resolve the namespace after taking the catalog lock and bail with a
  // plain return, leaking it shared forever. Reads kept working, so the damage
  // only showed on the next write that had to create a collection -- which is
  // the second half of this check, and would hang rather than fail.
  let dbLevelErr = null;
  try {
    await db.aggregate([{ $listLocalSessions: {} }]).toArray();
  } catch (e) {
    dbLevelErr = e;
  }
  check(
    'database-level aggregate gives a real error, not an empty reply',
    dbLevelErr !== null && typeof dbLevelErr.message === 'string' && dbLevelErr.message !== 'n/a',
    String(dbLevelErr && dbLevelErr.message).slice(0, 60),
  );
  const afterDbLevel = await db.collection('lock_probe').insertOne({ _id: 1 });
  check('a write creating a collection still completes afterwards', afterDbLevel.insertedId === 1);

  // --- unacknowledged writes must not desync the connection ---
  // An OP_MSG request with moreToCome set gets no reply. Sending one anyway
  // left it unread in the socket, so the *next* command on that connection
  // read the wrong reply. maxPoolSize 1 pins both operations to one socket,
  // which is what makes the bug visible; with a larger pool the driver may
  // hand out a different connection and hide it. The driver also does this to
  // itself on close, via endSessions with {w: 0}.
  const w0client = new MongoClient(URL, { maxPoolSize: 1 });
  try {
    await w0client.connect();
    const w0 = w0client.db('e2e').collection('unack');
    await w0.deleteMany({});
    await w0.insertOne({ _id: 1, v: 'acknowledged' });
    const unack = await w0.insertOne({ _id: 2, v: 'unacknowledged' }, { writeConcern: { w: 0 } });
    check('unacknowledged insert is not acknowledged', unack.acknowledged === false, JSON.stringify(unack));
    // The assertion that matters: the same socket still works afterwards.
    const after = await w0.countDocuments({});
    check('connection survives an unacknowledged write', after === 2, `count=${after}`);
  } finally {
    await w0client.close();
  }

  // --- duplicate key ---
  let dupErr = null;
  try {
    await users.insertOne({ _id: many.insertedIds[0], name: 'clobber' });
  } catch (e) {
    dupErr = e;
  }
  check('duplicate key rejected', dupErr?.code === 11000, dupErr?.message);

  // --- listCollections / listDatabases ---
  const colls = await db.listCollections({}, { nameOnly: true }).toArray();
  check('listCollections', colls.some((c) => c.name === 'users'), JSON.stringify(colls));
  const dbs = await client.db('admin').admin().listDatabases();
  check('listDatabases', dbs.databases.some((d) => d.name === 'e2e'), JSON.stringify(dbs.databases.map((d) => d.name)));

  // --- delete ---
  const del1 = await users.deleteOne({ name: 'dave' });
  check('deleteOne', del1.deletedCount === 1, del1);
  const delMany = await users.deleteMany({});
  check('deleteMany', delMany.deletedCount === 3, delMany);
  check('empty after delete', (await users.countDocuments({})) === 0);

  await client.close();

  const failed = results.filter((r) => !r.ok);
  console.log(`\n${results.length - failed.length}/${results.length} checks passed`);
  if (failed.length) {
    console.log('FAILED:', failed.map((f) => f.name).join(', '));
    process.exit(1);
  }
  console.log('E2E_OK');
}

main().catch((e) => {
  console.error('E2E_FAIL', e);
  process.exit(1);
});