// Record an index corpus by asking a real mongod what the answer is.
//
// Partial and hashed indexes: M3's last row. `docs/M3_INDEX_TYPES_DESIGN_REVIEW.md`
// found that `partialFilterExpression` was accepted and ignored here, which
// made a *unique* partial index refuse inserts mongod accepts -- and that no
// test in this repository covered the row, in any suite. The pinned corpus is
// crud and aggregate; `e2e5.js` and `e2e6.js` test indexes but write neither
// a partial nor a hashed spec.
//
// Unlike `tests/spec/operators/`, a case here is a *sequence*: create an
// index, insert against it, read back, list it. So the source format carries
// a list of operations rather than one, and the recorder walks them in order,
// stopping at the first that throws -- which is what a client would see.
//
//   node tests/spec/indexes/record.js --mongod-port 27099
//
// Options:
//   --mongod-port <n>  a running mongod to measure against (default 27099)
//   --only <name>      record just one source file
const fs = require('fs');
const path = require('path');
const DRIVER = path.join(__dirname, '..', '..', 'e2e', 'node_modules', 'mongodb');
const { MongoClient } = require(DRIVER);
const { EJSON, ObjectId } = require(path.join(DRIVER, 'lib', 'bson.js'));

const argv = process.argv.slice(2);
function opt(name, dflt) {
    const i = argv.indexOf('--' + name);
    if (i < 0) return dflt;
    const v = argv[i + 1];
    return v === undefined || v.startsWith('--') ? true : v;
}

const PORT = parseInt(opt('mongod-port', '27099'), 10);
const ONLY = opt('only', null);
const SRC_DIR = path.join(__dirname, 'sources');
const DB_NAME = 'index-corpus';
const COLL = 'coll';
const SCHEMA_VERSION = '1.4';

/// An ObjectId is the one value no source authors, so masking it is
/// unambiguous. Nothing else here is unpredictable: an index name, a key
/// specification and a document count are all decided by the input.
function mask(value) {
    if (value instanceof ObjectId) return { $$type: 'objectId' };
    if (Array.isArray(value)) return value.map(mask);
    if (value && typeof value === 'object' && value.constructor === Object) {
        const out = {};
        for (const [k, v] of Object.entries(value)) out[k] = mask(v);
        return out;
    }
    return value;
}

async function main() {
    const client = new MongoClient(`mongodb://127.0.0.1:${PORT}`, { serverSelectionTimeoutMS: 3000 });
    try {
        await client.connect();
    } catch (e) {
        console.error(`no mongod on :${PORT} -- start one first:\n` +
            `  mongod --port ${PORT} --dbpath <dir>\n${e.message}`);
        process.exit(2);
    }
    const build = await client.db('admin').command({ buildInfo: 1 });
    console.log(`recording against mongod ${build.version} on :${PORT}`);

    const sources = fs.readdirSync(SRC_DIR).filter((f) => f.endsWith('.json'))
        .filter((f) => !ONLY || f === ONLY || f === ONLY + '.json')
        .sort();
    for (const file of sources) {
        // Plain JSON, deliberately, and the cost is worth stating: a source
        // cannot name a BSON type the JSON grammar has no syntax for, so
        // `5.0` reaches the driver as an int32 and no source here can ask a
        // cross-type question. Reading sources as EJSON instead was tried and
        // reverted -- EJSON's wrapper namespace collides with the query
        // operators these sources are made of. `{"$regex": "x"}` parses to a
        // BSONRegExp, `structuredClone` below then flattens it to
        // `{pattern, options}`, and "a filter using $regex is refused"
        // silently became a filter mongod accepts.
        const src = JSON.parse(fs.readFileSync(path.join(SRC_DIR, file), 'utf8'));
        const name = path.basename(file, '.json');
        const out = await record(client, name, src);
        fs.writeFileSync(path.join(__dirname, `${name}.json`), EJSON.stringify(out, { relaxed: false, indent: 2 }) + '\n');
        const errs = out.tests.filter((t) => t.operations.some((o) => o.expectError)).length;
        console.log(`  ${name}: ${out.tests.length} cases, ${errs} of them reaching an error`);
    }
    await client.close();
    console.log('RECORDED');
}

async function record(client, name, src) {
    const db = client.db(DB_NAME);
    const coll = db.collection(COLL);
    const tests = [];

    for (const c of src.cases) {
        const documents = c.documents === undefined ? src.documents : c.documents;
        // Dropped rather than emptied: an index outlives a `deleteMany`, and
        // every case here is about which indexes exist.
        await coll.drop().catch(() => {});
        if (documents.length) await coll.insertMany(structuredClone(documents));

        const operations = [];
        // A case that brings its own documents reseeds through operations,
        // because `initialData` is per file and seeded once per test.
        if (c.documents !== undefined) {
            operations.push({ object: 'collection0', name: 'deleteMany', arguments: { filter: {} } });
            if (documents.length) {
                operations.push({
                    object: 'collection0',
                    name: 'insertMany',
                    arguments: { documents: structuredClone(documents) },
                });
            }
        }
        for (const op of c.ops) {
            const rec = { object: 'collection0', name: op.name, arguments: structuredClone(op.arguments) };
            try {
                rec.expectResult = mask(await invoke(coll, op.name, structuredClone(op.arguments)));
            } catch (e) {
                // The code, not the message. mongod's index-specification
                // errors embed a rendering of the whole spec, which no
                // formatter here produces.
                delete rec.expectResult;
                rec.expectError = { isError: true, errorCode: e.code };
                operations.push(rec);
                break; // a client would stop here too
            }
            operations.push(rec);
        }

        const after = await coll.find({}, { sort: { _id: 1 } }).toArray();
        tests.push({
            description: c.description,
            operations,
            outcome: [{ collectionName: COLL, databaseName: DB_NAME, documents: after.map(mask) }],
        });
    }
    await coll.drop().catch(() => {});

    return {
        description: name,
        schemaVersion: SCHEMA_VERSION,
        // Recorded, not authored. Regenerate with tests/spec/indexes/record.js.
        createEntities: [
            { client: { id: 'client0' } },
            { database: { id: 'database0', client: 'client0', databaseName: DB_NAME } },
            { collection: { id: 'collection0', database: 'database0', collectionName: COLL } },
        ],
        initialData: [{ collectionName: COLL, databaseName: DB_NAME, documents: src.documents }],
        tests,
    };
}

async function invoke(coll, name, args) {
    switch (name) {
        case 'createIndex': {
            const { keys, ...rest } = args;
            return await coll.createIndex(keys, rest);
        }
        case 'listIndexes':
            return await coll.listIndexes().toArray();
        case 'dropIndex':
            return plain(await coll.dropIndex(args.name));
        case 'insertMany':
            return plain(await coll.insertMany(args.documents));
        case 'insertOne':
            return plain(await coll.insertOne(args.document));
        case 'find':
            return await coll.find(args.filter || {}, { sort: args.sort }).toArray();
        case 'countDocuments':
            return await coll.countDocuments(args.filter || {});
        case 'deleteMany':
            return plain(await coll.deleteMany(args.filter || {}));
        case 'updateOne':
            return plain(await coll.updateOne(args.filter, args.update, args));
        default:
            throw new Error(`record.js does not know the operation '${name}'`);
    }
}

/// Driver results carry `acknowledged` and driver-side types; the unified
/// format's expectations are the plain counts and ids.
function plain(result) {
    const out = {};
    for (const k of ['insertedCount', 'insertedId', 'insertedIds', 'deletedCount', 'matchedCount', 'modifiedCount', 'upsertedCount']) {
        if (result[k] !== undefined) out[k] = result[k];
    }
    return out;
}

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