/**
 * Test Database Setup and Cleanup Utilities
 *
 * This file provides utilities for setting up and cleaning up test databases
 * to ensure test isolation and prevent test data pollution.
 */

import { MongoClient, Db } from 'mongodb';

let testClient: MongoClient | null = null;
let testDb: Db | null = null;

/**
 * Get or create a connection to the test database
 */
export async function getTestDatabase(): Promise<Db> {
  if (testDb) {
    return testDb;
  }

  const mongoUrl = process.env.TEST_MONGO_URL || 'mongodb://localhost:27017';
  const dbName = process.env.TEST_DB_NAME || 'flink_oauth_test';

  testClient = await MongoClient.connect(mongoUrl);
  testDb = testClient.db(dbName);

  return testDb;
}

/**
 * Clean up all test collections
 */
export async function cleanupTestDatabase(): Promise<void> {
  if (!testDb) {
    return;
  }

  const collections = await testDb.listCollections().toArray();

  for (const collection of collections) {
    await testDb.collection(collection.name).deleteMany({});
  }
}

/**
 * Close test database connection
 */
export async function closeTestDatabase(): Promise<void> {
  if (testClient) {
    await testClient.close();
    testClient = null;
    testDb = null;
  }
}

/**
 * Drop the entire test database (use with caution)
 */
export async function dropTestDatabase(): Promise<void> {
  if (!testDb) {
    return;
  }

  await testDb.dropDatabase();
}

/**
 * Insert test data into a collection
 */
export async function insertTestData<T>(
  collectionName: string,
  documents: T[]
): Promise<void> {
  const db = await getTestDatabase();
  await db.collection(collectionName).insertMany(documents as any[]);
}

/**
 * Get all documents from a test collection
 */
export async function getTestData<T>(collectionName: string): Promise<T[]> {
  const db = await getTestDatabase();
  return db.collection(collectionName).find({}).toArray() as Promise<T[]>;
}

/**
 * Clear a specific test collection
 */
export async function clearTestCollection(collectionName: string): Promise<void> {
  const db = await getTestDatabase();
  await db.collection(collectionName).deleteMany({});
}

/**
 * Setup function to run before each test
 */
export async function beforeEachTest(): Promise<void> {
  await cleanupTestDatabase();
}

/**
 * Teardown function to run after all tests
 */
export async function afterAllTests(): Promise<void> {
  await cleanupTestDatabase();
  await closeTestDatabase();
}