import * as plugins from './plugins.js';
import { TsmdbServer } from '../ts_tsmdb/index.js';
import type { MongoClient } from 'mongodb';

export interface ILocalTsmDbOptions {
  folderPath: string;
  port?: number;
  host?: string;
}

/**
 * LocalTsmDb - Convenience class for local MongoDB-compatible database
 *
 * This class wraps TsmdbServer and provides a simple interface for
 * starting a local file-based MongoDB-compatible server and connecting to it.
 *
 * @example
 * ```typescript
 * import { LocalTsmDb } from '@push.rocks/smartmongo';
 *
 * const db = new LocalTsmDb({ folderPath: './data' });
 * const client = await db.start();
 *
 * // Use the MongoDB client
 * const collection = client.db('mydb').collection('users');
 * await collection.insertOne({ name: 'Alice' });
 *
 * // When done
 * await db.stop();
 * ```
 */
export class LocalTsmDb {
  private options: ILocalTsmDbOptions;
  private server: TsmdbServer | null = null;
  private client: MongoClient | null = null;

  constructor(options: ILocalTsmDbOptions) {
    this.options = options;
  }

  /**
   * Find an available port starting from the given port
   */
  private async findAvailablePort(startPort = 27017): Promise<number> {
    return new Promise((resolve, reject) => {
      const server = plugins.net.createServer();
      server.listen(startPort, '127.0.0.1', () => {
        const addr = server.address();
        const port = typeof addr === 'object' && addr ? addr.port : startPort;
        server.close(() => resolve(port));
      });
      server.on('error', () => {
        this.findAvailablePort(startPort + 1).then(resolve).catch(reject);
      });
    });
  }

  /**
   * Start the local TsmDB server and return a connected MongoDB client
   */
  async start(): Promise<MongoClient> {
    if (this.server && this.client) {
      throw new Error('LocalTsmDb is already running');
    }

    const port = this.options.port ?? await this.findAvailablePort();
    const host = this.options.host ?? '127.0.0.1';

    this.server = new TsmdbServer({
      port,
      host,
      storage: 'file',
      storagePath: this.options.folderPath,
    });
    await this.server.start();

    // Dynamically import mongodb to avoid requiring it as a hard dependency
    const mongodb = await import('mongodb');
    this.client = new mongodb.MongoClient(this.server.getConnectionUri(), {
      directConnection: true,
      serverSelectionTimeoutMS: 5000,
    });
    await this.client.connect();

    return this.client;
  }

  /**
   * Get the MongoDB client (throws if not started)
   */
  getClient(): MongoClient {
    if (!this.client) {
      throw new Error('LocalTsmDb is not running. Call start() first.');
    }
    return this.client;
  }

  /**
   * Get the underlying TsmdbServer instance (throws if not started)
   */
  getServer(): TsmdbServer {
    if (!this.server) {
      throw new Error('LocalTsmDb is not running. Call start() first.');
    }
    return this.server;
  }

  /**
   * Get the connection URI
   */
  getConnectionUri(): string {
    if (!this.server) {
      throw new Error('LocalTsmDb is not running. Call start() first.');
    }
    return this.server.getConnectionUri();
  }

  /**
   * Check if the server is running
   */
  get running(): boolean {
    return this.server !== null && this.server.running;
  }

  /**
   * Stop the local TsmDB server and close the client connection
   */
  async stop(): Promise<void> {
    if (this.client) {
      await this.client.close();
      this.client = null;
    }
    if (this.server) {
      await this.server.stop();
      this.server = null;
    }
  }
}