import nntpConfig from '#config/nntp'
import { NNTP } from "nntp-js";

class NntpService {
  private readonly poolSize: number;
  private allConnections: Set<any>;
  private idleConnections: any[];
  private waiters: ((conn: any) => void)[];
  private createdCount: number;

  constructor(poolSize = 10) {
    this.poolSize = poolSize;
    this.allConnections = new Set();
    this.idleConnections = [];
    this.waiters = [];
    this.createdCount = 0;
    console.log(`NNTP Pool initialized with size ${this.poolSize}`)
  }

  private async _createConnection() {
    // This connection logic is based on the older, working pool implementation.
    const conn = new NNTP(nntpConfig.host, nntpConfig.port);
    await conn.connect();
    if (nntpConfig.user) {
      await conn.login(nntpConfig.user, nntpConfig.password?.release());
    }
    this.allConnections.add(conn);
    return conn;
  }

  public async acquire() {
    if (this.idleConnections.length > 0) {
        console.log('Reusing existing connection from pool.');
      return this.idleConnections.pop();
    }

    if (this.createdCount < this.poolSize) {
      this.createdCount++;
        console.log(`Creating new connection (${this.createdCount}/${this.poolSize}).`);
      return this._createConnection();
    }

      console.log(`Pool maxed out at ${this.poolSize}. Waiting for a connection to become available.`);
    return new Promise(resolve => this.waiters.push(resolve));
  }

  public release(conn: any) {
    if (this.waiters.length > 0) {
        console.log('Releasing connection directly to a waiting task.');
      const resolve = this.waiters.shift();
      if(resolve) resolve(conn);
    } else {
        console.log('Returning connection to the idle pool.');
      this.idleConnections.push(conn);
    }
  }

  public async shutdown() {
      console.log('Shutting down all connections in the pool.');
    const shutdownPromises: Promise<any>[] = [];
    for (const conn of this.allConnections) {
      shutdownPromises.push(conn.quit());
    }
    await Promise.all(shutdownPromises);
    this.allConnections.clear();
    this.idleConnections.length = 0;
    this.waiters.length = 0;
    this.createdCount = 0;
  }
}

export default new NntpService();