const mysql = require("mysql2/promise");
const { Client } = require("ssh2");
const dotenv = require("dotenv");
const path = require("path");

// Helper function to setup SSH tunnel
async function setupSshTunnel(sshConfig) {
  return new Promise((resolve, reject) => {
    const ssh = new Client();

    ssh.on('error', (err) => {
      console.error('SSH connection error:', err);
    });

    ssh.on('end', () => {
      console.log('SSH connection ended normally');
    });

    ssh.on('close', () => {
      console.log('SSH connection closed');
    });

    ssh
      .on("ready", () => {
        ssh.forwardOut(
          "127.0.0.1",
          0,
          sshConfig.prodDbConfig.host,
          sshConfig.prodDbConfig.port,
          async (err, stream) => {
            if (err) reject(err);
            resolve({ ssh, stream });
          }
        );
      })
      .connect(sshConfig.ssh);
  });
}

// Helper function to setup database connections
async function setupConnections(sshConfig) {
  const tunnel = await setupSshTunnel(sshConfig);
  
  const prodConnection = await mysql.createConnection({
    ...sshConfig.prodDbConfig,
    stream: tunnel.stream,
  });

  const localConnection = await mysql.createPool({
    ...sshConfig.localDbConfig,
    waitForConnections: true,
    connectionLimit: 10,
    queueLimit: 0
  });

  return {
    ssh: tunnel.ssh,
    prodConnection,
    localConnection
  };
}

// Helper function to close connections
async function closeConnections(connections) {
  const { ssh, prodConnection, localConnection } = connections;
  
  try {
    if (prodConnection) await prodConnection.end();
    if (localConnection) await localConnection.end();
    
    // Wait a bit for any pending data to be written before closing SSH
    await new Promise(resolve => setTimeout(resolve, 100));
    
    if (ssh) {
      ssh.on('close', () => {
        console.log('SSH connection closed cleanly');
      });
      ssh.end();
    }
  } catch (err) {
    console.error('Error during cleanup:', err);
  }
}

module.exports = {
  setupConnections,
  closeConnections
};