const { Client } = require('ssh2');
const fs = require('fs');
const path = require('path');

class SSHService {
  constructor(config) {
    this.config = config;
    this.client = null;
  }

  connect() {
    return new Promise((resolve, reject) => {
      this.client = new Client();

      this.client.on('ready', () => {
        resolve();
      });

      this.client.on('error', (err) => {
        reject(err);
      });

      this.client.connect({
        host: this.config.host,
        port: this.config.port || 22,
        username: this.config.username,
        password: this.config.password
      });
    });
  }

  disconnect() {
    if (this.client) {
      this.client.end();
      this.client = null;
    }
  }

  exec(command) {
    return new Promise((resolve, reject) => {
      if (!this.client) {
        reject(new Error('Not connected'));
        return;
      }

      this.client.exec(command, (err, stream) => {
        if (err) {
          reject(err);
          return;
        }

        let output = '';
        let errorOutput = '';

        stream.on('close', (code) => {
          if (code !== 0 && errorOutput) {
            reject(new Error(errorOutput));
          } else {
            resolve(output);
          }
        });

        stream.on('data', (data) => {
          output += data.toString();
        });

        stream.stderr.on('data', (data) => {
          errorOutput += data.toString();
        });
      });
    });
  }

  uploadFile(localPath, remotePath) {
    return new Promise((resolve, reject) => {
      if (!this.client) {
        reject(new Error('Not connected'));
        return;
      }

      this.client.sftp((err, sftp) => {
        if (err) {
          reject(err);
          return;
        }

        const readStream = fs.createReadStream(localPath);
        const writeStream = sftp.createWriteStream(remotePath);

        writeStream.on('close', () => {
          resolve();
        });

        writeStream.on('error', (err) => {
          reject(err);
        });

        readStream.pipe(writeStream);
      });
    });
  }

  downloadFile(remotePath, localPath) {
    return new Promise((resolve, reject) => {
      if (!this.client) {
        reject(new Error('Not connected'));
        return;
      }

      this.client.sftp((err, sftp) => {
        if (err) {
          reject(err);
          return;
        }

        // Ensure local directory exists
        const localDir = path.dirname(localPath);
        if (!fs.existsSync(localDir)) {
          fs.mkdirSync(localDir, { recursive: true });
        }

        const readStream = sftp.createReadStream(remotePath);
        const writeStream = fs.createWriteStream(localPath);

        writeStream.on('close', () => {
          resolve();
        });

        writeStream.on('error', (err) => {
          reject(err);
        });

        readStream.on('error', (err) => {
          reject(err);
        });

        readStream.pipe(writeStream);
      });
    });
  }

  readRemoteFile(remotePath) {
    return new Promise((resolve, reject) => {
      if (!this.client) {
        reject(new Error('Not connected'));
        return;
      }

      this.client.sftp((err, sftp) => {
        if (err) {
          reject(err);
          return;
        }

        sftp.readFile(remotePath, 'utf-8', (err, data) => {
          if (err) {
            reject(err);
          } else {
            resolve(data);
          }
        });
      });
    });
  }

  listDirectory(remotePath) {
    return new Promise((resolve, reject) => {
      if (!this.client) {
        reject(new Error('Not connected'));
        return;
      }

      this.client.sftp((err, sftp) => {
        if (err) {
          reject(err);
          return;
        }

        sftp.readdir(remotePath, (err, list) => {
          if (err) {
            reject(err);
          } else {
            resolve(list.map(item => ({
              name: item.filename,
              isDirectory: item.attrs.isDirectory(),
              size: item.attrs.size,
              mtime: item.attrs.mtime
            })));
          }
        });
      });
    });
  }
}

module.exports = { SSHService };