import { execInContainer, resizeExec } from '../services/docker.js';

/**
 * Handle WebSocket terminal session
 * Path: /ws/terminal/{containerId}
 * 
 * Creates an interactive shell (docker exec) in the container
 * and bridges it to the WebSocket connection.
 * 
 * Client messages:
 *  - { type: 'input', data: '...' } — stdin data
 *  - { type: 'resize', cols: N, rows: N } — terminal resize
 */
export async function handleTerminal(ws, containerId) {
  let execInstance = null;
  let stream = null;

  try {
    ws.send(JSON.stringify({ type: 'info', data: `Connecting to container ${containerId.slice(0, 12)}...` }));

    const result = await execInContainer(containerId, ['/bin/sh', '-c', 'if command -v bash > /dev/null; then exec bash; else exec sh; fi']);
    execInstance = result.exec;
    stream = result.stream;

    ws.send(JSON.stringify({ type: 'connected', data: 'Terminal connected' }));

    // Docker exec stream → WebSocket
    stream.on('data', (chunk) => {
      if (ws.readyState === 1) {
        ws.send(JSON.stringify({ type: 'output', data: chunk.toString('utf8') }));
      }
    });

    stream.on('end', () => {
      if (ws.readyState === 1) {
        ws.send(JSON.stringify({ type: 'info', data: 'Terminal session ended' }));
        ws.close();
      }
    });

    stream.on('error', (err) => {
      if (ws.readyState === 1) {
        ws.send(JSON.stringify({ type: 'error', data: `Stream error: ${err.message}` }));
      }
    });

    // WebSocket → Docker exec stream
    ws.on('message', (message) => {
      try {
        const msg = JSON.parse(message.toString());

        if (msg.type === 'input' && stream && stream.writable) {
          stream.write(msg.data);
        } else if (msg.type === 'resize' && execInstance) {
          resizeExec(execInstance.id, msg.cols || 80, msg.rows || 24);
        }
      } catch {
        // If raw text, treat as stdin input
        if (stream && stream.writable) {
          stream.write(message.toString());
        }
      }
    });

  } catch (err) {
    ws.send(JSON.stringify({ type: 'error', data: `Failed to connect: ${err.message}` }));
    ws.close();
    return;
  }

  ws.on('close', () => {
    try {
      if (stream) stream.end();
    } catch {}
  });

  ws.on('error', () => {
    try {
      if (stream) stream.end();
    } catch {}
  });
}