import sockjs, { Connection } from 'sockjs';
// import { sync as osLocaleSync } from 'os-locale';
// umiui:UmiUI:terminal
import { debugTerminal as _log } from './debug';

export interface IOpts {
  cwd: string;
}

/**
 * get user default shell
 * /bin/zsh /bin/bash
 */
export const getDefaultShell = () => {
  if (process.platform === 'darwin') {
    return process.env.SHELL || '/bin/bash';
  }

  if (process.platform === 'win32') {
    return process.env.COMSPEC || 'cmd.exe';
  }
  return process.env.SHELL || '/bin/sh';
};

/**
 * Security Check
 *
 */
const securityCheck = (conn: Connection) => {
  if (process.env.HOST === '0.0.0.0') {
    conn.write('The current environment is not safe.');
    return false;
  }
  return true;
};

export const connectionHandler = (conn: Connection, opts: IOpts) => {
  const { cwd } = opts;
  // insecurity env to run shell
  const safe = securityCheck(conn);
  let spawn;
  try {
    // eslint-disable-next-line prefer-destructuring
    spawn = require('node-pty').spawn;
  } catch (e) {
    conn.write(
      'Failed to install or prebuild node-pty module, please see docs: https://umijs.org/guide/faq.html#terminal-need-node-pty-module',
    );
    return false;
  }
  if (safe) {
    const defaultShell = getDefaultShell();
    const defaultShellArgs = ['--login'];
    const pty = spawn(defaultShell, defaultShellArgs, {
      name: 'xterm-color',
      cols: 80,
      rows: 30,
      cwd,
      env: {
        ...process.env,
        // LANG: `${osLocaleSync()}.UTF-8`,
        TERM: 'xterm-256color',
        COLORTERM: 'truecolor',
      },
    });
    /**
     * stringify command shell string
     * @param command ls/... shell commands
     */
    pty.onData(chunk => {
      _log('ptyProcess data', chunk);
      conn.write(chunk);
    });
    pty.resize(100, 40);

    // === socket listener ===
    conn.on('data', data => {
      _log('terminal conn message', data);
      pty.write(data);
    });
    conn.on('close', () => {
      pty.kill();
    });
  }
};

/**
 * export terminal socket init needs bind express app server
 */
export default (app, opts: IOpts = { cwd: process.cwd() }) => {
  const terminalSS = sockjs.createServer();
  terminalSS.on('connection', conn => connectionHandler(conn, opts));
  terminalSS.installHandlers(app, {
    prefix: '/terminal',
    log: () => {},
  });
};