const { EventEmitter } = require('events');
const path = require('path');
const { execFile, exec } = require('child_process');

class ClipboardEventListener extends EventEmitter {
  constructor() {
    super();
    this.child = null;
  }
  startListening() {
    const { platform } = process;
    if (platform === 'win32') {
      this.child = execFile(path.join(__dirname, 'platform/clipboard-event-handler-mac'));
    }
    else if (platform === 'linux') {
      // manually install clipboard-event-handler-linux to /usr/local/bin
      this.child = exec('clipboard-event-handler-linux')
    }
    else if (platform === 'darwin') {
      this.child = execFile(path.join(__dirname, 'platform/clipboard-event-handler-mac'));
    }
    else {
      throw 'Not yet supported';
    }
    this.child.stdout.on('data', (data) => {
      if (data.trim() === 'CLIPBOARD_CHANGE') {
        this.emit('change');
      }
    });
    this.child.stdout.on('close', (code) => {
      this.emit('close', code);
    });
    this.child.stdout.on('exit', (code) => {
      this.emit('exit', code);
    });
  }
  stopListening() {
    const res = this.child.kill();
    return res;
  }
}

module.exports = new ClipboardEventListener();