// TODO: read /dev to recalculate devices and remake subprocess

import { Service, Utils } from '../imports.js';


class Pointers extends Service {
  static {
    Service.register(this, {
      'proc-started': ['boolean'],
      'proc-destroyed': ['boolean'],
      'device-fetched': ['boolean'],
      'new-line': ['string'],
    });
  }

  proc;
  output = "";
  devices = new Map();

  get proc() { return this.proc; }
  get output() { return this.output; }
  get devices() { return this.devices; }

  constructor() {
    super();
    this.parseDevices();
  }

  parseDevices() {
    Utils.execAsync(['libinput', 'list-devices']).then(out => {
      let lines = out.split('\n');
      let device = null;
      let devices = new Map();

      lines.forEach(line => {
        let parts = line.split(':');

        if (parts[0] === 'Device') {
          device = {};
          devices.set(parts[1].trim(), device);
        }
        else if (device && parts[1]) {
          let key = parts[0].trim();
          let value = parts[1].trim();
          device[key] = value;
        }
      });
      this.devices = Array.from(devices).filter(dev => dev.Capabilities &&
                                                dev.Capabilities.includes('pointer'));
      this.emit('device-fetched', true);
    }).catch(print);
  }

  startProc() {
    let args = [];
    this.devices.forEach(dev => {
      if (dev.Kernel) {
        args.push('--device');
        args.push(dev.Kernel);
      }
    });

    this.proc = Utils.subprocess(
      ['libinput', 'debug-events', ...args],
      (output) => {
        if (output.includes('BTN') && output.includes('released') ||
            output.includes('TOUCH_UP') ||
            output.includes('HOLD_END') && !output.includes('cancelled')) {

          this.output = output;
          this.emit('new-line', output);
        }
      },
      (err) => logError(err)
    );
    this.emit('proc-started', true);
  }

  killProc() {
    if (this.proc) {
      this.proc.force_exit();
      this.emit('proc-destroyed', true);
    }
  }
}

const pointersService = new Pointers();
export default pointersService;