import { EventEmitter as Emitter } from 'events'
import path from 'path'
import chokidar from 'chokidar'

class Watcher extends Emitter {
  constructor(options) {
    super()
    // pass in ignores
    const opts = {
      ignored: '**/node_modules/**',
      ignoreInitial: true
    }
    const watcher = chokidar.watch(options.source, opts)
    this.watcher = watcher
  }

  start() {
    const handler = (type, f) => {
      const fname = path.basename(f)
      if ( fname.toLowerCase() === 'package.json')
        if (type !=='change') {
          this.emit('error',new Error('package.json was added or removed, ignoring sync and reinstall'))
          return
        } else{
          this.emit('install', f)
        }
      this.emit('sync', f)
    } // end handler
    this.watcher
      .on('add', handler.bind(this, 'add'))
      .on('change', handler.bind(this, 'change'))
      .on('unlink', handler.bind(this, 'remove'))
  }

  stop() {
    this.watcher.close()
  }

}

export default Watcher