const child_process = require('child_process')
// import * as child_process from 'child_process'
// import { logger } from '../logger'

const logger = {
  error: console.error,
  debug: console.log
}

type Callback = (data: string) => void;

class ACPIController {
  public constructor() {
    if (this.checkAcpi()) this.listen()
    else logger.error('ACPI: acpi_listen does not exists')
  }

  protected tries = 0;
  protected callbacks: Callback[] = [];

  public connect(cb: Callback): void {
    this.callbacks.push(cb)
  }

  public disconnect(cb: Callback): void {
    const ind = this.callbacks.findIndex((c) => {
      return c === cb
    })
    if (ind == -1) return
    this.callbacks.splice(ind, 1)
  }

  private checkAcpi(): boolean {
    const res = child_process.spawnSync('which', ['acpi_listen'], {
      encoding: 'utf-8'
    })
    if (res.status == 0) return true
    else return false
  }

  private listen(): void {
    const acpi = child_process.spawn('acpi_listen')
    acpi.on('error', (err) => {
      logger.error('ACPI: ' + err.message)
    })
    acpi.on('close', () => {
      if (this.tries < 5) {
        this.tries++
        logger.debug('Restarting acpi_listen')
        return this.listen()
      }
    })

    acpi.stdout.addListener('data', (d: Buffer) => {
      const data = d.toString().trim()
      this.callbacks.forEach((cb) => {
        if (cb !== undefined) cb(data)
      })
    })
  }
}

const ACPI = new ACPIController()

export { ACPI }