import DeadJim from 'death'
import { Gpio } from 'onoff'
import to from 'await-to-js'


import logger from '@uci-utils/logger'

let log = logger({package:'@uci/gpio', file:'/src/gpio.js'})

class Pin extends Gpio {
  constructor(pin, opts = {}) {
    if (typeof pin !=='number') pin = parseInt(pin)  // make sure pin is a number!
    // TODO check against a set of known acceptable pin numbers based on SBC
    log.debug({pin:pin, msg:'construtor - creating gpio pin'})
    if (isNaN(pin)) throw new Error('not a valid gpio pin number')
    super(pin,opts.direction || 'out',opts)
    this.id = (opts.id || 'gpio') + ':' + pin
    log.debug({ pin: pin, opts: opts, method:'constructor', line:15, msg:'created gpio with these opts'})
    this.number = pin
    this.direction = opts.direction || 'out'
    this.value = opts.init || 0
  } // end constructor

  async init() {
    await this.set(this.value)
    DeadJim((signal,err) => {
      log.warn({signal:signal, method:'init', line:56, error:err, msg:'gpio process was killed, unexporting pin'})
      this.unexport() // kill the kernel entry
    })
  }

  async on() { return await this.set(1) }
  async off() { return await this.set(0) }
  async toggle() { return await this.set(!this.value) }

  async set(value) {
    log.debug({msg:'set a pin', value:value, number:this.number})
    // this.write(parseInt(value) || 0).then(res => console.log('returning from write'))
    let [err] = await to(this.write(parseInt(value) || 0))
    if (err) {
      log.warn({error:err, pin:this.number, msg:'error reading gpio pin'})
      throw err
    }
    let curValue = await this.read()
    if (value !== curValue) throw new Error(`pin ${this.number} was not set correctly: ${value}:${curValue}`)
    return curValue
  }

  async read() {
    let [err, res] = await to(super.read())  // super.read here just calls this.read making an infinite loop and blowing the stack, should call onoff's read
    if (err) {
      log.warn({error:err, pin:this.pin, msg:'error reading gpio pin'})
      return err
    }
    this.value=res
    this.state = res ? 'on' : 'off'
    return this.value
  }

  async get() {
    return this.value
  }

} // end Class

export default Pin


//example hook
// async function defaultHook(packet) {
// return a promise or use await if anything async happens in hook
// new Promise((resolve) => {
// console.log('==========default hook =============')
// return packet
// resolve(packet)
// })
// }