'use strict'

// Creates an ES6 Interrupt class wrapper using the pigio C library and pigpio javascript wrapper package
// The pigipio C library is specifically coded for the Raspberry Pi but might be adapatable to any single board computer (sbc) with Gpios
// assuming they would be pigio C, compatiable.
// Must have pigpio C library installed first.
// On interrupt emits "fired" which can be caught by the code calling this interrupt instance for handling
//  Understand there are two interrupts here.  One is this class and one on the sbc/rpi via pigpio
//  The sbc/pigpio interrupt emits an event which is listened for by this class which then emits
//  a "fired" event which can be can be listed to by having a handle to an instance this class.

const
	pigpio = require('pigpio'),
	sbcGpio = pigpio.Gpio,
	EventEmitter = require('events')

class Interrupt extends EventEmitter {
	constructor(pin_number, handler, opts = {}) {
		super()
		this.pin_number = pin_number
		this.handler = handler
		this.mode = sbcGpio.INPUT
		this.pull = opts.pull ? opts.pull : sbcGpio.PUD_DOWN
		this.edge = opts.edge ? opts.edge : sbcGpio.RISING_EDGE
		this.sbc_interrupt = new sbcGpio(
			this.pin_number, {
				mode: this.mode,
				pullUpDown: this.pull,
				// do not! set edge here as it will start the emitter -- see pigio js
			}
		)
	}

	// init() {
	//
	// 	// console.log(`initialize interrupt ${this.pin_number}`)
	// 	return Promise.resolve()
	//
	// }

	get pin() {
		return this.pin_number
	}

	async start() {

		console.log(`starting interrupt on pin ${ this.pin_number}`)

		// for cntrl-c exit of interrupt
		process.on('SIGINT', () => {
			this.exit().then((resp) => console.log('\n', resp)) // unexport on cntrl-c
				.catch(err => console.log('error:', err))
		})
		let interrupt = this // scope `this` for use in the listener for each interrupt
		// console.log(`interrupt listener set for rpi ${interrupt.pin_number}`)
		this.sbc_interrupt.on('interrupt', function () {
			// console.log(`the sbc interrupt tripped by sbc pin  ${interrupt.pin_number}`)
			interrupt.emit('fired') // emit an event that can be listened for by the device that created the interrupt instance
		})

		// rock n roll!!, start the pigpio interrupt
		this.sbc_interrupt.enableInterrupt(this.edge)

	}

	// manual firing for testing
	fire() {
		let interrupt = this
		console.log('manually firing interrupt', this.handler)
		this.emit('fired')
	}

	exit() {
		pigpio.terminate()
		return Promise.reject(`keyboard termination...terminating interrupt on pin ${this.pin_number}`)
	}
}

module.exports = Interrupt