'use strict'

const i2c = require('i2c-bus'),
	pify = require('pify'),
	PQueue = require('p-queue')

// TODO Create a Bus master class then BusRPi classes etc for actual hardware.

class Bus {

	constructor(busnum = 1) {
		this.busnum = busnum
		this.queue = new PQueue({ concurrency: 1 });
		this.qAdd = (p) => { this.queue.add(() => p) } // p is a promise
		this.bus = i2c.open(this.busnum, () => {})
	}

	scan() { return pify(this.bus.scan).bind(this.bus)() }
	close() { return pify(this.bus.close).bind(this.bus)() }

	readRaw(address, length, buffer) {
		return pify(this.bus.i2cRead).bind(this.bus)(address, length, buffer)
	}

	writeRaw(address, length, buffer) {
		return pify(this.bus.i2cWrite).bind(this.bus)(address, length, buffer)
	}

	read(address, cmd) {
		// console.log("read: address, cmd", address, cmd)
		return pify(this.bus.readByte).bind(this.bus)(address, cmd)
	}

	write(address, cmd, byte) {
		// console.log('write: address, cmd, byte', address, cmd, byte)
		return pify(this.bus.writeByte.bind(this.bus))(address, cmd, byte)
	}

	read2(address, cmd) {
		return pify(this.bus.readWord.bind(this.bus))(address, cmd)
	}

	write2(address, cmd, bytes) {
		return pify(this.bus.writeWord.bind(this.bus))(address, cmd, bytes)
	}

} // end of Bus Class

module.exports = {
	Bus
};