const config = require('../config/config_node_app');

const http = require('http');
const { Server } = require('socket.io');
const { SerialPort } = require('serialport');

const server = http.createServer();
const io = new Server(server, {
	cors: {
		origin: config.corsURL
	}
});


// Track connected ports
let armLightPort = null;
let vendPort = null;


// Track reconnection timers
let armLightReconnectTimer = null;
let vendReconnectTimer = null;


// Open serial port
function openPort(portInfo, label) {
	const port = new SerialPort({ path: portInfo.path, baudRate: 9600 });

	port.on('open', () => console.log(`${label} port opened on ${portInfo.path}`));
	
	port.on('data', data => {
		const msg = data.toString().trim();
		console.log(`${label} →`, msg);
		
		if (msg.includes('LEVER PULLED')) {
			// This is an arm pull, so we notify the front end.
			// The armLight controller also sends data after a light command is sent, which we want to ignore.
			console.log ('Button pressed');
			console.log (`${label}:data`, msg);
			io.emit(`${label}:data`, msg);
		}
	
	});

	port.on('error', err => {
		console.error(`${label} port error:`, err.message);
		scheduleReconnect(label);
	});

	port.on('close', () => {
		console.log(`${label} port closed`);
		scheduleReconnect(label);
	});

	return port;
}


// Try to find and open a specific device by vendor ID
async function findAndOpenDevice(vendorId, label) {
	try {
		const ports = await SerialPort.list();
		const match = ports.find(
			p => (p.vendorId || '').toLowerCase().replace(/^0x/, '') === vendorId
		);

		if (match) {
			console.log(`Found ${label} controller on ${match.path}`);
			return openPort(match, label);
		} else {
			console.log(`No ${label} controller detected.`);
			return null;
		}
	} catch (err) {
		console.error(`Error listing ports for ${label}:`, err);
		return null;
	}
}


// USB Reconnection
function scheduleReconnect(label) {
	let timerRef;
	let vendorId;

	if (label === 'ArmLight') {
		if (armLightReconnectTimer) return; // already trying
		timerRef = 'armLightReconnectTimer';
		vendorId = '2341';
	
	} else if (label === 'Vend') {
		if (vendReconnectTimer) return; // already trying
		timerRef = 'vendReconnectTimer';
		vendorId = '1a86';
	
	} else return;

	console.log(`Starting reconnection attempts for ${label}...`);

	const tryReconnect = async () => {
		const newPort = await findAndOpenDevice(vendorId, label);
		if (newPort) {
			console.log(`${label} reconnected successfully!`);
			
			if (label === 'ArmLight') {
				armLightPort = newPort;
				clearInterval(armLightReconnectTimer);
				armLightReconnectTimer = null;
			
			} else {
				vendPort = newPort;
				clearInterval(vendReconnectTimer);
				vendReconnectTimer = null;
			}
		
		}
	};

	// Try every 3 seconds until success
	const interval = setInterval(tryReconnect, 3000);
	if (label === 'ArmLight') armLightReconnectTimer = interval;
	else vendReconnectTimer = interval;
}


// Socket.IO setup
io.on('connection', socket => {
	console.log('Client connected:', socket.id);

	socket.on('disconnect', () => {
		console.log('Client disconnected:', socket.id);
	});

	socket.on('sendCommand', data => {
		const { target, command } = data;
		console.log(`Received command for ${target}: ${command}`);

		let port = null;

		if (target === 'vend') port = vendPort;
		else if (target === 'armlight') port = armLightPort;

		if (port && port.writable) {
			port.write(command, err => {
				if (err) console.error(`Error writing to ${target}:`, err.message);
				else console.log(`Sent "${command}" to ${target}`);
			});
		
		} else {
			console.warn(`Port for ${target} not available.`);
		
		}
	});
});


// Startup
server.listen(config.serverPORT, async () => {
	console.log(`Socket.IO server running on port ${config.serverPORT}`);
	
	armLightPort = await findAndOpenDevice(config.armLight_vendorID, 'ArmLight');
	vendPort = await findAndOpenDevice(config.vend_vendorID, 'Vend');
});