const Component = require("./_component");
const dgram = require('node:dgram');
const fs = require('fs');

function logger (...p) {
	return;
	console.debug("[UDP reverse]:", ...p);
};

function isFirewalled () {  // TODO: Firewall
	return false;
}

module.exports = class UDPServer extends Component {
	static type () {
		return "udp-proxy";
	}

	constructor (adr, syntaxTree) {
		super(adr, syntaxTree);
		if (syntaxTree.firewall) {
			throw new Error("Firewall doesn't supports");
		}
	}
	
	run () {
		const server = dgram.createSocket('udp4', (srvSocket) => {});
		const connections = {};
		// const connectionsTimeout = {};
		
		const remote = {
			ip: this.syntax.target.split(/:/)[0],
			port: this.syntax.target.split(/:/)[1],
		};
		
		server.on('error', (err) => {
			logger("Caught UDP server socket error: ");
			logger(err.stack);
		});
		
		server.on('connect', (peer) => {
			logger("connect event:", peer);
			if (!isFirewalled(peer.address)) {
				logger(`${peer.address}:${peer.port} connected!`);
				connections[`${peer.address}:${peer.port}`] = dgram.createSocket('udp4');
				connections[`${peer.address}:${peer.port}`].on('message', (data, rmt) => {
					if (`${rmt.address}:${rmt.port}` === `${remote.ip}:${remote.port}`) {
						logger(`to ${peer.address}:${peer.port} sended: ${data.length} bytes`);
						server.send(data, peer.port, peer.address, (err) => {
							if (err)
								logger(`error: ${peer.address}:${peer.port} throwed: ${err.name}`);
						});
					}
				});
			}
			else {
				logger(`${peer.address} firewalled, reject`);
			}
		});
		
		server.on('message', (data, peer) => {
			logger(`from ${peer.address}:${peer.port} attempt send to ${remote.ip}:${remote.port} ${data.length} bytes`);
			if (`${peer.address}:${peer.port}` !== `${remote.ip}:${remote.port}`) {
				logger(`from ${peer.address}:${peer.port} sended: ${data.length} bytes to ${remote.ip}:${remote.port}`);
				if (connections[`${peer.address}:${peer.port}`] === undefined) {
					server.emit("connect", peer);
				}
				if (connections[`${peer.address}:${peer.port}`] !== undefined) {
					connections[`${peer.address}:${peer.port}`].send(data, remote.port, remote.ip, (err) => {
						if (err)
							logger(`error: ${peer.address} (remote) throwed: ${err.name}`);
					});
				}
			}
		});
		
		server.on('listening', () => {
			const address = server.address();
			console.log(`UDP reverse proxy server listening on ${address.address}:${address.port}`);
		});
		
		server.bind(this.adr.port, this.adr.address, (err) => {
			if (err) throw err;
			console.log("UDP reverse proxy connected!");
		});
		
		server.on('error', (err) => {
			logger("Error of server");
			logger(err.stack);
		});
		
		this.server = server;
	}
}