const dns = require('dns');
const fs = require('fs');
const path = require('path');
const config = require(__dirname+'/config');
const logger = require(__dirname+'/logger');
const webirc_data_path = path.resolve(__dirname+'/../webirc.data.json');

let webirc_data = {};
let timeouts = {};

function writeToFile() {
	fs.writeFile(webirc_data_path, JSON.stringify(webirc_data, null, '\t'), function (err) {if (err) throw err;});
}

function timeoutRefresh(address, seconds) {
	if(timeouts[address])
		clearTimeout(timeouts[address]);

	timeouts[address] = setTimeout(()=>{resolveAddress(address);}, seconds*1000);
}

function resolveAddress(address, force) {
	logger.debugLog('** WEBIRC ** Attempting to update IP for '+address);
	let obj = webirc_data[address];
	
	if(!obj) return;

	if((Date.now() - obj.last_update)/1000 < config.webirc.resolveInterval && !force) {
		let nextTime = (config.webirc.resolveInterval - (Date.now() - obj.last_update)/1000);
		
		logger.debugLog('** WEBIRC ** {0} IP is {1}, refresh in {2} seconds'.format(address, obj.cached_ip, Math.floor(nextTime)));

		return timeoutRefresh(address, nextTime);
	}

	new Promise((resolve, reject) => {
		if(address === '127.0.0.1' || address === '0.0.0.0' || address === 'localhost') {
			logger.debugLog('** WEBIRC ** Ignoring localhost entry..');
			return resolve('127.0.0.1');
		}
		
		dns.resolve(address, (err, data) => {
			if(err!=null) return reject(err);
			let ip = data.length > 0 ? data[0] : null;

			if(ip) {
				resolve(ip);
			} else {
				reject(new Error('no ips'));
			}
		});
	}).then((data) => {
		logger.debugLog('** WEBIRC ** Updated DNS for {0}; IP is now {1}'.format(address, data));

		webirc_data[address].last_update = Date.now();
		webirc_data[address].cached_ip = data;
		
		writeToFile();
		timeoutRefresh(address, config.webirc.resolveInterval);
	}, (err) => {
		logger.debugLog('** WEBIRC ** Failed to updated DNS for {0}; IP is still {1}'.format(address, webirc_data[address].cached_ip));

		timeoutRefresh(address, (config.webirc.resolveInterval+60));
	});
}

function reload(force) {
	if(!config.webirc.enabled) return;

	try {
		fs.accessSync(webirc_data_path, fs.F_OK);

		webirc_data = require(webirc_data_path);

		if (require.cache && require.cache[webirc_data_path]) {
			delete require.cache[webirc_data_path];
		}
	} catch(e) {
		writeToFile();
	}

	for(let adr in webirc_data) {
		resolveAddress(adr, force);
	}
}

function get_password(server_ip) {
	let ip = null;
	for(let a in webirc_data) {
		if(webirc_data[a].cached_ip == server_ip)
			ip = webirc_data[a];
	}

	return ip;
}

class WebIRCAuthenticator {
	constructor(userInfo) {
		this.userInfo = userInfo;
	}

	authenticate(connection) {
		let serverpass = get_password(connection.config.address);
		if(serverpass)
			connection.socket.write('WEBIRC {0} {1} {2} {3}\r\n'.format(serverpass.password, connection.config.username, 
				this.userInfo.hostname, this.userInfo.ipaddr));
	}
}

module.exports = {
	reload: reload,
	authenticator: WebIRCAuthenticator,
	get_password: get_password,
	writeToFile: writeToFile
};

process.on('SIGUSR1', () => {
	logger.log('\n!!! Received SIGUSR1; Reloading webirc data.. !!!\n');
	reload(true);
});

reload(false);