/* Establishes all requirements for the server. */
var client = require("socket.io").listen(8001).sockets;
var mysql = require("mysql");
var colors = require("colors");
var crypto = require("crypto");
var sanitizer = require("sanitizer");
var fs = require("fs");

/* Declares all variables for the server config "file". */
var config = {
	host: "localhost",
	user: "root",
	password: "",
	database: "login"
};

/* Contains all users within the database. */
var users = {};
var awaitingReset = {};

/* The connection variable for the SQL database. */
var con;

/* Used to log any information with the current time and coloring. */
function log(text, color) {
	let d = new Date(),
		h = d.getHours(),
		m = d.getMinutes(),
		ap = "AM";

	if (h > 12) { h -= 12; ap = "PM"; }
	if (h === 12) { ap = "PM"; }
    if (m < 10) { m = "0" + m; }
    time = h + ":" + m + " " + ap;

    if (typeof(color) == "undefined") console.log(colors.grey(time) + ": " + text);

	console.log(colors.grey(time) + ": " + colors[color](text));
}

/* Attempts to establish a connection to the SQL database. */
function handleConnection() {
	con = mysql.createConnection(config);

	con.connect(function(err) {
		if (err) {
			log("An error has occurred while connection: " + err, "red");
			setTimeout(handleConnection, 2000);
		} else {
			log("Connection successful.", "green");
		}
	});

	con.on("error", function(err) {
		console.log("Error: " + err);
		if (err.code === "PROTOCOL_CONNECTION_LOST") {
			handleConnection();
		}

		throw err;
	});
}

/* Updates the SQL database when called. */
function updateSQLDatabase() {
	let set = [];

	for (let user in users) {
		set.push({username: user, password: users[user].password,
				  question: users[user].question, answer: users[user].answer});
	}

	con.query("TRUNCATE TABLE user", function(err, res) {
		if (err) log(err, "red");
	});

	for (let i = 0; i < set.length; i++) {
		con.query("INSERT INTO user SET ?", set[i], function(err, res) {
			if (err) log(err, "red");
		});
	}
}

function login(socket, data) {
	let cleanedUsername = sanitizer.sanitize(data["username"]),
	secret = 'tcL7YThah4PzdjTDSfJT',
	salt = '1DNmIP5Y51xu5E9hggHU',
	hashedPassword = crypto.createHmac('sha256', salt + data.password).update(secret).digest('hex');

	if (users[cleanedUsername] !== undefined) {
		if (users[cleanedUsername].password === hashedPassword) {
			socket.emit("login", {result: 0, info: "Successfully logged in.", username: cleanedUsername, code: genID(20)});
			log("> LOGIN: " + cleanedUsername, "cyan");
		} else {
			socket.emit("login", {result: 1, info: "Username or password is incorrect."});
		}
	} else {
		socket.emit("login", {result: 1, info: "Username or password is incorrect."});
	}
}

function register(socket, data) {
	let cleanedUsername = sanitizer.sanitize(data["username"]),
	secret = 'tcL7YThah4PzdjTDSfJT',
	salt = '1DNmIP5Y51xu5E9hggHU',
	hashedConfirmation = crypto.createHmac('sha256', salt + data.confirm).update(secret).digest('hex');
	hashedPassword = crypto.createHmac('sha256', salt + data.password).update(secret).digest('hex');

	if (users[cleanedUsername] === undefined) {
		if (hashedConfirmation === hashedPassword) {
			users[cleanedUsername] = {
				password: hashedPassword,
				question: data.question,
				answer: data.answer
			};

			socket.emit("register", {result: 0, info: "Successfully registered."});
			log("> REGISTER: " + cleanedUsername, "cyan");
			login(socket, data);
			updateSQLDatabase();

		} else {
			socket.emit("register", {result: 1, info: "Passwords do not match."});
		}
	} else {
		socket.emit("register", {result: 1, info: "Username already exists."});
	}
}

/* Adds all users from the SQL database to the users variable. */
function getUserList() {
	if (con) {
		con.query("SELECT * FROM user", function(err, res) {
			if (err) log(err, "red");

			for (let result in res) {
				users[res[result].username] = {
					password: res[result].password,
					question: res[result].question,
					answer: res[result].answer
				};
			}

			log("All current users have been loaded.", "green");
		});
	} else {
		log("Cannot load users as connection has not been established.", "red");
	}
}

/* Generates an alphanumeric string (also includes - and _) of desired length. */
function genID(length) {
	let chars = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVYXYZ-_',
		result = '';

	for (var i = length; i > 0; --i) result += chars[Math.floor(Math.random() * chars.length)];

    return result;
}

/* Methods/functions called upon server start up. */
handleConnection();
getUserList();

/* Declares all socket "on" and "emit" upon client connection. */
client.on("connection", function(socket) {

connectedClients.push(socket);

socket.on("disconnect", function(data) {
	if (connectedClients.indexOf(socket) > -1) connectedClients.splice(socket, 1);
});

socket.on("login", function(data) {
	login(socket, data);
});

socket.on("register", function(data) {
	register(socket, data);
});

socket.on("recovery", function(data) {
	switch (data.type) {
		case 0:
			if (users[data.username] !== undefined) {
				socket.emit("recovery", {type: 0, question: users[data.username].question});
			}
		break;

		case 1:
			if (users[data.username] !== undefined) {
				if (users[data.username].answer === data.answer) {
					awaitingReset[data.username] = {code: genID(20)};
					socket.emit("recovery", {type: 2, resetCode: awaitingReset[data.username].code})
				} else {
					socket.emit("recovery", {type: 3, info: "You answered the security question incorrectly."});
				}
			}
		break;

		case 4:
			let secret = 'tcL7YThah4PzdjTDSfJT',
				salt = '1DNmIP5Y51xu5E9hggHU';

			if (awaitingReset[data.username] !== undefined) {
				if (data.resetCode === awaitingReset[data.username].code) {
					users[data.username].password = crypto.createHmac('sha256', salt + data.password).update(secret).digest('hex');
					updateSQLDatabase();
					socket.emit("recovery", {type: 5});
					awaitingReset[data.username] = null;
					log(data.username + " has recovered their password.", "cyan");
				} else {
					log("Reset code incorrect for " + data.username + " - potential hack attempt.", "yellow");
				}
			}

		break;
	}
});

});