<?php
class system {
	public function __construct() {
		# Allows access to the database
		global $database;

		# Make sure we are connected to the database
		$database->connectToDatabase();
	}

	# Checks if the user is logged in, if they are it returns true, else false
	public function loggedin() {
		# Allows access to the database
		global $database;

		# If the session hasn't already been started, start one
		if (!isset($_SESSION)) {
			session_start();
		}

		# Check if the username and password sessions are set, if they are then the user is logged in
		if (isset($_SESSION['sys_username']) AND isset($_SESSION['sys_password'])) {
			return true;
		}
		else {
			# Not logged in, return false
			return false;
		}
	}

	# Returns the current user's username
	public function username() {
		# Allows access to the database
		global $database;

		# If the session hasn't already been started, start one
		if (!isset($_SESSION)) {
			session_start();
		}

		# Returns the value of the 'sys_username' session
		return $_SESSION['sys_username'];
	}

	# Returns the current user's email
	public function email() {
		# Allows access to the database
		global $database;

		# If the session hasn't already been started, start one
		if (!isset($_SESSION)) {
			session_start();
		}

		# Returns the value of the 'sys_email' session
		return $_SESSION['sys_email'];
	}

	# Function to prevent MySQL injection
	public function clean($string) {
		# Allows access to the database
		global $database;

		# Clean $string
		$string = stripslashes($string);
		$string = mysql_real_escape_string($string);

		# Send back the cleaned string
		return $string;
	}

	# Retrieve the salt for a user from the database
	public function retrieveSalt($username) {
		# Clean the username
		$username = $this->clean($username);

		# Query database to retrieve salt
		$sql = "SELECT salt FROM users WHERE username='$username'";
		$result = mysql_query($sql);

		# Get the results from the database
		$res = mysql_fetch_array($result);

		# Retrieve the result from the array
		$salt = $res['salt'];

		# Returns the salt
		return $salt;
	}

	# Check if a username and password combination is valid, returns true if valid, else false
	public function validate($username, $password) {
		# Allows access to the database
		global $database;

		# Check if the IP address is banned
		if (!$this->checkIPBanned($_SERVER['REMOTE_ADDR'])) {
			# The IP address is not banned, continue as normal

			# Clean the username and password to prevent injection
			$username = $this->clean($username);
			$password = $this->clean($password);

			# Get the user's salt
			$salt = $this->retrieveSalt($username);

			# MD5 the password
			$password = md5($salt . $password);

			# Search for records where username and password match
			$sql = "SELECT * FROM users WHERE username='$username' AND password='$password'";
			$result = mysql_query($sql);

			# Count the number of returned rows
			$count = mysql_num_rows($result);

			# If the rows returned are equal to or greater than 1, the username and password are valid
			if ($count >= 1) {
				# If session hasnt been started, start one
				if (!isset($_SESSION)) {
					session_start();
				}

				# Get the returned results
				$result = mysql_fetch_array($result);

				# Check if the user is banned
				if ($result['usergroup'] == "banned") {
					# User is banned, return false (fail)
					return false;
				}
				else {
					# Set the results from the query as sessions
					$_SESSION['sys_username'] = $result['username'];
					$_SESSION['sys_password'] = $result['password'];
					$_SESSION['sys_email'] = $result['email'];

					# Get the user's IP address and clean it
					$ip = $this->clean($_SERVER['REMOTE_ADDR']);

					# The user has logged in successfully, delete all entries from the authentication logs
					$sql = "DELETE FROM authentication_fails_log WHERE ip='$ip'";
					mysql_query($sql);

					# Return true as login was successful
					return true;
				}
			}
			else {
				# Return false (failed)
				return false;
			}
		}
		else {
			# The IP address is banned, return false (fail)
			return false;
		}
	}

	# Logs the user out
	public function logout() {
		# Unset the session variables
		unset($_SESSION['sys_username']);
		unset($_SESSION['sys_password']);
		unset($_SESSION['sys_email']);
	}

	# Generates a random string
	public function generateRandom($length) {
		# Characters that can be used in the string
		$characters = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

		# Just set the variable so that we dont get errors appending it
		$string = "";

		# Create the random string
		for ($p = 0; $p < $length; $p++) {
			$string .= $characters[mt_rand(0, strlen($characters) - 1)];
		}

		return $string;
	}

	public function recover($username) {
		# Allows access to the database
		global $database;

		# Clean the userame
		$username = $this->clean($username);

		# Search if there are any users with the entered username
		$sql = "SELECT * FROM users WHERE username='$username'";
		$result = mysql_query($sql);

		# Count the number of rows
		$count = mysql_num_rows($result);

		# If the number or results is equal to or greater than 1, it is a valid username
		if ($count <= 1) {
			# Fetch the results of the query so that we can get the user's email address
			$res = mysql_fetch_array($result);

			# Get the user's email address from the results array
			$to = $res['email'];

			# The subject for the email
			$subject = "Password Recovery";

			$random_password = $this->generateRandom(6);

			# Get the MD5 version of the password which is what we put in the database
			$random_password_md5 = md5($random_password);

			# Update the user's password in the database
			$sql1 = "UPDATE users SET password='$random_password_md5' WHERE username='$username'";
			$result1 = mysql_query($sql1);

			# Check if the update was successful
			if (!$result1) {
				# Didn't change, exit
				return false;
			}
			else {
				# The body of the email
				$body = "We recieved a request to reset the password for your account at Twaddlr from " . $_SERVER['REMOTE_ADDR'] . "\n\nUsername: " . $username . "\nPassword: " . $random_password;

				# Check if the email was sent successfully
				if (mail($to, $subject, $body)) {
					# Sent successfully, the function has succeeded
					return true;
				}
				else {
					# Send failed, the subject has not succeeded
					return false;
				}
			}
		}
	}

	public function changePassword($username, $oldPassword, $newPassword) {
		# Allows access to the database
		global $database;

		# Clean the strings
		$username = $this->clean($username);
		$oldPassword = $this->clean($oldPassword);
		$newPassword = $this->clean($newPassword);

		# Check if the username and password match
		if ($this->validate($username, $oldPassword)) {
			# Retrieve the user's salt
			$salt = $this->retrieveSalt($username);

			# Encrypt the new password
			$newPassword = md5($salt . $newPassword);

			# Update the user's password
			$sql = "UPDATE users SET password='$newPassword' WHERE username='$username'";
			$result = mysql_query($sql);

			# Check if it was successful or not
			if ($result) {
				# Changed successfully, return true
				return true;
			}
			else {
				# Change failed, return false
				return false;
			}
		}
		else {
			# Username and password were not correct, function failed
			return false;
		}
	}

	public function changeEmail($username, $password, $newEmail) {
		# Allows access to the database
		global $database;

		# Clean the submitted data
		$username = $this->clean($username);
		$password = $this->clean($password);
		$newEmail = $this->clean($newEmail);

		# Check if the username and password are valid
		if ($this->validate($username, $password)) {
			# Username and password are valid
			$sql = "UPDATE users SET email='$newEmail' WHERE username='$username'";
			$result = mysql_query($sql);

			# Check if the field was updated successfuly
			if ($result) {
				# It was updated, return true (success)
				return true;
			}
			else {
				# Could not update the field, return false (fail)
				return false;
			}
		}
		else {
			# Username and password were wrong, return false (fail)
			return false;
		}
	}

	# Check if a username is already in use
	public function usernameAvalible($username) {
		# Clean the input
		$username = $this->clean($username);

		# Select all rows from the database where username matches
		$sql = "SELECT * FROM users WHERE username='$username'";
		$result = mysql_query($sql);

		# Count the number of rows returned
		$count = mysql_num_rows($result);

		# Check if $count is equal to or greater than 1
		if ($count == 0) {
			# No rows returned. The username is avalible. Return true (success)
			return true;
		}
		else {
			# Rows returned. The username is in use. Return false (failed)
			return false;
		}
	}

	# Register a user
	public function register($username, $password, $email) {
		# Check if the username is avalible
		if (!$this->usernameAvalible($username)) {
			# The username is taken, return false (failed)
			return false;
		}
		else {
			# Get the user's IP address
			$ip = $_SERVER['REMOTE_ADDR'];

			# Clean the inputs
			$username = $this->clean($username);
			$password = $this->clean($password);
			$email = $this->clean($email);
			$ip = $this->clean($ip);

			# Generates a salt
			$salt = $this->generateRandom(10);

			# Encrypt the password
			$password = md5($salt . $password);

			# Insert them into the database
			$sql = "INSERT INTO users (username, password, salt, email, signup_ip) VALUES ('$username', '$password', '$salt', '$email', '$ip')";
			$result = mysql_query($sql);

			# Check if the query was successful
			if ($result) {
				# Query was successful, return true (success)
				return true;
			}
			else {
				# Query was not successful, return false (fail)
				return false;
			}
		}
	}

	# Check if a user is banned
	public function checkBanned($username) {
		# Clean the username
		$username = $this->clean($username);

		# Get the rows in bannedips relevant to the username
		$sql = "SELECT * FROM users WHERE username='$username' AND group='banned'";
		$result = mysql_query($sql);

		# Get the number of rows returned
		$count = mysql_num_rows($result);

		# If the count is equal to 0, they are not banned
		if ($count == 0) {
			# The user is not banned, return false;
			return false;
		}
		else {
			# The user is banned, return true
			return true;
		}
	}

	# Check if an IP address is banned from logging in
	public function checkIPBanned($ip) {
		# Clean the IP address of the user
		$ip = $this->clean($ip);

		# Get the rows in bannedips relevant to the IP address
		$sql = "SELECT * FROM bannedips WHERE ip='$ip'";
		$result = mysql_query($sql);

		# Get the number of rows returned
		$count = mysql_num_rows($result);

		# If the count is equal to 0, they are not banned
		if ($count == 0) {
			# The IP address is not banned, return false
			return false;
		}
		else {
			# The IP address is banned, return true
			return true;
		}
	}

	# Verifies if an email is valid
	public function verifyEmail($email) {
		if (!preg_match( "/^([a-zA-Z0-9])+([a-zA-Z0-9\._-])*@([a-zA-Z0-9_-])+([a-zA-Z0-9\._-]+)+$/", $email)) {
			return false;
		}
		else {
			return true;
		}
	}

	####################################################################################################
	## ADMIN FUNCTIONS #################################################################################
	####################################################################################################

	# Function to ban users
	public function banUser($username) {
		# Clean the username
		$username = $this->clean($username);

		# Update the user's group as banned
		$sql = "UPDATE users SET usergroup='banned' WHERE username='$username'";
		$result = mysql_query($sql);

		# Check if the query was successful
		if ($result) {
			# Query successful, user is banned, return true
			return true;
		}
		else {
			# Query was not successful, could not ban user, return false
			return false;
		}
	}

	# Function to unban users
	public function unbanUser($username) {
		# Clean the username
		$username = $this->clean($username);

		# Update the user's group as banned
		$sql = "UPDATE users SET usergroup='user' WHERE username='$username'";
		$result = mysql_query($sql) or die(mysql_error());

		# Check if the query was successful
		if ($result) {
			# Query successful, user has been unbanned, return true
			return true;
		}
		else {
			# Query was not successful, could not unban user, return false
			return false;
		}
	}

	# Function to ban IP addresses
	public function banIP($ip, $reason = NULL) {
		# Clean the IP address and $reason
		$ip = $this->clean($ip);
		$reason = $this->clean($reason);

		# Insert the IP address and reason into the database
		$sql = "INSERT INTO bannedips (ip, reason) VALUES ('$ip', '$reason')";
		$result = mysql_query($sql);

		# Check if the query was successful
		if ($result) {
			# Query successful, return true
			return true;
		}
		else {
			# Query was not successful, return false
			return false;
		}
	}

	# Function to un-ban IP addresses
	public function unbanIP($ip) {
		# Clean the IP address
		$ip = $this->clean($ip);

		# Delete the rows where the IP address is mentioned
		$sql = "DELETE FROM bannedips WHERE ip='$ip'";
		$result = mysql_query($sql);

		# Check if the query was successful
		if ($result) {
			# Query successful, return true
			return true;
		}
		else {
			# Query was not successful, return false
			return false;
		}
	}

	# Function to retrieve the reason for an IP address being banned
	public function reasonForIPBan($ip) {
		# Clean the IP address
		$ip = $this->clean($ip);

		# Get the row where it is banned
		$sql = "SELECT * FROM bannedips WHERE ip='$ip'";
		$result = mysql_query($sql);

		# Count the number of rows returned
		$count = mysql_num_rows($result);

		# If $count is equal to or greater than 1, then the IP is banned
		if ($count == 0) {
			# IP address is not banned, message to be returned
			$reason = "This IP address does not appear to be banned";

			# Return reason
			return $reason;
		}
		else {
			# IP address is banned, get the row's contents
			$result = mysql_fetch_array($result);

			# Get the reason
			$reason = $result['reason'];

			if ($reason == "") {
				$reason = "No reason specified";
			}

			# Return the reason
			return $reason;
		}
	}
}

$system = new system;
?>