<?php

/**
 * Basic IRC client for fetching IRCScraper.
 *
 * Class IRCClient
 */
class IRCClient
{
	/**
	 * Hostname IRC server used when connecting.
	 *
	 * @var string
	 * @access protected
	 */
	protected $_remote_host = '';

	/**
	 * Port number IRC server.
	 *
	 * @var int
	 * @access protected
	 */
	protected $_remote_port = 6667;

	/**
	 * Socket transport type for the IRC server.
	 *
	 * @var string
	 * @access protected
	 */
	protected $_remote_transport = 'tcp';


	/**
	 * Hostname the IRC server sent us back.
	 *
	 * @var string
	 * @access protected
	 */
	protected $_remote_host_received = '';

	/**
	 * String used when creating the stream socket.
	 *
	 * @var string
	 * @access protected
	 */
	protected $_remote_socket_string = '';

	/**
	 * Are we using tls/ssl?
	 *
	 * @var bool
	 * @access protected
	 */
	protected $_remote_tls = false;

	/**
	 * Time in seconds to timeout on connect.
	 *
	 * @var int
	 * @access protected
	 */
	protected $_remote_connection_timeout = 30;

	/**
	 * Time in seconds before we timeout when sending/receiving a command.
	 *
	 * @var int
	 * @access protected
	 */
	protected $_socket_timeout = 180;

	/**
	 * How many times to retry when connecting to IRC.
	 *
	 * @var int
	 * @access protected
	 */
	protected $_reconnectRetries = 3;

	/**
	 * Seconds to delay when reconnecting fails.
	 *
	 * @var int
	 * @access protected
	 */
	protected $_reconnectDelay = 5;

	/**
	 * Stream socket client.
	 *
	 * @var resource
	 * @access protected
	 */
	protected $_socket = null;

	/**
	 * Buffer contents.
	 *
	 * @var string
	 * @access protected
	 */
	protected $_buffer = null;

	/**
	 * When someone types something into a channel, buffer it.
	 * array(
	 *     'nickname' => string(The nick name of the person who posted.),
	 *     'channel'  => string(The channel name.),
	 *     'message'  => string(The message the person posted.)
	 * );
	 *
	 * @note   Used with the processChannelMessages() function.
	 * @var array
	 * @access protected
	 */
	protected $_channelData = array();

	/**
	 * Nick name when we log in.
	 *
	 * @var string
	 * @access protected
	 */
	protected $_nickName;

	/**
	 * User name when we log in.
	 *
	 * @var string
	 * @access protected
	 */
	protected $_userName;

	/**
	 * "Real" name when we log in.
	 *
	 * @var string
	 * @access protected
	 */
	protected $_realName;

	/**
	 * Password when we log in.
	 *
	 * @var string
	 * @access protected
	 */
	protected $_password;

	/**
	 * List of channels and passwords to join.
	 *
	 * @var array
	 * @access protected
	 */
	protected $_channels;

	/**
	 * Last time we received a ping or sent a ping to the server.
	 *
	 * @var int
	 * @access protected
	 */
	protected $_lastPing;

	/**
	 * How many times we've tried to reconnect to IRC.
	 *
	 * @var int
	 * @access protected
	 */
	protected $_currentRetries = 0;

	/**
	 * Turns on or off debugging.
	 *
	 * @var bool
	 */
	protected $_debug = true;

	/**
	 * Are we already logged in to IRC?
	 *
	 * @var bool
	 */
	protected $_alreadyLoggedIn = false;

	/**
	 * Disconnect from IRC.
	 *
	 * @access public
	 */
	public function __destruct()
	{
		$this->quit();
	}

	/**
	 * Time before giving up when trying to read or write to the IRC server.
	 * The default is fine, it will ping the server if the server does not ping us
	 * within this time to keep the connection alive.
	 *
	 * @param int $timeout Seconds.
	 *
	 * @access public
	 */
	public function setSocketTimeout($timeout)
	{
		if (!is_numeric($timeout)) {
			echo 'ERROR: IRC socket timeout must be a number!' . PHP_EOL;
		} else {
			$this->_socket_timeout = $timeout;
		}
	}

	/**
	 * Amount of time to wait before giving up when connecting.
	 *
	 * @param int $timeout Seconds.
	 *
	 * @access public
	 */
	public function setConnectionTimeout($timeout)
	{
		if (!is_numeric($timeout)) {
			echo 'ERROR: IRC connection timeout must be a number!' . PHP_EOL;
		} else {
			$this->_remote_connection_timeout = $timeout;
		}
	}

	/**
	 * Amount of times to retry before giving up when connecting.
	 *
	 * @param int $retries
	 *
	 * @access public
	 */
	public function setConnectionRetries($retries)
	{
		if (!is_numeric($retries)) {
			echo 'ERROR: IRC connection retries must be a number!' . PHP_EOL;
		} else {
			$this->_reconnectRetries = $retries;
		}
	}

	/**
	 * Amount of time to wait between failed connects.
	 *
	 * @param int $delay Seconds.
	 *
	 * @access public
	 */
	public function setReConnectDelay($delay)
	{
		if (!is_numeric($delay)) {
			echo 'ERROR: IRC reconnect delay must be a number!' . PHP_EOL;
		} else {
			$this->_reconnectDelay = $delay;
		}
	}

	/**
	 * Connect to a IRC server.
	 *
	 * @param string $hostname Host name of the IRC server (can be a IP or a name).
	 * @param int    $port     Port number of the IRC server.
	 * @param bool   $tls      Use encryption for the socket transport? (make sure the port is right).
	 *
	 * @return bool
	 *
	 * @access public
	 */
	public function connect($hostname, $port = 6667, $tls = false)
	{
		$this->_alreadyLoggedIn = false;
		$transport = ($tls === true ? 'tls' : 'tcp');

		$socket_string = $transport . '://' . $hostname . ':' . $port;
		if ($socket_string !== $this->_remote_socket_string || !$this->_connected()) {
			if (!is_string($hostname) || $hostname == '') {
				echo 'ERROR: IRC host name must not be empty!' . PHP_EOL;

				return false;
			}

			if (!is_numeric($port)) {
				echo 'ERROR: IRC port must be a number!' . PHP_EOL;

				return false;
			}

			$this->_remote_host = $hostname;
			$this->_remote_port = $port;
			$this->_remote_transport = $transport;
			$this->_remote_tls = $tls;
			$this->_remote_socket_string = $socket_string;

			// Try to connect until we run out of retries.
			while ($this->_reconnectRetries >= $this->_currentRetries++) {
				$this->_initiateStream();
				if ($this->_connected()) {
					break;
				} else {
					// Sleep between retries.
					sleep($this->_reconnectDelay);
				}
			}
		} else {
			$this->_alreadyLoggedIn = true;
		}

		// Set last ping time to now.
		$this->_lastPing = time();
		// Reset retries.
		$this->_currentRetries = $this->_reconnectRetries;

		return $this->_connected();
	}

	/**
	 * Log in to a IRC server.
	 *
	 * @param string $nickName The nick name - visible in the channel.
	 * @param string $userName The user name - visible in the host name.
	 * @param string $realName The real name - visible in the WhoIs.
	 * @param null   $password The password  - some servers require a password.
	 *
	 * @return bool
	 *
	 * @access public
	 */
	public function login($nickName, $userName, $realName, $password = null)
	{
		if (!$this->_connected()) {
			echo 'ERROR: You must connect to IRC first!' . PHP_EOL;

			return false;
		}

		if (empty($nickName) || empty($userName) || empty($realName)) {
			echo 'ERROR: nick/user/real name must not be empty!' . PHP_EOL;

			return false;
		}

		$this->_nickName = $nickName;
		$this->_userName = $userName;
		$this->_realName = $realName;
		$this->_password = $password;

		if (($password !== null && !empty($password)) && !$this->_writeSocket('PASSWORD ' . $password)) {
			return false;
		}

		if (!$this->_writeSocket('NICK ' . $nickName)) {
			return false;
		}

		if (!$this->_writeSocket('USER ' . $userName . ' 0 * :' . $realName)) {
			return false;
		}

		// Loop over socket buffer until we find "001".
		while (true) {
			$this->_readSocket();

			// We got pinged, reply with a pong.
			if (preg_match('/^PING\s*:(.+?)$/', $this->_buffer, $matches)) {
				$this->_pong($matches[1]);

			} else if (preg_match('/^:(.*?)\s+(\d+).*?(:.+?)?$/', $this->_buffer, $matches)) {
				// We found 001, which means we are logged in.
				if ($matches[2] == 001) {
					$this->_remote_host_received = $matches[1];
					break;

					// We got 464, which means we need to send a password.
				} else if ($matches[2] == 464) {
					// Before the lower check, set the password : username:password
					$tempPass = $userName . ':' . $password;

					// Check if the user has his password in this format: username/server:password
					if (preg_match('/^.+?\/.+?:.+?$/', $password)) {
						$tempPass = $password;
					}

					if ($password !== null && !$this->_writeSocket('PASS ' . $tempPass)) {
						return false;
					} else if (isset($matches[3]) && strpos(strtolower($matches[3]), 'invalid password')) {
						echo 'Invalid password or username for (' . $this->_remote_host . ').';

						return false;
					}
				}
				//ERROR :Closing Link: kevin123[100.100.100.100] (This server is full.)
			} else if (preg_match('/^ERROR\s*:/', $this->_buffer)) {
				echo $this->_buffer . PHP_EOL;

				return false;
			}
		}

		return true;
	}

	/**
	 * Quit from IRC.
	 *
	 * @param string $message Optional disconnect message.
	 *
	 * @return bool
	 *
	 * @access public
	 */
	public function quit($message = null)
	{
		if ($this->_connected()) {
			$this->_writeSocket('QUIT' . ($message === null ? '' : ' :' . $message));
		}
		$this->_closeStream();

		return $this->_connected();
	}

	/**
	 * Read the incoming buffer in a loop.
	 *
	 * @access public
	 */
	public function readIncoming()
	{
		while (true) {

			$this->_readSocket();

			// If the server pings us, return it a pong.
			if (preg_match('/^PING\s*:(.+?)$/', $this->_buffer, $matches)) {
				if ($matches[1] === $this->_remote_host_received) {
					$this->_pong($matches[1]);
				}

				// Check for a channel message.
			} else if (preg_match('/^:(?P<nickname>.+?)\!.+?\s+PRIVMSG\s+(?P<channel>#.+?)\s+:\s*(?P<message>.+?)\s*$/',
				$this->_stripControlCharacters($this->_buffer),
				$matches
			)
			) {

				$this->_channelData =
					array(
						'nickname' => $matches['nickname'],
						'channel'  => $matches['channel'],
						'message'  => $matches['message']
					);

				$this->processChannelMessages();
			}

			// Ping the server if it has not sent us a ping in a while.
			if ((time() - $this->_lastPing) > ($this->_socket_timeout / 2)) {
				$this->_ping($this->_remote_host_received);
			}
		}
	}

	/**
	 * Join a channel or multiple channels.
	 *
	 * @param array $channels Array of channels with their passwords (null if the channel doesn't need a password).
	 *                        array( '#exampleChannel' => 'thePassword', '#exampleChan2' => null );
	 *
	 * @return bool
	 *
	 * @access public
	 */
	public function joinChannels($channels = array())
	{
		$this->_channels = $channels;

		if (!$this->_connected()) {
			echo 'ERROR: You must connect to IRC first!' . PHP_EOL;

			return false;
		}

		if (!empty($channels)) {
			foreach ($channels as $channel => $password) {
				$this->_joinChannel($channel, $password);
			}
		}

		return false;
	}

	/**
	 * Implementation.
	 * Extended classes will use this function to parse the messages in the channel using $this->_channelData.
	 *
	 * @access protected
	 */
	protected function processChannelMessages()
	{
	}

	/**
	 * Join a channel.
	 *
	 * @param string $channel
	 * @param string $password
	 *
	 * @access protected.
	 */
	protected function _joinChannel($channel, $password)
	{
		$this->_writeSocket('JOIN ' . $channel . ($password === null ? '' : ' ' . $password));
	}

	/**
	 * Send PONG to a host.
	 *
	 * @param string $host
	 *
	 * @access protected
	 */
	protected function _pong($host)
	{
		if ($this->_writeSocket('PONG ' . $host) === false) {
			$this->_reconnect();
		}

		// If we got a ping from the IRC server, set the last ping time to now.
		if ($host === $this->_remote_host_received) {
			$this->_lastPing = time();
		}
	}

	/**
	 * Send PING to a host.
	 *
	 * @param string $host
	 *
	 * @access protected
	 */
	protected function _ping($host)
	{
		$pong = $this->_writeSocket('PING ' . $host);

		// Check if there's a connection error.
		if ($pong === false || ((time() - $this->_lastPing) > ($this->_socket_timeout / 2) && !preg_match('/^PONG/', $this->_buffer))) {
			$this->_reconnect();
		}

		// If sent a ping from the IRC server, set the last ping time to now.
		if ($host === $this->_remote_host_received) {
			$this->_lastPing = time();
		}
	}

	/**
	 * Attempt to reconnect to IRC.
	 *
	 * @access protected
	 */
	protected function _reconnect()
	{
		if (!$this->connect($this->_remote_host, $this->_remote_port, $this->_remote_tls)) {
			exit('FATAL: Could not reconnect to (' . $this->_remote_host . ') after (' . $this->_reconnectRetries . ') tries.' . PHP_EOL);
		}

		if ($this->_alreadyLoggedIn === false) {
			if (!$this->login($this->_nickName, $this->_userName, $this->_realName, $this->_password)) {
				exit('FATAL: Could not log in to (' . $this->_remote_host . ')!' . PHP_EOL);
			}

			$this->joinChannels($this->_channels);
		}
	}

	/**
	 * Read response from the IRC server.
	 *
	 * @access protected
	 */
	protected function _readSocket()
	{
		$buffer = '';
		do {
			stream_set_timeout($this->_socket, $this->_socket_timeout);
			$buffer .= fgets($this->_socket, 1024);
		} while (!empty($buffer) && !preg_match('/\v+$/', $buffer));
		$this->_buffer = trim($buffer);

		if ($this->_debug && $this->_buffer !== '') {
			echo 'RECV ' . $this->_buffer . PHP_EOL;
		}
	}

	/**
	 * Send a command to the IRC server.
	 *
	 * @param string $command
	 *
	 * @return bool
	 *
	 * @access protected
	 */
	protected function _writeSocket($command)
	{
		$command .= "\r\n";
		for ($written = 0; $written < strlen($command); $written += $fWrite) {
			stream_set_timeout($this->_socket, $this->_socket_timeout);
			$fWrite = $this->_writeSocketChar(substr($command, $written));

			// http://www.php.net/manual/en/function.fwrite.php#96951 | fwrite can return 0 causing an infinite loop.
			if ($fWrite === false || $fWrite <= 0) {

				// If it failed, try a second time.
				$fWrite = $this->_writeSocketChar(substr($command, $written));
				if ($fWrite === false || $fWrite <= 0) {
					echo 'ERROR: Could no write to socket! (the IRC server might have closed the connection)' . PHP_EOL;

					return false;
				}
			}
		}

		if ($this->_debug) {
			echo 'SEND :' . $command;
		}

		return true;
	}

	/**
	 * Write a single character to the socket.
	 *
	 * @param string (char) $character A single character.
	 *
	 * @return int|bool Number of bytes written or false.
	 */
	protected function _writeSocketChar($character)
	{
		return @fwrite($this->_socket, $character);
	}

	/**
	 * Initiate stream socket to IRC server.
	 *
	 * @access protected
	 */
	protected function _initiateStream()
	{
		$this->_closeStream();

		$socket = stream_socket_client(
			$this->_remote_socket_string,
			$error_number,
			$error_string,
			$this->_remote_connection_timeout
		);

		if ($socket === false) {
			echo 'ERROR: ' . $error_string . ' (' . $error_number . ')' . PHP_EOL;
		} else {
			$this->_socket = $socket;
		}
	}

	/**
	 * Close the socket.
	 *
	 * @access protected
	 */
	protected function _closeStream()
	{
		if (!is_null($this->_socket)) {
			$this->_socket = null;
		}
	}

	/**
	 * Check if we are connected to the IRC server.
	 *
	 * @return bool
	 *
	 * @access protected
	 */
	protected function _connected()
	{
		return (is_resource($this->_socket) && !feof($this->_socket));
	}

	/**
	 * Strips control characters from a IRC message.
	 *
	 * @param string $text
	 *
	 * @return string
	 *
	 * @access protected
	 */
	protected function _stripControlCharacters($text)
	{
		return preg_replace(
			array(
				'/(\x03(?:\d{1,2}(?:,\d{1,2})?)?)/', // Color code
				'/\x02/', // Bold
				'/\x0F/', // Escaped
				'/\x16/', // Italic
				'/\x1F/', // Underline
				'/\x12/' // Device control 2
			),
			'',
			$text
		);
	}
}