<?php
/**
 *  Copyright (C) 2010  Kai Dorschner
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @author Kai Dorschner <the-hide@address.com>
 * @copyright Copyright 2010, Kai Dorschner
 * @license http://www.gnu.org/licenses/gpl.html GPLv3
 * @package mocovi
 * @subpackage helpers
 */

/**
 * Require MVC Exception
 */
class_exists('MvcException')		or require $GLOBALS['library'].'autoload/MvcException.php';
interface_exists('EventListener')	or require $GLOBALS['library'].'autoload/EventListener.php';

/**
 * Modifies HTTP Header
 *
 * @package mocovi
 */
class Header implements EventListener
{
	protected $statuscodes = array
	( 100 => 'Continue'
	, 101 => 'Switching Protocols'
	, 200 => 'OK'
	, 201 => 'Created'
	, 202 => 'Accepted'
	, 203 => 'Non-Authoritative Information'
	, 204 => 'No Content'
	, 205 => 'Reset Content'
	, 206 => 'Partial Content'
	, 300 => 'Multiple Choices'
	, 301 => 'Moved Permanently'
	, 302 => 'Found'
	, 303 => 'See Other'
	, 304 => 'Not Modified'
	, 305 => 'Use Proxy'
	, 307 => 'Temporary Redirect'
	, 400 => 'Bad Request'
	, 401 => 'Unauthorized'
	, 402 => 'Payment Required'
	, 403 => 'Forbidden'
	, 404 => 'Not Found'
	, 405 => 'Method Not Allowed'
	, 406 => 'Not Acceptable'
	, 407 => 'Proxy Authentication Required'
	, 408 => 'Request Timeout'
	, 409 => 'Conflict'
	, 410 => 'Gone'
	, 411 => 'Length Required'
	, 412 => 'Precondition Failed'
	, 413 => 'Request Entity Too Large'
	, 414 => 'Request-URI Too Long'
	, 415 => 'Unsupported Media Type'
	, 416 => 'Requested Range Not Satisfiable'
	, 417 => 'Expectation Failed'
	, 500 => 'Internal Server Error'
	, 501 => 'Not Implemented'
	, 502 => 'Bad Gateway'
	, 503 => 'Service Unavailable'
	, 504 => 'Gateway Timeout'
	, 505 => 'HTTP Version Not Supported'
	);

	/**
	 * Var containing the singleton instance.
	 */
	protected static $instance;
	/**
	 * Flag which indicated wether the header has already been sent.
	 *
	 * @access private
	 */
	protected $sent = false;

	/**
	 * Internal header buffer.
	 *
	 * Saves all header strings.
	 *
	 * @access protected
	 */
	protected $buffer = array();

	protected $cookiesBuffer = array();

	/**
	 * Singleton-pattern constructor set protected to deny direct access.
	 */
	protected function __construct()
	{
		$this->sent = headers_sent();
	}

	public function __destruct() {return $this->sendHeader();}


	/**
	 * Singleton-pattern method to get instance.
	 */
	public static function getInstance()
	{
		if(!isset($instance))
			self::$instance = new Header();
		return self::$instance;
	}

	public function sendHeader()
	{
		if(!$this->sent && !headers_sent())
		{
			foreach($this->buffer as $part)
				if(strlen($part[1]) > 0)
					header($part[0].': '.$part[1]);
				else
					header($part[0]);
			$this->sendCookies();
			return true;
		}
		$this->sent = true;
		return false;
	}

	public function sendCookies()
	{
		$return = true;
		foreach($this->cookiesBuffer as $cookie)
			$return &= setcookie($cookie['name'], $cookie['value'], $cookie['expire']);
		return $return;
	}

	public function addCookie($name, $value, $expire)
	{
		$this->cookiesBuffer[] = array
			( 'name'	=> $name
			, 'value'	=> $value
			, 'expire'	=> $expire
			);
	}

	public function notModified()
	{
		$this->status(304);
	}

	public function location($location)
	{
		$this->add('Location', $location);
	}

	public function contentType($media, $charset = '')
	{
		$this->add('Content-Type', $media.(empty($charset) ? '': '; charset='.$charset));
	}

	public function contentDisposition($filename, $disposition = 'inline')
	{
		$this->add('Content-Disposition', $disposition.'; filename="'.$filename.'"');
	}

	public function contentLength($length)
	{
		$this->add('Content-Length', (int)$length);
	}

	public function status($statuscode)
	{
		$this->add('HTTP/1.1 '.$statuscode.' '.$this->statuscodes[$statuscode]);
	}

	public function lastModified($date)
	{
		$this->add('Last-Modified', $date);
	}

	public function etag($etag)
	{
		$this->add('Etag', $etag);
	}

	public function triggerEvent(&$context)
	{
		$this->sendHeader();
	}

	protected function add($type, $value = '')
	{
		if(!($this->sent = headers_sent()))
		{
			$type[0] = strtoupper($type[0]);
			$this->buffer[] = array($type, $value);
		}
		else
			throw new MvcException('Cannot add a buffer. Header already sent.');
	}
}