<?php
/**
 * A class for an HTTP response on an HTTP request
 *
 * @author		Roland Haeder <webmaster@ship-simu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, this is free software
 * @license		GNU GPL 3.0 or any newer version
 * @link		http://www.ship-simu.org
 *
 * 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/>.
 *
 * The extended headers are taken from phpMyAdmin setup tool, written by
 * Michal Cihar <michal@cihar.com>, licensed under GNU GPL 2.0.
 */
class HttpResponse extends BaseFrameworkSystem implements Responseable {
	/**
	 * Response status
	 */
	private $responseStatus = "200 OK";

	/**
	 * Array with all headers
	 */
	private $responseHeaders = array();

	/**
	 * Cookies we shall sent out
	 */
	private $cookies = array();

	/**
	 * Body of the response
	 */
	private $responseBody = "";

	/**
	 * Instance of the template engine
	 */
	private $templateInstance = null;

	/**
	 * Fatal resolved messages from filters and so on
	 */
	private $fatalMessages = array();

	/**
	 * Protected constructor
	 *
	 * @return	void
	 */
	protected function __construct () {
		// Call parent constructor
		parent::__construct(__CLASS__);

		// Clean up a little
		$this->removeNumberFormaters();
		$this->removeSystemArray();
	}

	/**
	 * Creates an object of this class
	 *
	 * @param	$appInstance		An instance of a manageable application
	 * @return	$responseInstance	A prepared instance of this class
	 */
	public final static function createHttpResponse (ManageableApplication $appInstance) {
		// Get a new instance
		$responseInstance = new HttpResponse();

		// Set the application instance
		$responseInstance->setApplicationInstance($appInstance);

		// Initialize the template engine here
		$responseInstance->initTemplateEngine($appInstance);

		// Return the prepared instance
		return $responseInstance;
	}

	/**
	 * Setter for status
	 *
	 * @param	$status		New response status
	 * @return	void
	 */
	public final function setResponseStatus ($status) {
		$this->responseStatus = (string) $status;
	}

	/**
	 * Add header element
	 *
	 * @param	$name	Name of header element
	 * @param	$value	Value of header element
	 * @return	void
	 */
	public final function addHeader ($name, $value) {
		$this->responseHeaders[$name] = $value;
	}

	/**
	 * Reset the header array
	 *
	 * @return	void
	 */
	public final function resetResponseHeaders () {
		$this->responseHeaders = array();
	}

	/**
	 * "Writes" data to the response body
	 *
	 * @param	$output		Output we shall sent in the HTTP response
	 * @return	void
	 */
	public function writeToBody ($output) {
		$this->responseBody .= $output;
	}

	/**
	 * Sets the response body to something new
	 *
	 * @param	$output		Output we shall sent in the HTTP response
	 * @return	void
	 */
	public function setResponseBody ($output) {
		$this->responseBody = $output;
	}

	/**
	 * Flushs the cached HTTP response to the outer world
	 *
	 * @param	$force	Wether we shall force the output or abort if headers are
	 *					already sent with an exception
	 * @return	void
	 * @throws	ResponseHeadersAlreadySentException		Thrown if headers are
	 *													already sent
	 */
	public function flushBuffer ($force=false) {
		if ((headers_sent()) && (!$force)) {
			// Headers are already sent!
			throw new ResponseHeadersAlreadySentException($this, self::EXCEPTION_HEADERS_ALREADY_SENT);
		} elseif (!headers_sent()) {
			// Send headers out
			header("HTTP/1.1 {$this->responseStatus}");

			// Used later
			$now = gmdate('D, d M Y H:i:s') . ' GMT';

			// General header for no caching
			$this->addHeader('Expired', $now); // rfc2616 - Section 14.21
			$this->addHeader('Last-Modified', $now);
			$this->addHeader('Cache-Control', 'no-store, no-cache, must-revalidate, pre-check=0, post-check=0, max-age=0'); // HTTP/1.1
			$this->addHeader('Pragma', 'no-cache'); // HTTP/1.0

			// Define the charset to be used
			//$this->addHeader('Content-Type:', sprintf("text/html; charset=%s", $this->getConfigInstance()->readConfig('header_charset')));

			foreach ($this->responseHeaders as $name=>$value) {
				header("{$name}: {$value}");
			} // END - foreach

			// Send cookies out?
			if (count($this->cookies) > 0) {
				// Send all cookies
				$cookieString = implode(" ", $this->cookies);
				header("Set-Cookie: {$cookieString}");

				// Remove them all
				$this->cookies = array();
			} // END - if
		}

		// Are there some error messages?
		if (count($this->fatalMessages) == 0) {
			// Flush the output to the world
			$this->getWebOutputInstance()->output($this->responseBody);
		} else {
			// Display all error messages
			$this->getApplicationInstance()->handleFatalMessages($this->fatalMessages);

			// Send the error messages out to the world
			$this->getWebOutputInstance()->output($this->responseBody);
		}

		// Clear response header and body
		$this->setResponseBody("");
		$this->resetResponseHeaders();
	}

	/**
	 * Initializes the template engine instance
	 *
	 * @param	$appInstance	An instance of a manageable application
	 * @return	void
	 */
	public final function initTemplateEngine (ManageableApplication $appInstance) {
		$this->setTemplateInstance($this->prepareTemplateInstance($appInstance));
	}

	/**
	 * Adds a fatal message id to the response. The added messages can then be
	 * processed and outputed to the world
	 *
	 * @param	$messageId	The message id we shall add
	 * @return	void
	 */
	public final function addFatalMessage ($messageId) {
		// Adds the resolved message id to the fatal message list
		$this->fatalMessages[] = $this->getApplicationInstance()->getLanguageInstance()->getMessage($messageId);
	}

	/**
	 * Adds a cookie to the response
	 *
	 * @param	$cookieName		Cookie's name
	 * @param	$cookieValue	Value to store in the cookie
	 * @param	$encrypted		Do some extra encryption on the value
	 * @param	$expires		Timestamp of expiration (default: configured)
	 * @return	void
	 * @throws	ResponseHeadersAlreadySentException		If headers are already sent
	 * @todo	Encryption of cookie data not yet supported.
	 * @todo	Why are these parameters conflicting?
	 * @todo	If the return statement is removed and setcookie() commented out,
	 * @todo	this will send only one cookie out, the first one.
	 */
	public function addCookie ($cookieName, $cookieValue, $encrypted = false, $expires = null) {
		//* DEBUG: */ echo $cookieName."=".$cookieValue."<br />\n";
		// Are headers already sent?
		if (headers_sent()) {
			// Throw an exception here
			//* DEBUG: */ return;
			throw new ResponseHeadersAlreadySentException($this, self::EXCEPTION_HEADERS_ALREADY_SENT);
		} // END - if

		// Shall we encrypt the cookie?
		if ($encrypted === true) {
		} // END - if

		// For slow browsers set the cookie array element first
		$_COOKIE[$cookieName] = $cookieValue;

		// Get all config entries
		if (is_null($expires)) {
			$expires = (time() + $this->getConfigInstance()->readConfig('cookie_expire'));
		} // END - if

		$path = $this->getConfigInstance()->readConfig('cookie_path');
		$domain = $this->getConfigInstance()->readConfig('cookie_domain');

		setcookie($cookieName, $cookieValue, $expires);
		//, $path, $domain, (isset($_SERVER['HTTPS']))
		return;

		// Now construct the full header
		$cookieString = $cookieName . "=" . $cookieValue . "; ";
		$cookieString .= "expires=" . date("D, d-F-Y H:i:s", $expires) . " GMT";
		// $cookieString .= "; path=".$path."; domain=".$domain;

		// Set the cookie as a header
		$this->cookies[$cookieName] = $cookieString;
	}

	/**
	 * Redirect to a configured URL. The URL can be absolute or relative. In
	 * case of relative URL it will be extended automatically.
	 *
	 * @param	$configEntry	The configuration entry which holds our URL
	 * @return	void
	 * @throws	ResponseHeadersAlreadySentException		If headers are already sent
	 */
	public function redirectToConfiguredUrl ($configEntry) {
		// Is the header not yet sent?
		if (headers_sent()) {
			// Throw an exception here
			throw new ResponseHeadersAlreadySentException($this, self::EXCEPTION_HEADERS_ALREADY_SENT);
		} // END - if

		// Get the url from config
		$url = $this->getConfigInstance()->readConfig($configEntry);

		// Do we have a "http" in front of the URL?
		if (substr(strtolower($url), 0, 4) != "http") {
			// Is there a / in front of the relative URL?
			if (substr($url, 0, 1) == "/") $url = substr($url, 1);

			// No, then extend it with our base URL
			$url = $this->getConfigInstance()->readConfig('base_url') . "/" . $url;
		} // END - if

		// Add redirect header
		$this->addHeader("Location", $url);

		// Set correct response status
		$this->setResponseStatus("301 Moved Permanently");

		// Clear the body
		$this->setResponseBody("");

		// Flush the result
		$this->flushBuffer();

		// All done here...
		exit();
	}

	/**
	 * Expires the given cookie if it is set
	 *
	 * @param	$cookieName		Cookie to expire
	 * @return	void
	 */
	public function expireCookie ($cookieName) {
		// Is the cookie there?
		if (isset($_COOKIE[$cookieName])) {
			// Then expire it with 20 minutes past
			$this->addCookie($cookieName, "", false, (time() - 1200));

			// Remove it from array
			unset($_COOKIE[$cookieName]);
		} // END - if
	}

	/**
	 * Refreshs a given cookie. This will make the cookie live longer
	 *
	 * @param	$cookieName		Cookie to refresh
	 * @return	void
	 */
	public function refreshCookie ($cookieName) {
		// Only update existing cookies
		if (isset($_COOKIE[$cookieName])) {
			// Update the cookie
			$this->addCookie($cookieName, $_COOKIE[$cookieName], false);
		} // END - if
	}

	/**
	 * Getter for default command
	 *
	 * @return	$defaultCommand		Default command for this response
	 */
	public function getDefaultCommand () {
		$defaultCommand = $this->getConfigInstance()->readConfig('default_web_command');
		return $defaultCommand;
	}
}

// [EOF]
?>