<?php
/*
 * Copyright � 2003-2010, The ESUP-Portail consortium & the JA-SIG Collaborative.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *		 * Redistributions of source code must retain the above copyright notice,
 *			 this list of conditions and the following disclaimer.
 *		 * Redistributions in binary form must reproduce the above copyright notice,
 *			 this list of conditions and the following disclaimer in the documentation
 *			 and/or other materials provided with the distribution.
 *		 * Neither the name of the ESUP-Portail consortium & the JA-SIG
 *			 Collaborative nor the names of its contributors may be used to endorse or
 *			 promote products derived from this software without specific prior
 *			 written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

require_once(dirname(__FILE__).'/../Abstract.php');
require_once(dirname(__FILE__).'/../Http.php');
include_once(dirname(__FILE__).'/../Exception.php');
include_once(dirname(__FILE__).'/../../InvalidArgumentException.php');
include_once(dirname(__FILE__).'/../../OutOfSequenceException.php');


/**
 * This class implements common methods for ProxiedService implementations included
 * with phpCAS.
 */
abstract class CAS_ProxiedService_Http_Abstract
	extends CAS_ProxiedService_Abstract
	implements CAS_ProxiedService_Http
{
	/**
	 * The HTTP request mechanism talking to the target service.
	 *
	 * @var CAS_RequestInterface $_requestHandler
	 */
	protected $_requestHandler;
	
	/**
	 * The storage mechanism for cookies set by the target service.
	 *
	 * @var CAS_CookieJar $_cookieJar
	 */
	private $_cookieJar;
	
	/**
	 * Constructor.
	 * 
	 * @param CAS_RequestInterface $requestHandler
	 * @param CAS_CookieJar $cookieJar
	 * @return void
	 */
	public function __construct (CAS_RequestInterface $requestHandler, CAS_CookieJar $cookieJar) {
		$this->_requestHandler = $requestHandler;
		$this->_cookieJar = $cookieJar;
	}
	
	/**
	 * The target service url.
	 * @var string $_url;
	 */
	private $_url;
	
	/**
	 * Answer a service identifier (URL) for whom we should fetch a proxy ticket.
	 * 
	 * @return string
	 * @throws Exception If no service url is available.
	 */
	public function getServiceUrl () {
		if (empty($this->_url))
			throw new CAS_ProxiedService_Exception('No URL set via '.get_class($this).'->setUrl($url).');
		
		return $this->_url;
	}
	
	/*********************************************************
	 * Configure the Request
	 *********************************************************/

	/**
	 * Set the URL of the Request
	 *
	 * @param string $url
	 * @return void
	 * @throws CAS_OutOfSequenceException If called after the Request has been sent.
	 */
	public function setUrl ($url) {
		if ($this->hasBeenSent())
			throw new CAS_OutOfSequenceException('Cannot set the URL, request already sent.');
		if (!is_string($url))
			throw new CAS_InvalidArgumentException('$url must be a string.');
		
		$this->_url = $url;
	}
	
	/*********************************************************
	 * 2. Send the Request
	 *********************************************************/

	/**
	 * Perform the request.
	 *
	 * @return void
	 * @throws CAS_OutOfSequenceException If called multiple times.
	 * @throws CAS_ProxyTicketException If there is a proxy-ticket failure.
	 *		The code of the Exception will be one of: 
	 *			PHPCAS_SERVICE_PT_NO_SERVER_RESPONSE 
	 *			PHPCAS_SERVICE_PT_BAD_SERVER_RESPONSE
	 *			PHPCAS_SERVICE_PT_FAILURE
	 * @throws CAS_ProxiedService_Exception If there is a failure sending the request to the target service.
	 */
	public function send () {
		if ($this->hasBeenSent())
			throw new CAS_OutOfSequenceException('Cannot send, request already sent.');
		
		phpCAS::traceBegin();
		
		// Get our proxy ticket and append it to our URL.
		$this->initializeProxyTicket();
		$url = $this->getServiceUrl();
		if ( strstr($url,'?') === FALSE ) {
			$url = $url.'?ticket='.$this->getProxyTicket();
		} else {
			$url = $url.'&ticket='.$this->getProxyTicket();
		}
		
		try {
			$this->makeRequest($url);
		} catch (Exception $e) {
			phpCAS::traceEnd();
			throw $e;
		}
	}
	
	/**
	 * Indicator of the number of requests (including redirects performed.
	 *
	 * @var int $_numRequests;  
	 */
	private $_numRequests = 0;
	
	/**
	 * The response headers.
	 *
	 * @var array $_responseHeaders;  
	 */
	private $_responseHeaders = array();
	
	/**
	 * The response status code.
	 *
	 * @var string $_responseStatusCode;  
	 */
	private $_responseStatusCode = '';
	
	/**
	 * The response headers.
	 *
	 * @var string $_responseBody;  
	 */
	private $_responseBody = '';
	
	/**
	 * Build and perform a request, following redirects
	 * 
	 * @param string $url
	 * @return void
	 * @throws CAS_ProxyTicketException If there is a proxy-ticket failure.
	 *		The code of the Exception will be one of: 
	 *			PHPCAS_SERVICE_PT_NO_SERVER_RESPONSE 
	 *			PHPCAS_SERVICE_PT_BAD_SERVER_RESPONSE
	 *			PHPCAS_SERVICE_PT_FAILURE
	 * @throws CAS_ProxiedService_Exception If there is a failure sending the request to the target service.
	 */
	protected function makeRequest ($url) {
		// Verify that we are not in a redirect loop
		$this->_numRequests++;
		if ($this->_numRequests > 4) {
			$message = 'Exceeded the maximum number of redirects (3) in proxied service request.';
			phpCAS::trace($message);
			throw new CAS_ProxiedService_Exception($message);
		}
		
		// Create a new request.
		$request = clone $this->_requestHandler;
		$request->setUrl($url);
		
		// Add any cookies to the request.
		$request->addCookies($this->_cookieJar->getCookies($url));
		
		// Add any other parts of the request needed by concrete classes
		$this->populateRequest($request);
		
		// Perform the request.
		phpCAS::trace('Performing proxied service request to \''.$url.'\'');
		if (!$request->send()) {
			$message = 'Could not perform proxied service request to URL`'.$url.'\'. '.$request->getErrorMessage();
			phpCAS::trace($message);
			throw new CAS_ProxiedService_Exception($message);
		}
		
		// Store any cookies from the response;
		$this->_cookieJar->storeCookies($url, $request->getResponseHeaders());
		
		// Follow any redirects
		if ($redirectUrl = $this->getRedirectUrl($request->getResponseHeaders())) {
			phpCAS :: trace('Found redirect:'.$redirectUrl);
			$this->makeRequest($redirectUrl);
		} else {
			
			$this->_responseHeaders = $request->getResponseHeaders();
			$this->_responseBody = $request->getResponseBody();
			$this->_responseStatusCode = $request->getResponseStatusCode();
		}
	}
	
	/**
	 * Add any other parts of the request needed by concrete classes
	 * 
	 * @param CAS_RequestInterface $request
	 * @return void
	 */
	abstract protected function populateRequest (CAS_RequestInterface $request);
	
	/**
	 * Answer a redirect URL if a redirect header is found, otherwise null.
	 * 
	 * @param array $responseHeaders
	 * @return string or null
	 */
	private function getRedirectUrl (array $responseHeaders) {
		// Check for the redirect after authentication
		foreach($responseHeaders as $header){
			if (preg_match('/^(Location:|URI:)\s*([^\s]+.*)$/', $header, $matches)) {
				return trim(array_pop($matches));
			}
		}
		return null;
	}

	/*********************************************************
	 * 3. Access the response
	 *********************************************************/
	
	/**
	 * Answer true if our request has been sent yet.
	 * 
	 * @return boolean
	 */
	protected function hasBeenSent () {
		return ($this->_numRequests > 0);
	}

	/**
	 * Answer the headers of the response.
	 *
	 * @return array An array of header strings.
	 * @throws CAS_OutOfSequenceException If called before the Request has been sent.
	 */
	public function getResponseHeaders () {
		if (!$this->hasBeenSent())
			throw new CAS_OutOfSequenceException('Cannot access response, request not sent yet.');
		
		return $this->_responseHeaders;
	}
	
	/**
	 * Answer HTTP status code of the response
	 *
	 * @return integer
	 * @throws CAS_OutOfSequenceException If called before the Request has been sent.
	 */
	public function getResponseStatusCode () {
		if (!$this->hasBeenSent())
			throw new CAS_OutOfSequenceException('Cannot access response, request not sent yet.');
		
		return $this->_responseStatusCode;
	}

	/**
	 * Answer the body of response.
	 *
	 * @return string
	 * @throws CAS_OutOfSequenceException If called before the Request has been sent.
	 */
	public function getResponseBody () {
		if (!$this->hasBeenSent())
			throw new CAS_OutOfSequenceException('Cannot access response, request not sent yet.');
		
		return $this->_responseBody;
	}
	
}