<?php
  
  /**
   * ownCloud - App Framework
   *
   * @author Bernhard Posselt, Thomas Tanghus, Bart Visscher

   * @copyright 2012 Bernhard Posselt <dev@bernhard-posselt.com>

   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
   * License as published by the Free Software Foundation; either
   * version 3 of the License, or any later version.
   *
   * This library 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 AFFERO GENERAL PUBLIC LICENSE for more details.
   *
   * You should have received a copy of the GNU Affero General Public
   * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
   *
   */
  
  
  namespace OC\AppFramework\Http;
  
  use \OC\AppFramework\Middleware\MiddlewareDispatcher;
  use \OC\AppFramework\Http;

  use \OC\AppFramework\Utility\ControllerMethodReflector;

  use OCP\AppFramework\Controller;

  use OCP\AppFramework\Http\Response;
  use OCP\IRequest;

  
  
  /**
   * Class to dispatch the request to the middleware dispatcher
   */
  class Dispatcher {
  
  	private $middlewareDispatcher;
  	private $protocol;

  	private $reflector;
  	private $request;

  
  	/**
  	 * @param Http $protocol the http protocol with contains all status headers
  	 * @param MiddlewareDispatcher $middlewareDispatcher the dispatcher which
  	 * runs the middleware

  	 * @param ControllerMethodReflector the reflector that is used to inject
  	 * the arguments for the controller
  	 * @param IRequest $request the incoming request

  	 */
  	public function __construct(Http $protocol,

  								MiddlewareDispatcher $middlewareDispatcher,
  								ControllerMethodReflector $reflector,
  								IRequest $request) {

  		$this->protocol = $protocol;
  		$this->middlewareDispatcher = $middlewareDispatcher;

  		$this->reflector = $reflector;
  		$this->request = $request;

  	}
  
  
  	/**
  	 * Handles a request and calls the dispatcher on the controller
  	 * @param Controller $controller the controller which will be called
  	 * @param string $methodName the method name which will be called on
  	 * the controller
  	 * @return array $array[0] contains a string with the http main header,
  	 * $array[1] contains headers in the form: $key => value, $array[2] contains
  	 * the response output
  	 */
  	public function dispatch(Controller $controller, $methodName) {
  		$out = array(null, array(), null);
  
  		try {

  			// prefill reflector with everything thats needed for the
  			// middlewares
  			$this->reflector->reflect($controller, $methodName);

  
  			$this->middlewareDispatcher->beforeController($controller,
  				$methodName);

  			$response = $this->executeController($controller, $methodName);

  
  			// if an exception appears, the middleware checks if it can handle the
  			// exception and creates a response. If no response is created, it is
  			// assumed that theres no middleware who can handle it and the error is
  			// thrown again
  		} catch(\Exception $exception){
  			$response = $this->middlewareDispatcher->afterException(
  				$controller, $methodName, $exception);
  			if (is_null($response)) {
  				throw $exception;
  			}
  		}
  
  		$response = $this->middlewareDispatcher->afterController(
  			$controller, $methodName, $response);
  
  		// get the output which should be printed and run the after output
  		// middleware to modify the response
  		$output = $response->render();
  		$out[2] = $this->middlewareDispatcher->beforeOutput(
  			$controller, $methodName, $output);
  
  		// depending on the cache object the headers need to be changed
  		$out[0] = $this->protocol->getStatusHeader($response->getStatus(),
  			$response->getLastModified(), $response->getETag());
  		$out[1] = $response->getHeaders();
  
  		return $out;
  	}

  	/**
  	 * Uses the reflected parameters, types and request parameters to execute
  	 * the controller
  	 * @param Controller $controller the controller to be executed
  	 * @param string $methodName the method on the controller that should be executed
  	 * @return Response
  	 */
  	private function executeController($controller, $methodName) {
  		$arguments = array();
  
  		// valid types that will be casted
  		$types = array('int', 'integer', 'bool', 'boolean', 'float');
  
  		foreach($this->reflector->getParameters() as $param => $default) {
  
  			// try to get the parameter from the request object and cast
  			// it to the type annotated in the @param annotation
  			$value = $this->request->getParam($param, $default);
  			$type = $this->reflector->getType($param);
  
  			// if this is submitted using GET or a POST form, 'false' should be
  			// converted to false
  			if(($type === 'bool' || $type === 'boolean') &&
  				$value === 'false' &&
  				(
  					$this->request->method === 'GET' ||
  					strpos($this->request->getHeader('Content-Type'),
  						'application/x-www-form-urlencoded') !== false
  				)
  			) {
  				$value = false;
  
  			} elseif($value !== null && in_array($type, $types)) {
  				settype($value, $type);
  			}
  
  			$arguments[] = $value;
  		}
  
  		$response = call_user_func_array(array($controller, $methodName), $arguments);
  
  		// format response if not of type response
  		if(!($response instanceof Response)) {
  
  			// get format from the url format or request format parameter
  			$format = $this->request->getParam('format');
  
  			// if none is given try the first Accept header
  			if($format === null) {
  				$headers = $this->request->getHeader('Accept');
  				$format = $controller->getResponderByHTTPHeader($headers);
  			}
  
  			$response = $controller->buildResponse($response, $format);
  		}
  
  		return $response;
  	}

  }