<?php

    /**
     * NRE
     *
     * @author      coderkun <olli@coderkun.de>
     * @copyright   2013 coderkun (http://www.coderkun.de)
     * @license     http://www.gnu.org/licenses/gpl.html
     * @link        http://www.coderkun.de/projects/nre
     */

    namespace nre\core;


    /**
     * Abstract class to implement an API.
     * 
     * The API is the center of each application and specifies how and what
     * to run and render.
     * 
     * @author  coderkun <olli@coderkun.de>
     */
    abstract class Api
    {
        /**
         * Die aktuelle Anfrage
         * 
         * @var Request
         */
        protected $request;
        /**
         * Der Toplevelagent
         * 
         * @var \nre\agents\ToplevelAgent
         */
        private $toplevelAgent = null;
        /**
         * Die aktuelle Antwort
         * 
         * @var Response
         */
        protected $response;
        /**
         * Log-System
         * 
         * @var Logger
         */
        protected $log;


        /**
         * Construct a new API.
         * 
         * @param   Request     $request    Current request
         * @param   Response    $response   Current response
         */
        public function __construct(Request $request, Response $response)
        {
            // Store request
            $this->request = $request;

            // Store response
            $this->response = $response;

            // Init logging
            $this->log = new \nre\core\Logger();
        }


        /**
         * Run the application.
         * 
         * @throws  \nre\exceptions\DatamodelException
         * @throws  \nre\exceptions\DriverNotValidException
         * @throws  \nre\exceptions\DriverNotFoundException
         * @throws  \nre\exceptions\ViewNotFoundException
         * @throws  \nre\exceptions\ModelNotValidException
         * @throws  \nre\exceptions\ModelNotFoundException
         * @throws  \nre\exceptions\ControllerNotValidException
         * @throws  \nre\exceptions\ControllerNotFoundException
         * @throws  \nre\exceptions\AgentNotValidException
         * @throws  \nre\exceptions\AgentNotFoundException
         * @return  \Exception  Last occurred exception of an subagent
         */
        public function run()
        {
            // Load ToplevelAgent
            $this->loadToplevelAgent();

            // Run ToplevelAgent
            return $this->toplevelAgent->run($this->request, $this->response);
        }


        /**
         * Render the output.
         */
        public function render()
        {
            // Check exit-status
            if($this->response->getExit()) {
                return;
            }

            // Render ToplevelAgent
            $this->response->setOutput($this->toplevelAgent->render());
        }


        /**
         * Log an exception
         * 
         * @param   \Exception  $exception  Occurred exception
         * @param   int         $logMode    Log-mode
         */
        protected function log($exception, $logMode)
        {
            $this->log->log(
                $exception->getMessage(),
                $logMode
            );
        }


        /**
         * Load the ToplevelAgent specified by the request.
         * 
         * @throws  \nre\exceptions\ServiceUnavailableException
         * @throws  \nre\exceptions\AgentNotValidException
         * @throws  \nre\exceptions\AgentNotFoundException
         */
        private function loadToplevelAgent()
        {
            // Determine agent
            $agentName = $this->response->getParam(0);
            if(is_null($agentName)) {
                $agentName = $this->request->getParam(0, 'toplevel');
                $this->response->addParam($agentName);
            }

            // Load agent
            \nre\agents\ToplevelAgent::load($agentName);

            // Construct agent
            $this->toplevelAgent = \nre\agents\ToplevelAgent::factory(
                $agentName,
                $this->request,
                $this->response,
                $this->log
            );
        }

    }

?>