<?php
/**
 * LICENSE
 *
 * "THE BEER-WARE LICENSE" (Revision 42):
 * "Sven Strittmatter" <ich@weltraumschaf.de> wrote this file.
 * As long as you retain this notice you can do whatever you want with
 * this stuff. If we meet some day, and you think this stuff is worth it,
 * you can buy me a beer in return.
 *
 * @author    Sven Strittmatter <ich@weltraumschaf.de>
 * @copyright Copyright (c) 2010, Sven Strittmatter.
 * @version   0.2.0
 * @license   http://www.weltraumschaf.de/the-beer-ware-license.txt
 */

/**
 * @see Api_Kwick_Config
 */
require_once 'Api/Kwick/Config.php';
/**
 * @see Api_Kwick_Request
 */
require_once 'Api/Kwick/Request.php';
/**
 * @see Api_Log
 */
require_once 'Api/Log.php';

/**
 * Simple front controller implementation.
 *
 * HAndles all requests from the Ajax client and passes them via
 * Api_Kwick_Requets to the KWICK! API. Returns the original result as JSON
 * added with some logging.
 *
 * @see htdocs/service.php
 */
class Api_Controller {
    /**
     * Prefix for special purpose GET/POST parameter names.
     *
     * @var string
     */
    const RESERVED_PARAMETER_PREFIX = '__kapit__';
    /**
     * Object which performs the API request.
     *
     * @var Api_Kwick_Request
     */
    private $apiRequest;

    /**
     * Initializes the controller with a request object.
     * 
     * @param Api_Kwick_Request $request Request obejct.
     */
    public function  __construct(Api_Kwick_Request $request) {
        $this->apiRequest = $request;
    }

    public function getService() {
        return $this->getRequestParameter('service', Api_Kwick_Request::DEFAULT_SERVICE);
    }

    public function getMethod() {
        return $this->getRequestParameter('method', Api_Kwick_Request::DEFAULT_METHOD);
    }

    public function getSecret() {
        return $this->getRequestParameter('secret', null);
    }

    public function getApiSecret() {
        return $this->getRequestParameter('__kapit__secret');
    }

    public function getApiKey() {
        return $this->getRequestParameter('__kapit__apiKey');
    }

    public function getBaseUri() {
        return $this->getRequestParameter('__kapit__apiUri');
    }
    
    /**
     * Signals if the passed name is a reserved parameter name.
     *
     * Reserved parameternames start with self::RESERVED_PARAMETER_PREFIX.
     * @param string $name Checked parameter name.
     * @return boolean
     */
    public function isReservedParameter($name) {
        return strpos($name, self::RESERVED_PARAMETER_PREFIX) === 0;
    }

    /**
     * These parameters are not passed directly to the API.
     *
     * Signals which GET/POST parameters are special handeled/processed
     * and not directly passed to the API.
     * 
     * @param string $name Checked parameter name.
     * @return bool
     */
    public function isSkippedParameter($name) {
        if (in_array($name, array('service', 'method', 'secret'))) {
            return true;
        }

        return false;
    }

    /**
     * Returns a GET/POST parameter.
     *
     * First checks GET, second POST and returns the matched name.
     * Neither GET nor POST matches $default will be returned.
     * 
     * @param string $name
     * @param string $default
     * @return string
     */
    public function getRequestParameter($name, $default = '') {
        $parameter = $default;

        if (isset($_GET[$name]) && !empty($_GET[$name])) {
            $parameter = $_GET[$name];
        }

        if (isset($_POST[$name]) && !empty($_POST[$name])) {
            $parameter = $_POST[$name];
        }

        return $parameter;
    }

    /**
     * Sets all GET/POS parameters on the APIs request object.
     */
    public function prepareParametersOnRequest() {
        foreach (array($_GET, $_POST) as $params) {
            foreach ($params as $name => $value) {
                if ($this->isSkippedParameter($name) || $this->isReservedParameter($name) ||
                    empty($value))
                {
                    continue;
                }

                $this->apiRequest->setParameter($name, $value);
            }
        }

        if (!empty($_FILES)) {
            $this->apiRequest->setFiles($_FILES);
        }
    }

    /**
     * Handles the AJAX calls from KAPIT.
     *
     * @see htdocs/service.php
     */
    public function dispatch() {
        Api_Log::log('Dispatching ' . $this->getService() . '.' . $this->getMethod());
        $this->apiRequest->setService($this->getService());
        $this->apiRequest->setMethod($this->getMethod());
        $secret = $this->getSecret();

        if (null !== $secret) { // use session based secret
            Api_Log::log('Set user secret: ' . $secret);
            $this->apiRequest->setSecret($secret);
        } else { // use application based secret
            if ($this->getApiSecret() !== $this->apiRequest->getSecret()) {
                Api_Log::log('Set custom secret: ' . $this->getApiSecret());
                $this->apiRequest->setSecret($this->getApiSecret());
            }
        }

        if ($this->getApiKey() !== $this->apiRequest->getApiKey()) {
            Api_log::Log('Set custom api key: ' . $this->getApiKey());
            $this->apiRequest->setApiKey($this->getApiKey());
        }

        if ($this->getBaseUri() !== $this->apiRequest->getBaseUri()) {
            Api_Log::log('Setting custom base uri: ' . $this->getBaseUri());
            $this->apiRequest->setBaseUri($this->getBaseUri());
        }

        $this->prepareParametersOnRequest();

        try {
            $data = array('response' => json_decode($this->apiRequest->send()));
        } catch (Exception $e) {
            $data = array('exception' => $e->getMessage());
        }

        $data['log'] = Api_Log::get();
        echo json_encode($data);
    }
}