<?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   0.2.2
 * @license   http://www.weltraumschaf.de/the-beer-ware-license.txt
 */

/**
 * @see Api_Log
 */
require_once 'Api/Log.php';

/**
 * This class abstracts a KWICK! API request.
 *
 * It utilizes the HttpRequest class from pecl_http.
 *
 * It does for you the signature generating stuff.
 */
class Api_Kwick_Request {
    /**
     * URI suffix for version 2.0.
     *
     * @var string
     */
    const VERSION_20 = '2.0';
    /**
     * Deafult method name.
     * IS called if method or service was ommited.
     *
     * @var string
     */
    const DEFAULT_METHOD  = 'getAPIVersion';
    /**
     * Deafult service name.
     * IS called if method or service was ommited.
     *
     * @var string
     */
    const DEFAULT_SERVICE = 'application';

    /**
     * The base URI for the API requests.
     *
     * @see configs/app.sample.php
     * @var string
     */
    private $baseUri;
    /**
     * A md5 hash you got after registering your app.
     *
     * @var string
     */
    private $apiKey;
    /**
     * A sha1 hash.
     *
     * You have to deal with to secrets, which is not so obvious in the dcumentation.
     * First you have a so called app secret which you got after resgistering your app.
     * After the authentication process (which each user of your app need to perform)
     * you got a session hash and a so called user secret. All authenticated
     * API calls needs the second user secret. The app secret is only neccessary
     * to perform authentication.
     *
     * @var string
     */
    private $secret;
    /**
     * The API version.
     *
     * Is appended to the base URI. There is only version 2.0 yet.
     * @var <type>
     */
    private $version;
    /**
     * The called method.
     *
     * @var string
     */
    private $method;
    /**
     * The called service.
     *
     * @var string
     */
    private $service;
    /**
     * Assoc array with the API calls parameters.
     *
     * The key is the parameter name:
     * <code>
     * <?php
     * $params = array(
     *     'name1' => 'foo',
     *     'name2' => 'bar',
     *     //...
     *     'namen' => '...'
     * );
     *
     * @var array
     */
    private $parameters;
    private $files;

    public function  __construct(Api_Kwick_Config $config) {
        $this->setBaseUri($config->get('baseUri'));
        $this->setApiKey($config->get('apiKey'));
        $this->setSecret($config->get('secret'));
        $this->version    = $config->get('version', self::VERSION_20);
        $this->service    = self::DEFAULT_SERVICE;
        $this->method     = self::DEFAULT_METHOD;
        $this->parameters = array();
        $this->files      = array();
    }

    public function setBaseUri($uri) {
        $this->baseUri = (string) $uri;
    }

    public function getBaseUri() {
        return $this->baseUri;
    }

    public function setApiKey($key) {
        $this->apiKey = (string) $key;
    }

    public function getApiKey() {
        return $this->apiKey;
    }
    
    public function setFiles(array $files) {
        $this->files = $files;
    }

    public function setSecret($secret) {
        $this->secret = (string) $secret;
    }

    public function getSecret() {
        return $this->secret;
    }

    public function setParameter($name, $value) {
		if (isset($this->parameters[$name])) {
			Api_Log::log("Parameter '$name' already set.");

			if ($this->parameters[$name] !== $value) {
				Api_Log::log("Change parameter '$name' from '{$this->parameters[$name]}' to '{$value}'.");
			}
			else {
				return;
			}
		}

		$trace = debug_backtrace();
		$frame = $trace[1];
        Api_Log::log("Set parameter: '$name' with: '$value' in {$frame['class']}::{$frame['function']}." );
        $this->parameters[$name] = $value;
    }

    public function setMethod($method) {
        Api_Log::log('Set method to: ' . $method);
        $this->method = (string) $method;
    }

    public function setService($service) {
        Api_Log::log('Set service to: ' . $service);
        $this->service = (string) $service;
    }

    public function send(HttpRequest $httpRequest = null) {
        if (null === $httpRequest) {
            if (!class_exists('HttpRequest', false)) {
                throw new RuntimeException('Can not find class HttpRequest! Install pecl http.');
            }

            $httpRequest = new HttpRequest();
        }

        $url = $this->generateUri();

        if (!empty($this->files)) {
            foreach ($this->files as $fileName => $fileUpload) {
                $httpRequest->addPostFile($fileName, $fileUpload['tmp_name']);
            }
        }

        Api_Log::log('Send request with url: ' . $url);
        $httpRequest->setUrl($url);
        $httpRequest->setMethod(HttpRequest::METH_POST);
        $start = microtime(true);
        $httpRequest->send();
        $time  = microtime(true) - $start;
        Api_Log::log('Duration of api request: ' . round($time, 3) . 's');

        if ($httpRequest->getResponseCode() < 500) {
            switch ($httpRequest->getResponseCode()) {
                case 401:
                    $message = 'Authroization required on URI: ' . $url;
                    throw new RuntimeException($message, 401);
                case 404:
                    $message = 'Not found URI: ' . $url;
                    throw new RuntimeException($message, 404);
                default:
                    return $httpRequest->getResponseBody();
            }
        }

        $message = 'Got a server error response on URI: ' . $url;
        throw new RuntimeException($message, $httpRequest->getResponseCode());
    }

    /**
     * @deprecated Please use generateUri() instead.
     * @return string
     */
    public function generateUrl() {
        return $this->generateUri();
    }

    /**
     *
     * @return string
     */
    public function generateUri() {
        $url  = $this->baseUri . '?';
        $url .= 'api_key=' . $this->apiKey . '&';
        $url .= 'v=' . $this->version . '&';
        $url .= 'method=' . $this->getQualifiedMethod() . '&';
        $url .= 'sig=' . $this->generateSignature();

        if (!empty($this->parameters)) {
            foreach ($this->parameters as $name => $value) {
                $url .= '&' . $name . '=' . urlencode($value);
            }
        }

        return $url;
    }

    public function getQualifiedMethod() {
        return $this->service . '.' . $this->method;
    }

    public function generateParamString() {
        $parameters = array_merge($this->parameters, array(
                'api_key' => $this->apiKey,
                'v'       => $this->version,
                'method'  => $this->getQualifiedMethod()
        ));
        ksort($parameters);
        $parameterString = '';

        foreach ($parameters as $name => $value) {
            $parameterString .= $name . '=' . $value;
        }

        return $parameterString;
    }

    public function generateSignature() {
        $plain = $this->generateParamString() . $this->secret;
        Api_Log::log('Hashing plain signature: ' . $plain);
        return md5($plain);
    }
}