<?php

/**
 * web loader
 * @author Salimane Adjao Moustapha
 */

class Web
{
    protected $_urls            = null;
    protected $_requestUrl      = null;
    public    $params           = null;
    static protected $_instance = NULL;


    /**
     * create instance of Web object. Only use this method
     * to get an instance of Web.
     *
     * @author Salimane Adjao Moustapha
     */

    public static function &instance()
    {
        if (self::$_instance == NULL) {
            self::$_instance = new Web();
        }
        return self::$_instance;
    }


    /**
     * requestUri
     *
     * inspects $_SERVER['REQUEST_URI'] and returns a sanitized
     * path without a leading/trailing slashes
     * @return void
     * @author Salimane Adjao Moustapha
     */

    private function requestUri()
    {
        // have seen apache set either or.
        $uri = isset($_SERVER['REDIRECT_URL']) ? $_SERVER['REDIRECT_URL']
                                               : $_SERVER['REQUEST_URI'];

        // sanitize it
        $uri = filter_var($uri, FILTER_SANITIZE_URL);

        // kill query string off REQUEST_URI
        if ( strpos($uri,'?') !== false ) {
               $uri = substr($uri,0,strpos($uri,'?'));
        }

        // strip off first slash
        if(substr($uri, 0, 1) == "/"){
            $uri = substr($uri, 1);
        }

        // knock off last slash
        if (substr($uri, -1) == "/") {
            $uri = substr($uri, 0, -1);
        }

        $this->request_uri = $uri;
    }

    /**
     * send 303 by default so browser won't cache the 200 or 301 headers
     *
     * @param string $location
     * @param string $status
     * @return void
     * @author Salimane Adjao Moustapha
     */

    public static function redirect($location, $status=303)
    {
        self::httpHeader($status);
        header("Location: $location");
    }

    /**
     * send header code to browser
     *
     * @param string $code
     * @return void
     * @author Salimane Adjao Moustapha
     */

    public static function httpHeader($code)
    {
        $http = array (
               100 => "HTTP/1.1 100 Continue",
               101 => "HTTP/1.1 101 Switching Protocols",
               200 => "HTTP/1.1 200 OK",
               201 => "HTTP/1.1 201 Created",
               202 => "HTTP/1.1 202 Accepted",
               203 => "HTTP/1.1 203 Non-Authoritative Information",
               204 => "HTTP/1.1 204 No Content",
               205 => "HTTP/1.1 205 Reset Content",
               206 => "HTTP/1.1 206 Partial Content",
               300 => "HTTP/1.1 300 Multiple Choices",
               301 => "HTTP/1.1 301 Moved Permanently",
               302 => "HTTP/1.1 302 Found",
               303 => "HTTP/1.1 303 See Other",
               304 => "HTTP/1.1 304 Not Modified",
               305 => "HTTP/1.1 305 Use Proxy",
               307 => "HTTP/1.1 307 Temporary Redirect",
               400 => "HTTP/1.1 400 Bad Request",
               401 => "HTTP/1.1 401 Unauthorized",
               402 => "HTTP/1.1 402 Payment Required",
               403 => "HTTP/1.1 403 Forbidden",
               404 => "HTTP/1.1 404 Not Found",
               405 => "HTTP/1.1 405 Method Not Allowed",
               406 => "HTTP/1.1 406 Not Acceptable",
               407 => "HTTP/1.1 407 Proxy Authentication Required",
               408 => "HTTP/1.1 408 Request Time-out",
               409 => "HTTP/1.1 409 Conflict",
               410 => "HTTP/1.1 410 Gone",
               411 => "HTTP/1.1 411 Length Required",
               412 => "HTTP/1.1 412 Precondition Failed",
               413 => "HTTP/1.1 413 Request Entity Too Large",
               414 => "HTTP/1.1 414 Request-URI Too Large",
               415 => "HTTP/1.1 415 Unsupported Media Type",
               416 => "HTTP/1.1 416 Requested range not satisfiable",
               417 => "HTTP/1.1 417 Expectation Failed",
               500 => "HTTP/1.1 500 Internal Server Error",
               501 => "HTTP/1.1 501 Not Implemented",
               502 => "HTTP/1.1 502 Bad Gateway",
               503 => "HTTP/1.1 503 Service Unavailable",
               504 => "HTTP/1.1 504 Gateway Time-out"
           );
        header($http[$code]);
    }


    /**
     * inspect urls, find matched class and then run requested method
     *
     * @param string $array
     * @param string $_baseURLPath
     * @return void
     * @author Salimane Adjao Moustapha
     */

    public static function run(array $urls)
    {
        if (empty($urls)) {
            throw new Exception("You must pass an array of valid urls to web::run()");
            return;
        }

        // get instance of Web
        $instance = self::instance();

        // process the request uri
        $instance->requestUri();

        $route = array();

        foreach ($urls as $url_path => $options) {
            if (preg_match($url_path, $instance->request_uri, $matches)) {
              // assuming pattern => array(class, function) in URLS array
              $route = array_merge($matches, array('module' => $options));
              unset($matches);
              $instance->params = $route;
              break;
            }
        }

        // if there is no uri match - module not at least set, throw a 404 error.
        if (!array_key_exists('module', $route)) {
            throw new RequestErrorException("Page not found.", 404);
            return;
        }

        // lets check matches for named patterns
        // be aware this is somewhat tied into __autoload function
        $class_to_load = $route['module'][0];

        // finds it based on __autoload function
        // instantiate class
        $loaded_class = new $class_to_load();

        // see if class has any pre-run hooks
        if (method_exists($loaded_class, 'preRun')) {
            $retval = $loaded_class->preRun();

            // if pre-run hook returns false, stop processing.
            if($retval === false) {
                return;
            }
        }

        // check for class method based on REQUEST_METHOD
        $method = $route['module'][1];

        // see if currently loaded class even supports it
        if (!method_exists($loaded_class, $method)) {
            throw new RequestErrorException("HTTP Method not supported by class.", 405);
            return;
        }

        // run request
        $loaded_class->$method();

        // see if class has any post-run hooks
        if (method_exists($loaded_class, 'postRun')) {
            $retval = $loaded_class->postRun();

            // if post-run hook returns false, stop processing.
            if($retval === false) {
                return;
            }
        }
    }


    /**
     * params
     *
     * @return stored web params from request_uri
     * @author Salimane Adjao Moustapha
     */
    public static function params()
    {
        return self::instance()->params;
    }

}