<?php
class Route {

  private static $routes = Array();
  private static $pathNotFound = null;
  private static $methodNotAllowed = null;

  /**
    * Function used to add a new route
    * @param string $expression    Route string or expression
    * @param callable $function    Function to call if route with allowed method is found
    * @param string|array $method  Either a string of allowed method or an array with string values
    *
    */
  public static function add($expression, $function, $method = 'get'){
    array_push(self::$routes, Array(
      'expression' => $expression,
      'function' => $function,
      'method' => $method
    ));
  }

  public static function pathNotFound($function) {
    self::$pathNotFound = $function;
  }

  public static function methodNotAllowed($function) {
    self::$methodNotAllowed = $function;
  }

  public static function run($basepath = '/', $case_matters = false, $trailing_slash_matters = false) {
    // Parse current URL
    $parsed_url = parse_url($_SERVER['REQUEST_URI']);

    if (isset($parsed_url['path']) && $parsed_url['path'] != '/') {
	  if ($trailing_slash_matters) {
		$path = $parsed_url['path'];
	  } else {
		$path = rtrim($parsed_url['path'], '/');
	  }
    } else {
      $path = '/';
    }

    // Get current request method
    $method = $_SERVER['REQUEST_METHOD'];

    $path_match_found = false;

    $route_match_found = false;

    foreach (self::$routes as $route) {

      // If the method matches check the path

      // Add basepath to matching string
      if ($basepath != '' && $basepath != '/') {
        $route['expression'] = '('.$basepath.')'.$route['expression'];
      }

      // Add 'find string start' automatically
      $route['expression'] = '^'.$route['expression'];

      // Add 'find string end' automatically
      $route['expression'] = $route['expression'].'$';

      // Check path match
      if (preg_match('#'.$route['expression'].'#'.($case_matters ? '' : 'i'), $path, $matches)) {
        $path_match_found = true;

        // Cast allowed method to array if it's not one already, then run through all methods
        foreach ((array)$route['method'] as $allowedMethod) {
            // Check method match
          if (strtolower($method) == strtolower($allowedMethod)) {
            array_shift($matches); // Always remove first element. This contains the whole string

            if ($basepath != '' && $basepath != '/') {
              array_shift($matches); // Remove basepath
            }

            call_user_func_array($route['function'], $matches);

            $route_match_found = true;

            // Do not check other routes
            break;
          }
        }
      }
    }

    // No matching route was found
    if (!$route_match_found) {
      // But a matching path exists
      if ($path_match_found) {
        header('HTTP/1.0 405 Method Not Allowed');
        if (self::$methodNotAllowed) {
          call_user_func_array(self::$methodNotAllowed, Array($path,$method));
        }
      } else {
        header('HTTP/1.0 404 Not Found');
        if (self::$pathNotFound) {
          call_user_func_array(self::$pathNotFound, Array($path));
        }
      }

    }
  }

}