<?php

namespace Symfony\Components\Routing\Generator;

use Symfony\Components\Routing\Route;
use Symfony\Components\Routing\RouteCollection;

/*
 * This file is part of the symfony framework.
 *
 * (c) Fabien Potencier <fabien.potencier@symfony-project.com>
 *
 * This source file is subject to the MIT license that is bundled
 * with this source code in the file LICENSE.
 */

/**
 * UrlGenerator generates URL based on a set of routes.
 *
 * @package    symfony
 * @subpackage routing
 * @author     Fabien Potencier <fabien.potencier@symfony-project.com>
 */
class UrlGenerator implements UrlGeneratorInterface
{
  protected $routes;
  protected $defaults;
  protected $context;
  protected $cache;

  /**
   * Constructor.
   *
   * @param RouteCollection $routes   A RouteCollection instance
   * @param array           $context  The context
   * @param array           $defaults The default values
   */
  public function __construct(RouteCollection $routes, array $context = array(), array $defaults = array())
  {
    $this->routes = $routes;
    $this->context = array_merge(array('base_url' => ''), $context);
    $this->defaults = $defaults;
    $this->cache = array();
  }

  /**
   * Generates a URL from the given parameters.
   *
   * @param  string  $name       The name of the route
   * @param  array   $parameters An array of parameters
   * @param  Boolean $absolute   Whether to generate an absolute URL
   *
   * @return string The generated URL
   */
  public function generate($name, array $parameters, $absolute = false)
  {
    if (null === $route = $this->routes->getRoute($name))
    {
      throw new \InvalidArgumentException(sprintf('Route "%s" does not exist.', $name));
    }

    if (!isset($this->cache[$name]))
    {
      $this->cache[$name] = $route->compile();
    }

    return $this->doGenerate($this->cache[$name]->getVariables(), $route->getDefaults(), $route->getRequirements(), $this->cache[$name]->getTokens(), $parameters, $name, $absolute);
  }

  protected function doGenerate($variables, $defaults, $requirements, $tokens, $parameters, $name, $absolute)
  {
    $defaults = array_merge($this->defaults, $defaults);
    $tparams = array_merge($defaults, $parameters);

    // all params must be given
    if ($diff = array_diff_key($variables, $tparams))
    {
      throw new \InvalidArgumentException(sprintf('The "%s" route has some missing mandatory parameters (%s).', $name, implode(', ', $diff)));
    }

    $url = '';
    $optional = true;
    foreach ($tokens as $token)
    {
      if ('variable' === $token[0])
      {
        if (false === $optional || !isset($defaults[$token[3]]) || (isset($parameters[$token[3]]) && $parameters[$token[3]] != $defaults[$token[3]]))
        {
          // check requirement
          if (isset($requirements[$token[3]]) && !preg_match('#^'.$requirements[$token[3]].'$#', $tparams[$token[3]]))
          {
            throw new \InvalidArgumentException(sprintf('Parameter "%s" for route "%s" must match "%s" ("%s" given).', $token[3], $name, $requirements[$token[3]], $tparams[$token[3]]));
          }

          $url = $token[1].urlencode($tparams[$token[3]]).$url;
          $optional = false;
        }
      }
      elseif ('text' === $token[0])
      {
        $url = $token[1].$token[2].$url;
        $optional = false;
      }
      else
      {
        // handle custom tokens
        if ($segment = call_user_func_array(array($this, 'generateFor'.ucfirst(array_shift($token))), array_merge(array($optional, $tparams), $token)))
        {
          $url = $segment.$url;
          $optional = false;
        }
      }
    }

    if (!$url)
    {
      $url = '/';
    }

    // add a query string if needed
    if ($extra = array_diff_key($parameters, $variables, $defaults))
    {
      $url .= '?'.http_build_query($extra);
    }

    $url = $this->context['base_url'].$url;

    if ($absolute && isset($this->context['host']))
    {
      $url = 'http'.(isset($this->context['is_secure']) && $this->context['is_secure'] ? 's' : '').'://'.$this->context['host'].$url;
    }

    return $url;
  }
}