<?php

/*

 * This file is part of the Symfony package.

 *

 * (c) Fabien Potencier <fabien@symfony.com>

 *

 * For the full copyright and license information, please view the LICENSE

 * file that was distributed with this source code.

 */

namespace Symfony\Bundle\TwigBundle;

use Symfony\Bundle\FrameworkBundle\Templating\EngineInterface;

use Symfony\Bundle\FrameworkBundle\Templating\GlobalVariables;

use Symfony\Component\Templating\TemplateNameParserInterface;

use Symfony\Component\HttpFoundation\Response;

use Symfony\Component\DependencyInjection\ContainerInterface;

/**

 * This engine knows how to render Twig templates.

 *

 * @author Fabien Potencier <fabien@symfony.com>

 */

class TwigEngine implements EngineInterface

{

    protected $environment;

    protected $parser;

    /**

     * Constructor.

     *

     * @param \Twig_Environment           $environment A \Twig_Environment instance

     * @param TemplateNameParserInterface $parser      A TemplateNameParserInterface instance

     * @param GlobalVariables|null        $globals     A GlobalVariables instance or null

     */

    public function __construct(\Twig_Environment $environment, TemplateNameParserInterface $parser, GlobalVariables $globals = null)

    {

        $this->environment = $environment;

        $this->parser = $parser;

        if (null !== $globals) {

            $environment->addGlobal('app', $globals);

        }

    }

    /**

     * Renders a template.

     *

     * @param mixed $name       A template name

     * @param array $parameters An array of parameters to pass to the template

     *

     * @return string The evaluated template as a string

     *

     * @throws \InvalidArgumentException if the template does not exist

     * @throws \RuntimeException         if the template cannot be rendered

     */

    public function render($name, array $parameters = array())

    {

        return $this->load($name)->render($parameters);

    }

    /**

     * Returns true if the template exists.

     *

     * @param mixed $name A template name

     *

     * @return Boolean true if the template exists, false otherwise

     */

    public function exists($name)

    {

        try {

            $this->load($name);

        } catch (\InvalidArgumentException $e) {

            return false;

        }

        return true;

    }

    /**

     * Returns true if this class is able to render the given template.

     *

     * @param string $name A template name

     *

     * @return Boolean True if this class supports the given resource, false otherwise

     */

    public function supports($name)

    {

        if ($name instanceof \Twig_Template) {

            return true;

        }

        $template = $this->parser->parse($name);

        return 'twig' === $template->get('engine');

    }

    /**

     * Renders a view and returns a Response.

     *

     * @param string   $view       The view name

     * @param array    $parameters An array of parameters to pass to the view

     * @param Response $response   A Response instance

     *

     * @return Response A Response instance

     */

    public function renderResponse($view, array $parameters = array(), Response $response = null)

    {

        if (null === $response) {

            $response = new Response();

        }

        $response->setContent($this->render($view, $parameters));

        return $response;

    }

    /**

     * Loads the given template.

     *

     * @param mixed $name A template name or an instance of Twig_Template

     *

     * @return \Twig_TemplateInterface A \Twig_TemplateInterface instance

     *

     * @throws \InvalidArgumentException if the template does not exist

     */

    protected function load($name)

    {

        if ($name instanceof \Twig_Template) {

            return $name;

        }

        try {

            return $this->environment->loadTemplate($name);

        } catch (\Twig_Error_Loader $e) {

            throw new \InvalidArgumentException($e->getMessage(), $e->getCode(), $e);

        }

    }

}