<?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\Component\Templating;

/**

 * DelegatingEngine selects an engine for a given template.

 *

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

 *

 * @api

 */

class DelegatingEngine implements EngineInterface

{

    protected $engines;

    /**

     * Constructor.

     *

     * @param array $engines An array of EngineInterface instances to add

     *

     * @api

     */

    public function __construct(array $engines = array())

    {

        $this->engines = array();

        foreach ($engines as $engine) {

            $this->addEngine($engine);

        }

    }

    /**

     * Renders a template.

     *

     * @param mixed $name       A template name or a TemplateReferenceInterface instance

     * @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

     *

     * @api

     */

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

    {

        return $this->getEngine($name)->render($name, $parameters);

    }

    /**

     * Returns true if the template exists.

     *

     * @param mixed $name A template name or a TemplateReferenceInterface instance

     *

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

     *

     * @api

     */

    public function exists($name)

    {

        return $this->getEngine($name)->exists($name);

    }

    /**

     * Adds an engine.

     *

     * @param EngineInterface $engine An EngineInterface instance

     *

     * @api

     */

    public function addEngine(EngineInterface $engine)

    {

        $this->engines[] = $engine;

    }

    /**

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

     *

     * @param mixed $name A template name or a TemplateReferenceInterface instance

     *

     * @return Boolean true if this class supports the given template, false otherwise

     *

     * @api

     */

    public function supports($name)

    {

        try {

            $this->getEngine($name);

        } catch (\RuntimeException $e) {

            return false;

        }

        return true;

    }

    /**

     * Get an engine able to render the given template.

     *

     * @param mixed $name A template name or a TemplateReferenceInterface instance

     *

     * @return EngineInterface The engine

     *

     * @throws \RuntimeException if no engine able to work with the template is found

     *

     * @api

     */

    protected function getEngine($name)

    {

        foreach ($this->engines as $engine) {

            if ($engine->supports($name)) {

                return $engine;

            }

        }

        throw new \RuntimeException(sprintf('No engine is able to work with the template "%s".', $name));

    }

}