<?php

/*

 * This file is part of the Assetic package, an OpenSky project.

 *

 * (c) 2010-2011 OpenSky Project Inc

 *

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

 * file that was distributed with this source code.

 */

namespace Assetic\Extension\Twig;

use Assetic\Factory\Loader\FormulaLoaderInterface;

use Assetic\Factory\Resource\ResourceInterface;

/**

 * Loads asset formulae from Twig templates.

 *

 * @author Kris Wallsmith <kris.wallsmith@gmail.com>

 */

class TwigFormulaLoader implements FormulaLoaderInterface

{

    private $twig;

    public function __construct(\Twig_Environment $twig)

    {

        $this->twig = $twig;

    }

    public function load(ResourceInterface $resource)

    {

        try {

            $tokens = $this->twig->tokenize($resource->getContent(), (string) $resource);

            $nodes  = $this->twig->parse($tokens);

        } catch (\Exception $e) {

            return array();

        }

        return $this->loadNode($nodes);

    }

    /**

     * Loads assets from the supplied node.

     *

     * @return array An array of asset formulae indexed by name

     */

    private function loadNode(\Twig_Node $node)

    {

        $formulae = array();

        if ($node instanceof AsseticNode) {

            $formulae[$node->getAttribute('name')] = array(

                $node->getAttribute('inputs'),

                $node->getAttribute('filters'),

                array(

                    'output'  => $node->getAttribute('asset')->getTargetPath(),

                    'name'    => $node->getAttribute('name'),

                    'debug'   => $node->getAttribute('debug'),

                    'combine' => $node->getAttribute('combine'),

                ),

            );

        } elseif ($node instanceof \Twig_Node_Expression_Function) {

            $name = $node->getNode('name')->getAttribute('name');

            if ($this->twig->getFunction($name) instanceof AsseticFilterFunction) {

                $arguments = array();

                foreach ($node->getNode('arguments') as $argument) {

                    $arguments[] = eval('return '.$this->twig->compile($argument).';');

                }

                $invoker = $this->twig->getExtension('assetic')->getFilterInvoker($name);

                $inputs  = isset($arguments[0]) ? (array) $arguments[0] : array();

                $filters = $invoker->getFilters();

                $options = array_replace($invoker->getOptions(), isset($arguments[1]) ? $arguments[1] : array());

                if (!isset($options['name'])) {

                    $options['name'] = $invoker->getFactory()->generateAssetName($inputs, $filters, $options);

                }

                $formulae[$options['name']] = array($inputs, $filters, $options);

            }

        }

        foreach ($node as $child) {

            if ($child instanceof \Twig_Node) {

                $formulae += $this->loadNode($child);

            }

        }

        return $formulae;

    }

}