<?php

/*

 * This file is part of Twig.

 *

 * (c) 2009 Fabien Potencier

 * (c) 2009 Armin Ronacher

 *

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

 * file that was distributed with this source code.

 */

/**

 * Tests a condition.

 *

 * <pre>

 * {% if users %}

 *  <ul>

 *    {% for user in users %}

 *      <li>{{ user.username|e }}</li>

 *    {% endfor %}

 *  </ul>

 * {% endif %}

 * </pre>

 */

class Twig_TokenParser_If extends Twig_TokenParser

{

    /**

     * Parses a token and returns a node.

     *

     * @param Twig_Token $token A Twig_Token instance

     *

     * @return Twig_NodeInterface A Twig_NodeInterface instance

     */

    public function parse(Twig_Token $token)

    {

        $lineno = $token->getLine();

        $expr = $this->parser->getExpressionParser()->parseExpression();

        $this->parser->getStream()->expect(Twig_Token::BLOCK_END_TYPE);

        $body = $this->parser->subparse(array($this, 'decideIfFork'));

        $tests = array($expr, $body);

        $else = null;

        $end = false;

        while (!$end) {

            switch ($this->parser->getStream()->next()->getValue()) {

                case 'else':

                    $this->parser->getStream()->expect(Twig_Token::BLOCK_END_TYPE);

                    $else = $this->parser->subparse(array($this, 'decideIfEnd'));

                    break;

                case 'elseif':

                    $expr = $this->parser->getExpressionParser()->parseExpression();

                    $this->parser->getStream()->expect(Twig_Token::BLOCK_END_TYPE);

                    $body = $this->parser->subparse(array($this, 'decideIfFork'));

                    $tests[] = $expr;

                    $tests[] = $body;

                    break;

                case 'endif':

                    $end = true;

                    break;

                default:

                    throw new Twig_Error_Syntax(sprintf('Unexpected end of template. Twig was looking for the following tags "else", "elseif", or "endif" to close the "if" block started at line %d)', $lineno), -1);

            }

        }

        $this->parser->getStream()->expect(Twig_Token::BLOCK_END_TYPE);

        return new Twig_Node_If(new Twig_Node($tests), $else, $lineno, $this->getTag());

    }

    public function decideIfFork(Twig_Token $token)

    {

        return $token->test(array('elseif', 'else', 'endif'));

    }

    public function decideIfEnd(Twig_Token $token)

    {

        return $token->test(array('endif'));

    }

    /**

     * Gets the tag name associated with this token parser.

     *

     * @param string The tag name

     */

    public function getTag()

    {

        return 'if';

    }

}