<?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.

 */

/**

 * Default parser implementation.

 *

 * @package twig

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

 */

class Twig_Parser implements Twig_ParserInterface

{

    protected $stream;

    protected $parent;

    protected $handlers;

    protected $visitors;

    protected $expressionParser;

    protected $blocks;

    protected $blockStack;

    protected $macros;

    protected $env;

    protected $reservedMacroNames;

    protected $importedFunctions;

    protected $tmpVarCount;

    protected $traits;

    /**

     * Constructor.

     *

     * @param Twig_Environment $env A Twig_Environment instance

     */

    public function __construct(Twig_Environment $env)

    {

        $this->env = $env;

    }

    public function getVarName()

    {

        return sprintf('__internal_%s_%d', substr($this->env->getTemplateClass($this->stream->getFilename()), strlen($this->env->getTemplateClassPrefix())), ++$this->tmpVarCount);

    }

    /**

     * Converts a token stream to a node tree.

     *

     * @param  Twig_TokenStream $stream A token stream instance

     *

     * @return Twig_Node_Module A node tree

     */

    public function parse(Twig_TokenStream $stream)

    {

        $this->tmpVarCount = 0;

        // tag handlers

        $this->handlers = $this->env->getTokenParsers();

        $this->handlers->setParser($this);

        // node visitors

        $this->visitors = $this->env->getNodeVisitors();

        if (null === $this->expressionParser) {

            $this->expressionParser = new Twig_ExpressionParser($this, $this->env->getUnaryOperators(), $this->env->getBinaryOperators());

        }

        $this->stream = $stream;

        $this->parent = null;

        $this->blocks = array();

        $this->macros = array();

        $this->traits = array();

        $this->blockStack = array();

        $this->importedFunctions = array(array());

        try {

            $body = $this->subparse(null);

            if (null !== $this->parent) {

                if (null === $body = $this->filterBodyNodes($body)) {

                    $body = new Twig_Node();

                }

            }

        } catch (Twig_Error_Syntax $e) {

            if (null === $e->getTemplateFile()) {

                $e->setTemplateFile($this->stream->getFilename());

            }

            throw $e;

        }

        $node = new Twig_Node_Module($body, $this->parent, new Twig_Node($this->blocks), new Twig_Node($this->macros), new Twig_Node($this->traits), $this->stream->getFilename());

        $traverser = new Twig_NodeTraverser($this->env, $this->visitors);

        return $traverser->traverse($node);

    }

    public function subparse($test, $dropNeedle = false)

    {

        $lineno = $this->getCurrentToken()->getLine();

        $rv = array();

        while (!$this->stream->isEOF()) {

            switch ($this->getCurrentToken()->getType()) {

                case Twig_Token::TEXT_TYPE:

                    $token = $this->stream->next();

                    $rv[] = new Twig_Node_Text($token->getValue(), $token->getLine());

                    break;

                case Twig_Token::VAR_START_TYPE:

                    $token = $this->stream->next();

                    $expr = $this->expressionParser->parseExpression();

                    $this->stream->expect(Twig_Token::VAR_END_TYPE);

                    $rv[] = new Twig_Node_Print($expr, $token->getLine());

                    break;

                case Twig_Token::BLOCK_START_TYPE:

                    $this->stream->next();

                    $token = $this->getCurrentToken();

                    if ($token->getType() !== Twig_Token::NAME_TYPE) {

                        throw new Twig_Error_Syntax('A block must start with a tag name', $token->getLine(), $this->stream->getFilename());

                    }

                    if (null !== $test && call_user_func($test, $token)) {

                        if ($dropNeedle) {

                            $this->stream->next();

                        }

                        if (1 === count($rv)) {

                            return $rv[0];

                        }

                        return new Twig_Node($rv, array(), $lineno);

                    }

                    $subparser = $this->handlers->getTokenParser($token->getValue());

                    if (null === $subparser) {

                        throw new Twig_Error_Syntax(sprintf('Unknown tag name "%s"', $token->getValue()), $token->getLine(), $this->stream->getFilename());

                    }

                    $this->stream->next();

                    $node = $subparser->parse($token);

                    if (null !== $node) {

                        $rv[] = $node;

                    }

                    break;

                default:

                    throw new Twig_Error_Syntax('Lexer or parser ended up in unsupported state.', -1, $this->stream->getFilename());

            }

        }

        if (1 === count($rv)) {

            return $rv[0];

        }

        return new Twig_Node($rv, array(), $lineno);

    }

    public function addHandler($name, $class)

    {

        $this->handlers[$name] = $class;

    }

    public function addNodeVisitor(Twig_NodeVisitorInterface $visitor)

    {

        $this->visitors[] = $visitor;

    }

    public function getBlockStack()

    {

        return $this->blockStack;

    }

    public function peekBlockStack()

    {

        return $this->blockStack[count($this->blockStack) - 1];

    }

    public function popBlockStack()

    {

        array_pop($this->blockStack);

    }

    public function pushBlockStack($name)

    {

        $this->blockStack[] = $name;

    }

    public function hasBlock($name)

    {

        return isset($this->blocks[$name]);

    }

    public function setBlock($name, $value)

    {

        $this->blocks[$name] = $value;

    }

    public function hasMacro($name)

    {

        return isset($this->macros[$name]);

    }

    public function setMacro($name, Twig_Node_Macro $node)

    {

        if (null === $this->reservedMacroNames) {

            $this->reservedMacroNames = array();

            $r = new ReflectionClass($this->env->getBaseTemplateClass());

            foreach ($r->getMethods() as $method) {

                $this->reservedMacroNames[] = $method->getName();

            }

        }

        if (in_array($name, $this->reservedMacroNames)) {

            throw new Twig_Error_Syntax(sprintf('"%s" cannot be used as a macro name as it is a reserved keyword', $name), $node->getLine());

        }

        $this->macros[$name] = $node;

    }

    public function addTrait($trait)

    {

        $this->traits[] = $trait;

    }

    public function addImportedFunction($alias, $name, Twig_Node_Expression $node)

    {

        $this->importedFunctions[0][$alias] = array('name' => $name, 'node' => $node);

    }

    public function getImportedFunction($alias)

    {

        foreach ($this->importedFunctions as $functions) {

            if (isset($functions[$alias])) {

                return $functions[$alias];

            }

        }

    }

    public function pushLocalScope()

    {

        array_unshift($this->importedFunctions, array());

    }

    public function popLocalScope()

    {

        array_shift($this->importedFunctions);

    }

    /**

     * Gets the expression parser.

     *

     * @return Twig_ExpressionParser The expression parser

     */

    public function getExpressionParser()

    {

        return $this->expressionParser;

    }

    public function getParent()

    {

        return $this->parent;

    }

    public function setParent($parent)

    {

        $this->parent = $parent;

    }

    /**

     * Gets the token stream.

     *

     * @return Twig_TokenStream The token stream

     */

    public function getStream()

    {

        return $this->stream;

    }

    /**

     * Gets the current token.

     *

     * @return Twig_Token The current token

     */

    public function getCurrentToken()

    {

        return $this->stream->getCurrent();

    }

    protected function filterBodyNodes(Twig_NodeInterface $node)

    {

        // check that the body does not contain non-empty output nodes

        if (

            ($node instanceof Twig_Node_Text && !ctype_space($node->getAttribute('data')))

            ||

            (!$node instanceof Twig_Node_Text && !$node instanceof Twig_Node_BlockReference && $node instanceof Twig_NodeOutputInterface)

        ) {

            throw new Twig_Error_Syntax(sprintf('A template that extends another one cannot have a body (%s).', $node), $node->getLine(), $this->stream->getFilename());

        }

        if ($node instanceof Twig_NodeOutputInterface) {

            return null;

        }

        foreach ($node as $k => $n) {

            if (null !== $n && null === $n = $this->filterBodyNodes($n)) {

                $node->removeNode($k);

            }

        }

        return $node;

    }

}