<?php

/* SVN FILE: $Id$ */

/**

 * SassFunctionDefinitionNode class file.

 * @author      Chris Yates <chris.l.yates@gmail.com>

 * @copyright   Copyright (c) 2010 PBM Web Development

 * @license      http://phamlp.googlecode.com/files/license.txt

 * @package      PHamlP

 * @subpackage  Sass.tree

 */



/**

 * SassFunctionDefinitionNode class.

 * Represents a Function definition.

 * @package      PHamlP

 * @subpackage  Sass.tree

 */

class SassFunctionDefinitionNode extends SassNode {

  const NODE_IDENTIFIER = FALSE;

  const MATCH = '/^@function\s+([_-\w]+)\s*(?:\((.*?)\))?\s*$/im';

  const IDENTIFIER = 1;

  const NAME = 1;

  const ARGUMENTS = 2;



  /**

   * @var string name of the function

   */

  private $name;

  /**

   * @var array arguments for the function as name=>value pairs were value is the

   * default value or null for required arguments

   */

  private $args = array();



  public $parent;



  /**

   * SassFunctionDefinitionNode constructor.

   * @param object source token

   * @return SassFunctionDefinitionNode

   */

  public function __construct($token) {

    // if ($token->level !== 0) {

    //   throw new SassFunctionDefinitionNodeException('Functions can only be defined at root level', $token);

    // }

    parent::__construct($token);

    preg_match(self::MATCH, $token->source, $matches);

    if (empty($matches)) {

      throw new SassFunctionDefinitionNodeException('Invalid Function', $token);

    }

    $this->name = $matches[self::NAME];

    $this->name = preg_replace('/[^a-z0-9_]/', '_', strtolower($this->name));

    if (isset($matches[self::ARGUMENTS])) {

      if (strlen(trim($matches[self::ARGUMENTS]))) {

        foreach (explode(',', $matches[self::ARGUMENTS]) as $arg) {

          $arg = explode(($matches[self::IDENTIFIER] === self::NODE_IDENTIFIER ? '=' : ':'), trim($arg));

          $this->args[substr(trim($arg[0]), 1)] = (count($arg) == 2 ? trim($arg[1]) : null);

        } // foreach

      }

    }

  }



  /**

   * Parse this node.

   * Add this function to  the current context.

   * @param SassContext the context in which this node is parsed

   * @return array the parsed node - an empty array

   */

  public function parse($context) {

    $context->addFunction($this->name, $this);

    return array();

  }



  /**

   * Returns the arguments with default values for this function

   * @return array the arguments with default values for this function

   */

  public function getArgs() {

    return $this->args;

  }



  /**

   * Returns a value indicating if the token represents this type of node.

   * @param object token

   * @return boolean true if the token represents this type of node, false if not

   */

  public static function isa($token) {

    return $token->source[0] === self::NODE_IDENTIFIER;

  }



  /**

   * Evalutes the function in the given context, with the provided arguments

   * @param SassContext - the parent context

   * @param array - the list of provided variables

   * @throws SassReturn - if the @return is fired then this is thrown to break early

   * @return SassBoolean(false) - if no @return was fired, return false

   */

  public function execute($pcontext, $provided) {

    list($arguments, $context) = SassScriptFunction::fill_parameters($this->args, $provided, $pcontext, $this);

    $context->setVariables($arguments);



    $parser = $this->parent->parser;



    $children = array();

    try {

      foreach ($this->children as $child) {

        $child->parent = $this;

        $children = array_merge($children, $child->parse($context));

      }

    } catch (SassReturn $e) {

      return $e->value;

    }



    return new SassBoolean('false');

  }

}