<?php 

/*

 * Created on 2009 Jan 02

 * by Martin Wernstahl <m4rw3r@gmail.com>

 */



/**

 * A context which renders the tags for the parser.

 * 

 * @package FTL_Parser

 * @author Martin Wernstahl <m4rw3r@gmail.com>

 * @copyright Copyright (c) 2008, Martin Wernstahl <m4rw3r@gmail.com>

 */

class FTL_Context

{	

	/**

	 * Contains tag definitions.

	 * 

	 * @var array

	 */

	public $definitions = array();

	

	/**

	 * Reverse tag finder tree.

	 * 

	 * @var array

	 */

	public $tree = array();

	

	/**

	 * The global data.

	 * 

	 * @var FTL_VarStack

	 */

	public $globals;

	

	/**

	 * A stack of the tag bindings.

	 * 

	 * @var FTL_Binding

	 */

	protected $tag_binding_stack = array();

	

	/**

	 * A stack of tag names.

	 * 

	 * @var array(string)

	 */

	protected $tag_name_stack = array();

	

	// --------------------------------------------------------------------

		

	/**

	 * Init.

	 * 

	 * Creates a var_stack.

	 */

	function __construct()

	{

		$this->globals = new FTL_VarStack();

	}

	

	// --------------------------------------------------------------------

		

	/**

	 * Defines a tag.

	 * 

	 * @param  string    The name of the tags (nestings are separated with ":")

	 * @param  callable  The function/method to be called

	 * @return void

	 */

	public function define_tag($name, $callable)

	{

		$this->definitions[$name] = $callable;

		

		if(strpos($name, ':') === false)

		{

			// No nesting, no need for a reverse mapping tree

			return;

		}

		

		// Create reverse mapping tree, for tags with more than one segment

		$l = explode(':', $name);

		

		$c = count($l);

		

		// # key is a tag name

		

		// Fast and nice (currently only up to 5 segment tags):

		if($c == 2)

		{

			$this->tree[$l[1]][$l[0]]['#'] = $name;

		}

		elseif($c == 3)

		{

			$this->tree[$l[2]][$l[1]][$l[0]]['#'] = $name;

		}

		elseif($c == 4)

		{

			$this->tree[$l[3]][$l[2]][$l[1]][$l[0]]['#'] = $name;

		}

		elseif($c == 5)

		{

			$this->tree[$l[4]][$l[3]][$l[2]][$l[1]][$l[0]]['#'] = $name;

		}

		

		// TODO: To support more segments, add more rows like this

	}

	

	// --------------------------------------------------------------------

		

	/**

	 * Renders the tags with the name and args supplied.

	 * 

	 * @param  string  The tag name

	 * @param  array   The args

	 * @param  array   The nested block

	 */

	public function render_tag($name, $args = array(), $block = null)

	{

		// do we have a compund tag?

		if(($pos = strpos($name, ':')) != 0)

		{

			// split them and parse them separately, as if they are nested

			$name1 = substr($name, 0, $pos);

			$name2 = substr($name, $pos + 1);



			return $this->render_tag($name1, array(), array(

					'name' => $name2,

					'args' => $args,

					'content' => $block

				));

		}

		else

		{

			$qname = $this->qualified_tag_name($name);



			if(is_string($qname) && array_key_exists($qname, $this->definitions))

			{

				// render

				return $this->stack($name, $args, $block, $this->definitions[$qname]);

			}

			else

			{

				return $this->tag_missing($name, $args, $block);

			}

		}

	}

	

	// --------------------------------------------------------------------

		

	/**

	 * Traverses the stack and handles the bindings and var_stack(s).

	 * 

	 * @param  string	The tag name

	 * @param  array	The tag args

	 * @param  array 	The nested block

	 * @param  callable	The function/method to call

	 * @return string

	 */

	protected function stack($name, $args, $block, $call)

	{

		// get previous locals, to let the data "stack"

		$previous = end($this->tag_binding_stack);

		$previous_locals = $previous == null ? $this->globals : $previous->locals;

		

		// create the stack and binding

		$locals = new FTL_VarStack($previous_locals);

		$binding = new FTL_Binding($this, $locals, $name, $args, $block);

		

		$this->tag_binding_stack[] = $binding;

		$this->tag_name_stack[]    = $name;

		

		// Check if we have a function or a method

		if(is_callable($call))

		{

			$result = call_user_func($call, $binding);

		}

		else

		{

			show_error('Error in definition of tag "'.$name.'", the associated <b>static function</b> "'.$call.'" cannot be called.');

		}

		

		// jump out

		array_pop($this->tag_binding_stack);

		array_pop($this->tag_name_stack);

		

		return $result;

	}



	// --------------------------------------------------------------------



	/**

	 * Makes a qualified guess of the tag definition requested depending on the current nesting.

	 * 

	 * @param  string  The name of the tag

	 * @return string

	 */

	function qualified_tag_name($name)

	{

		// Get the path array

		$path_chunks = array_merge($this->tag_name_stack, array($name));

		// For literal matches

		$path = implode(':', $path_chunks);

		

		// Check if we have a tag or a variable

		if( ! isset($this->definitions[$path]) && ! isset($this->globals->hash[$name]))

		{

			// Reverse the chunks, we're starting with the most precise name

			$path_chunks = array_reverse($path_chunks);

			

			// Set default tag, which is the last one

			$last = current($path_chunks);

			

			// Do we have a tag which ends at the correct name?

			if( ! isset($this->tree[$last]))

			{

				// Nope

				return $last;

			}

			

			// Start

			$c =& $this->tree;

//echo('<pre>');

//var_dump($this->tree);

//echo('</pre>');

			

			// Go through the whole name

			while( ! empty($path_chunks))

			{

				// Get next

				$e = array_shift($path_chunks);

				

				// Do we have a matching segment?

				if(isset($c[$e]))

				{

					// Yes

					

					// Do we have a tag here?

					if(isset($c[$e]['#']))

					{

						// Yes

						$last = $c[$e]['#'];

					}

					

					// Move deeper, to make sure that we don't have any more specific tags

					$c =& $c[$e];

				}

			}

			

			return $last;

		}

		else

		{

			return $path;

		}

	}

	

	// --------------------------------------------------------------------

		

	/**

	 * Raises a tag missing error.

	 * 

	 * @param  string The tag name

	 * @param  array  The tag parameters

	 * @param  array  The nested block

	 * @return string Or abort if needed (default)

	 */

	public function tag_missing($name, $args = array(), $block = null)

	{

		throw new Exception('Tag missing: "'.$name.'", scope: "'.$this->current_nesting().'".');

	}

	

	// --------------------------------------------------------------------

		

	/**

	 * Returns the state of the current render stack.

	 * 

	 * Useful from inside a tag definition. Normally just use XT_Binding::nesting().

	 * 

	 * @return string

	 */

	function current_nesting()

	{

		return implode(':', $this->tag_name_stack);

	}

}



/* End of file context.php */

/* Location: ./application/libraries/xt_parser/context.php */