<?php
/*=====================================================================*\
|| ###################################################################
|| # Blue Static ISSO Framework
|| # Copyright Š2002-[#]year[#] Blue Static
|| #
|| # This program is free software; you can redistribute it and/or modify
|| # it under the terms of the GNU General Public License as published by
|| # the Free Software Foundation; version [#]gpl[#] of the License.
|| #
|| # This program is distributed in the hope that it will be useful, but
|| # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|| # or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|| # more details.
|| #
|| # You should have received a copy of the GNU General Public License along
|| # with this program; if not, write to the Free Software Foundation, Inc.,
|| # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
|| ###################################################################
\*=====================================================================*/

/**
* Database-Driven Template System
* template.php
*
* @package	ISSO
*/

/**
* Database-Driven Template System
*
* This framework is a backend to the database template engine and
* contains all the parsing algorithms.
*
* Hooks:
*		$this->pre_parse_hook - Name of the function to execute on
*								a template before the parsing occurs
*
* @author		Blue Static
* @copyright	Copyright Š2002 - [#]year[#], Blue Static
* @version		$Revision$
* @package		ISSO
* 
*/
class Template
{
	/**
	* Framework registry object
	* @var	object
	* @access	private
	*/
	var $registry = null;
	
	/**
	* Name of the database table templates are in
	* @var	string
	* @access	private
	*/
	var $tablename = '';
	
	/**
	* Name of the table column template names are in
	* @var	string
	* @access	private
	*/
	var $namecolumn = '';
	
	/**
	* Name of the table column templates are in
	* @var	string
	* @access	private
	*/
	var $datacolumn = '';
	
	/**
	* Additional WHERE clauses for the template fetch SQL
	* @var	string
	* @access	private
	*/
	var $extrawhere = '';
	
	/**
	* The name of the function phrases are fetched with
	* @var	string
	* @access	private
	*/
	var $langcall = 'gettext';
	
	/**
	* The name of the function phrases are sprintf() parsed with
	* @var	string
	* @access	private
	*/
	var $langconst = 'sprintf';
	
	/**
	* Array of pre-compiled templates that are stored to decrease server load
	* @var	array
	* @access	private
	*/
	var $cache = array();
	
	/**
	* A list of the number of times each template has been used
	* @var	array
	* @access	private
	*/
	var $usage = array();
	
	/**
	* A list of templates that weren't cached, but are still used
	* @var	array
	* @access	private
	*/
	var $uncached = array();
	
	/**
	* Whether or not the page has been flush()'d already
	* @var	bool
	* @access	private
	*/
	var $doneflush = false;
	
	/**
	* The name of a function that is called before template parsing of phrases and conditionals occurs
	* @var	string
	* @access	private
	*/
	var $pre_parse_hook = ':=NO METHOD=:';
	
	// ###################################################################
	/**
	* Constructor
	*/
	function __construct(&$registry)
	{
		$this->registry =& $registry;
	}
	
	// ###################################################################
	/**
	* (PHP 4) Constructor
	*/
	function Template(&$registry)
	{
		$this->__construct($registry);
	}
	
	// ###################################################################
	/**
	* Initializes the class and all subclasses under a common package name
	*
	* @access	protected
	*
	* @return	string	The package name
	*/
	function init_as_package()
	{
		return 'template';
	}
	
	// ###################################################################
	/**
	* Sets tablename
	*
	* @access	public
	*
	* @param	string	Table name
	*/
	function setTableName($name)
	{
		$this->tablename = $name;
	}
	
	// ###################################################################
	/**
	* Sets namecolumn
	*
	* @access	public
	*
	* @param	string	Name column name
	*/
	function setNameColumn($name)
	{
		$this->namecolumn = $name;
	}
	
	// ###################################################################
	/**
	* Sets datacolumn
	*
	* @access	public
	*
	* @param	string	Data column name
	*/
	function setDataColumn($name)
	{
		$this->datacolumn = $name;
	}
	
	// ###################################################################
	/**
	* Sets extrawhere
	*
	* @access	public
	*
	* @param	string	Extra WHERE SQL clause
	*/
	function setExtraWhere($sql)
	{
		$this->extrawhere = $sql;
	}
	
	// ###################################################################
	/**
	* Sets the pre-parse hook
	*
	* @access	public
	*
	* @param	string	Method name
	*/
	function setPreParseHook($name)
	{
		$this->pre_parse_hook = $name;
	}
	
	// ###################################################################
	/**
	* Takes an array of template names, loads them, and then stores a
	* parsed version for optimum speed.
	*
	* @access	public
	*
	* @param	array	List of template names to be cached
	*/
	function cache($namearray)
	{
		if (sizeof($this->cache) > 0)
		{
			trigger_error('You cannot cache templates more than once per initialization', E_USER_WARNING);
		}
		else
		{
			$templates = $this->registry->modules[ISSO_DB_LAYER]->query("SELECT * FROM " . $this->tablename . " WHERE " . $this->namecolumn . " IN ('" . implode("', '", $namearray) . "')" . ($this->extrawhere ? ' ' . $this->extrawhere : ''));
			while ($template = $this->registry->modules[ISSO_DB_LAYER]->fetch_array($templates))
			{
				$this->cache[ $template[ $this->namecolumn ] ] = $this->_parse($template[ $this->datacolumn ]);
				$this->usage[ $template[ $this->namecolumn ] ] = 0;
			}
		}
	}
	
	// ###################################################################
	/**
	* Loads a template from the cache or the _load function and stores the
	* parsed version of it
	*
	* @access	public
	*
	* @param	string	The name of the template
	*
	* @return	string	A parsed and loaded template
	*/
	function fetch($name)
	{
		if (isset($this->cache["$name"]))
		{
			$template = $this->cache["$name"];
		}
		else
		{
			$this->uncached[] = $name;
			$this->registry->debug("Manually loading template `$name`");
			$template = $this->_load($name);
			$template = $this->_parse($template);
		}
		
		if (!isset($this->usage["$name"]))
		{
			$this->usage["$name"] = 0;
		}
		
		$this->usage["$name"]++;
		
		return $template;
	}
	
	// ###################################################################
	/**
	* Output a template fully compiled to the browser
	*
	* @access	public
	*
	* @param	string	Compiled and ready template
	*/
	function flush($template)
	{
		ob_start();
		
		if (empty($template))
		{
			trigger_error('There was no output to print', E_USER_ERROR);
			exit;
		}
		
		if ($this->registry->debug AND isset($_GET['query']))
		{
			if (is_array($this->registry->modules[ISSO_DB_LAYER]->history))
			{
				foreach ($this->registry->modules[ISSO_DB_LAYER]->history AS $query)
				{
					echo $this->registry->modules[ISSO_DB_LAYER]->construct_query_debug($query);
				}
			}
			exit;
		}
		
		if ($this->doneflush)
		{
			trigger_error('A template has already been sent to the output buffer', E_USER_ERROR);
			exit;
		}
		
		$template = str_replace('</body>', $this->registry->construct_debug_block(true) . '</body>', $template);

		print($template);
	}
	
	// ###################################################################
	/**
	* Loads an additional template from the database
	*
	* @access	private
	*
	* @param	string	The name of the template
	*
	* @return	string	Template data from the database
	*/
	function _load($name)
	{
		if ($template = $this->registry->modules[ISSO_DB_LAYER]->query_first("SELECT * FROM " . $this->tablename . " WHERE " . $this->namecolumn . " = '$name'" . ($this->extrawhere ? ' ' . $this->extrawhere : '')))
		{
			return $template[ $this->datacolumn ];
		}
		else
		{
			trigger_error("The template '$name' could not be loaded", E_USER_ERROR);
			exit;
		}
	}
	
	// ###################################################################
	/**
	* A wrapper for all the parsing functions and compiling functins
	*
	* @access	protected
	*
	* @param	string	Unparsed template data
	*
	* @return	string	Parsed template data
	*/
	function _parse($template)
	{
		$template = str_replace('"', '\"', $template);
		
		if (function_exists($this->pre_parse_hook))
		{
			$template = call_user_func($this->pre_parse_hook, $template);
		}
		
		$template = $this->_parse_phrases($template);
		$template = $this->_parse_conditionals($template);
		return $template;
	}
	
	// ###################################################################
	/**
	* Prepares language and locale information inside templates
	*
	* @access	private
	*
	* @param	string	Template data to be processed
	*
	* @return	string	Language-ready template data
	*/
	function _parse_phrases($template)
	{
		$tag_start = '<lang ';
		$tag_start_end = '\">';
		$tag_end = '</lang>';
		
		$location_start = -1;
		$location_end = -1;
		
		while (1)
		{
			// Find the start language object tag
			$location_start = strpos($template, $tag_start, $location_end + 1);
			if ($location_start === false)
			{
				break;
			}
		
			// Find the end tag
			$location_end = strpos($template, $tag_end, $location_end + strlen($tag_end));
			if ($location_end === false)
			{
				break;
			}
			
			// Extract the language object
			$phrase_bunch = substr($template, $location_start, ($location_end + strlen($tag_end)) - $location_start);
			
			// Find the close to the opening <lang>
			$close_of_open = strpos($phrase_bunch, $tag_start_end);
			if ($close_of_open === false)
			{
				break;
			}
			
			// Extract the opening tag so it can be parsed
			$init_tag = substr($phrase_bunch, 0, ($close_of_open + strlen($tag_start_end)));
			$init_tag = str_replace($tag_start, '', $init_tag);
			$init_tag = substr($init_tag, 0, strlen($init_tag) - 1);
			
			// Get the args out of the tag
			$args = preg_split('#([0-9].*?)=#', $init_tag);
			foreach ($args AS $arg)
			{
				if ($arg AND $arg != ' ')
				{
					$arg = trim($arg);
					$arg = substr($arg, 2);
					$arg = substr($arg, 0, strlen($arg) - 2);
					$arglist[] = $arg;
				}
			}
			
			// Just get the phrase name
			$phrase_name = preg_replace('#<lang(.*?)>(.*?)</lang>#i', '$2', $phrase_bunch);
			
			// Wrap the parsed data into the build function
			$function_wrap = '" . ' . $this->langconst . '("' . /*str_replace(array('\"', "'"), array('"', "\'"),*/ $phrase_name/*)*/ . '", "' . implode('", "', $arglist) . '") . "';
			
			// Replace the fully-parsed string back into the template
			$template = substr_replace($template, $function_wrap, $location_start, $location_end + strlen($tag_end) - $location_start);
			
			unset($arglist);
		}
		
		// Process the empty phrase objects -- do this now so we don't have to worry about it when we're parsing later
		$template = preg_replace('#\{@\\\"(.*?)\\\"\}#ise', '$this->_phrase_string(\'$1\')', $template);
		
		return $template;
	}
	
	// ###################################################################
	/**
	* Turns a localized phrase tag into a function call
	*
	* @access	private
	*
	* @param	string	Phrase text
	*
	* @return	string	Function call for phrase text
	*/
	function _phrase_string($text)
	{
		return '" . ' . $this->langcall . '(\'' . str_replace(array('\\\"', "'"), array('"', "\'"), $text) . '\') . "';
	}
	
	// ###################################################################
	/**
	* Parser for in-line template conditionals
	*
	* @access	private
	*
	* @param	string	Template data awaiting processing
	*
	* @return	string	Parsed template data
	*/
	function _parse_conditionals($template)
	{
		// tag data
		$tag_start = '<if condition=\"';
		$tag_start_end = '\">';
		$tag_else = '<else />';
		$tag_end = '</if>';
		
		// tag stack
		$stack = array();
		
		// the information about the current active tag
		$tag_full = array();
		$parsed = array();
		
		// start at 0
		$offset = 0;
		
		while (1)
		{
			if (strpos($template, $tag_start) === false)
			{
				break;
			}
			
			for ($i = $offset; $i < strlen($template); $i++)
			{
				// we've found ourselves a conditional!
				if (substr($template, $i, strlen($tag_start)) == $tag_start)
				{
					// push the position into the tag stack
					if ($tag_full)
					{
						array_push($stack, $i);
					}
					else
					{
						$tag_full['posi'] = $i;
					}
				}
				// locate else tags
				else if (substr($template, $i, strlen($tag_else)) == $tag_else)
				{
					if (sizeof($stack) == 0 AND !isset($tag_full['else']))
					{
						$tag_full['else'] = $i;
					}
				}
				// do we have an end tag?
				else if (substr($template, $i, strlen($tag_end)) == $tag_end)
				{
					if (sizeof($stack) != 0)
					{
						array_pop($stack);
						continue;
					}
					
					// calculate the position of the end tag
					$tag_full['posf'] = $i + strlen($tag_end) - 1;
					
					// extract the entire conditional from the template
					$fullspread = substr($template, $tag_full['posi'], $tag_full['posf'] - $tag_full['posi'] + 1);
					
					// remove the beginning tag
					$conditional = substr($fullspread, strlen($tag_start));
					
					// find the end of the expression
					$temp_end = strpos($conditional, $tag_start_end);
					
					// save the expression
					$parsed[0] = stripslashes(substr($conditional, 0, $temp_end));
					
					// remove the expression from the conditional
					$conditional = substr($conditional, strlen($parsed[0]) + strlen($tag_start_end));
					
					// remove the tailing end tag
					$conditional = substr($conditional, 0, strlen($conditional) - strlen($tag_end));
					
					// handle the else
					if (isset($tag_full['else']))
					{
						// now relative to the start of the <if>
						$relpos = $tag_full['else'] - $tag_full['posi'];
						
						// calculate the length of the expression and opening tag
						$length = strlen($parsed[0]) + strlen($tag_start) + strlen($tag_start_end);
						
						// relative to the start of iftrue
						$elsepos = $relpos - $length;
	
						$parsed[1] = substr($conditional, 0, $elsepos);
						$parsed[2] = substr($conditional, $elsepos + strlen($tag_else));
					}
					// no else to handle
					else
					{
						$parsed[1] = $conditional;
						$parsed[2] = '';
					}
					#var_dump($parsed);
					
					// final parsed output
					$parsed = '" . ((' . stripslashes($parsed[0]) . ') ? "' . $parsed[1] . '" : "' . $parsed[2] . '") . "';
					
					// replace the conditional
					$template = str_replace($fullspread, $parsed, $template);
					
					// reset the parser
					$offset = $tag_full['posi'] + strlen($tag_start) + strlen($tag_start_end);
					$tag_full = array();
					$stack = array();
					$parsed = array();
					unset($fullspread, $conditional, $temp_end, $relpos, $length, $elsepos);
					break;
				}
			}
		}

		return $template;
	}
}

// ###################################################################
/**
* Debugging function used to print characters in a string that are
* around a certain position.
*
* @access	private
*
* @param	string	The haystack string
* @param	integer	Position to print around
*/
function print_around($str, $pos)
{
	echo '>>> PA >>>>>>>>[';
	echo htmlspecialchars($str[ $pos - 5 ]);
	echo htmlspecialchars($str[ $pos - 4 ]);
	echo htmlspecialchars($str[ $pos - 3 ]);
	echo htmlspecialchars($str[ $pos - 2 ]);
	echo htmlspecialchars($str[ $pos - 1 ]);
	echo 'Š';
	echo htmlspecialchars($str[ $pos + 0 ]);
	echo htmlspecialchars($str[ $pos + 1 ]);
	echo htmlspecialchars($str[ $pos + 2 ]);
	echo htmlspecialchars($str[ $pos + 3 ]);
	echo htmlspecialchars($str[ $pos + 4 ]);
	echo htmlspecialchars($str[ $pos + 5 ]);
	echo ']<<<<<<<< PA <<<';
}

/*=====================================================================*\
|| ###################################################################
|| # $HeadURL$
|| # $Id$
|| ###################################################################
\*=====================================================================*/
?>