<?php
/*=====================================================================*\
|| ###################################################################
|| # Blue Static ISSO Framework
|| # Copyright (c)2005-2008 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 2 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
*/

require_once(ISSO . '/Functions.php');

/**
* File-Based Template System
*
* This framework merely replaces the template loading functions with
* file-system based ones. It has an optional caching system in which
* template data will remain stored in the database as long as the filesystem
* file is modified. To do this, pass a table name to setDatabaseCache() and make sure
* there's a DB module that has access to a table with this schema:
*
* CREATE TABLE template (filename VARCHAR (250) NOT NULL, template TEXT NOT NULL, timestamp INT NOT NULL);
*
* @author		Blue Static
* @copyright	Copyright (c)2005 - 2008, Blue Static
* @package		ISSO
* 
*/
class BSTemplate
{
	/**
	* The path, from the path of the application, where templates are stored
	* @var	string
	*/
	private $templateDir = '';
	
	/**
	* The extension all the template files have
	* @var	string
	*/
	private $extension = 'tpl';
	
	/**
	* The database table name for the template cache
	* @var string
	*/
	private $dbCacheTable = null;
	
	/**
	* The name of the function phrases are fetched with
	* @var	string
	*/
	private $langcall = 'gettext';
	
	/**
	* The name of the function phrases are sprintf() parsed with
	* @var	string
	*/
	private $langconst = 'sprintf';
	
	/**
	* Array of pre-compiled templates that are stored to decrease server load
	* @var	array
	*/
	protected $cache = array();
	
	/**
	* A list of templates that weren't cached, but are still used
	* @var	array
	*/
	protected $uncached = array();
	
	/**
	* Whether or not the page has been flush()'d already
	* @var	bool
	*/
	private $doneflush = false;
	
	/**
	* The name of a function that is called before template parsing of phrases and conditionals occurs
	* @var	string
	*/
	private $preParseHook = ':undefined:';
	
	// ###################################################################
	/**
	* Sets the template directory name
	*
	* @param	string	Template directory name
	*/
	public function setTemplateDirectory($dir)
	{
		$this->templateDir = BSFunctions::fetch_source_path($dir);
	}
	
	// ###################################################################
	/**
	* Sets the file extension for the templates
	*
	* @param	string	File extension
	*/
	public function setExtension($ext)
	{
		$this->extension = $ext;
	}
	
	// ###################################################################
	/**
	* Sets the name of the table to access for the datbase cache
	*
	* @param	string	DB table name
	*/
	public function setDatabaseCache($table)
	{
		$this->dbCacheTable = $table;
	}
	
	// ###################################################################
	/**
	* Sets the pre-parse hook method which is called before any other
	* processing is done on the template.
	*
	* @param	string	Method name
	*/
	public function setPreParseHook($hook)
	{
		$this->preParseHook = $hook;
	}
	
	// ###################################################################
	/**
	* Takes an array of template names, loads them, and then stores a
	* parsed version for optimum speed.
	*
	* @param	array	List of template names to be cached
	*/
	public function cache($namearray)
	{
		if (sizeof($this->cache) > 0)
		{
			throw new Exception('You cannot cache templates more than once per initialization');
		}
		else
		{
			$dbCache = array();
			if ($this->dbCacheTable)
			{
				$db =& BSApp::$db;
				$cache = $db->query("SELECT * FROM {$this->dbCacheTable} WHERE filename IN ('" . implode("', '", $namearray) . "')");
				while ($tpl = $cache->fetchArray())
				{
					$time = filemtime($this->templateDir . $tpl['filename'] . '.' . $this->extension);
					$template = $tpl['template'];
					if ($time > $tpl['timestamp'])
					{
						$template = $this->_parseTemplate($this->_loadTemplate($tpl['filename']));
						$db->query("UPDATE {$this->dbCacheTable} SET template = '" . $db->escapeString($template) . "', timestamp = " . TIMENOW . " WHERE filename = '" . $tpl['filename'] . "'");
						$tpl['template'] = $template;
					}
					$dbCache["$tpl[filename]"] = $template;
				}
			}
			foreach ($namearray as $name)
			{
				if ($this->dbCacheTable)
				{
					if (isset($dbCache["$name"]))
					{
						$template = $dbCache["$name"];
					}
					else
					{
						$template = $this->_parseTemplate($this->_loadTemplate($name));
						$db->query("INSERT INTO {$this->dbCacheTable} (filename, template, timestamp) VALUES ('$name', '" . $db->escapeString($template) . "', " . TIMENOW . ")");
					}
				}
				else
				{
					$template = $this->_parseTemplate($this->_loadTemplate($name));
				}
				
				$this->cache[$name] = $template;
			}
		}
	}
	
	// ###################################################################
	/**
	* Loads a template from the cache or the _load function and stores the
	* parsed version of it
	*
	* @param	string	The name of the template
	*
	* @return	string	A parsed and loaded template
	*/
	public function fetch($name)
	{
		if (isset($this->cache[$name]))
		{
			$template = $this->cache[$name];
		}
		else
		{
			$this->uncached[$name] = (isset($this->uncached[$name]) ? $this->uncached[$name] + 1 : 0);
			BSApp::debug("Manually loading template '$name'");
			$template = $this->_loadTemplate($name);
			$template = $this->_parseTemplate($template);
		}
		
		return $template;
	}
	
	// ###################################################################
	/**
	* Output a template fully compiled to the browser
	*
	* @param	string	Compiled and ready template
	*/
	public function flush($template)
	{
		ob_start();
		
		if (empty($template))
		{
			throw new Exception('There was no output to print');
		}
		
		if ($this->doneflush)
		{
			throw new Exception('A template has already been sent to the output buffer');
		}
		
		$debugBlock = '';
		if (BSApp::get_debug())
		{			
			$debugBlock .= "\n<div align=\"center\">Executed in " . round(BSFunctions::fetch_microtime_diff('0 ' . $_SERVER['REQUEST_TIME']), 10) . ' seconds</div>';
			$debugBlock .= "\n<br /><div align=\"center\">" . BSApp::get_debug_list() . "</div>";
			
			if (sizeof($this->uncached) > 0)
			{
				foreach ($this->uncached as $name => $count)
				{
					$tpls[] = $name . "($count)";
				}
				$debugBlock .= "<br /><div style=\"color: red\" align=\"center\"><strong>Uncached Templates:</strong>" . implode(', ', $tpls) . " )</div>\n";
			}
			
			if (BSApp::$db)
			{
				$queries = BSApp::$db->getHistory();
				
				$debugBlock .= "<br />\n" . '<table cellpadding="4" cellspacing="1" border="0" align="center" width="30%" style="background-color: rgb(60, 60, 60); color: white">' . "\n\t" . '<tr><td><strong>Query Debug</strong></td></tr>';
				
				foreach ($queries as $query)
				{
					$debugBlock .= "\n\t<tr style=\"background-color: rgb(230, 230, 230); color: black\">";
					$debugBlock .= "\n\t\t<td>";
					$debugBlock .= "\n\t\t\t$query[query]\n\n\t\t\t<div style=\"font-size: 9px;\">($query[time])</div>\n<!--\n$query[trace]\n-->\n\t\t</td>\n\t</tr>";
				}
				
				$debugBlock .= "\n</table>\n\n\n";
			}
			
			$template = str_replace('</body>', $debugBlock . '</body>', $template);
		}

		print($template);
	}
	
	// ###################################################################
	/**
	* Loads an additional template from the database
	*
	* @param	string	The name of the template
	*
	* @return	string	Template data from the database
	*/
	protected function _loadTemplate($name)
	{
		$path = $this->templateDir . $name . '.' . $this->extension;
		if (is_file($path) && is_readable($path))
		{
			return @file_get_contents($path);
		}
		else
		{
			throw new Exception("Could not load the template '$path'");
		}
	}
	
	// ###################################################################
	/**
	* A wrapper for all the parsing functions and compiling functins
	*
	* @param	string	Unparsed template data
	*
	* @return	string	Parsed template data
	*/
	protected function _parseTemplate($template)
	{
		$template = str_replace('"', '\"', $template);
		
		if (function_exists($this->preParseHook))
		{
			$template = call_user_func($this->preParseHook, $template);
		}
		
		$template = $this->_parseBlocksAndTokens($template);
		$template = $this->_parsePhrases($template);
		$template = $this->_parseConditionals($template);
		return $template;
	}
	
	// ###################################################################
	/**
	* Parses anything with curly braces {} (including phrases)
	*
	* @param	string	Template data
	*
	* @return	string	Parsed template data
	*/
	private function _parseBlocksAndTokens($template)
	{
		$stack = array();
		$tokens = array();
		
		while (1)
		{
			for ($i = 0; $i < strlen($template); $i++)
			{
				// we've run through the template and there's nothing in the stack--done
				if ($i == strlen($template) - 1 && sizeof($stack) == 0)
				{
					return $template;
				}
				
				if ($template[$i] == '{')
				{
					// ignore escaped sequences
					if ($template[$i - 1] != '\\')
					{
						array_push($stack, $i);
					}
				}
				else if ($template[$i] == '}')
				{
					// there's no stack so it was probably escaped
					if (sizeof($stack) == 0)
					{
						continue;
					}
					// we're good and nested
					else if (sizeof($stack) == 1)
					{
						$open = array_pop($stack);
						$token = substr($template, $open, $i - $open + 1);
						$template = str_replace($token, $this->_parseToken($token), $template);
						break;
					}
					// just pop it off
					else
					{
						array_pop($stack);
					}
				}
			}
		}
	}
	
	// ###################################################################
	/**
	* Parses a curly brace token {}
	*
	* @param	string	Token
	*
	* @return	string	Parsed value
	*/
	private function _parseToken($token)
	{
		// knock of the braces
		$token = substr($token, 1, strlen($token) - 2);
		
		// language token
		if ($token[0] == '@' && $token[1] == '\\' && $token[2] == '"')
		{
			return '" . ' . $this->langcall . '(\'' . str_replace(array('\\\"', "'"), array('"', "\'"), substr($token, 3, strlen($token) - 5)) . '\')' . ' . "';
		}
		// normal PHP code
		else
		{
			return '" . (' . $token . ') . "';
		}
	}
	
	// ###################################################################
	/**
	* Prepares language and locale information inside templates
	*
	* @param	string	Template data to be processed
	*
	* @return	string	Language-ready template data
	*/
	private function _parsePhrases($template)
	{
		$tagStart = '<lang ';
		$tagEnd = '</lang>';
		
		$start = -1; // start of open tag
		$end = -1; // start of the close tag
		$varEnd = -1; // end of the open tag
		
		while ($start <= strlen($template))
		{
			// reset
			$varMap = array(); // storage for all the substitution indices
			
			// Find the start language object tag
			$start = strpos($template, $tagStart, $end + 1);
			if ($start === false)
			{
				break;
			}
			
			// look ahead to parse out all the variables
			$i = $start + strlen($tagStart); // current position
			$capture = ''; // current capture
			$capturePos = $i; // the place to start capturing
			$varNum = -1; // variable placeholder index
			while ($i < strlen($template))
			{
				if ($template[$i] == '=')
				{
					// backtrack to find the previous variable substitution
					$backPos = $i;
					while ($backPos >= $start)
					{
						if ($template[$backPos] == '"')
						{
							// startPosition + length(startTag) + length(=\")
							$varMap[intval($varNum)] = BSFunctions::substring($template, $capturePos + 3, $backPos - 1);
							// remove our old substitution from the capture
							$capture = BSFunctions::substring($template, $backPos + 1, $i);
							break;
						}
						$backPos--;
					}
					
					// do we have a valid index?
					if (intval($capture) > 0)
					{
						// set aside the index and restart capturing
						$varNum = $capture;
						$capture = '';
						$capturePos = $i;
					}
					else
					{
						throw new Exception('Invalid language variable index "' . $capture . '"');
					}
				}
				else if ($template[$i] == '>' && $template[$i - 1] == '"')
				{
					// the final variable substitution
					$varMap[intval($varNum)] = BSFunctions::substring($template, $capturePos + 3, $i - 2);
					$varEnds = $i;
					break;
				}
				
				$capture .= $template[$i];
				$i++;
			}
			
			// locate the end tag
			$end = strpos($template, $tagEnd, $i);
			if ($end === false)
			{
				break;
			}
			
			// this is the string that gets variable replacement
			$str = BSFunctions::substring($template, $varEnds + 1, $end);
			
			// create the complete varmap
			
			for ($i = max(array_keys($varMap)); $i > 0; $i--)
			{
				if (!isset($varMap[$i]))
				{
					$varMap[$i] = '<strong>[MISSING SUBSTITUTION INDEX: ' . $i . ']</strong>';
				}
			}
			
			// put all the keys in corresponding argument order
			ksort($varMap);
			
			// FINALLY, construct the call to sprintf()
			$template = substr_replace($template, '" . ' . $this->langconst . '(\'' . $str . '\', "' . implode('", "', $varMap) . '") . "', $start, ($end + strlen($tagEnd)) - $start);
		}
		
		return $template;
	}
	
	// ###################################################################
	/**
	* Parser for in-line template conditionals
	*
	* @param	string	Template data awaiting processing
	*
	* @return	string	Parsed template data
	*/
	private function _parseConditionals($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 && !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] = '';
					}
					
					// 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;
	}
}

?>