<?php
/**
 * TTemplateManager and TTemplate class file
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2014 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @package Prado\Web\UI
 */

namespace Prado\Web\UI;
use Prado\Prado;

/**
 * TTemplateManager class
 *
 * TTemplateManager manages the loading and parsing of control templates.
 *
 * There are two ways of loading a template, either by the associated template
 * control class name, or the template file name.
 * The former is via calling {@link getTemplateByClassName}, which tries to
 * locate the corresponding template file under the directory containing
 * the class file. The name of the template file is the class name with
 * the extension '.tpl'. To load a template from a template file path,
 * call {@link getTemplateByFileName}.
 *
 * By default, TTemplateManager is registered with {@link TPageService} as the
 * template manager module that can be accessed via {@link TPageService::getTemplateManager()}.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package Prado\Web\UI
 * @since 3.0
 */
class TTemplateManager extends \Prado\TModule
{
	/**
	 * Template file extension
	 */
	const TEMPLATE_FILE_EXT='.tpl';
	/**
	 * Prefix of the cache variable name for storing parsed templates
	 */
	const TEMPLATE_CACHE_PREFIX='prado:template:';

	/**
	 * Initializes the module.
	 * This method is required by IModule and is invoked by application.
	 * It starts output buffer if it is enabled.
	 * @param TXmlElement module configuration
	 */
	public function init($config)
	{
		$this->getService()->setTemplateManager($this);
	}

	/**
	 * Loads the template corresponding to the specified class name.
	 * @return ITemplate template for the class name, null if template doesn't exist.
	 */
	public function getTemplateByClassName($className)
	{
		$class=new \ReflectionClass($className);
		$tplFile=dirname($class->getFileName()).DIRECTORY_SEPARATOR.$className.self::TEMPLATE_FILE_EXT;
		return $this->getTemplateByFileName($tplFile);
	}

	/**
	 * Loads the template from the specified file.
	 * @return ITemplate template parsed from the specified file, null if the file doesn't exist.
	 */
	public function getTemplateByFileName($fileName)
	{
		if(($fileName=$this->getLocalizedTemplate($fileName))!==null)
		{
			Prado::trace("Loading template $fileName",'System.Web.UI.TTemplateManager');
			if(($cache=$this->getApplication()->getCache())===null)
				return new TTemplate(file_get_contents($fileName),dirname($fileName),$fileName);
			else
			{
				$array=$cache->get(self::TEMPLATE_CACHE_PREFIX.$fileName);
				if(is_array($array))
				{
					list($template,$timestamps)=$array;
					if($this->getApplication()->getMode()===TApplicationMode::Performance)
						return $template;
					$cacheValid=true;
					foreach($timestamps as $tplFile=>$timestamp)
					{
						if(!is_file($tplFile) || filemtime($tplFile)>$timestamp)
						{
							$cacheValid=false;
							break;
						}
					}
					if($cacheValid)
						return $template;
				}
				$template=new TTemplate(file_get_contents($fileName),dirname($fileName),$fileName);
				$includedFiles=$template->getIncludedFiles();
				$timestamps=array();
				$timestamps[$fileName]=filemtime($fileName);
				foreach($includedFiles as $includedFile)
					$timestamps[$includedFile]=filemtime($includedFile);
				$cache->set(self::TEMPLATE_CACHE_PREFIX.$fileName,array($template,$timestamps));
				return $template;
			}
		}
		else
			return null;
	}

	/**
	 * Finds a localized template file.
	 * @param string template file.
	 * @return string|null a localized template file if found, null otherwise.
	 */
	protected function getLocalizedTemplate($filename)
	{
		if(($app=$this->getApplication()->getGlobalization(false))===null)
			return is_file($filename)?$filename:null;
		foreach($app->getLocalizedResource($filename) as $file)
		{
			if(($file=realpath($file))!==false && is_file($file))
				return $file;
		}
		return null;
	}
}