<?php
/**
 * File containing the eZTranslationCache class.
 *
 * @copyright Copyright (C) 1999-2012 eZ Systems AS. All rights reserved.
 * @license http://www.gnu.org/licenses/gpl-2.0.txt GNU General Public License v2
 * @version  2012.8
 * @package lib
 */

/*!
  \class eZTranslationCache eztranslationcache.php
  \brief Cache handling for translations.

*/

class eZTranslationCache
{
    const CODE_DATE = 1058863428;

    /*!
     \static
     \return the cache table which has cache keys and cache data.
    */
    static function cacheTable()
    {
        if ( !isset( $GLOBALS['eZTranslationCacheTable'] ) )
        {
            $GLOBALS['eZTranslationCacheTable'] = array();
        }
        return $GLOBALS['eZTranslationCacheTable'];
    }

    /*!
     \static
     \return the cache translation context which is stored with the cache key \a $contextName.
             Returns \c null if no cache data was found.
    */
    static function contextCache( $contextName )
    {
        $translationCache = eZTranslationCache::cacheTable();
        if ( isset( $translationCache[$contextName] ) )
        {
            return $translationCache[$contextName]['root'];
        }
        return null;
    }

    /*!
     \static
     Sets the translation context \a $context to be cached with the cache key $contextName.
     \note Trying to overwrite and existing cache key will give a warning and fail.
    */
    static function setContextCache( $contextName, $context )
    {
        if ( $context === null )
        {
            return;
        }
        if ( isset( $GLOBALS['eZTranslationCacheTable'][$contextName] ) )
        {
            eZDebug::writeWarning( "Translation cache for context '$contextName' already exists", __METHOD__ );
        }
        else
        {
            $GLOBALS['eZTranslationCacheTable'][$contextName] = array();
        }
        $GLOBALS['eZTranslationCacheTable'][$contextName]['root'] = $context;
        $GLOBALS['eZTranslationCacheTable'][$contextName]['info'] = array( 'context' => $contextName );
    }

    /*!
     \static
     \return the cache directory for translation cache files.
    */
    static function cacheDirectory()
    {
        $cacheDirectory =& $GLOBALS['eZTranslationCacheDirectory'];
        if ( !isset( $cacheDirectory ) )
        {
            $ini = eZINI::instance();
            $locale = $ini->variable( 'RegionalSettings', 'Locale' );

            $rootCacheDirectory = eZTranslationCache::rootCacheDirectory();
            $cacheDirectory = eZDir::path( array( $rootCacheDirectory, $locale ) );

        }
        return $cacheDirectory;
    }

    /*!
     \static
    */
    static function rootCacheDirectory()
    {
        $internalCharset = eZTextCodec::internalCharset();

        $ini = eZINI::instance();
        $translationRepository = $ini->variable( 'RegionalSettings', 'TranslationRepository' );
        $translationExtensions = $ini->variable( 'RegionalSettings', 'TranslationExtensions' );

        $uniqueParts = array( $internalCharset, $translationRepository, implode( ';', $translationExtensions ) );

        $sharedTsCacheDir = $ini->hasVariable( 'RegionalSettings', 'SharedTranslationCacheDir' ) ?
                            trim( $ini->variable( 'RegionalSettings', 'SharedTranslationCacheDir' ) ) :
                            '';
        if ( $sharedTsCacheDir !== '')
        {
            $rootCacheDirectory = eZDir::path( array( $sharedTsCacheDir, md5( implode( '-', $uniqueParts ) ) ) );
        }
        else
        {
            $rootCacheDirectory = eZDir::path( array( eZSys::cacheDirectory(), 'translation', md5( implode( '-', $uniqueParts ) ) ) );
        }
        return $rootCacheDirectory;
    }

    /*!
     \static
     \return true if the cache with the key \a $key can be restored.
             A cache file is found restorable when it exists and has a timestamp
             higher or equal to \a $timestamp.
    */
    static function canRestoreCache( $key, $timestamp )
    {
        $translationCache = eZTranslationCache::cacheTable();
        if ( isset( $translationCache[$key] ) )
        {
            return false;
        }
//         $internalCharset = eZTextCodec::internalCharset();
//         $cacheFileKey = "$key-$internalCharset";
        $cacheFileKey = $key;
        $cacheFileName = md5( $cacheFileKey ) . '.php';

        $php = new eZPHPCreator( eZTranslationCache::cacheDirectory(), $cacheFileName );
        return $php->canRestore( $timestamp );
    }

    /*!
     \static
     Loads the cache with the key \a $key from a file and sets the result in the cache table.
     \return true if the cache was successfully restored.
    */
    static function restoreCache( $key )
    {
        $translationCache = eZTranslationCache::cacheTable();
        if ( isset( $translationCache[$key] ) )
        {
            eZDebug::writeWarning( "Translation cache for key '$key' already exist, cannot restore cache", __METHOD__ );
            return false;
        }
//         $internalCharset = eZTextCodec::internalCharset();
//         $cacheFileKey = "$key-$internalCharset";
        $cacheFileKey = $key;
        $cacheFileName = md5( $cacheFileKey ) . '.php';

        $php = new eZPHPCreator( eZTranslationCache::cacheDirectory(), $cacheFileName );
        $variables = $php->restore( array( 'info' => 'TranslationInfo',
                                           'root' => 'TranslationRoot',
                                           'cache-date' => 'eZTranslationCacheCodeDate' ) );
        if ( !isset($variables['cache-date']) || $variables['cache-date'] != self::CODE_DATE )
            return false;
        eZTranslationCache::setContextCache( $key, $variables['root'] );
        return true;
    }

    /*!
     \static
     Stores the data of the cache with the key \a $key to a file.
     \return false if the cache does not exist.
    */
    static function storeCache( $key )
    {
        $translationCache = eZTranslationCache::cacheTable();
        if ( !isset( $translationCache[$key] ) )
        {
            eZDebug::writeWarning( "Translation cache for key '$key' does not exist, cannot store cache", __METHOD__ );
            return;
        }
        $internalCharset = eZTextCodec::internalCharset();
//         $cacheFileKey = "$key-$internalCharset";
        $cacheFileKey = $key;
        $cacheFileName = md5( $cacheFileKey ) . '.php';

        $cache =& $translationCache[$key];

        if ( !file_exists( eZTranslationCache::cacheDirectory() ) )
        {
            eZDir::mkdir( eZTranslationCache::cacheDirectory(), false, true );
        }
        $php = new eZPHPCreator( eZTranslationCache::cacheDirectory(), $cacheFileName );
        $php->addRawVariable( 'eZTranslationCacheCodeDate', self::CODE_DATE );
        $php->addSpace();
        $php->addRawVariable( 'CacheInfo', array( 'charset' => $internalCharset ) );
        $php->addRawVariable( 'TranslationInfo', $cache['info'] );
        $php->addSpace();
        $php->addRawVariable( 'TranslationRoot', $cache['root'] );
        $php->store();
    }

    /*!
     \static
     Reset values strored in $GLOABLS variable
    */
    static function resetGlobals()
    {
        unset( $GLOBALS['eZTranslationCacheDirectory'] );
        unset( $GLOBALS['eZTranslationCacheTable'] );
    }
}

?>