<?php
/**
* This source file is subject to the new BSD license that is bundled
* with this package in the file LICENSE.txt.
* 
* @copyright Copyright (c) 2008-2009 Ne8, LLC <josh.ribakoff@gmail.com>
* @license New BSD License
*/
abstract class Shuffler_DB_Refactor
{
    /**
    * @var Shuffler_Db_Factory
    */
    protected $factory;
    
    public function __construct( Shuffler_Db_Factory $factory )
    {
        $this->factory = $factory;
    }
    
    /**
    * @return integer
    */
    abstract protected function getCurrentVersion();
    
    /**
    * @return array
    */
    abstract protected function getTables();
    
    abstract protected function createDatabases();
    
    abstract protected function dropDatabases();
    abstract protected function createVersionTable();
    abstract protected function getSchemaNameForVersionTable();
    abstract protected function getMysqlCommand();
    
    public function execute( $pathToScripts, $reset = false, $toVersion = null )
    {
        try
        {
            $currentVersion = $this->getCurrentVersion();
        } catch ( Exception $e )
        {
            $this->createDatabases();
            $currentVersion = 0;
        }

        if( $reset || $currentVersion == 0 )
        {
            $this->dropDatabases(); 
            $this->createDatabases();
            $this->createVersionTable();
            $currentVersion = 0;           
        }                                                                  
         
        self::migrate( $pathToScripts, $currentVersion, $toVersion );
    }
    
    /**
    * Bring the database to a requested version #
    */
    function migrate( $pathToScripts, $fromVersion = 0, $toVersion = NULL )
    {
        // get all the database refactoring scripts
        $files = glob( $pathToScripts . '/*' );
        foreach( $files as $key => $val )
        {
            $files[ $key ] = basename( $val );
        }
        // sort the files in version order
        asort( $files, SORT_NUMERIC );
        foreach( $files as $file )
        {
            // get the version # from the filename
            preg_match( '#^([0-9]+)_#', basename( $file ), $matches );
            if( !isset( $matches[1] ) )
            {
                continue;
            }
            $version = $matches[1];
            if( $version <= $fromVersion )
            {
                // already loaded this version, skip it
                continue;
            }
            if( !is_null( $toVersion ) )
            {
                if( $version > $toVersion )
                {
                    echo 'stopping short at version ' . $toVersion;
                    break;
                }
            }
            self::runScript( $version, $pathToScripts . '/' . $file );
        }
    }
    
    /**
    * run the version + script as php or SQL
    * updates the version table
    */
    function runScript( $version, $file )
    {
        ob_implicit_flush();
        echo basename($file) .  "\n";
        
        $schema = '';
        if( $version != 1 )
        {
            $schema = $this->getSchemaNameForVersionTable();
        }
        
        if( substr( $file, -3 ) == 'php' )
        {
            if( $version != 1 )
            {
                mysql_select_db( $schema );
            }
            require( $file );
        }
        else // or as sql
        {
            
            $cmd = $this->getMysqlCommand() . ' ' . $schema . ' < "' . $file . '"';
            //echo( $cmd );
            passthru( $cmd );
        }
        mysql_query( 'UPDATE `version` SET `version` = ' . (int)$version );
    }

    /**
    * Drop requested tables
    * 
    * @param Shuffler_Factory
    * @param array of tables
    */
    function dropTables( $factory, $tables )
    {    
        foreach( $tables as $table )
        {
            mysql_query( 'DROP TABLE `' . $table . '`' ); 
        }                    
    }
}