<?php
/*
 *  $Id$
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information, see
 * <http://www.doctrine-project.org>.
 */

namespace Doctrine\DBAL\Schema;

use \Doctrine\DBAL\Platforms\AbstractPlatform;

/**
 * Schema Diff
 *
 * @license http://www.opensource.org/licenses/lgpl-license.php LGPL
 * @link    www.doctrine-project.org
 * @copyright Copyright (C) 2005-2009 eZ Systems AS. All rights reserved.
 * @license http://ez.no/licenses/new_bsd New BSD License
 * @since   2.0
 * @version $Revision$
 * @author  Benjamin Eberlei <kontakt@beberlei.de>
 */
class SchemaDiff
{
    /**
     * All added tables
     *
     * @var array(string=>ezcDbSchemaTable)
     */
    public $newTables = array();

    /**
     * All changed tables
     *
     * @var array(string=>ezcDbSchemaTableDiff)
     */
    public $changedTables = array();

    /**
     * All removed tables
     *
     * @var array(string=>Table)
     */
    public $removedTables = array();

    /**
     * @var array
     */
    public $newSequences = array();

    /**
     * @var array
     */
    public $changedSequences = array();

    /**
     * @var array
     */
    public $removedSequences = array();

    /**
     * @var array
     */
    public $orphanedForeignKeys = array();

    /**
     * Constructs an SchemaDiff object.
     *
     * @param array(string=>Table)      $newTables
     * @param array(string=>TableDiff)  $changedTables
     * @param array(string=>bool)                  $removedTables
     */
    public function __construct( $newTables = array(), $changedTables = array(), $removedTables = array() )
    {
        $this->newTables = $newTables;
        $this->changedTables = $changedTables;
        $this->removedTables = $removedTables;
    }

    /**
     * The to save sql mode ensures that the following things don't happen:
     *
     * 1. Tables are deleted
     * 2. Sequences are deleted
     * 3. Foreign Keys which reference tables that would otherwise be deleted.
     *
     * This way it is ensured that assets are deleted which might not be relevant to the metadata schema at all.
     *
     * @param AbstractPlatform $platform
     * @return array
     */
    public function toSaveSql(AbstractPlatform $platform)
    {
        return $this->_toSql($platform, true);
    }

    /**
     * @param AbstractPlatform $platform
     * @return array
     */
    public function toSql(AbstractPlatform $platform)
    {
        return $this->_toSql($platform, false);
    }

    /**
     * @param AbstractPlatform $platform
     * @param bool $saveMode
     * @return array
     */
    protected function _toSql(AbstractPlatform $platform, $saveMode = false)
    {
        $sql = array();

        if ($platform->supportsForeignKeyConstraints()) {
            foreach ($this->orphanedForeignKeys AS $orphanedForeignKey) {
                $sql[] = $platform->getDropForeignKeySql($orphanedForeignKey, $orphanedForeignKey->getLocalTableName());
            }
        }

        if ($platform->supportsSequences() == true) {
            foreach ($this->changedSequences AS $sequence) {
                $sql[] = $platform->getDropSequenceSql($sequence);
                $sql[] = $platform->getCreateSequenceSql($sequence);
            }

            if ($saveMode === false) {
                foreach ($this->removedSequences AS $sequence) {
                    $sql[] = $platform->getDropSequenceSql($sequence);
                }
            }

            foreach ($this->newSequences AS $sequence) {
                $sql[] = $platform->getCreateSequenceSql($sequence);
            }
        }

        foreach ($this->newTables AS $table) {
            $sql = array_merge(
                $sql,
                $platform->getCreateTableSql($table, AbstractPlatform::CREATE_FOREIGNKEYS|AbstractPlatform::CREATE_INDEXES)
            );
        }

        if ($saveMode === true) {
            foreach ($this->removedTables AS $table) {
                $sql[] = $platform->getDropTableSql($table);
            }
        }

        foreach ($this->changedTables AS $tableDiff) {
            $sql = array_merge($sql, $platform->getAlterTableSql($tableDiff));
        }

        return $sql;
    }
}