<?php

/**
 * This file is part of the Propel package.
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 *
 * @license     MIT License
 */

require_once dirname(__FILE__) . '/../Index.php';

/**
 * Service class for comparing Index objects
 * Heavily inspired by Doctrine2's Migrations
 * (see http://github.com/doctrine/dbal/tree/master/lib/Doctrine/DBAL/Schema/)
 *
 * @package     propel.generator.model.diff
 */
class PropelIndexComparator
{
    /**
     * Compute the difference between two index objects
     *
     * @param Index   $fromIndex
     * @param Index   $toIndex
     * @param boolean $caseInsensitive Whether the comparison is case insensitive.
     *                                 False by default.
     *
     * @return boolean false if the two indices are similar, true if they have differences
     */
    public static function computeDiff(Index $fromIndex, Index $toIndex, $caseInsensitive = false)
    {
        // Check for removed index columns in $toIndex
        $fromIndexColumns = $fromIndex->getColumns();
        for ($i = 0; $i < count($fromIndexColumns); $i++) {
            $indexColumn = $fromIndexColumns[$i];
            if (!$toIndex->hasColumnAtPosition($i, $indexColumn, null, $caseInsensitive)) {
                return true;
            }
        }

        // Check for new index columns in $toIndex
        $toIndexColumns = $toIndex->getColumns();
        for ($i = 0; $i < count($toIndexColumns); $i++) {
            $indexColumn = $toIndexColumns[$i];
            if (!$fromIndex->hasColumnAtPosition($i, $indexColumn, null, $caseInsensitive)) {
                return true;
            }
        }

        // Check for difference in unicity
        if ($fromIndex->isUnique() != $toIndex->isUnique()) {
            return true;
        }

        return false;
    }
}
