<?php

/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2017, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package	CodeIgniter
 * @author	EllisLab Dev Team
 * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright	Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
 * @license	http://opensource.org/licenses/MIT	MIT License
 * @link	https://codeigniter.com
 * @since	Version 3.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * PDO DBLIB Forge Class
 *
 * @category	Database
 * @author		EllisLab Dev Team
 * @link		https://codeigniter.com/user_guide/database/
 */
class CI_DB_pdo_dblib_forge extends CI_DB_pdo_forge {

    /**
     * CREATE TABLE IF statement
     *
     * @var	string
     */
    protected $_create_table_if = "IF NOT EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'%s') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\nCREATE TABLE";

    /**
     * DROP TABLE IF statement
     *
     * @var	string
     */
    protected $_drop_table_if = "IF EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'%s') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\nDROP TABLE";

    /**
     * UNSIGNED support
     *
     * @var	array
     */
    protected $_unsigned = array(
        'TINYINT' => 'SMALLINT',
        'SMALLINT' => 'INT',
        'INT' => 'BIGINT',
        'REAL' => 'FLOAT'
    );

    // --------------------------------------------------------------------

    /**
     * ALTER TABLE
     *
     * @param	string	$alter_type	ALTER type
     * @param	string	$table		Table name
     * @param	mixed	$field		Column definition
     * @return	string|string[]
     */
    protected function _alter_table($alter_type, $table, $field) {
        if (in_array($alter_type, array('ADD', 'DROP'), TRUE)) {
            return parent::_alter_table($alter_type, $table, $field);
        }

        $sql = 'ALTER TABLE ' . $this->db->escape_identifiers($table) . ' ALTER COLUMN ';
        $sqls = array();
        for ($i = 0, $c = count($field); $i < $c; $i++) {
            $sqls[] = $sql . $this->_process_column($field[$i]);
        }

        return $sqls;
    }

    // --------------------------------------------------------------------

    /**
     * Field attribute TYPE
     *
     * Performs a data type mapping between different databases.
     *
     * @param	array	&$attributes
     * @return	void
     */
    protected function _attr_type(&$attributes) {
        if (isset($attributes['CONSTRAINT']) && strpos($attributes['TYPE'], 'INT') !== FALSE) {
            unset($attributes['CONSTRAINT']);
        }

        switch (strtoupper($attributes['TYPE'])) {
            case 'MEDIUMINT':
                $attributes['TYPE'] = 'INTEGER';
                $attributes['UNSIGNED'] = FALSE;
                return;
            case 'INTEGER':
                $attributes['TYPE'] = 'INT';
                return;
            default: return;
        }
    }

    // --------------------------------------------------------------------

    /**
     * Field attribute AUTO_INCREMENT
     *
     * @param	array	&$attributes
     * @param	array	&$field
     * @return	void
     */
    protected function _attr_auto_increment(&$attributes, &$field) {
        if (!empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE && stripos($field['type'], 'int') !== FALSE) {
            $field['auto_increment'] = ' IDENTITY(1,1)';
        }
    }

}
