<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2019, 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 - 2019, British Columbia Institute of Technology (https://bcit.ca/)
 * @license	https://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 Oracle Forge Class
 *
 * @category	Database
 * @author		EllisLab Dev Team
 * @link		https://codeigniter.com/userguide3/database/
 */
class CI_DB_pdo_oci_forge extends CI_DB_pdo_forge {

	/**
	 * CREATE DATABASE statement
	 *
	 * @var	string
	 */
	protected $_create_database	= FALSE;

	/**
	 * CREATE TABLE IF statement
	 *
	 * @var	string
	 */
	protected $_create_table_if	= FALSE;

	/**
	 * DROP DATABASE statement
	 *
	 * @var	string
	 */
	protected $_drop_database	= FALSE;

	/**
	 * UNSIGNED support
	 *
	 * @var	bool|array
	 */
	protected $_unsigned		= FALSE;

	/**
	 * NULL value representation in CREATE/ALTER TABLE statements
	 *
	 * @var	string
	 */
	protected $_null		= 'NULL';

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

	/**
	 * 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, $field)
	{
		if ($alter_type === 'DROP')
		{
			return parent::_alter_table($alter_type, $table, $field);
		}
		elseif ($alter_type === 'CHANGE')
		{
			$alter_type = 'MODIFY';
		}

		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
		$sqls = array();
		for ($i = 0, $c = count($field); $i < $c; $i++)
		{
			if ($field[$i]['_literal'] !== FALSE)
			{
				$field[$i] = "\n\t".$field[$i]['_literal'];
			}
			else
			{
				$field[$i]['_literal'] = "\n\t".$this->_process_column($field[$i]);

				if ( ! empty($field[$i]['comment']))
				{
					$sqls[] = 'COMMENT ON COLUMN '
						.$this->db->escape_identifiers($table).'.'.$this->db->escape_identifiers($field[$i]['name'])
						.' IS '.$field[$i]['comment'];
				}

				if ($alter_type === 'MODIFY' && ! empty($field[$i]['new_name']))
				{
					$sqls[] = $sql.' RENAME COLUMN '.$this->db->escape_identifiers($field[$i]['name'])
						.' TO '.$this->db->escape_identifiers($field[$i]['new_name']);
				}
			}
		}

		$sql .= ' '.$alter_type.' ';
		$sql .= (count($field) === 1)
				? $field[0]
				: '('.implode(',', $field).')';

		// RENAME COLUMN must be executed after MODIFY
		array_unshift($sqls, $sql);
		return $sql;
	}

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

	/**
	 * 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'], 'number') !== FALSE && version_compare($this->db->version(), '12.1', '>='))
		{
			$field['auto_increment'] = ' GENERATED ALWAYS AS IDENTITY';
		}
	}

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

	/**
	 * Process column
	 *
	 * @param	array	$field
	 * @return	string
	 */
	protected function _process_column($field)
	{
		return $this->db->escape_identifiers($field['name'])
			.' '.$field['type'].$field['length']
			.$field['unsigned']
			.$field['default']
			.$field['auto_increment']
			.$field['null']
			.$field['unique'];
	}

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

	/**
	 * Field attribute TYPE
	 *
	 * Performs a data type mapping between different databases.
	 *
	 * @param	array	&$attributes
	 * @return	void
	 */
	protected function _attr_type(&$attributes)
	{
		switch (strtoupper($attributes['TYPE']))
		{
			case 'TINYINT':
				$attributes['TYPE'] = 'NUMBER';
				return;
			case 'MEDIUMINT':
				$attributes['TYPE'] = 'NUMBER';
				return;
			case 'INT':
				$attributes['TYPE'] = 'NUMBER';
				return;
			case 'BIGINT':
				$attributes['TYPE'] = 'NUMBER';
				return;
			default: return;
		}
	}
}
