<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2018, 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 - 2018, 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 Informix Database Adapter Class
 *
 * Note: _DB is an extender class that the app controller
 * creates dynamically based on whether the query builder
 * class is being used or not.
 *
 * @package		CodeIgniter
 * @subpackage	Drivers
 * @category	Database
 * @author		EllisLab Dev Team
 * @link		https://codeigniter.com/user_guide/database/
 */
class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {

	/**
	 * Sub-driver
	 *
	 * @var	string
	 */
	public $subdriver = 'informix';

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

	/**
	 * ORDER BY random keyword
	 *
	 * @var	array
	 */
	protected $_random_keyword = array('ASC', 'ASC'); // Currently not supported

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

	/**
	 * Class constructor
	 *
	 * Builds the DSN if not already set.
	 *
	 * @param	array	$params
	 * @return	void
	 */
	public function __construct($params)
	{
		parent::__construct($params);

		if (empty($this->dsn))
		{
			$this->dsn = 'informix:';

			// Pre-defined DSN
			if (empty($this->hostname) && empty($this->host) && empty($this->port) && empty($this->service))
			{
				if (isset($this->DSN))
				{
					$this->dsn .= 'DSN='.$this->DSN;
				}
				elseif ( ! empty($this->database))
				{
					$this->dsn .= 'DSN='.$this->database;
				}

				return;
			}

			if (isset($this->host))
			{
				$this->dsn .= 'host='.$this->host;
			}
			else
			{
				$this->dsn .= 'host='.(empty($this->hostname) ? '127.0.0.1' : $this->hostname);
			}

			if (isset($this->service))
			{
				$this->dsn .= '; service='.$this->service;
			}
			elseif ( ! empty($this->port))
			{
				$this->dsn .= '; service='.$this->port;
			}

			empty($this->database) OR $this->dsn .= '; database='.$this->database;
			empty($this->server) OR $this->dsn .= '; server='.$this->server;

			$this->dsn .= '; protocol='.(isset($this->protocol) ? $this->protocol : 'onsoctcp')
				.'; EnableScrollableCursors=1';
		}
	}

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

	/**
	 * Show table query
	 *
	 * Generates a platform-specific query string so that the table names can be fetched
	 *
	 * @param	bool	$prefix_limit
	 * @return	string
	 */
	protected function _list_tables($prefix_limit = FALSE)
	{
		$sql = 'SELECT "tabname" FROM "systables"
			WHERE "tabid" > 99 AND "tabtype" = \'T\' AND LOWER("owner") = '.$this->escape(strtolower($this->username));

		if ($prefix_limit === TRUE && $this->dbprefix !== '')
		{
			$sql .= ' AND "tabname" LIKE \''.$this->escape_like_str($this->dbprefix)."%' "
				.sprintf($this->_like_escape_str, $this->_like_escape_chr);
		}

		return $sql;
	}

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

	/**
	 * Show column query
	 *
	 * Generates a platform-specific query string so that the column names can be fetched
	 *
	 * @param	string	$table
	 * @return	string
	 */
	protected function _list_columns($table = '')
	{
		if (strpos($table, '.') !== FALSE)
		{
			sscanf($table, '%[^.].%s', $owner, $table);
		}
		else
		{
			$owner = $this->username;
		}

		return 'SELECT "colname" FROM "systables", "syscolumns"
			WHERE "systables"."tabid" = "syscolumns"."tabid"
				AND "systables"."tabtype" = \'T\'
				AND LOWER("systables"."owner") = '.$this->escape(strtolower($owner)).'
				AND LOWER("systables"."tabname") = '.$this->escape(strtolower($table));
	}

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

	/**
	 * Returns an object with field data
	 *
	 * @param	string	$table
	 * @return	array
	 */
	public function field_data($table)
	{
		$sql = 'SELECT "syscolumns"."colname" AS "name",
				CASE "syscolumns"."coltype"
					WHEN 0 THEN \'CHAR\'
					WHEN 1 THEN \'SMALLINT\'
					WHEN 2 THEN \'INTEGER\'
					WHEN 3 THEN \'FLOAT\'
					WHEN 4 THEN \'SMALLFLOAT\'
					WHEN 5 THEN \'DECIMAL\'
					WHEN 6 THEN \'SERIAL\'
					WHEN 7 THEN \'DATE\'
					WHEN 8 THEN \'MONEY\'
					WHEN 9 THEN \'NULL\'
					WHEN 10 THEN \'DATETIME\'
					WHEN 11 THEN \'BYTE\'
					WHEN 12 THEN \'TEXT\'
					WHEN 13 THEN \'VARCHAR\'
					WHEN 14 THEN \'INTERVAL\'
					WHEN 15 THEN \'NCHAR\'
					WHEN 16 THEN \'NVARCHAR\'
					WHEN 17 THEN \'INT8\'
					WHEN 18 THEN \'SERIAL8\'
					WHEN 19 THEN \'SET\'
					WHEN 20 THEN \'MULTISET\'
					WHEN 21 THEN \'LIST\'
					WHEN 22 THEN \'Unnamed ROW\'
					WHEN 40 THEN \'LVARCHAR\'
					WHEN 41 THEN \'BLOB/CLOB/BOOLEAN\'
					WHEN 4118 THEN \'Named ROW\'
					ELSE "syscolumns"."coltype"
				END AS "type",
				"syscolumns"."collength" as "max_length",
				CASE "sysdefaults"."type"
					WHEN \'L\' THEN "sysdefaults"."default"
					ELSE NULL
				END AS "default"
			FROM "syscolumns", "systables", "sysdefaults"
			WHERE "syscolumns"."tabid" = "systables"."tabid"
				AND "systables"."tabid" = "sysdefaults"."tabid"
				AND "syscolumns"."colno" = "sysdefaults"."colno"
				AND "systables"."tabtype" = \'T\'
				AND LOWER("systables"."owner") = '.$this->escape(strtolower($this->username)).'
				AND LOWER("systables"."tabname") = '.$this->escape(strtolower($table)).'
			ORDER BY "syscolumns"."colno"';

		return (($query = $this->query($sql)) !== FALSE)
			? $query->result_object()
			: FALSE;
	}

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

	/**
	 * Update statement
	 *
	 * Generates a platform-specific update string from the supplied data
	 *
	 * @param	string	$table
	 * @param	array	$values
	 * @return	string
	 */
	protected function _update($table, $values)
	{
		$this->qb_limit = FALSE;
		$this->qb_orderby = array();
		return parent::_update($table, $values);
	}

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

	/**
	 * Truncate statement
	 *
	 * Generates a platform-specific truncate string from the supplied data
	 *
	 * If the database does not support the TRUNCATE statement,
	 * then this method maps to 'DELETE FROM table'
	 *
	 * @param	string	$table
	 * @return	string
	 */
	protected function _truncate($table)
	{
		return 'TRUNCATE TABLE ONLY '.$table;
	}

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

	/**
	 * Delete statement
	 *
	 * Generates a platform-specific delete string from the supplied data
	 *
	 * @param	string	$table
	 * @return	string
	 */
	protected function _delete($table)
	{
		$this->qb_limit = FALSE;
		return parent::_delete($table);
	}

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

	/**
	 * LIMIT
	 *
	 * Generates a platform-specific LIMIT clause
	 *
	 * @param	string	$sql	$SQL Query
	 * @return	string
	 */
	protected function _limit($sql)
	{
		$select = 'SELECT '.($this->qb_offset ? 'SKIP '.$this->qb_offset : '').'FIRST '.$this->qb_limit.' ';
		return preg_replace('/^(SELECT\s)/i', $select, $sql, 1);
	}

}