<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2015, 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. (http://ellislab.com/)
 * @copyright	Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
 * @license	http://opensource.org/licenses/MIT	MIT License
 * @link	http://codeigniter.com
 * @since	Version 3.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * Firebird/Interbase 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		http://codeigniter.com/user_guide/database/
 */
class CI_DB_ibase_driver extends CI_DB {

	/**
	 * Database driver
	 *
	 * @var	string
	 */
	public $dbdriver = 'ibase';

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

	/**
	 * ORDER BY random keyword
	 *
	 * @var	array
	 */
	protected $_random_keyword = array('RAND()', 'RAND()');

	/**
	 * IBase Transaction status flag
	 *
	 * @var	resource
	 */
	protected $_ibase_trans;

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

	/**
	 * Non-persistent database connection
	 *
	 * @param	bool	$persistent
	 * @return	resource
	 */
	public function db_connect($persistent = FALSE)
	{
		return ($persistent === TRUE)
			? ibase_pconnect($this->hostname.':'.$this->database, $this->username, $this->password, $this->char_set)
			: ibase_connect($this->hostname.':'.$this->database, $this->username, $this->password, $this->char_set);
	}

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

	/**
	 * Database version number
	 *
	 * @return	string
	 */
	public function version()
	{
		if (isset($this->data_cache['version']))
		{
			return $this->data_cache['version'];
		}

		if (($service = ibase_service_attach($this->hostname, $this->username, $this->password)))
		{
			$this->data_cache['version'] = ibase_server_info($service, IBASE_SVC_SERVER_VERSION);

			// Don't keep the service open
			ibase_service_detach($service);
			return $this->data_cache['version'];
		}

		return FALSE;
	}

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

	/**
	 * Execute the query
	 *
	 * @param	string	$sql	an SQL query
	 * @return	resource
	 */
	protected function _execute($sql)
	{
		return ibase_query($this->conn_id, $sql);
	}

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

	/**
	 * Begin Transaction
	 *
	 * @param	bool	$test_mode
	 * @return	bool
	 */
	public function trans_begin($test_mode = FALSE)
	{
		// When transactions are nested we only begin/commit/rollback the outermost ones
		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
		{
			return TRUE;
		}

		// Reset the transaction failure flag.
		// If the $test_mode flag is set to TRUE transactions will be rolled back
		// even if the queries produce a successful result.
		$this->_trans_failure = ($test_mode === TRUE);

		$this->_ibase_trans = ibase_trans($this->conn_id);

		return TRUE;
	}

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

	/**
	 * Commit Transaction
	 *
	 * @return	bool
	 */
	public function trans_commit()
	{
		// When transactions are nested we only begin/commit/rollback the outermost ones
		if ( ! $this->trans_enabled OR $this->_trans->depth > 0)
		{
			return TRUE;
		}

		return ibase_commit($this->_ibase_trans);
	}

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

	/**
	 * Rollback Transaction
	 *
	 * @return	bool
	 */
	public function trans_rollback()
	{
		// When transactions are nested we only begin/commit/rollback the outermost ones
		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
		{
			return TRUE;
		}

		return ibase_rollback($this->_ibase_trans);
	}

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

	/**
	 * Affected Rows
	 *
	 * @return	int
	 */
	public function affected_rows()
	{
		return ibase_affected_rows($this->conn_id);
	}

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

	/**
	 * Insert ID
	 *
	 * @param	string	$generator_name
	 * @param	int	$inc_by
	 * @return	int
	 */
	public function insert_id($generator_name, $inc_by = 0)
	{
		//If a generator hasn't been used before it will return 0
		return ibase_gen_id('"'.$generator_name.'"', $inc_by);
	}

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

	/**
	 * List 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)
	{
		$sql = 'SELECT TRIM("RDB$RELATION_NAME") AS TABLE_NAME FROM "RDB$RELATIONS" WHERE "RDB$RELATION_NAME" NOT LIKE \'RDB$%\' AND "RDB$RELATION_NAME" NOT LIKE \'MON$%\'';

		if ($prefix_limit !== FALSE && $this->dbprefix !== '')
		{
			return $sql.' AND TRIM("RDB$RELATION_NAME") AS TABLE_NAME 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 = '')
	{
		return 'SELECT TRIM("RDB$FIELD_NAME") AS COLUMN_NAME FROM "RDB$RELATION_FIELDS" WHERE "RDB$RELATION_NAME" = '.$this->escape($table);
	}

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

	/**
	 * Returns an object with field data
	 *
	 * @param	string	$table
	 * @return	array
	 */
	public function field_data($table)
	{
		$sql = 'SELECT "rfields"."RDB$FIELD_NAME" AS "name",
				CASE "fields"."RDB$FIELD_TYPE"
					WHEN 7 THEN \'SMALLINT\'
					WHEN 8 THEN \'INTEGER\'
					WHEN 9 THEN \'QUAD\'
					WHEN 10 THEN \'FLOAT\'
					WHEN 11 THEN \'DFLOAT\'
					WHEN 12 THEN \'DATE\'
					WHEN 13 THEN \'TIME\'
					WHEN 14 THEN \'CHAR\'
					WHEN 16 THEN \'INT64\'
					WHEN 27 THEN \'DOUBLE\'
					WHEN 35 THEN \'TIMESTAMP\'
					WHEN 37 THEN \'VARCHAR\'
					WHEN 40 THEN \'CSTRING\'
					WHEN 261 THEN \'BLOB\'
					ELSE NULL
				END AS "type",
				"fields"."RDB$FIELD_LENGTH" AS "max_length",
				"rfields"."RDB$DEFAULT_VALUE" AS "default"
			FROM "RDB$RELATION_FIELDS" "rfields"
				JOIN "RDB$FIELDS" "fields" ON "rfields"."RDB$FIELD_SOURCE" = "fields"."RDB$FIELD_NAME"
			WHERE "rfields"."RDB$RELATION_NAME" = '.$this->escape($table).'
			ORDER BY "rfields"."RDB$FIELD_POSITION"';

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

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

	/**
	 * Error
	 *
	 * Returns an array containing code and message of the last
	 * database error that has occured.
	 *
	 * @return	array
	 */
	public function error()
	{
		return array('code' => ibase_errcode(), 'message' => ibase_errmsg());
	}

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

	/**
	 * 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)
	{
		$this->qb_limit = FALSE;
		return parent::_update($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 'DELETE FROM '.$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)
	{
		// Limit clause depends on if Interbase or Firebird
		if (stripos($this->version(), 'firebird') !== FALSE)
		{
			$select = 'FIRST '.$this->qb_limit
				.($this->qb_offset ? ' SKIP '.$this->qb_offset : '');
		}
		else
		{
			$select = 'ROWS '
				.($this->qb_offset ? $this->qb_offset.' TO '.($this->qb_limit + $this->qb_offset) : $this->qb_limit);
		}

		return preg_replace('`SELECT`i', 'SELECT '.$select, $sql, 1);
	}

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

	/**
	 * Close DB Connection
	 *
	 * @return	void
	 */
	protected function _close()
	{
		ibase_close($this->conn_id);
	}

}
