<?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');

/**
 * SQLite3 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		Andrey Andreev
 * @link		http://codeigniter.com/user_guide/database/
 */
class CI_DB_sqlite3_driver extends CI_DB {

	/**
	 * Database driver
	 *
	 * @var	string
	 */
	public $dbdriver = 'sqlite3';

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

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

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

	/**
	 * Non-persistent database connection
	 *
	 * @param	bool	$persistent
	 * @return	SQLite3
	 */
	public function db_connect($persistent = FALSE)
	{
		if ($persistent)
		{
			log_message('debug', 'SQLite3 doesn\'t support persistent connections');
		}

		try
		{
			return ( ! $this->password)
				? new SQLite3($this->database)
				: new SQLite3($this->database, SQLITE3_OPEN_READWRITE | SQLITE3_OPEN_CREATE, $this->password);
		}
		catch (Exception $e)
		{
			return FALSE;
		}
	}

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

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

		$version = SQLite3::version();
		return $this->data_cache['version'] = $version['versionString'];
	}

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

	/**
	 * Execute the query
	 *
	 * @todo	Implement use of SQLite3::querySingle(), if needed
	 * @param	string	$sql
	 * @return	mixed	SQLite3Result object or bool
	 */
	protected function _execute($sql)
	{
		return $this->is_write_type($sql)
			? $this->conn_id->exec($sql)
			: $this->conn_id->query($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);

		return $this->conn_id->exec('BEGIN TRANSACTION');
	}

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

	/**
	 * 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 $this->conn_id->exec('END TRANSACTION');
	}

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

	/**
	 * 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 $this->conn_id->exec('ROLLBACK');
	}

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

	/**
	 * Platform-dependant string escape
	 *
	 * @param	string
	 * @return	string
	 */
	protected function _escape_str($str)
	{
		return $this->conn_id->escapeString($str);
	}

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

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

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

	/**
	 * Insert ID
	 *
	 * @return	int
	 */
	public function insert_id()
	{
		return $this->conn_id->lastInsertRowID();
	}

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

	/**
	 * 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)
	{
		return 'SELECT "NAME" FROM "SQLITE_MASTER" WHERE "TYPE" = \'table\''
			.(($prefix_limit !== FALSE && $this->dbprefix != '')
				? ' AND "NAME" LIKE \''.$this->escape_like_str($this->dbprefix).'%\' '.sprintf($this->_like_escape_str, $this->_like_escape_chr)
				: '');
	}

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

	/**
	 * Fetch Field Names
	 *
	 * @param	string	$table	Table name
	 * @return	array
	 */
	public function list_fields($table)
	{
		// Is there a cached result?
		if (isset($this->data_cache['field_names'][$table]))
		{
			return $this->data_cache['field_names'][$table];
		}

		if (($result = $this->query('PRAGMA TABLE_INFO('.$this->protect_identifiers($table, TRUE, NULL, FALSE).')')) === FALSE)
		{
			return FALSE;
		}

		$this->data_cache['field_names'][$table] = array();
		foreach ($result->result_array() as $row)
		{
			$this->data_cache['field_names'][$table][] = $row['name'];
		}

		return $this->data_cache['field_names'][$table];
	}

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

	/**
	 * Returns an object with field data
	 *
	 * @param	string	$table
	 * @return	array
	 */
	public function field_data($table)
	{
		if (($query = $this->query('PRAGMA TABLE_INFO('.$this->protect_identifiers($table, TRUE, NULL, FALSE).')')) === FALSE)
		{
			return FALSE;
		}

		$query = $query->result_array();
		if (empty($query))
		{
			return FALSE;
		}

		$retval = array();
		for ($i = 0, $c = count($query); $i < $c; $i++)
		{
			$retval[$i]			= new stdClass();
			$retval[$i]->name		= $query[$i]['name'];
			$retval[$i]->type		= $query[$i]['type'];
			$retval[$i]->max_length		= NULL;
			$retval[$i]->default		= $query[$i]['dflt_value'];
			$retval[$i]->primary_key	= isset($query[$i]['pk']) ? (int) $query[$i]['pk'] : 0;
		}

		return $retval;
	}

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

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

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

	/**
	 * Replace statement
	 *
	 * Generates a platform-specific replace string from the supplied data
	 *
	 * @param	string	$table	Table name
	 * @param	array	$keys	INSERT keys
	 * @param	array	$values	INSERT values
	 * @return	string
	 */
	protected function _replace($table, $keys, $values)
	{
		return 'INSERT OR '.parent::_replace($table, $keys, $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;
	}

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

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

}
