<?php defined('SYSPATH') or die('No direct script access.');
/**
 * PDO database connection.
 *
 * @package    Database
 * @author     Kohana Team
 * @copyright  (c) 2008-2009 Kohana Team
 * @license    http://kohanaphp.com/license
 */
class Kohana_Database_PDO extends Database {

	// PDO uses no quoting for identifiers
	protected $_identifier = '';

	public function connect()
	{
		if ($this->_connection)
			return;

		// Extract the connection parameters, adding required variabels
		extract($this->_config['connection'] + array(
			'dsn'        => '',
			'username'   => NULL,
			'password'   => NULL,
			'persistent' => FALSE,
		));

		// Clear the connection parameters for security
		unset($this->_config['connection']);

		// Force PDO to use exceptions for all errors
		$attrs = array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION);

		if ( ! empty($persistent))
		{
			// Make the connection persistent
			$attrs[PDO::ATTR_PERSISTENT] = TRUE;
		}

		// Create a new PDO connection
		$this->_connection = new PDO($dsn, $username, $password, $attrs);

		if ( ! empty($this->_config['charset']))
		{
			// Set the character set
			$this->set_charset($this->_config['charset']);
		}
	}

	public function disconnect()
	{
		// Destroy the PDO object
		$this->_connection = NULL;

		return TRUE;
	}

	public function set_charset($charset)
	{
		// Make sure the database is connected
		$this->_connection or $this->connect();

		// Execute a raw SET NAMES query
		$this->_connection->exec('SET NAMES '.$this->quote($charset));
	}

	public function query($type, $sql, $as_object)
	{
		// Make sure the database is connected
		$this->_connection or $this->connect();

		if ( ! empty($this->_config['profiling']))
		{
			// Benchmark this query for the current instance
			$benchmark = Profiler::start("Database ({$this->_instance})", $sql);
		}

		try
		{
			$result = $this->_connection->query($sql);
		}
		catch (Exception $e)
		{
			if (isset($benchmark))
			{
				// This benchmark is worthless
				Profiler::delete($benchmark);
			}

			// Rethrow the exception
			throw $e;
		}

		if (isset($benchmark))
		{
			Profiler::stop($benchmark);
		}

		// Set the last query
		$this->last_query = $sql;

		if ($type === Database::SELECT)
		{
			// Convert the result into an array, as PDOStatement::rowCount is not reliable
			if ($as_object === FALSE)
			{
				$result->setFetchMode(PDO::FETCH_ASSOC);
			}
			elseif (is_string($as_object))
			{
				$result->setFetchMode(PDO::FETCH_CLASS, $as_object);
			}
			else
			{
				$result->setFetchMode(PDO::FETCH_CLASS, 'stdClass');
			}
			
			$result = $result->fetchAll();

			// Return an iterator of results
			return new Database_Result_Cached($result, $sql, $as_object);
		}
		elseif ($type === Database::INSERT)
		{
			// Return a list of insert id and rows created
			return array(
				$this->_connection->lastInsertId(),
				$result->rowCount(),
			);
		}
		else
		{
			// Return the number of rows affected
			return $result->rowCount();
		}
	}

	public function list_tables($like = NULL)
	{
		throw new Kohana_Exception('Database method :method is not supported by :class',
			array(':method' => __FUNCTION__, ':class' => __CLASS__));
	}

	public function list_columns($table, $like = NULL)
	{
		throw new Kohana_Exception('Database method :method is not supported by :class',
			array(':method' => __FUNCTION__, ':class' => __CLASS__));
	}

	public function escape($value)
	{
		// Make sure the database is connected
		$this->_connection or $this->connect();

		return $this->_connection->quote($value);
	}

} // End Database_PDO
