<?php
/**
 * Piwik - Open source web analytics
 *
 * @link http://piwik.org
 * @license http://www.gnu.org/licenses/gpl-3.0.html Gpl v3 or later
 * @version $Id$
 *
 * @category Piwik
 * @package Piwik
 */

/**
 * Simple database wrapper.
 * We can't afford to have a dependency with the Zend_Db module in Tracker.
 * We wrote this simple class 
 *
 * @package Piwik
 * @subpackage Piwik_Tracker
 */
abstract class Piwik_Tracker_Db
{
	protected static $profiling = false;

	protected $queriesProfiling = array();

	/**
	 * Enables the SQL profiling. 
	 * For each query, saves in the DB the time spent on this query. 
	 * Very useful to see the slow query under heavy load.
	 * You can then use Piwik::printSqlProfilingReportTracker(); 
	 * to display the SQLProfiling report and see which queries take time, etc.
	 */
	public static function enableProfiling()
	{
		self::$profiling = true;
	}

	/** 
	 * Disables the SQL profiling logging.
	 */
	public static function disableProfiling()
	{
		self::$profiling = false;
	}

	/**
	 * Returns true if the SQL profiler is enabled
	 * Only used by the unit test that tests that the profiler is off on a  production server
	 * 
	 * @return bool 
	 */
	public function isProfilingEnabled()
	{
		return self::$profiling;
	}

	/**
	 * Initialize profiler
	 *
	 * @return Piwik_Timer
	 */
	protected function initProfiler()
	{
		return new Piwik_Timer;
	}

	/**
	 * Record query profile
	 *
	 * @param string $query
	 * @param Piwik_Timer $timer
	 */	
	protected function recordQueryProfile( $query, $timer )
	{
		if(!isset($this->queriesProfiling[$query])) $this->queriesProfiling[$query] = array('sum_time_ms' => 0, 'count' => 0);
		$time = $timer->getTimeMs(2);
		$time += $this->queriesProfiling[$query]['sum_time_ms'];
		$count = $this->queriesProfiling[$query]['count'] + 1;
		$this->queriesProfiling[$query]	= array('sum_time_ms' => $time, 'count' => $count);
	}
	
	/**
	 * When destroyed, if SQL profiled enabled, logs the SQL profiling information
	 */
	public function recordProfiling()
	{
		if(is_null($this->connection)) 
		{
			return;
		}
	
		// turn off the profiler so we don't profile the following queries 
		self::$profiling = false;
		
		foreach($this->queriesProfiling as $query => $info)
		{
			$time = $info['sum_time_ms'];
			$count = $info['count'];

			$queryProfiling = "INSERT INTO ".Piwik_Common::prefixTable('log_profiling')."
						(query,count,sum_time_ms) VALUES (?,$count,$time)
						ON DUPLICATE KEY 
							UPDATE count=count+$count,sum_time_ms=sum_time_ms+$time";
			$this->query($queryProfiling,array($query));
		}
		
		// turn back on profiling
		self::$profiling = true;
	}

	/**
	 * Connects to the DB
	 * 
	 * @throws Exception if there was an error connecting the DB
	 */
	abstract public function connect();
	
	/**
	 * Disconnects from the server
	 */
	public function disconnect()
	{
		$this->connection = null;
	}
	
	/**
	 * Returns an array containing all the rows of a query result, using optional bound parameters.
	 * 
	 * @param string Query 
	 * @param array Parameters to bind
	 * @see also query()
	 * @throws Exception if an exception occured
	 */
	abstract public function fetchAll( $query, $parameters = array() );
	
	/**
	 * Returns the first row of a query result, using optional bound parameters.
	 * 
	 * @param string Query 
	 * @param array Parameters to bind
	 * @see also query()
	 * 
	 * @throws Exception if an exception occured
	 */
	abstract public function fetch( $query, $parameters = array() );
	
	/**
	 * This function is a proxy to fetch(), used to maintain compatibility with Zend_Db interface
	 * @see fetch()
	 */
	public function fetchRow( $query, $parameters = array() )
	{
		return $this->fetch($query, $parameters);
	}

	/**
	 * Return number of affected rows in last query
	 *
	 * @param mixed $queryResult Result from query()
	 * @return int
	 */
	abstract public function rowCount($queryResult);

	/**
	 * Executes a query, using optional bound parameters.
	 * 
	 * @param string Query 
	 * @param array|string Parameters to bind array('idsite'=> 1)
	 * 
	 * @return PDOStatement or false if failed
	 * @throws Exception if an exception occured
	 */
	abstract public function query($query, $parameters = array());

	/**
	 * Returns the last inserted ID in the DB
	 * Wrapper of PDO::lastInsertId()
	 * 
	 * @return int
	 */
	abstract public function lastInsertId();

	/**
	 * Test error number
	 *
	 * @param Exception $e
	 * @param string $errno
	 * @return bool True if error number matches; false otherwise
	 */
	abstract public function isErrNo($e, $errno);
}