<?php
  /**
   * Copyright (c) 2013 Bart Visscher <bartv@thisnet.nl>
   * This file is licensed under the Affero General Public License version 3 or
   * later.
   * See the COPYING-README file.
   */
  
  namespace OC\DB;
  use Doctrine\DBAL\Driver;
  use Doctrine\DBAL\Configuration;
  use Doctrine\DBAL\Cache\QueryCacheProfile;
  use Doctrine\Common\EventManager;
  
  class Connection extends \Doctrine\DBAL\Connection {
  	/**
  	 * @var string $tablePrefix
  	 */
  	protected $tablePrefix;
  
  	/**
  	 * @var \OC\DB\Adapter $adapter
  	 */
  	protected $adapter;
  
  	/**
  	 * @var \Doctrine\DBAL\Driver\Statement[] $preparedQueries
  	 */
  	protected $preparedQueries = array();
  
  	protected $cachingQueryStatementEnabled = true;
  
  	/**
  	 * Initializes a new instance of the Connection class.
  	 *
  	 * @param array $params  The connection parameters.
  	 * @param \Doctrine\DBAL\Driver $driver
  	 * @param \Doctrine\DBAL\Configuration $config
  	 * @param \Doctrine\Common\EventManager $eventManager
  	 * @throws \Exception
  	 */
  	public function __construct(array $params, Driver $driver, Configuration $config = null,
  		EventManager $eventManager = null)
  	{
  		if (!isset($params['adapter'])) {
  			throw new \Exception('adapter not set');
  		}
  		if (!isset($params['tablePrefix'])) {
  			throw new \Exception('tablePrefix not set');
  		}
  		parent::__construct($params, $driver, $config, $eventManager);
  		$this->adapter = new $params['adapter']($this);
  		$this->tablePrefix = $params['tablePrefix'];
  	}
  
  	/**
  	 * Prepares an SQL statement.
  	 *
  	 * @param string $statement The SQL statement to prepare.
  	 * @param int $limit
  	 * @param int $offset
  	 * @return \Doctrine\DBAL\Driver\Statement The prepared statement.
  	 */
  	public function prepare( $statement, $limit=null, $offset=null ) {
  		if ($limit === -1) {
  			$limit = null;
  		}
  		if (!is_null($limit)) {
  			$platform = $this->getDatabasePlatform();
  			$statement = $platform->modifyLimitQuery($statement, $limit, $offset);
  		} else {
  			if (isset($this->preparedQueries[$statement]) && $this->cachingQueryStatementEnabled) {
  				return $this->preparedQueries[$statement];
  			}
  			$origStatement = $statement;
  		}
  		$statement = $this->replaceTablePrefix($statement);
  		$statement = $this->adapter->fixupStatement($statement);
  
  		if(\OC_Config::getValue( 'log_query', false)) {
  			\OC_Log::write('core', 'DB prepare : '.$statement, \OC_Log::DEBUG);
  		}
  		$result = parent::prepare($statement);
  		if (is_null($limit) && $this->cachingQueryStatementEnabled) {
  			$this->preparedQueries[$origStatement] = $result;
  		}
  		return $result;
  	}
  
  	/**
  	 * Executes an, optionally parameterized, SQL query.
  	 *
  	 * If the query is parameterized, a prepared statement is used.
  	 * If an SQLLogger is configured, the execution is logged.
  	 *
  	 * @param string $query The SQL query to execute.
  	 * @param array $params The parameters to bind to the query, if any.
  	 * @param array $types The types the previous parameters are in.
  	 * @param QueryCacheProfile $qcp
  	 * @return \Doctrine\DBAL\Driver\Statement The executed statement.
  	 * @internal PERF: Directly prepares a driver statement, not a wrapper.
  	 */
  	public function executeQuery($query, array $params = array(), $types = array(), QueryCacheProfile $qcp = null)
  	{
  		$query = $this->replaceTablePrefix($query);
  		$query = $this->adapter->fixupStatement($query);
  		return parent::executeQuery($query, $params, $types, $qcp);
  	}
  
  	/**
  	 * Executes an SQL INSERT/UPDATE/DELETE query with the given parameters
  	 * and returns the number of affected rows.
  	 *
  	 * This method supports PDO binding types as well as DBAL mapping types.
  	 *
  	 * @param string $query The SQL query.
  	 * @param array $params The query parameters.
  	 * @param array $types The parameter types.
  	 * @return integer The number of affected rows.
  	 * @internal PERF: Directly prepares a driver statement, not a wrapper.
  	 */
  	public function executeUpdate($query, array $params = array(), array $types = array())
  	{
  		$query = $this->replaceTablePrefix($query);
  		$query = $this->adapter->fixupStatement($query);
  		return parent::executeUpdate($query, $params, $types);
  	}
  
  	/**
  	 * Returns the ID of the last inserted row, or the last value from a sequence object,
  	 * depending on the underlying driver.
  	 *
  	 * Note: This method may not return a meaningful or consistent result across different drivers,
  	 * because the underlying database may not even support the notion of AUTO_INCREMENT/IDENTITY
  	 * columns or sequences.
  	 *
  	 * @param string $seqName Name of the sequence object from which the ID should be returned.
  	 * @return string A string representation of the last inserted ID.
  	 */
  	public function lastInsertId($seqName = null)
  	{
  		if ($seqName) {
  			$seqName = $this->replaceTablePrefix($seqName);
  		}
  		return $this->adapter->lastInsertId($seqName);
  	}
  
  	// internal use
  	public function realLastInsertId($seqName = null)
  	{
  		return parent::lastInsertId($seqName);
  	}
  
  	/**
  	 * @brief Insert a row if a matching row doesn't exists.
  	 * @param string $table. The table to insert into in the form '*PREFIX*tableName'
  	 * @param array $input. An array of fieldname/value pairs
  	 * @return bool The return value from execute()
  	 */
  	public function insertIfNotExist($table, $input) {
  		return $this->adapter->insertIfNotExist($table, $input);
  	}
  
  	/**
  	 * returns the error code and message as a string for logging
  	 * works with DoctrineException
  	 * @return string
  	 */
  	public function getError() {
  		$msg = $this->errorCode() . ': ';
  		$errorInfo = $this->errorInfo();
  		if (is_array($errorInfo)) {
  			$msg .= 'SQLSTATE = '.$errorInfo[0] . ', ';
  			$msg .= 'Driver Code = '.$errorInfo[1] . ', ';
  			$msg .= 'Driver Message = '.$errorInfo[2];
  		}
  		return $msg;
  	}
  
  	// internal use
  	/**
  	 * @param string $statement
  	 * @return string
  	 */
  	protected function replaceTablePrefix($statement) {
  		return str_replace( '*PREFIX*', $this->tablePrefix, $statement );
  	}
  
  	public function enableQueryStatementCaching() {
  		$this->cachingQueryStatementEnabled = true;
  	}
  
  	public function disableQueryStatementCaching() {
  		$this->cachingQueryStatementEnabled = false;
  		$this->preparedQueries = array();
  	}
  }