<?php 
/**
 * Pimcore
 *
 * This source file is subject to the GNU General Public License version 3 (GPLv3)
 * For the full copyright and license information, please view the LICENSE.md and gpl-3.0.txt
 * files that are distributed with this source code.
 *
 * @copyright  Copyright (c) 2009-2016 pimcore GmbH (http://www.pimcore.org)
 * @license    http://www.pimcore.org/license     GNU General Public License version 3 (GPLv3)
 */

namespace Pimcore;

use Pimcore\Db\Wrapper;

class Db {

    /**
     * @var string
     */
    protected static $_sqlLogFilename;

    /**
     * @var bool
     */
    protected static $_logProfilerWasEnabled;

    /**
     * @var bool
     */
    protected static $_logCaptureActive = false;

    /**
     * @static
     * @return string
     */
    public static function getType () {
        return "mysql";
    }

    /**
     * @param bool $raw
     * @param bool $writeOnly
     * @return Wrapper|\Zend_Db_Adapter_Abstract
     * @throws \Exception
     * @throws \Zend_Db_Profiler_Exception
     */
    public static function getConnection ($raw = false, $writeOnly = false) {

        // just return the wrapper (for compatibility reasons)
        // the wrapper itself get's then the connection using $raw = true
        if(!$raw) {
            return new Wrapper();
        }

        $charset = "UTF8";

        // explicit set charset for connection (to the adapter)
        $config = Config::getSystemConfig()->database->toArray();

        // write only handling
        if($writeOnly && isset($config["writeOnly"])) {
            // overwrite params with write only configuration
            $config["params"] = $config["writeOnly"]["params"];
        } else if ($writeOnly) {
            throw new \Exception("writeOnly connection is requested but not configured");
        }

        $config["params"]["charset"] = $charset;

        try {
            $db = \Zend_Db::factory($config["adapter"], $config["params"]);
            $db->query("SET NAMES " . $charset);
        } catch (\Exception $e) {
            \Logger::emerg($e);
            \Pimcore\Tool::exitWithError("Database Error! See debug.log for details");
        }

        // try to set innodb as default storage-engine
        try {
            $db->query("SET storage_engine=InnoDB;");
        } catch (\Exception $e) {
            \Logger::warn($e);
        }

        // try to set mysql mode
        try {
            $db->query("SET sql_mode = '';");
        } catch (\Exception $e) {
            \Logger::warn($e);
        }

        $connectionId = $db->fetchOne("SELECT CONNECTION_ID()");

        // enable the db-profiler if the devmode is on and there is no custom profiler set (eg. in system.xml)
        if((PIMCORE_DEVMODE && !$db->getProfiler()->getEnabled()) || (array_key_exists("pimcore_log", $_REQUEST) && \Pimcore::inDebugMode())) {
            $profiler = new \Pimcore\Db\Profiler('All DB Queries');
            $profiler->setEnabled(true);
            $profiler->setConnectionId($connectionId);
            $db->setProfiler($profiler);
        }

        \Logger::debug(get_class($db) . ": Successfully established connection to MySQL-Server, Process-ID: " . $connectionId);

        return $db;
    }

    /**
     * @static
     * @return \Zend_Db_Adapter_Abstract
     */
    public static function reset(){

        // close old connections
        self::close();

        return self::get();
    }

    /**
     * @static
     * @return mixed|\Zend_Db_Adapter_Abstract
     */
    public static function get() {

        try {
            if(\Zend_Registry::isRegistered("Pimcore_Db")) {
                $connection = \Zend_Registry::get("Pimcore_Db");
                if($connection instanceof Wrapper) {
                    return $connection;
                }
            }
        }
        catch (\Exception $e) {
            \Logger::error($e);
        }

        // get new connection
        try {
            $db = self::getConnection();
            self::set($db);
            return $db;
        }
        catch (\Exception $e) {

            $errorMessage = "Unable to establish the database connection with the given configuration in /website/var/config/system.php, for details see the debug.log. \nReason: " . $e->getMessage();

            \Logger::emergency($errorMessage);
            \Logger::emergency($e);
            \Pimcore\Tool::exitWithError($errorMessage);
        }
    }

    /**
     * @param $connection
     */
    public static function set($connection) {

        if($connection instanceof Wrapper) {
            // set default adapter for \Zend_Db_Table -> use getResource() because setDefaultAdapter()
            // accepts only instances of \Zend_Db but $connection is an instance of Pimcore\Db\Wrapper
            \Zend_Db_Table::setDefaultAdapter($connection->getResource());
        }

        // register globally
        \Zend_Registry::set("Pimcore_Db", $connection);
    }

    /**
     * @static
     * @return void
     */
    public static function close () {
        try {
            if(\Zend_Registry::isRegistered("Pimcore_Db")) {
                $db = \Zend_Registry::get("Pimcore_Db");

                if($db instanceof Wrapper) {
                    // the following select causes an infinite loop (eg. when the connection is lost -> error handler)
                    //\Logger::debug("closing mysql connection with ID: " . $db->fetchOne("SELECT CONNECTION_ID()"));
                    $db->closeResource();
                    $db->closeWriteResource();
                }
            }
        } catch (\Exception $e) {
            \Logger::error($e);
        }
    }

    /**
     * @param $query
     * @return bool
     */
    public static function isDDLQuery($query) {
        return (bool) preg_match("/(ALTER|CREATE|DROP|RENAME|TRUNCATE)(.*)(DATABASE|EVENT|FUNCTION|PROCEDURE|TABLE|TABLESPACE|VIEW|INDEX|TRIGGER)/i", $query);
    }

    /**
     * @param $query
     * @return bool
     */
    public static function isDMSQuery($query) {
        return (bool) preg_match("/^(INSERT|UPDATE|DELETE|CALL|LOAD|REPLACE) /i", trim($query));
    }

    /**
     * @static
     * @param string $method
     * @param array $args
     */
    public static function startCapturingDefinitionModifications ($connection, $method, $args) {
        if($method == "query") {
            if(self::isDDLQuery($args[0])) {
                self::logDefinitionModification($args[0]);
            }
        } else {
            $tablesToCheck = array("classes","users_permission_definitions");

            if(in_array($args[0], $tablesToCheck)) {
                self::$_logProfilerWasEnabled = $connection->getProfiler()->getEnabled();
                $connection->getProfiler()->setEnabled(true);
                self::$_logCaptureActive = true;
            }
        }
    }

    /**
     * @static
     *
     */
    public static function stopCapturingDefinitionModifications ($connection) {

        if(self::$_logCaptureActive) {
            $query = $connection->getProfiler()->getLastQueryProfile()->getQuery();
            $params = $connection->getProfiler()->getLastQueryProfile()->getQueryParams();

            // @TODO named parameters
            if(!empty($params)) {
                for ($i=1; $i<=count($params); $i++) {
                    $query = substr_replace($query, $connection->quote($params[$i]), strpos($query, "?"), 1);
                }
            }

            self::logDefinitionModification($query);
            $connection->getProfiler()->setEnabled(self::$_logProfilerWasEnabled);
        }

        self::$_logCaptureActive = false;
    }

    /**
     * @param $method
     * @param $args
     * @return bool
     */
    public static function isWriteQuery($method, $args) {

        $methodsToCheck = array("update","delete","insert","lastInsertId");
        if(in_array($method, $methodsToCheck)) {
            return true;
        }

        if($method == "query" && isset($args[0]) && (self::isDDLQuery($args[0]) || self::isDMSQuery($args[0]))) {
            return true;
        }

        return false;
    }

    /**
     * @static
     * @param string $sql
     */
    public static function logDefinitionModification ($sql) {

        // add trailing semicolon if necessary;
        $sql = trim($sql, " ;");
        $sql .= ";";

        if(!self::$_sqlLogFilename) {
            self::$_sqlLogFilename = "db-change-log_". time() ."-" . uniqid() . ".sql";
        }

        // write sql change log for deploying to production system
        $sql .= "\n\n/*--NEXT--*/\n\n";

        $file = PIMCORE_SYSTEM_TEMP_DIRECTORY."/". self::$_sqlLogFilename;
        if(defined("PIMCORE_DB_CHANGELOG_DIRECTORY")) {
            $file = PIMCORE_DB_CHANGELOG_DIRECTORY."/" . self::$_sqlLogFilename;
        }

        $handle = fopen($file,"a");
        fwrite($handle, $sql);
        fclose($handle);
    }


    /**
     * @param $method
     * @param $args
     * @param $exception
     * @param bool $logError
     * @throws \Exception
     */
    public static function errorHandler ($method, $args, $exception, $logError = true) {

        if($logError) {
            \Logger::error($exception);
            \Logger::error(array(
                "message" => $exception->getMessage(),
                "method" => $method,
                "arguments" => $args
            ));
        }

        $lowerErrorMessage = strtolower($exception->getMessage());

        // check if the mysql-connection is the problem (timeout issues, ...)
        if(strpos($lowerErrorMessage, "mysql server has gone away") !== false || strpos($lowerErrorMessage, "lost connection") !== false) {
            // wait a few seconds
            sleep(5);

            // the connection to the server has probably been lost, try to reconnect and call the method again
            try {
                \Logger::warning("The connection to the MySQL-Server has probably been lost, try to reconnect...");
                self::reset();
                \Logger::warning("Reconnecting to the MySQL-Server was successful, sending the command again to the server.");
                $r = self::get()->callResourceMethod($method, $args);
                \Logger::warning("Resending the command was successful");
                return $r;
            } catch (\Exception $e) {
                \Logger::error($e);
                throw $e;
            }
        }

        // no handling throw it again
        throw $exception;
    }


    /**
     * check if autogenerated views (eg. localized fields, ...) are still valid, if not, they're removed
     * @static
     */
    public static function cleanupBrokenViews () {

        $db = self::get();

        $tables = $db->fetchAll("SHOW FULL TABLES");
        foreach ($tables as $table) {

            reset($table);
            $name = current($table);
            $type = next($table);

            if ($type == "VIEW") {
                try {
                    $createStatement = $db->fetchRow("SHOW FIELDS FROM " . $name);
                } catch (\Exception $e) {
                    if(strpos($e->getMessage(), "references invalid table") !== false) {
                        \Logger::err("view " . $name . " seems to be a broken one, it will be removed");
                        \Logger::err("error message was: " . $e->getMessage());

                        $db->query("DROP VIEW " . $name);
                    } else {
                        \Logger::error($e);
                    }
                }
            }
        }
    }
}
