/*
    Copyright (c) 2009 Volker Krause <vkrause@kde.org>

    This library is free software; you can redistribute it and/or modify it
    under the terms of the GNU Library General Public License as published by
    the Free Software Foundation; either version 2 of the License, or (at your
    option) any later version.

    This library is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
    License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to the
    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    02110-1301, USA.
*/

#include "dbaccess.h"

#include <akonadi/servermanager.h>
#include <akonadi/private/xdgbasedirs_p.h>

#include <QSettings>
#include <QSqlDatabase>
#include <QSqlQuery>
#include <QSqlError>

#include <KLocalizedString>
#include <KMessageBox>

using namespace Akonadi;

class DbAccessPrivate
{
  public:
    DbAccessPrivate()
    {
      init();
    }

    void init()
    {
      const QString serverConfigFile = saveDir( "config" ) + QLatin1String("/akonadiserverrc");
      QSettings settings( serverConfigFile, QSettings::IniFormat );

      const QString driver = settings.value( "General/Driver", "QMYSQL" ).toString();
      database = QSqlDatabase::addDatabase( driver );
      settings.beginGroup( driver );
      database.setHostName( settings.value( "Host", QString() ).toString() );
      database.setDatabaseName( settings.value( "Name", "akonadi" ).toString() );
      database.setUserName( settings.value( "User", QString() ).toString() );
      database.setPassword( settings.value( "Password", QString() ).toString() );
      database.setConnectOptions( settings.value( "Options", QString() ).toString() );
      if ( !database.open() ) {
        KMessageBox::error( 0, i18n( "Failed to connect to database: %1", database.lastError().text() ) );
      }
    }

    QString saveDir(const char* resource, const QString& relPath = QString() )
    {
      QString fullRelPath = QLatin1String("akonadi");
      if ( ServerManager::hasInstanceIdentifier() )
        fullRelPath += QLatin1String("/instance/") + ServerManager::instanceIdentifier();
      if ( !relPath.isEmpty() )
        fullRelPath += QLatin1Char('/') + relPath;
      return XdgBaseDirs::saveDir( resource, fullRelPath );
    }

    QSqlDatabase database;
};

K_GLOBAL_STATIC( DbAccessPrivate, sInstance )
QSqlDatabase DbAccess::database()
{
  // hack to detect database gone away error
  QSqlQuery query( sInstance->database );
  // prepare or exec of "SELECT 1" will only fail when we are not connected to database
  if ( !query.prepare( QLatin1String( "SELECT 1" ) ) || !query.exec() ) {
    sInstance->database.close();
    QSqlDatabase::removeDatabase(sInstance->database.connectionName());
    sInstance->init();
  }
  return sInstance->database;
}