/*
    Copyright (c) 2008 Volker Krause <vkrause@kde.org>

    Inspired by kdelibs/kdecore/io/kdebug.h
    Copyright (C) 1997 Matthias Kalle Dalheimer (kalle@kde.org)
                  2002 Holger Freyther (freyther@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 "akdebug.h"
#include "akcrash.h"
#include "akstandarddirs.h"

#include <libs/xdgbasedirs_p.h>
using Akonadi::XdgBaseDirs;

#include <QDir>
#include <QFile>
#include <QFileInfo>
#include <QMutex>

#include <cassert>

class FileDebugStream : public QIODevice
{
  public:
    FileDebugStream()
      : mType( QtCriticalMsg )
    {
      open( WriteOnly );
    }

    bool isSequential() const { return true; }
    qint64 readData( char *, qint64 ) { return 0;  }
    qint64 readLineData( char *, qint64 ) { return 0; }
    qint64 writeData( const char *data, qint64 len )
    {
      QByteArray buf = QByteArray::fromRawData( data, len );

      if ( !mFileName.isEmpty() ) {
        QFile outputFile( mFileName );
        outputFile.open( QIODevice::WriteOnly | QIODevice::Append | QIODevice::Unbuffered );
        outputFile.write( data, len );
        outputFile.putChar( '\n' );
        outputFile.close();
      }

      qt_message_output( mType,
#if QT_VERSION >= QT_VERSION_CHECK(5, 0, 0)
                         QMessageLogContext(),
                         QString::fromLatin1( buf.trimmed() ) );
#else
                         buf.trimmed().constData() );
#endif
      return len;
    }

    void setFileName( const QString &fileName )
    {
      mFileName = fileName;
    }

    void setType( QtMsgType type )
    {
      mType = type;
    }
  private:
    QString mFileName;
    QtMsgType mType;
};

class DebugPrivate
{
  public:
    DebugPrivate()
      : fileStream( new FileDebugStream() )
    {
    }

    ~DebugPrivate()
    {
      delete fileStream;
    }

    QString errorLogFileName() const
    {
      return AkStandardDirs::saveDir( "data" )
          + QDir::separator()
          + name
          + QString::fromLatin1( ".error" );
    }

    QDebug stream( QtMsgType type )
    {
      QMutexLocker locker( &mutex );
#ifndef QT_NO_DEBUG_OUTPUT
      if ( type == QtDebugMsg ) {
        return qDebug();
      }
#endif
      fileStream->setType( type );
      return QDebug( fileStream );
    }

    void setName( const QString &appName )
    {
      // Keep only the executable name, e.g. akonadi_control
      name = appName.mid( appName.lastIndexOf( QLatin1Char( '/' ) ) + 1 );
      fileStream->setFileName( errorLogFileName() );
    }

    QMutex mutex;
    FileDebugStream *fileStream;
    QString name;
};

Q_GLOBAL_STATIC( DebugPrivate, sInstance )

QDebug akFatal()
{
  return sInstance()->stream( QtFatalMsg );
}

QDebug akError()
{
  return sInstance()->stream( QtCriticalMsg );
}

#ifndef QT_NO_DEBUG_OUTPUT
QDebug akDebug()
{
  return sInstance()->stream( QtDebugMsg );
}
#endif

void akInit( const QString &appName )
{
  AkonadiCrash::init();
  sInstance()->setName( appName );

  QFileInfo infoOld( sInstance()->errorLogFileName() + QString::fromLatin1( ".old" ) );
  if ( infoOld.exists() ) {
    QFile fileOld( infoOld.absoluteFilePath() );
    const bool success = fileOld.remove();
    if ( !success ) {
      qFatal( "Cannot remove old log file - running on a readonly filesystem maybe?" );
    }
  }
  QFileInfo info( sInstance()->errorLogFileName() );
  if ( info.exists() ) {
    QFile file( info.absoluteFilePath() );
    const bool success = file.rename( sInstance()->errorLogFileName() + QString::fromLatin1( ".old" ) );
    if ( !success ) {
      qFatal( "Cannot rename log file - running on a readonly filesystem maybe?" );
    }
  }
}

QString getEnv( const char *name, const QString &defaultValue )
{
  const QString v = QString::fromLocal8Bit( qgetenv( name ) );
  return !v.isEmpty() ? v : defaultValue;
}