// Copyright (c) 2013, Razvan Petru
// All rights reserved.

// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:

// * Redistributions of source code must retain the above copyright notice, this
//   list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice, this
//   list of conditions and the following disclaimer in the documentation and/or other
//   materials provided with the distribution.
// * The name of the contributors may not be used to endorse or promote products
//   derived from this software without specific prior written permission.

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
// IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
// OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
// OF THE POSSIBILITY OF SUCH DAMAGE.

#include "QsLogDestFile.h"
#include <QTextCodec>
#include <QDateTime>
#include <QtGlobal>
#include <iostream>

const int QsLogging::SizeRotationStrategy::MaxBackupCount = 10;

QsLogging::RotationStrategy::~RotationStrategy()
{
}

QsLogging::SizeRotationStrategy::SizeRotationStrategy() : mCurrentSizeInBytes(0), mMaxSizeInBytes(0), mBackupsCount(0)
{
}

void QsLogging::SizeRotationStrategy::setInitialInfo(const QFile& file)
{
  mFileName = file.fileName();
  mCurrentSizeInBytes = file.size();
}

void QsLogging::SizeRotationStrategy::includeMessageInCalculation(const QString& message)
{
  mCurrentSizeInBytes += message.toUtf8().size();
}

bool QsLogging::SizeRotationStrategy::shouldRotate()
{
  return mCurrentSizeInBytes > mMaxSizeInBytes;
}

// Algorithm assumes backups will be named filename.X, where 1 <= X <= mBackupsCount.
// All X's will be shifted up.
void QsLogging::SizeRotationStrategy::rotate()
{
  if (!mBackupsCount)
  {
    if (!QFile::remove(mFileName))
      std::cerr << "QsLog: backup delete failed " << qPrintable(mFileName);
    return;
  }

  // 1. find the last existing backup than can be shifted up
  const QString logNamePattern = mFileName + QString::fromUtf8(".%1");
  int lastExistingBackupIndex = 0;
  for (int i = 1; i <= mBackupsCount; ++i)
  {
    const QString backupFileName = logNamePattern.arg(i);
    if (QFile::exists(backupFileName))
      lastExistingBackupIndex = qMin(i, mBackupsCount - 1);
    else
      break;
  }

  // 2. shift up
  for (int i = lastExistingBackupIndex; i >= 1; --i)
  {
    const QString oldName = logNamePattern.arg(i);
    const QString newName = logNamePattern.arg(i + 1);
    QFile::remove(newName);
    const bool renamed = QFile::rename(oldName, newName);
    if (!renamed)
    {
      std::cerr << "QsLog: could not rename backup " << qPrintable(oldName) << " to " << qPrintable(newName);
    }
  }

  // 3. rename current log file
  const QString newName = logNamePattern.arg(1);
  if (QFile::exists(newName))
    QFile::remove(newName);
  if (!QFile::rename(mFileName, newName))
  {
    std::cerr << "QsLog: could not rename log " << qPrintable(mFileName) << " to " << qPrintable(newName);
  }
}

QIODevice::OpenMode QsLogging::SizeRotationStrategy::recommendedOpenModeFlag()
{
  return QIODevice::Append;
}

void QsLogging::SizeRotationStrategy::setMaximumSizeInBytes(qint64 size)
{
  Q_ASSERT(size >= 0);
  mMaxSizeInBytes = size;
}

void QsLogging::SizeRotationStrategy::setBackupCount(int backups)
{
  Q_ASSERT(backups >= 0);
  mBackupsCount = qMin(backups, SizeRotationStrategy::MaxBackupCount);
}

qint64 QsLogging::SizeRotationStrategy::currentSizeInBytes()
{
  return mCurrentSizeInBytes;
}

QsLogging::FileDestination::FileDestination(const QString& filePath, RotationStrategyPtr rotationStrategy)
  : mRotationStrategy(rotationStrategy)
{
  mFile.setFileName(filePath);
  if (!mFile.open(QFile::WriteOnly | QFile::Text | mRotationStrategy->recommendedOpenModeFlag()))
    std::cerr << "QsLog: could not open log file " << qPrintable(filePath);
  mOutputStream.setDevice(&mFile);
  mOutputStream.setCodec("UTF-8");

  mRotationStrategy->setInitialInfo(mFile);
}

void QsLogging::FileDestination::write(const QString& message, Level)
{
  mRotationStrategy->includeMessageInCalculation(message);
  if (mRotationStrategy->shouldRotate())
    rotate();

  mOutputStream << message << "\n";
  mOutputStream.flush();
}

bool QsLogging::FileDestination::isValid()
{
  return mFile.isOpen();
}

void QsLogging::FileDestination::rotate()
{
  mOutputStream.setDevice(NULL);
  mFile.close();
  mRotationStrategy->rotate();
  if (!mFile.open(QFile::WriteOnly | QFile::Text | mRotationStrategy->recommendedOpenModeFlag()))
    std::cerr << "QsLog: could not reopen log file " << qPrintable(mFile.fileName());
  mRotationStrategy->setInitialInfo(mFile);
  mOutputStream.setDevice(&mFile);
  mOutputStream.setCodec("UTF-8");
}