/*
 *      Copyright (C) 2005-2009 Team XBMC
 *      http://www.xbmc.org
 *
 *  This Program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *
 *  This Program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with XBMC; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *  http://www.gnu.org/copyleft/gpl.html
 *
 */

#include "DDSImage.h"
#include "XBTF.h"
#include "lib/libsquish/squish.h"
#include <string.h>

#ifndef NO_XBMC_FILESYSTEM
#include "FileSystem/File.h"
using namespace XFILE;
#else
#include "SimpleFS.h"
#endif

CDDSImage::CDDSImage()
{
  m_data = NULL;
  memset(&m_desc, 0, sizeof(m_desc));
}

CDDSImage::CDDSImage(unsigned int width, unsigned int height, unsigned int format)
{
  m_data = NULL;
  Allocate(width, height, format);
}

CDDSImage::~CDDSImage()
{
  delete[] m_data;
}

unsigned int CDDSImage::GetWidth() const
{
  return m_desc.width;
}

unsigned int CDDSImage::GetHeight() const
{
  return m_desc.height;
}

unsigned int CDDSImage::GetFormat() const
{
  if (strncmp((const char *)&m_desc.pixelFormat.fourcc, "DXT1", 4) == 0)
    return XB_FMT_DXT1;
  if (strncmp((const char *)&m_desc.pixelFormat.fourcc, "DXT5", 4) == 0)
    return XB_FMT_DXT5;
  return 0;
}

unsigned int CDDSImage::GetSize() const
{
  return m_desc.linearSize;
}

unsigned char *CDDSImage::GetData() const
{
  return m_data;
}

bool CDDSImage::ReadFile(const std::string &inputFile)
{
  // open the file
  CFile file;
  if (!file.Open(inputFile))
    return false;

  // read the header
  uint32_t magic;
  if (file.Read(&magic, 4) != 4)
    return false;
  if (file.Read(&m_desc, sizeof(m_desc)) != sizeof(m_desc))
    return false;
  if (!GetFormat())
    return false;  // not supported

  // allocate our data
  m_data = new unsigned char[m_desc.linearSize];
  if (!m_data)
    return false;

  // and read it in
  if (file.Read(m_data, m_desc.linearSize) != m_desc.linearSize)
    return false;

  file.Close();
  return true;
}

bool CDDSImage::WriteFile(const std::string &outputFile) const
{
  // open the file
  CFile file;
  if (!file.OpenForWrite(outputFile, true))
    return false;

  // write the header
  file.Write("DDS ", 4);
  file.Write(&m_desc, sizeof(m_desc));
  // now the data
  file.Write(m_data, m_desc.linearSize);
  file.Close();
  return true;
}

unsigned int CDDSImage::GetStorageRequirements(unsigned int width, unsigned int height, unsigned int format) const
{
  unsigned int blockSize = (format == XB_FMT_DXT1) ? 8 : 16;
  return ((width + 3) / 4) * ((height + 3) / 4) * blockSize;
}

bool CDDSImage::Compress(unsigned int width, unsigned int height, unsigned int pitch, unsigned char const *brga, double maxMSE)
{
  delete[] m_data;
  m_data = new unsigned char[GetStorageRequirements(width, height, XB_FMT_DXT1)];
  
  // first try DXT1, which is only 4bits/pixel
  Allocate(width, height, XB_FMT_DXT1);
  
  squish::CompressImage(brga, width, height, pitch, m_data, squish::kDxt1 | squish::kSourceBGRA);
  if (maxMSE)
  { // want to bother with other formats
    double colorMSE, alphaMSE;
    squish::ComputeMSE(brga, width, height, pitch, m_data, squish::kDxt1 | squish::kSourceBGRA, colorMSE, alphaMSE);
    if (colorMSE < maxMSE && alphaMSE < maxMSE)
      return true;

    Allocate(width, height, XB_FMT_DXT3);
    
    if (alphaMSE == 0)
    { // no alpha channel, so DXT5YCoCg is going to be the best DXT5 format
      /*        squish::CompressImage(brga, width, height, pitch, data2, squish::kDxt5 | squish::kSourceBGRA);
       squish::ComputeMSE(brga, width, height, pitch, m_data, squish::kDxt5 | squish::kSourceBGRA, colorMSE, alphaMSE);
       if (colorMSE < maxMSE && alphaMSE < maxMSE)
       { // success - use it
       compressedSize = squish::GetStorageRequirements(width, height, squish::kDxt5);
       format = XB_FMT_DXT5_YCoCg;
       }
       */
    }
    if (alphaMSE > 0)
    { // try DXT3 and DXT5 - use whichever is better (color is the same, but alpha will be different)
      squish::CompressImage(brga, width, height, pitch, m_data, squish::kDxt3 | squish::kSourceBGRA);
      squish::ComputeMSE(brga, width, height, pitch, m_data, squish::kDxt3 | squish::kSourceBGRA, colorMSE, alphaMSE);
      if (colorMSE < maxMSE)
      { // color is fine, test DXT5 as well
        double dxt5MSE;
        unsigned char *data2 = new unsigned char[GetStorageRequirements(width, height, XB_FMT_DXT5)];
        squish::CompressImage(brga, width, height, pitch, data2, squish::kDxt5 | squish::kSourceBGRA);
        squish::ComputeMSE(brga, width, height, pitch, data2, squish::kDxt5 | squish::kSourceBGRA, colorMSE, alphaMSE);
        if (alphaMSE < maxMSE && alphaMSE < dxt5MSE)
        { // DXT3 passes and is best
          return true;
        }
        else if (dxt5MSE < maxMSE)
        { // DXT5 passes
          memcpy(&m_desc.pixelFormat.fourcc, "DXT5", 4);
          delete[] m_data;
          m_data = data2;
          return true;
        }
        delete[] data2;
      }
    }
    return false;
  }
  return true;
}

void CDDSImage::Allocate(unsigned int width, unsigned int height, unsigned int format)
{
  memset(&m_desc, 0, sizeof(m_desc));
  m_desc.size = sizeof(m_desc);
  m_desc.flags = ddsd_caps | ddsd_pixelformat | ddsd_width | ddsd_height | ddsd_linearsize;
  m_desc.height = height;
  m_desc.width = width;
  m_desc.linearSize = GetStorageRequirements(width, height, format);
  m_desc.pixelFormat.size = sizeof(m_desc.pixelFormat);
  m_desc.pixelFormat.flags = ddpf_fourcc;
  memcpy(&m_desc.pixelFormat.fourcc, GetFourCC(format), 4);
  m_desc.caps.flags1 = ddscaps_texture;
  delete[] m_data;
  m_data = new unsigned char[m_desc.linearSize];
}

const char *CDDSImage::GetFourCC(unsigned int format) const
{
  if (format == XB_FMT_DXT1)
    return "DXT1";
  else if (format == XB_FMT_DXT3)
    return "DXT3";
  else
    return "DXT5";
}