/*
  OpenMW - The completely unofficial reimplementation of Morrowind
  Copyright (C) 2009  Jacob Essex
  WWW: http://openmw.sourceforge.net/

  This file (cpp_generator.cpp) is part of the OpenMW package.

  OpenMW is distributed as free software: you can redistribute it
  and/or modify it under the terms of the GNU General Public License
  version 3, as published by the Free Software Foundation.

  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
  version 3 along with this program. If not, see
  http://www.gnu.org/licenses/ .

*/

class Generator
{
public:
  Generator(const std::string& baseFileName) :
    mBaseFileName(baseFileName)
  {
    mDataO.open(std::string(baseFileName+".data").c_str(), std::ios::binary);
  }

  inline void addLandData(RecordPtr record, const std::string& source)
  { mMWLand.addLandData(record, source); }

  inline void addLandTextureData(RecordPtr record, const std::string& source)
  { mMWLand.addLandTextureData(record, source); }

  void beginGeneration()
  {
    //maxiumum distance form 0, 0 in any direction
    int max = 0;
    max = std::max<int>(mMWLand.getMaxX(), max);
    max = std::max<int>(mMWLand.getMaxY(), max);
    max = std::max<int>(-mMWLand.getMinX(), max);
    max = std::max<int>(-mMWLand.getMinY(), max);

    //round up to nearest binary number. makes some stuff easier iirc
    //FIXME
    for ( int i = 1;;i++ ) {
      if ( max < pow((float)2, i) )
        {
          max = pow((float)2, i);
          break;
        }
      assert(i<=8); //don't go too high. Used for debug
    }

    int maxDepth = 0; //temp var used below
    // FIXME: make 8192 a constant
    mIndex.setRootSideLength(max*2*8192); //given that 8192 is the length of a cell

    //Keep deviding the root side length by 2 (thereby simulating a
    //split) until we reach the width of the base cell (or the
    //smallest quad)
    for (long i = mIndex.getRootSideLength(); i > 8192; i/=2 )
      maxDepth++;
    mIndex.setMaxDepth(maxDepth);
  }

  void generateLODLevel(int level, bool createTexture, int textureSize)
  {
    std::cout << "Generating Level " << level << "\n";

    assert(level <= mIndex.getMaxDepth());
    assert(level > 0 );
    assert(textureSize>2);
    assert(textureSize<=4096); //change to gpu max if pos

    const int initialLevel = level;

    // FIXME: Should probably use another name than 'level' here
    level = pow((float)2, level); //gap between verts that we want
    const int halfLevel = level/2;
    assert(halfLevel > 0 );

    // FIXME. Just search for all pow() calls, really
    int cellDist = pow((float)2, mIndex.getMaxDepth());

    // Temporary storage
    QuadData qd;
    qd.setVertexSeperation(128*halfLevel); //dist between two verts

    std::vector<float>& gh = qd.getHeightsRef(); //ref to the data storage in the quad
    std::vector<char>& gn  = qd.getNormalsRef();
    gh.resize(LAND_NUM_VERTS); //allocate memory for mesh functions
    gn.resize(LAND_NUM_VERTS*3);

    //the 16*16 array used for holding the LTEX records (what texure is splatted where)
    std::vector<int>& gl = qd.getTextureIndexRef();
    gl.resize((LAND_LTEX_WIDTH+2)*(LAND_LTEX_WIDTH+2));

    const std::string stringLevel(Ogre::StringConverter::toString(level)); //cache this
    const std::string defaultTexture(stringLevel + "_default.png");
    bool hasUsedDefault = false;

    // loops over the start of each quad we want to get
    for(   int y = -(cellDist/2); y < (cellDist/2); y+=halfLevel )
      for( int x = -(cellDist/2); x < (cellDist/2); x+=halfLevel )
        {

          qd.setParentTexture("");
          bool usingDefaultTexture = false;

          if ( initialLevel == 1 )
            generateLTEXData(x, y, gl);
          else if ( createTexture )
            {
              //this is the name of the file that OGRE will
              //look for
              std::string name =	stringLevel + "_" +
                Ogre::StringConverter::toString(x)  + "_" +
                Ogre::StringConverter::toString(y) + ".png";

              //where as the arg1 here is the file name to save it.
              bool hasGen = generateTexture(std::string(TEXTURE_OUTPUT) + name, textureSize, x, y, halfLevel);

              if ( hasGen ) qd.setTexture(name);
              else
                {
                  qd.setTexture(defaultTexture);
                  hasUsedDefault = true;
                  usingDefaultTexture = true;
                }
            }

          //calculate parent texture
          if ( initialLevel != mIndex.getMaxDepth() )
            {
              //calcualte the level one higher
              int higherLevel = pow((float)2, (initialLevel+1));
              int highHalfLevel = higherLevel/2;

              int higherX = x;
              if ( (higherX-halfLevel) % highHalfLevel == 0 )
                higherX -= halfLevel;


              int higherY = y;
              if ( (higherY-halfLevel) % highHalfLevel  == 0 )
                higherY -= halfLevel;

              std::string higherName = Ogre::StringConverter::toString(higherLevel) + "_" +
                Ogre::StringConverter::toString(higherX)  + "_" +
                Ogre::StringConverter::toString(higherY) + ".png";

              //check file exists without needing boost filesystenm libs
              FILE* fp = fopen((std::string(TEXTURE_OUTPUT) + higherName).c_str(), "r");
              if ( fp )
                {
                  qd.setParentTexture(higherName);
                  fclose(fp);
                }
              else
                qd.setParentTexture("");
            }
          generateMesh(gh, gn, x, y, halfLevel );

          bool isEmptyQuad = true;
          if ( usingDefaultTexture )
            {
              for ( int i = 0; i < LAND_NUM_VERTS; i++ ){
                if ( gh.at(i) != LAND_DEFAULT_HEIGHT ){
                  isEmptyQuad = false;
                  break;
                }
              }
            }
          else isEmptyQuad = false;

          if ( isEmptyQuad )
            continue;

          //save data
          //the data is the position of the generated quad
          mIndex.setOffset(x*8192+halfLevel*8192/2,
                           y*8192+halfLevel*8192/2,
                           mDataO.tellp());
          boost::archive::binary_oarchive oa(mDataO); //using boost fs to write the quad
          oa << qd;
        }

    //check if we have used a default texture
    if ( hasUsedDefault )
      {
        std::vector<int> ltex;
        ltex.resize(halfLevel*LAND_LTEX_WIDTH*halfLevel*LAND_LTEX_WIDTH, mPalette.getOrAddIndex("_land_default.dds"));
        renderTexture(std::string(TEXTURE_OUTPUT) + defaultTexture, ltex, textureSize, halfLevel*LAND_LTEX_WIDTH);
      }
  }

  void endGeneration()
  {
    // FIXME: Just write one file?
    std::ofstream ofi(std::string(mBaseFileName + ".index").c_str(), std::ios::binary);
    std::ofstream ofp(std::string(mBaseFileName + ".palette").c_str(), std::ios::binary);
    boost::archive::binary_oarchive oai(ofi);
    boost::archive::binary_oarchive oap(ofp);
    oai << mIndex;
    oap << mPalette;

    mDataO.close();
  }

private:

  void generateLTEXData(int x, int y, std::vector<int>& index)
  {
    for ( int texY = 0; texY < LAND_LTEX_WIDTH+2; texY++ )
      for ( int texX = 0; texX < LAND_LTEX_WIDTH+2; texX++ )
        {
          int tempX = x;
          int tempY = y;

          int sourceX = texX - 1;
          int sourceY = texY - 1;

          if ( sourceX == -1 )
            {
              tempX--;
              sourceX = LAND_LTEX_WIDTH-1;
            }
          else if ( sourceX == LAND_LTEX_WIDTH)
            {
              tempX++;
              sourceX = 0;
            }

          if ( sourceY == -1 )
            {
              tempY--;
              sourceY = LAND_LTEX_WIDTH-1;
            }
          else if ( sourceY == LAND_LTEX_WIDTH )
            {
              tempY++;
              sourceY = 0;
            }

          std::string source;
          short texID = 0;

          if ( mMWLand.hasData(tempX, tempY) )
            {
              source = mMWLand.getSource(tempX, tempY);
              texID = mMWLand.getLTEXIndex(tempX,tempY, sourceX, sourceY);
            }

          std::string texturePath = "_land_default.dds";
          if ( texID != 0 && mMWLand.hasLTEXRecord(source,--texID) )
            texturePath = mMWLand.getLTEXRecord(source,texID);

          // textures given as tga, when they are a dds. I hate that "feature"
          // FIXME: do we handle this already?
          size_t d = texturePath.find_last_of(".") + 1;
          texturePath = texturePath.substr(0, d) + "dds";
          std::transform(texturePath.begin(), texturePath.end(), texturePath.begin(), tolower);

          index[texY*(LAND_LTEX_WIDTH+2)+texX] = mPalette.getOrAddIndex(texturePath);
        }
  }

  bool generateTexture(const std::string& name, int size,
                       int blockX, int blockY, int halfLevel)
  {
    int width = size/(halfLevel*LAND_LTEX_WIDTH);
    assert(width>=1);

    std::vector<int> ltex; //prealloc, as we know exactly what size it needs to be
    ltex.resize(halfLevel*LAND_LTEX_WIDTH*halfLevel*LAND_LTEX_WIDTH, 0);

    //for each cell
    for ( int y = 0; y < halfLevel; y++ )
      for ( int x = 0; x < halfLevel; x++ )
        //for each texture in the cell
        for ( int texY = 0; texY < LAND_LTEX_WIDTH; texY++ )
          for ( int texX = 0; texX < LAND_LTEX_WIDTH; texX++ )
            {
              std::string source;
              short texID = 0;

              if ( mMWLand.hasData(x + blockX, y + blockY) )
                {
                  source = mMWLand.getSource(x + blockX, y + blockY);
                  texID = mMWLand.getLTEXIndex(x + blockX, y + blockY, texX, texY);
                }

              std::string texturePath = "_land_default.dds";
              if ( texID != 0 && mMWLand.hasLTEXRecord(source,--texID) )
                texturePath = mMWLand.getLTEXRecord(source,texID);

              //textures given as tga, when they are a dds. I hate that "feature"
              //FIXME: ditto earlier comment
              size_t d = texturePath.find_last_of(".") + 1;
              texturePath = texturePath.substr(0, d) + "dds";
              //FIXME: BTW, didn't we make the BSA reader case insensitive?
              std::transform(texturePath.begin(), texturePath.end(), texturePath.begin(), tolower);
              const int index = (y*LAND_LTEX_WIDTH+texY)*halfLevel*LAND_LTEX_WIDTH + x*LAND_LTEX_WIDTH+texX;
              ltex[index] = mPalette.getOrAddIndex(texturePath);
            }

    //see if we have used anything at all
    // FIXME: Now, I KNOW this isn't needed :)
    int sum = 0;
    for ( std::vector<int>::iterator i = ltex.begin(); i != ltex.end(); ++i )
      sum += *i;

    if ( sum == 0 ) //not used any textures
      return false;

    renderTexture(name, ltex, size, halfLevel*LAND_LTEX_WIDTH);

    return true;
  }

  // FIXME: renderTexture and getRenderedTexture don't strike me as
  // the optimal ways of doing this. For one it's hardware/driver
  // dependent, when it should be a simple computational exercise. But
  // understand what it actually does, before you change anything.

  void renderTexture(const std::string& outputName, std::vector<int>& ltex,
                     int texSize, int alphaSize)
  {
    std::cout << "  Creating " << outputName << "\n";

    assert(Ogre::Math::Sqrt(ltex.size())==alphaSize);
    std::list<Ogre::ResourcePtr> createdResources;

    // FIXME: Move out of this function?
    MaterialGenerator mg;
    mg.setTexturePaths(mPalette.getPalette());

    const int scaleDiv = alphaSize/LAND_LTEX_WIDTH;

    //genetate material/aplahas
    Ogre::MaterialPtr mp = mg.getAlphaMat(ltex, alphaSize, 0, scaleDiv,createdResources);
    Ogre::TexturePtr tex1 = getRenderedTexture(mp, "RTT_TEX_1",texSize, Ogre::PF_R8G8B8);
    tex1->getBuffer()->getRenderTarget()->writeContentsToFile(outputName);
    Ogre::MaterialManager::getSingleton().remove(mp->getHandle());

    //remove the texture we have just written to the fs
    Ogre::TextureManager::getSingleton().remove(tex1->getHandle());

    //remove all the materials
    const std::list<Ogre::ResourcePtr>::const_iterator iend = createdResources.end();
    for ( std::list<Ogre::ResourcePtr>::const_iterator itr = createdResources.begin();
          itr != iend;
          ++itr) {
      (*itr)->getCreator()->remove((*itr)->getHandle());
    }
  }

  Ogre::TexturePtr getRenderedTexture(Ogre::MaterialPtr mp, const std::string& name,
                                      int texSize, Ogre::PixelFormat tt)
  {
    Ogre::CompositorPtr cp = Ogre::CompositorManager::getSingleton().
      create("Rtt_Comp",
             Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME);

    //output pass
    Ogre::CompositionTargetPass* ctp = cp->createTechnique()->getOutputTargetPass();
    Ogre::CompositionPass* cpass = ctp->createPass();
    cpass->setType(Ogre::CompositionPass::PT_RENDERQUAD);
    cpass->setMaterial(mp);

    //create a texture to write the texture to...
    Ogre::TexturePtr texture = Ogre::TextureManager::getSingleton().
      createManual(
                   name,
                   Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME,
                   Ogre::TEX_TYPE_2D,
                   texSize,
                   texSize,
                   0,
                   tt,
                   Ogre::TU_RENDERTARGET
                   );

    Ogre::RenderTexture* renderTexture = texture->getBuffer()->getRenderTarget();
    Ogre::Viewport* vp = renderTexture->addViewport(mCamera);

    Ogre::CompositorManager::getSingleton().addCompositor(vp, "Rtt_Comp");
    Ogre::CompositorManager::getSingleton().setCompositorEnabled(vp,"Rtt_Comp", true);

    renderTexture->update();

    //required for some reason?
    //Not implementing resulted in a black tex using openGL, Linux, and a nvidia 6150 in 1.4.?
    Ogre::Root::getSingleton().renderOneFrame();

    Ogre::CompositorManager::getSingleton().removeCompositor(vp, "Rtt_Comp");
    Ogre::CompositorManager::getSingleton().remove(cp->getHandle());

    renderTexture->removeAllViewports(); //needed?

    return texture;
  }

  void generateMesh(std::vector<float>& gh, std::vector<char>& gn, int blockX,
                    int blockY, int halfLevel)
  {
    int gnc = 0;
    int ghc = 0;
    for ( int y = 0; y < LAND_VERT_WIDTH; y++ )
      for ( int x = 0; x < LAND_VERT_WIDTH; x++ )
        {
          //FIXME: Eh, what?
          int cellY = floor((float)y/LAND_VERT_WIDTH*halfLevel) + blockY;
          int cellX = floor((float)x/LAND_VERT_WIDTH*halfLevel) + blockX;

          std::vector<float>& ch = mMWLand.getHeights(cellX,cellY);
          std::vector<char>& cn =  mMWLand.getNormals(cellX,cellY);

          int vertY = (((float)y/LAND_VERT_WIDTH*halfLevel) -
                       (float)floor((float)y/LAND_VERT_WIDTH*halfLevel)) * LAND_VERT_WIDTH;
          int vertX = (((float)x/LAND_VERT_WIDTH*halfLevel) -
                       (float)floor((float)x/LAND_VERT_WIDTH*halfLevel)) * LAND_VERT_WIDTH;

          assert(vertY < LAND_VERT_WIDTH && vertX < LAND_VERT_WIDTH);

          //store data
          gh[ghc++] = ch[vertY*LAND_VERT_WIDTH+vertX];

          for ( int z = 0; z < 3; z++ )
            gn[gnc++] = cn[(vertY*LAND_VERT_WIDTH+vertX)*3+z];
        }
  }

  std::string mBaseFileName; ///base file name so we gen mBaseFileName + ".index" etc
  std::ofstream mDataO;

  Index mIndex; ///the index of the data. holds offsets and max depth, rsl etc
  TexturePalette mPalette; ///all the textures from all mods are merge into a single palette
  MWLand mMWLand; ///deals with MW land stuff
};