/*
---------------------------------------------------------------------------
Open Asset Import Library (ASSIMP)
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Copyright (c) 2006-2008, ASSIMP Development Team

All rights reserved.

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  following disclaimer.

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  derived from this software without specific prior
  written permission of the ASSIMP Development Team.

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*/

/** @file Implementation of the MDL importer class */

#include "AssimpPCH.h"

// internal headers
#include "MaterialSystem.h"
#include "HMPLoader.h"
#include "MD2FileData.h"

using namespace Assimp;

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
HMPImporter::HMPImporter()
{
	// nothing to do here
}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well 
HMPImporter::~HMPImporter()
{
	// nothing to do here
}

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file. 
bool HMPImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler) const
{
	// simple check of file extension is enough for the moment
	std::string::size_type pos = pFile.find_last_of('.');
	// no file extension - can't read
	if( pos == std::string::npos)return false;
	std::string extension = pFile.substr( pos);

	for( std::string::iterator it = extension.begin(); it != extension.end(); ++it)
		*it = tolower( *it);

	return extension == ".hmp";
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure. 
void HMPImporter::InternReadFile( const std::string& pFile, 
	aiScene* pScene, IOSystem* pIOHandler)
{
	boost::scoped_ptr<IOStream> file( pIOHandler->Open( pFile));

	// Check whether we can read from the file
	if( file.get() == NULL)
		throw new ImportErrorException( "Failed to open HMP file " + pFile + ".");

	// Check whether the HMP file is large enough to contain
	// at least the file header
	const size_t fileSize = file->FileSize();
	if( fileSize < 50)
		throw new ImportErrorException( "HMP File is too small.");

	// Allocate storage and copy the contents of the file to a memory buffer
	this->pScene = pScene;
	this->pIOHandler = pIOHandler;

	std::vector<uint8_t> buffer(fileSize+1);
	mBuffer = &buffer[0];
	file->Read( (void*)mBuffer, 1, fileSize);
	iFileSize = (unsigned int)fileSize;

	// Determine the file subtype and call the appropriate member function
	uint32_t iMagic = *((uint32_t*)this->mBuffer);


	// HMP4 format
	if (AI_HMP_MAGIC_NUMBER_LE_4 == iMagic ||
		AI_HMP_MAGIC_NUMBER_BE_4 == iMagic)
	{
		DefaultLogger::get()->debug("HMP subtype: 3D GameStudio A4, magic word is HMP4");
		InternReadFile_HMP4();
	}
	// HMP5 format
	else if (AI_HMP_MAGIC_NUMBER_LE_5 == iMagic ||
			 AI_HMP_MAGIC_NUMBER_BE_5 == iMagic)
	{
		DefaultLogger::get()->debug("HMP subtype: 3D GameStudio A5, magic word is HMP5");
		InternReadFile_HMP5();
	}
	// HMP7 format
	else if (AI_HMP_MAGIC_NUMBER_LE_7 == iMagic ||
			 AI_HMP_MAGIC_NUMBER_BE_7 == iMagic)
	{
		DefaultLogger::get()->debug("HMP subtype: 3D GameStudio A7, magic word is HMP7");
		InternReadFile_HMP7();
	}
	else
	{
		// Print the magic word to the logger
		char szBuffer[5];
		szBuffer[0] = ((char*)&iMagic)[0];
		szBuffer[1] = ((char*)&iMagic)[1];
		szBuffer[2] = ((char*)&iMagic)[2];
		szBuffer[3] = ((char*)&iMagic)[3];
		szBuffer[4] = '\0';

		// We're definitely unable to load this file
		throw new ImportErrorException( "Unknown HMP subformat " + pFile +
			". Magic word (" + szBuffer + ") is not known");
	}

	// Set the AI_SCENE_FLAGS_TERRAIN bit
	pScene->mFlags |= AI_SCENE_FLAGS_TERRAIN;

	// File buffer destructs automatically now
}

// ------------------------------------------------------------------------------------------------ 
void HMPImporter::ValidateHeader_HMP457( )
{
	const HMP::Header_HMP5* const pcHeader = (const HMP::Header_HMP5*)this->mBuffer;

	if (120 > this->iFileSize)
	{
		throw new ImportErrorException("HMP file is too small (header size is "
			"120 bytes, this file is smaller)");
	}

	if (!pcHeader->ftrisize_x || !pcHeader->ftrisize_y)
		throw new ImportErrorException("Size of triangles in either  x or y direction is zero");
	
	if(pcHeader->fnumverts_x < 1.0f || (pcHeader->numverts/pcHeader->fnumverts_x) < 1.0f)
		throw new ImportErrorException("Number of triangles in either x or y direction is zero");
	
	if(!pcHeader->numframes)
		throw new ImportErrorException("There are no frames. At least one should be there");

}

// ------------------------------------------------------------------------------------------------ 
void HMPImporter::InternReadFile_HMP4( )
{
	throw new ImportErrorException("HMP4 is currently not supported");
}

// ------------------------------------------------------------------------------------------------ 
void HMPImporter::InternReadFile_HMP5( )
{
	// read the file header and skip everything to byte 84
	const HMP::Header_HMP5* pcHeader = (const HMP::Header_HMP5*)mBuffer;
	const unsigned char* szCurrent = (const unsigned char*)(mBuffer+84);
	ValidateHeader_HMP457();

	// generate an output mesh
	pScene->mNumMeshes = 1;
	pScene->mMeshes = new aiMesh*[1];
	aiMesh* pcMesh = pScene->mMeshes[0] = new aiMesh();

	pcMesh->mMaterialIndex = 0;
	pcMesh->mVertices = new aiVector3D[pcHeader->numverts];
	pcMesh->mNormals = new aiVector3D[pcHeader->numverts];

	const unsigned int height = (unsigned int)(pcHeader->numverts / pcHeader->fnumverts_x);
	const unsigned int width =  (unsigned int)pcHeader->fnumverts_x;

	// generate/load a material for the terrain
	CreateMaterial(szCurrent,&szCurrent);

	// goto offset 120, I don't know why ...
	// (fixme) is this the frame header? I assume yes since it starts with 2. 
	szCurrent += 36;
	SizeCheck(szCurrent + sizeof(const HMP::Vertex_HMP7)*height*width);

	// now load all vertices from the file
	aiVector3D* pcVertOut = pcMesh->mVertices;
	aiVector3D* pcNorOut = pcMesh->mNormals;
	const HMP::Vertex_HMP5* src = (const HMP::Vertex_HMP5*) szCurrent;
	for (unsigned int y = 0; y < height;++y)
	{
		for (unsigned int x = 0; x < width;++x)
		{
			pcVertOut->x = x * pcHeader->ftrisize_x;
			pcVertOut->y = y * pcHeader->ftrisize_y;
			pcVertOut->z = (((float)src->z / 0xffff)-0.5f) * pcHeader->ftrisize_x * 8.0f; 
			MD2::LookupNormalIndex(src->normals162index, *pcNorOut );
			++pcVertOut;++pcNorOut;++src;
		}
	}

	// generate texture coordinates if necessary
	if (pcHeader->numskins)GenerateTextureCoords(width,height);

	// now build a list of faces
	CreateOutputFaceList(width,height);	

	// there is no nodegraph in HMP files. Simply assign the one mesh
	// (no, not the one ring) to the root node
	pScene->mRootNode = new aiNode();
	pScene->mRootNode->mName.Set("terrain_root");
	pScene->mRootNode->mNumMeshes = 1;
	pScene->mRootNode->mMeshes = new unsigned int[1];
	pScene->mRootNode->mMeshes[0] = 0;
}
// ------------------------------------------------------------------------------------------------ 
void HMPImporter::InternReadFile_HMP7( )
{
	// read the file header and skip everything to byte 84
	const HMP::Header_HMP5* const pcHeader = (const HMP::Header_HMP5*)mBuffer;
	const unsigned char* szCurrent = (const unsigned char*)(mBuffer+84);
	ValidateHeader_HMP457();

	// generate an output mesh
	pScene->mNumMeshes = 1;
	pScene->mMeshes = new aiMesh*[1];
	aiMesh* pcMesh = pScene->mMeshes[0] = new aiMesh();

	pcMesh->mMaterialIndex = 0;
	pcMesh->mVertices = new aiVector3D[pcHeader->numverts];
	pcMesh->mNormals = new aiVector3D[pcHeader->numverts];

	const unsigned int height = (unsigned int)(pcHeader->numverts / pcHeader->fnumverts_x);
	const unsigned int width = (unsigned int)pcHeader->fnumverts_x;

	// generate/load a material for the terrain
	CreateMaterial(szCurrent,&szCurrent);

	// goto offset 120, I don't know why ...
	// (fixme) is this the frame header? I assume yes since it starts with 2. 
	szCurrent += 36;

	SizeCheck(szCurrent + sizeof(const HMP::Vertex_HMP7)*height*width);

	// now load all vertices from the file
	aiVector3D* pcVertOut = pcMesh->mVertices;
	aiVector3D* pcNorOut = pcMesh->mNormals;
	const HMP::Vertex_HMP7* src = (const HMP::Vertex_HMP7*) szCurrent;
	for (unsigned int y = 0; y < height;++y)
	{
		for (unsigned int x = 0; x < width;++x)
		{
			pcVertOut->x = x * pcHeader->ftrisize_x;
			pcVertOut->y = y * pcHeader->ftrisize_y;

			// FIXME: What exctly is the correct scaling factor to use?
			// possibly pcHeader->scale_origin[2] in combination with a
			// signed interpretation of src->z?
			pcVertOut->z = (((float)src->z / 0xffff)-0.5f) * pcHeader->ftrisize_x * 8.0f; 

			pcNorOut->x = ((float)src->normal_x / 0x80 ); // * pcHeader->scale_origin[0];
			pcNorOut->y = ((float)src->normal_y / 0x80 ); // * pcHeader->scale_origin[1];
			pcNorOut->z = 1.0f;
			pcNorOut->Normalize();
			
			++pcVertOut;++pcNorOut;++src;
		}
	}

	// generate texture coordinates if necessary
	if (pcHeader->numskins)GenerateTextureCoords(width,height);

	// now build a list of faces
	CreateOutputFaceList(width,height);	

	// there is no nodegraph in HMP files. Simply assign the one mesh
	// (no, not the One Ring) to the root node
	pScene->mRootNode = new aiNode();
	pScene->mRootNode->mName.Set("terrain_root");
	pScene->mRootNode->mNumMeshes = 1;
	pScene->mRootNode->mMeshes = new unsigned int[1];
	pScene->mRootNode->mMeshes[0] = 0;
}

// ------------------------------------------------------------------------------------------------ 
void HMPImporter::CreateMaterial(const unsigned char* szCurrent,
	const unsigned char** szCurrentOut)
{
	aiMesh* const pcMesh = pScene->mMeshes[0];
	const HMP::Header_HMP5* const pcHeader = (const HMP::Header_HMP5*)mBuffer;

	// we don't need to generate texture coordinates if
	// we have no textures in the file ...
	if (pcHeader->numskins)
	{
		pcMesh->mTextureCoords[0] = new aiVector3D[pcHeader->numverts];
		pcMesh->mNumUVComponents[0] = 2;

		// now read the first skin and skip all others
		ReadFirstSkin(pcHeader->numskins,szCurrent,&szCurrent);
	}
	else
	{
		// generate a default material
		const int iMode = (int)aiShadingMode_Gouraud;
		MaterialHelper* pcHelper = new MaterialHelper();
		pcHelper->AddProperty<int>(&iMode, 1, AI_MATKEY_SHADING_MODEL);

		aiColor3D clr;
		clr.b = clr.g = clr.r = 0.6f;
		pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_DIFFUSE);
		pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_SPECULAR);

		clr.b = clr.g = clr.r = 0.05f;
		pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_AMBIENT);

		aiString szName;
		szName.Set(AI_DEFAULT_MATERIAL_NAME);
		pcHelper->AddProperty(&szName,AI_MATKEY_NAME);

		// add the material to the scene
		pScene->mNumMaterials = 1;
		pScene->mMaterials = new aiMaterial*[1];
		pScene->mMaterials[0] = pcHelper;
	}
	*szCurrentOut = szCurrent;
}

// ------------------------------------------------------------------------------------------------ 
void HMPImporter::CreateOutputFaceList(unsigned int width,unsigned int height)
{
	aiMesh* const pcMesh = this->pScene->mMeshes[0];

	// Allocate enough storage
	pcMesh->mNumFaces = (width-1) * (height-1);
	pcMesh->mFaces = new aiFace[pcMesh->mNumFaces];

	pcMesh->mNumVertices   = pcMesh->mNumFaces*4;
	aiVector3D* pcVertices = new aiVector3D[pcMesh->mNumVertices];
	aiVector3D* pcNormals  = new aiVector3D[pcMesh->mNumVertices];

	aiFace* pcFaceOut(pcMesh->mFaces);
	aiVector3D* pcVertOut = pcVertices;
	aiVector3D* pcNorOut = pcNormals;

	aiVector3D* pcUVs = pcMesh->mTextureCoords[0] ? new aiVector3D[pcMesh->mNumVertices] : NULL;
	aiVector3D* pcUVOut(pcUVs);

	// Build the terrain square
	unsigned int iCurrent = 0;
	for (unsigned int y = 0; y < height-1;++y)	{
		for (unsigned int x = 0; x < width-1;++x,++pcFaceOut)	{
			pcFaceOut->mNumIndices = 4;
			pcFaceOut->mIndices = new unsigned int[4];

			*pcVertOut++ = pcMesh->mVertices[y*width+x];
			*pcVertOut++ = pcMesh->mVertices[(y+1)*width+x];
			*pcVertOut++ = pcMesh->mVertices[(y+1)*width+x+1];
			*pcVertOut++ = pcMesh->mVertices[y*width+x+1];
			

			*pcNorOut++ = pcMesh->mNormals[y*width+x];
			*pcNorOut++ = pcMesh->mNormals[(y+1)*width+x];
			*pcNorOut++ = pcMesh->mNormals[(y+1)*width+x+1];
			*pcNorOut++ = pcMesh->mNormals[y*width+x+1];

			if (pcMesh->mTextureCoords[0])
			{
				*pcUVOut++ = pcMesh->mTextureCoords[0][y*width+x];
				*pcUVOut++ = pcMesh->mTextureCoords[0][(y+1)*width+x];
				*pcUVOut++ = pcMesh->mTextureCoords[0][(y+1)*width+x+1];
				*pcUVOut++ = pcMesh->mTextureCoords[0][y*width+x+1];
			}
			
			for (unsigned int i = 0; i < 4;++i)
				pcFaceOut->mIndices[i] = iCurrent++;
		}
	}
	delete[] pcMesh->mVertices;
	pcMesh->mVertices = pcVertices;

	delete[] pcMesh->mNormals;
	pcMesh->mNormals = pcNormals;

	if (pcMesh->mTextureCoords[0])
	{
		delete[] pcMesh->mTextureCoords[0];
		pcMesh->mTextureCoords[0] = pcUVs;
	}
}

// ------------------------------------------------------------------------------------------------ 
void HMPImporter::ReadFirstSkin(unsigned int iNumSkins, const unsigned char* szCursor,
	const unsigned char** szCursorOut)
{
	ai_assert(0 != iNumSkins && NULL != szCursor);

	// read the type of the skin ...
	// sometimes we need to skip 12 bytes here, I don't know why ...
	uint32_t iType = *((uint32_t*)szCursor);szCursor += sizeof(uint32_t);
	if (0 == iType)
	{
		szCursor += sizeof(uint32_t) * 2;
		iType = *((uint32_t*)szCursor);szCursor += sizeof(uint32_t);
		if (!iType)
			throw new ImportErrorException("Unable to read HMP7 skin chunk");
		
	}
	// read width and height
	uint32_t iWidth  = *((uint32_t*)szCursor); szCursor += sizeof(uint32_t);
	uint32_t iHeight = *((uint32_t*)szCursor); szCursor += sizeof(uint32_t);

	// allocate an output material
	MaterialHelper* pcMat = new MaterialHelper();

	// read the skin, this works exactly as for MDL7
	ParseSkinLump_3DGS_MDL7(szCursor,&szCursor,
		pcMat,iType,iWidth,iHeight);

	// now we need to skip any other skins ... 
	for (unsigned int i = 1; i< iNumSkins;++i)
	{
		iType   = *((uint32_t*)szCursor);   szCursor += sizeof(uint32_t);
		iWidth  = *((uint32_t*)szCursor);   szCursor += sizeof(uint32_t);
		iHeight = *((uint32_t*)szCursor);   szCursor += sizeof(uint32_t);

		SkipSkinLump_3DGS_MDL7(szCursor,&szCursor,iType,iWidth,iHeight);
		SizeCheck(szCursor);
	}

	// setup the material ...
	pScene->mNumMaterials = 1;
	pScene->mMaterials = new aiMaterial*[1];
	pScene->mMaterials[0] = pcMat;

	*szCursorOut = szCursor;
}
// ------------------------------------------------------------------------------------------------ 
void HMPImporter::GenerateTextureCoords(
	const unsigned int width, const unsigned int height)
{
	ai_assert(NULL != pScene->mMeshes && NULL != pScene->mMeshes[0] &&
		      NULL != pScene->mMeshes[0]->mTextureCoords[0]);

	aiVector3D* uv = pScene->mMeshes[0]->mTextureCoords[0];

	const float fY = (1.0f / height) + (1.0f / height) / (height-1);
	const float fX = (1.0f / width) + (1.0f / width) / (width-1);

	for (unsigned int y = 0; y < height;++y)	{
		for (unsigned int x = 0; x < width;++x,++uv)	{
			uv->y = 1.0f-fY*y;
			uv->x = fX*x;
			uv->z = 0.0f;
		}
	}
}