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

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*/

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

#include "AssimpPCH.h"
#include "MDRLoader.h"

using namespace Assimp;
using namespace Assimp::MDR;


// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
MDRImporter::MDRImporter()
{
}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well 
MDRImporter::~MDRImporter()
{
}

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file. 
bool MDRImporter::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);

	return !(extension.length() != 4 || extension[0] != '.' ||
			 extension[1] != 'm' && extension[1] != 'M' ||
			 extension[2] != 'd' && extension[2] != 'D' ||
			 extension[3] != 'r' && extension[3] != 'R');
}

// ------------------------------------------------------------------------------------------------
// Uncompress a matrix
void MDRImporter::MatrixUncompress(aiMatrix4x4& mat,const uint8_t * compressed)
{
	int value;

	// First decompress the translation part
	for (unsigned int n = 0; n < 3;++n)
	{
		value     = (int)((uint16_t *)(compressed))[n];
		mat[0][n] = ((float)(value-(1<<15)))/64.f;
	}

	// Then decompress the rotation matrix
	for (unsigned int n = 0, p = 3; n < 3;++n)
	{
		for (unsigned int m = 0; m < 3;++m,++p)
		{
			value =  (int)((uint16_t *)(compressed))[p];
			mat[n][m]=((float)(value-(1<<15)))*(1.0f/(float)((1<<(15))-2));
		}
	}

	// now zero the final row of the matrix
	mat[3][0] = mat[3][1] = mat[3][2] = 0.f;
	mat[3][3] = 1.f;
}

// ------------------------------------------------------------------------------------------------
// Validate the header of the given MDR file
void MDRImporter::ValidateHeader()
{
	// Check the magic word - '5MDR'
	if (pcHeader->ident != AI_MDR_MAGIC_NUMBER_BE &&
		pcHeader->ident != AI_MDR_MAGIC_NUMBER_LE)
	{
		char szBuffer[5];
		szBuffer[0] = ((char*)&pcHeader->ident)[0];
		szBuffer[1] = ((char*)&pcHeader->ident)[1];
		szBuffer[2] = ((char*)&pcHeader->ident)[2];
		szBuffer[3] = ((char*)&pcHeader->ident)[3];
		szBuffer[4] = '\0';

		throw new ImportErrorException("Invalid MDR magic word: should be 5MDR, the "
			"magic word found is " + std::string( szBuffer ));
	}

	// Big endian - swap the fields in the header
	AI_SWAP4(pcHeader->numBones);
	AI_SWAP4(pcHeader->numFrames);
	AI_SWAP4(pcHeader->ofsFrames);
	AI_SWAP4(pcHeader->ofsLODs);
	AI_SWAP4(pcHeader->ofsTags);
	AI_SWAP4(pcHeader->version);
	AI_SWAP4(pcHeader->numTags);
	AI_SWAP4(pcHeader->numLODs);

	// MDR file version should always be 2
	if (pcHeader->version != AI_MDR_VERSION)
		DefaultLogger::get()->warn("Unsupported MDR file version (2 was expected)");

	// We compute the vertex positions from the bones,
	// so we need at least one bone.
	if (!pcHeader->numBones)
		DefaultLogger::get()->warn("MDR: At least one bone must be there");

	// We should have at least the first LOD in the valid range
	if (pcHeader->ofsLODs > (int)fileSize) 
		throw new ImportErrorException("MDR: header is invalid - LOD out of range");

	// header::ofsFrames is negative if the frames are compressed
	if (pcHeader->ofsFrames < 0)
	{
		// Ugly, but it will be our only change to make further
		// reading easier
		int32_t* p = const_cast<int32_t*>(&pcHeader->ofsFrames);
		*p = -pcHeader->ofsFrames;
		compressed = true;
		DefaultLogger::get()->info("MDR: Compressed frames");
	}
	else compressed = false;

	// validate all frames
	if ( pcHeader->ofsFrames +    sizeof(MDR::Frame) * 
		(pcHeader->numBones -1) * sizeof(MDR::Bone)  * 
		 pcHeader->numFrames > fileSize)
	{
		throw new ImportErrorException("MDR: header is invalid - frame out of range");
	}

	// Check whether the requested frame is existing
	if (configFrameID >= (unsigned int) pcHeader->numFrames)
		throw new ImportErrorException("The requested frame is not available");
}

// ------------------------------------------------------------------------------------------------
// Validate the surface header of a given MDR file LOD
void MDRImporter::ValidateLODHeader(BE_NCONST MDR::LOD* pcLOD)
{
	AI_SWAP4(pcLOD->ofsSurfaces);
	AI_SWAP4(pcLOD->numSurfaces);
	AI_SWAP4(pcLOD->ofsEnd);

    const unsigned int iMax = fileSize - (unsigned int)((int8_t*)pcLOD-(int8_t*)pcHeader);

	// We should have at least one surface here
	if (!pcLOD->numSurfaces)
		throw new ImportErrorException("MDR: LOD has zero surfaces assigned");

	if (pcLOD->ofsSurfaces > iMax)
		throw new ImportErrorException("MDR: LOD header is invalid - surface out of range");
}

// ------------------------------------------------------------------------------------------------
// Validate the header of a given MDR file surface
void MDRImporter::ValidateSurfaceHeader(BE_NCONST MDR::Surface* pcSurf)
{
	AI_SWAP4(pcSurf->ident);
	AI_SWAP4(pcSurf->numBoneReferences);
	AI_SWAP4(pcSurf->numTriangles);
	AI_SWAP4(pcSurf->numVerts);
	AI_SWAP4(pcSurf->ofsBoneReferences);
	AI_SWAP4(pcSurf->ofsEnd);
	AI_SWAP4(pcSurf->ofsTriangles);
	AI_SWAP4(pcSurf->ofsVerts);
	AI_SWAP4(pcSurf->shaderIndex);

	// Find out how many bytes
    const unsigned int iMax = fileSize - (unsigned int)((int8_t*)pcSurf-(int8_t*)pcHeader);

	// Not exact - there could be extra data in the vertices.
	if (pcSurf->ofsTriangles + pcSurf->numTriangles*sizeof(MDR::Triangle) > iMax ||
		pcSurf->ofsVerts + pcSurf->numVerts*sizeof(MDR::Vertex) > iMax)
    {
		throw new ImportErrorException("MDR: Surface header is invalid");
    }
}

// ------------------------------------------------------------------------------------------------
// Setup configuration properties
void MDRImporter::SetupProperties(const Importer* pImp)
{
	// **************************************************************
	// The AI_CONFIG_IMPORT_MDR_KEYFRAME    option overrides the
	//     AI_CONFIG_IMPORT_GLOBAL_KEYFRAME option.
	// **************************************************************
	configFrameID = pImp->GetPropertyInteger(AI_CONFIG_IMPORT_MDR_KEYFRAME,0xffffffff);

	if(0xffffffff == configFrameID)
		configFrameID = pImp->GetPropertyInteger(AI_CONFIG_IMPORT_GLOBAL_KEYFRAME,0);
}

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

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

	// Check whether the mdr file is large enough to contain the file header
	fileSize = (unsigned int)file->FileSize();
	if( fileSize < sizeof(MDR::Header))
		throw new ImportErrorException( "MDR File is too small.");

	// Copy the contents of the file to a buffer
	std::vector<unsigned char> mBuffer2(fileSize);
	file->Read( &mBuffer2[0], 1, fileSize);
	mBuffer = &mBuffer2[0];

	// Validate the file header and do BigEndian byte swapping for all sub headers
	pcHeader = (BE_NCONST MDR::Header*)mBuffer;
	ValidateHeader();

	// Go to the first LOD
	LE_NCONST MDR::LOD* lod = (LE_NCONST MDR::LOD*)((uint8_t*)pcHeader+pcHeader->ofsLODs);
	std::vector<aiMesh*> outMeshes;
	outMeshes.reserve(lod->numSurfaces);

	// Get a pointer to the first surface and continue processing them all
	LE_NCONST MDR::Surface* surf = (LE_NCONST MDR::Surface*)((uint8_t*)lod+lod->ofsSurfaces);
	for (uint32_t i = 0; i < lod->numSurfaces; ++i)
	{
		// The surface must have a) faces b) vertices and c) bone references
		if (surf->numTriangles && surf->numVerts && surf->numBoneReferences)
		{
			outMeshes.push_back(new aiMesh());
			aiMesh* mesh = outMeshes.back();

			mesh->mNumFaces = surf->numTriangles;
			mesh->mNumVertices = mesh->mNumFaces*3;
			mesh->mNumBones = surf->numBoneReferences;

			mesh->mFaces = new aiFace[mesh->mNumFaces];
			mesh->mVertices = new aiVector3D[mesh->mNumVertices];
			mesh->mTextureCoords[0] = new aiVector3D[mesh->mNumVertices];
			mesh->mBones = new aiBone*[mesh->mNumBones];

			// Allocate output bones and generate proper names for them
			for (unsigned int p = 0; p < mesh->mNumBones;++p)
			{
				aiBone* bone = mesh->mBones[p] = new aiBone();
				bone->mName.length = ::sprintf(  bone->mName.data, "B_%i",p);
			}

			std::vector<BoneWeightInfo> mWeights;
			mWeights.reserve(surf->numVerts << 1);

			std::vector<VertexInfo> mVertices(surf->numVerts);

			// get a pointer to the first vertex
			LE_NCONST MDR::Vertex* v = (LE_NCONST MDR::Vertex*)((uint8_t*)surf+surf->ofsVerts);
			for (unsigned int m = 0; m < surf->numVerts; ++m)
			{
				// get a pointer to the next vertex
				v = (LE_NCONST MDR::Vertex*)((uint8_t*)(v+1) + v->numWeights*sizeof(MDR::Weight));

				// Big Endian - swap the vertex data structure
#ifndef AI_BUILD_BIG_ENDIAN
				AI_SWAP4(v->numWeights);
				AI_SWAP4(v->normal.x);
				AI_SWAP4(v->normal.y);
				AI_SWAP4(v->normal.z);
				AI_SWAP4(v->texCoords.x);
				AI_SWAP4(v->texCoords.y);
#endif        

				// Fill out output structure
				VertexInfo& vert = mVertices[m];

				vert.uv.x = v->texCoords.x;  vert.uv.y = v->texCoords.y; 
				vert.normal = v->normal;
				vert.start  = (unsigned int)mWeights.size();
				vert.num    = v->numWeights;

				// Now compute the final vertex position by averaging
				// the positions affecting this vertex, weighting by
				// the given vertex weights.
				for (unsigned int l = 0; l < vert.num; ++l)
				{
				}
			}

			// Find out how large the output weight buffers must be
			LE_NCONST MDR::Triangle* tri = (LE_NCONST MDR::Triangle*)((uint8_t*)surf+surf->ofsTriangles);
			LE_NCONST MDR::Triangle* const triEnd = tri + surf->numTriangles;
			for (; tri != triEnd; ++tri)
			{
				for (unsigned int o = 0; o < 3;++o)
				{
					// Big endian: swap the 32 Bit index
#ifndef AI_BUILD_BIG_ENDIAN        
					AI_SWAP4(tri->indexes[o]);
#endif          
					register unsigned int temp = tri->indexes[o];
					if (temp >= surf->numVerts)
						throw new ImportErrorException("MDR: Vertex index is out of range");

					VertexInfo& vert = mVertices[temp];
					for (unsigned int l = vert.start; l < vert.start + vert.num; ++l)
					{
						if (mWeights[l].first >= surf->numBoneReferences)
							throw new ImportErrorException("MDR: Bone index is out of range");

						++mesh->mBones[mWeights[l].first]->mNumWeights;
					}
				}
			}

			// Allocate storage for output bone weights
			for (unsigned int p = 0; p < mesh->mNumBones;++p)
			{
				aiBone* bone = mesh->mBones[p];
				ai_assert(0 != bone->mNumWeights);
				bone->mWeights = new aiVertexWeight[bone->mNumWeights];
			}

			// and build the final output buffers
		}

		// Get a pointer to the next surface and continue
		surf = (LE_NCONST MDR::Surface*)((uint8_t*)surf + surf->ofsEnd);	
	}

	// Copy the vector to the C-style output array
	pScene->mNumMeshes = (unsigned int) outMeshes.size();
	pScene->mMeshes = new aiMesh*[pScene->mNumMeshes];
	::memcpy(pScene->mMeshes,&outMeshes[0],sizeof(void*)*pScene->mNumMeshes);
}