/*
---------------------------------------------------------------------------
Open Asset Import Library (assimp)
---------------------------------------------------------------------------

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All rights reserved.

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  following disclaimer.

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*/

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

#include "AssimpPCH.h"
#ifndef ASSIMP_BUILD_NO_MDC_IMPORTER

// internal headers
#include "MDCLoader.h"
#include "MD3FileData.h"
#include "MDCNormalTable.h" // shouldn't be included by other units

using namespace Assimp;
using namespace Assimp::MDC;


// ------------------------------------------------------------------------------------------------
void MDC::BuildVertex(const Frame& frame,
	const BaseVertex& bvert,
	const CompressedVertex& cvert,
	aiVector3D& vXYZOut, 
	aiVector3D& vNorOut)
{
	// compute the position
	const float xd = (cvert.xd - AI_MDC_CVERT_BIAS) * AI_MDC_DELTA_SCALING;
	const float yd = (cvert.yd - AI_MDC_CVERT_BIAS) * AI_MDC_DELTA_SCALING;
	const float zd = (cvert.zd - AI_MDC_CVERT_BIAS) * AI_MDC_DELTA_SCALING;
	vXYZOut.x = frame.localOrigin.x + AI_MDC_BASE_SCALING * (bvert.x + xd);
	vXYZOut.y = frame.localOrigin.y + AI_MDC_BASE_SCALING * (bvert.y + yd);
	vXYZOut.z = frame.localOrigin.z + AI_MDC_BASE_SCALING * (bvert.z + zd);

	// compute the normal vector .. ehm ... lookup it in the table :-)
	vNorOut.x = mdcNormals[cvert.nd][0];
	vNorOut.y = mdcNormals[cvert.nd][1];
	vNorOut.z = mdcNormals[cvert.nd][2];
}

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

// ------------------------------------------------------------------------------------------------
// Destructor, private as well 
MDCImporter::~MDCImporter()
{
}
// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file. 
bool MDCImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool checkSig) const
{
	const std::string extension = GetExtension(pFile);
	if (extension == "mdc")
		return true;

	// if check for extension is not enough, check for the magic tokens 
	if (!extension.length() || checkSig) {
		uint32_t tokens[1]; 
		tokens[0] = AI_MDC_MAGIC_NUMBER_LE;
		return CheckMagicToken(pIOHandler,pFile,tokens,1);
	}
	return false;
}

// ------------------------------------------------------------------------------------------------
void MDCImporter::GetExtensionList(std::set<std::string>& extensions)
{
	extensions.insert("mdc");
}

// ------------------------------------------------------------------------------------------------
// Validate the header of the given MDC file
void MDCImporter::ValidateHeader()
{
	AI_SWAP4( this->pcHeader->ulVersion );
	AI_SWAP4( this->pcHeader->ulFlags );
	AI_SWAP4( this->pcHeader->ulNumFrames );
	AI_SWAP4( this->pcHeader->ulNumTags );
	AI_SWAP4( this->pcHeader->ulNumSurfaces );
	AI_SWAP4( this->pcHeader->ulNumSkins );
	AI_SWAP4( this->pcHeader->ulOffsetBorderFrames );

	if (pcHeader->ulIdent != AI_MDC_MAGIC_NUMBER_BE &&
		pcHeader->ulIdent != AI_MDC_MAGIC_NUMBER_LE)
	{
		char szBuffer[5];
		szBuffer[0] = ((char*)&pcHeader->ulIdent)[0];
		szBuffer[1] = ((char*)&pcHeader->ulIdent)[1];
		szBuffer[2] = ((char*)&pcHeader->ulIdent)[2];
		szBuffer[3] = ((char*)&pcHeader->ulIdent)[3];
		szBuffer[4] = '\0';

		throw DeadlyImportError("Invalid MDC magic word: should be IDPC, the "
			"magic word found is " + std::string( szBuffer ));
	}

	if (pcHeader->ulVersion != AI_MDC_VERSION)
		DefaultLogger::get()->warn("Unsupported MDC file version (2 (AI_MDC_VERSION) was expected)");

	if (pcHeader->ulOffsetBorderFrames + pcHeader->ulNumFrames * sizeof(MDC::Frame) > this->fileSize ||
		pcHeader->ulOffsetSurfaces + pcHeader->ulNumSurfaces * sizeof(MDC::Surface) > this->fileSize)
	{
		throw DeadlyImportError("Some of the offset values in the MDC header are invalid "
			"and point to something behind the file.");
	}

	if (this->configFrameID >= this->pcHeader->ulNumFrames)
		throw DeadlyImportError("The requested frame is not available");
}

// ------------------------------------------------------------------------------------------------
// Validate the header of a given MDC file surface
void MDCImporter::ValidateSurfaceHeader(BE_NCONST MDC::Surface* pcSurf)
{
	AI_SWAP4(pcSurf->ulFlags);
	AI_SWAP4(pcSurf->ulNumCompFrames);
	AI_SWAP4(pcSurf->ulNumBaseFrames);
	AI_SWAP4(pcSurf->ulNumShaders);
	AI_SWAP4(pcSurf->ulNumVertices);
	AI_SWAP4(pcSurf->ulNumTriangles);
	AI_SWAP4(pcSurf->ulOffsetTriangles);
	AI_SWAP4(pcSurf->ulOffsetTexCoords);
	AI_SWAP4(pcSurf->ulOffsetBaseVerts);
	AI_SWAP4(pcSurf->ulOffsetCompVerts);
	AI_SWAP4(pcSurf->ulOffsetFrameBaseFrames);
	AI_SWAP4(pcSurf->ulOffsetFrameCompFrames);
	AI_SWAP4(pcSurf->ulOffsetEnd);

    const unsigned int iMax = this->fileSize - (unsigned int)((int8_t*)pcSurf-(int8_t*)pcHeader);

    if (pcSurf->ulOffsetBaseVerts + pcSurf->ulNumVertices * sizeof(MDC::BaseVertex)			> iMax ||
        (pcSurf->ulNumCompFrames && pcSurf->ulOffsetCompVerts + pcSurf->ulNumVertices * sizeof(MDC::CompressedVertex)	> iMax) ||
        pcSurf->ulOffsetTriangles + pcSurf->ulNumTriangles * sizeof(MDC::Triangle)			> iMax ||
        pcSurf->ulOffsetTexCoords + pcSurf->ulNumVertices * sizeof(MDC::TexturCoord)		> iMax ||
        pcSurf->ulOffsetShaders + pcSurf->ulNumShaders * sizeof(MDC::Shader)				> iMax ||
        pcSurf->ulOffsetFrameBaseFrames + pcSurf->ulNumBaseFrames * 2						> iMax ||
        (pcSurf->ulNumCompFrames && pcSurf->ulOffsetFrameCompFrames + pcSurf->ulNumCompFrames * 2	> iMax))
    {
        throw DeadlyImportError("Some of the offset values in the MDC surface header "
            "are invalid and point somewhere behind the file.");
    }
}

// ------------------------------------------------------------------------------------------------
// Setup configuration properties
void MDCImporter::SetupProperties(const Importer* pImp)
{
	// The AI_CONFIG_IMPORT_MDC_KEYFRAME option overrides the
	// AI_CONFIG_IMPORT_GLOBAL_KEYFRAME option.
	if(static_cast<unsigned int>(-1) == (configFrameID = pImp->GetPropertyInteger(AI_CONFIG_IMPORT_MDC_KEYFRAME,-1))){
		configFrameID = pImp->GetPropertyInteger(AI_CONFIG_IMPORT_GLOBAL_KEYFRAME,0);
	}
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure. 
void MDCImporter::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 DeadlyImportError( "Failed to open MDC file " + pFile + ".");

	// check whether the mdc file is large enough to contain the file header
	fileSize = (unsigned int)file->FileSize();
	if( fileSize < sizeof(MDC::Header))
		throw DeadlyImportError( "MDC File is too small.");

	std::vector<unsigned char> mBuffer2(fileSize);
	file->Read( &mBuffer2[0], 1, fileSize);
	mBuffer = &mBuffer2[0];

	// validate the file header
	this->pcHeader = (BE_NCONST MDC::Header*)this->mBuffer;
	this->ValidateHeader();

	std::vector<std::string> aszShaders;

	// get a pointer to the frame we want to read
	BE_NCONST MDC::Frame* pcFrame = (BE_NCONST MDC::Frame*)(this->mBuffer+
		this->pcHeader->ulOffsetBorderFrames);

	// no need to swap the other members, we won't need them
	pcFrame += configFrameID;
	AI_SWAP4( pcFrame->localOrigin[0] );
	AI_SWAP4( pcFrame->localOrigin[1] );
	AI_SWAP4( pcFrame->localOrigin[2] );

	// get the number of valid surfaces
	BE_NCONST MDC::Surface* pcSurface, *pcSurface2;
	pcSurface = pcSurface2 = new (mBuffer + pcHeader->ulOffsetSurfaces) MDC::Surface;
	unsigned int iNumShaders = 0;
	for (unsigned int i = 0; i < pcHeader->ulNumSurfaces;++i)
	{
		// validate the surface header
		this->ValidateSurfaceHeader(pcSurface2);

		if (pcSurface2->ulNumVertices && pcSurface2->ulNumTriangles)++pScene->mNumMeshes;
		iNumShaders += pcSurface2->ulNumShaders;
		pcSurface2 = new ((int8_t*)pcSurface2 + pcSurface2->ulOffsetEnd) MDC::Surface;
	}
	aszShaders.reserve(iNumShaders);
	pScene->mMeshes = new aiMesh*[pScene->mNumMeshes];

	// necessary that we don't crash if an exception occurs
	for (unsigned int i = 0; i < pScene->mNumMeshes;++i)
		pScene->mMeshes[i] = NULL;

	// now read all surfaces
	unsigned int iDefaultMatIndex = UINT_MAX;
	for (unsigned int i = 0, iNum = 0; i < pcHeader->ulNumSurfaces;++i)
	{
		if (!pcSurface->ulNumVertices || !pcSurface->ulNumTriangles)continue;
		aiMesh* pcMesh = pScene->mMeshes[iNum++] = new aiMesh();

		pcMesh->mNumFaces = pcSurface->ulNumTriangles;
		pcMesh->mNumVertices = pcMesh->mNumFaces * 3;

		// store the name of the surface for use as node name.
		// FIX: make sure there is a 0 termination
		const_cast<char&>(pcSurface->ucName[AI_MDC_MAXQPATH-1]) = '\0';
		pcMesh->mTextureCoords[3] = (aiVector3D*)pcSurface->ucName;

		// go to the first shader in the file. ignore the others.
		if (pcSurface->ulNumShaders)
		{
			const MDC::Shader* pcShader = (const MDC::Shader*)((int8_t*)pcSurface + pcSurface->ulOffsetShaders);
			pcMesh->mMaterialIndex = (unsigned int)aszShaders.size();
			
			// create a new shader
			aszShaders.push_back(std::string( pcShader->ucName, std::min(
				::strlen(pcShader->ucName),sizeof(pcShader->ucName)) ));
		}
		// need to create a default material
		else if (UINT_MAX == iDefaultMatIndex)
		{
			pcMesh->mMaterialIndex = iDefaultMatIndex = (unsigned int)aszShaders.size();
			aszShaders.push_back(std::string());
		}
		// otherwise assign a reference to the default material
		else pcMesh->mMaterialIndex = iDefaultMatIndex;

		// allocate output storage for the mesh
		aiVector3D* pcVertCur	= pcMesh->mVertices			= new aiVector3D[pcMesh->mNumVertices];
		aiVector3D* pcNorCur	= pcMesh->mNormals			= new aiVector3D[pcMesh->mNumVertices];
		aiVector3D* pcUVCur		= pcMesh->mTextureCoords[0] = new aiVector3D[pcMesh->mNumVertices];
		aiFace* pcFaceCur		= pcMesh->mFaces			= new aiFace[pcMesh->mNumFaces];

		// create all vertices/faces
		BE_NCONST MDC::Triangle* pcTriangle = (BE_NCONST MDC::Triangle*)
			((int8_t*)pcSurface+pcSurface->ulOffsetTriangles);

		BE_NCONST MDC::TexturCoord* const pcUVs = (BE_NCONST MDC::TexturCoord*)
			((int8_t*)pcSurface+pcSurface->ulOffsetTexCoords);

		// get a pointer to the uncompressed vertices
		int16_t iOfs = *((int16_t*) ((int8_t*) pcSurface +
			pcSurface->ulOffsetFrameBaseFrames) +  this->configFrameID);

		AI_SWAP2(iOfs);

		BE_NCONST MDC::BaseVertex* const pcVerts = (BE_NCONST MDC::BaseVertex*)
			((int8_t*)pcSurface+pcSurface->ulOffsetBaseVerts) +
			((int)iOfs * pcSurface->ulNumVertices * 4);

		// do the main swapping stuff ...
#if (defined AI_BUILD_BIG_ENDIAN)

		// swap all triangles
		for (unsigned int i = 0; i < pcSurface->ulNumTriangles;++i)
		{
			AI_SWAP4( pcTriangle[i].aiIndices[0] );
			AI_SWAP4( pcTriangle[i].aiIndices[1] );
			AI_SWAP4( pcTriangle[i].aiIndices[2] );
		}

		// swap all vertices
		for (unsigned int i = 0; i < pcSurface->ulNumVertices*pcSurface->ulNumBaseFrames;++i)
		{
			AI_SWAP2( pcVerts->normal );
			AI_SWAP2( pcVerts->x );
			AI_SWAP2( pcVerts->y );
			AI_SWAP2( pcVerts->z );
		}

		// swap all texture coordinates
		for (unsigned int i = 0; i < pcSurface->ulNumVertices;++i)
		{
			AI_SWAP4( pcUVs->v );
			AI_SWAP4( pcUVs->v );
		}

#endif

		const MDC::CompressedVertex* pcCVerts = NULL;
		int16_t* mdcCompVert = NULL;

		// access compressed frames for large frame numbers, but never for the first
		if( this->configFrameID && pcSurface->ulNumCompFrames > 0 )
		{
			mdcCompVert = (int16_t*) ((int8_t*)pcSurface+pcSurface->ulOffsetFrameCompFrames) + this->configFrameID;
			AI_SWAP2P(mdcCompVert);
			if( *mdcCompVert >= 0 )
			{
				pcCVerts = (const MDC::CompressedVertex*)((int8_t*)pcSurface +
					pcSurface->ulOffsetCompVerts) + *mdcCompVert * pcSurface->ulNumVertices;
			}
			else mdcCompVert = NULL;
		}

		// copy all faces
		for (unsigned int iFace = 0; iFace < pcSurface->ulNumTriangles;++iFace,
			++pcTriangle,++pcFaceCur)
		{
			const unsigned int iOutIndex = iFace*3;
			pcFaceCur->mNumIndices = 3;
			pcFaceCur->mIndices = new unsigned int[3];

			for (unsigned int iIndex = 0; iIndex < 3;++iIndex,
				++pcVertCur,++pcUVCur,++pcNorCur)
			{
				uint32_t quak = pcTriangle->aiIndices[iIndex];
				if (quak >= pcSurface->ulNumVertices)
				{
					DefaultLogger::get()->error("MDC vertex index is out of range");
					quak = pcSurface->ulNumVertices-1;
				}

				// compressed vertices?
				if (mdcCompVert)
				{
					MDC::BuildVertex(*pcFrame,pcVerts[quak],pcCVerts[quak],
						*pcVertCur,*pcNorCur);
				}
				else
				{
					// copy position
					pcVertCur->x = pcVerts[quak].x * AI_MDC_BASE_SCALING;
					pcVertCur->y = pcVerts[quak].y * AI_MDC_BASE_SCALING;
					pcVertCur->z = pcVerts[quak].z * AI_MDC_BASE_SCALING;

					// copy normals
					MD3::LatLngNormalToVec3( pcVerts[quak].normal, &pcNorCur->x );

					// copy texture coordinates
					pcUVCur->x = pcUVs[quak].u;
					pcUVCur->y = 1.0f-pcUVs[quak].v; // DX to OGL
				}
				pcVertCur->x += pcFrame->localOrigin[0] ;
				pcVertCur->y += pcFrame->localOrigin[1] ;
				pcVertCur->z += pcFrame->localOrigin[2] ;
			}

			// swap the face order - DX to OGL
			pcFaceCur->mIndices[0] = iOutIndex + 2;
			pcFaceCur->mIndices[1] = iOutIndex + 1;
			pcFaceCur->mIndices[2] = iOutIndex + 0;
		}

		pcSurface =  new ((int8_t*)pcSurface + pcSurface->ulOffsetEnd) MDC::Surface;
	}

	// create a flat node graph with a root node and one child for each surface
	if (!pScene->mNumMeshes)
		throw DeadlyImportError( "Invalid MDC file: File contains no valid mesh");
	else if (1 == pScene->mNumMeshes)
	{
		pScene->mRootNode = new aiNode();
		pScene->mRootNode->mName.Set(std::string((const char*)pScene->mMeshes[0]->mTextureCoords[3]));
		pScene->mRootNode->mNumMeshes = 1;
		pScene->mRootNode->mMeshes = new unsigned int[1];
		pScene->mRootNode->mMeshes[0] = 0;
	}
	else
	{
		pScene->mRootNode = new aiNode();
		pScene->mRootNode->mNumChildren = pScene->mNumMeshes;
		pScene->mRootNode->mChildren = new aiNode*[pScene->mNumMeshes];
		pScene->mRootNode->mName.Set("<root>");
		for (unsigned int i = 0; i < pScene->mNumMeshes;++i)
		{
			aiNode* pcNode = pScene->mRootNode->mChildren[i] = new aiNode();
			pcNode->mParent = pScene->mRootNode;
			pcNode->mName.Set(std::string((const char*)pScene->mMeshes[i]->mTextureCoords[3]));
			pcNode->mNumMeshes = 1;
			pcNode->mMeshes = new unsigned int[1];
			pcNode->mMeshes[0] = i;
		}
	}

	// make sure we invalidate the pointer to the mesh name
	for (unsigned int i = 0; i < pScene->mNumMeshes;++i)
		pScene->mMeshes[i]->mTextureCoords[3] = NULL;

	// create materials
	pScene->mNumMaterials = (unsigned int)aszShaders.size();
	pScene->mMaterials = new aiMaterial*[pScene->mNumMaterials];
	for (unsigned int i = 0; i < pScene->mNumMaterials;++i)
	{
		aiMaterial* pcMat = new aiMaterial();
		pScene->mMaterials[i] = pcMat;

		const std::string& name = aszShaders[i];

		int iMode = (int)aiShadingMode_Gouraud;
		pcMat->AddProperty<int>(&iMode, 1, AI_MATKEY_SHADING_MODEL);

		// add a small ambient color value - RtCW seems to have one
		aiColor3D clr;
		clr.b = clr.g = clr.r = 0.05f;
		pcMat->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_AMBIENT);

		if (name.length())clr.b = clr.g = clr.r = 1.0f;
		else clr.b = clr.g = clr.r = 0.6f;

		pcMat->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_DIFFUSE);
		pcMat->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_SPECULAR);

		if (name.length())
		{
			aiString path;
			path.Set(name);
			pcMat->AddProperty(&path,AI_MATKEY_TEXTURE_DIFFUSE(0));
		}
	}
}

#endif // !! ASSIMP_BUILD_NO_MDC_IMPORTER