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

Copyright (c) 2006-2008, ASSIMP Development Team

All rights reserved.

Redistribution and use of this software in source and binary forms, 
with or without modification, are permitted provided that the following 
conditions are met:

* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the
  following disclaimer in the documentation and/or other
  materials provided with the distribution.

* Neither the name of the ASSIMP team, nor the names of its
  contributors may be used to endorse or promote products
  derived from this software without specific prior
  written permission of the ASSIMP Development Team.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/

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

#include "AssimpPCH.h"

// 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) 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);

	if (extension.length() < 4)return false;
	if (extension[0] != '.')return false;
	
	if( extension[1] != 'M' && extension[1] != 'm')return false; 
	if( extension[2] != 'D' && extension[2] != 'd')return false; 
	if( extension[3] != 'C' && extension[3] != 'c')return false; 

	return true;
}
// ------------------------------------------------------------------------------------------------
// 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 new ImportErrorException("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 new ImportErrorException("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 new ImportErrorException("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 new ImportErrorException("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(0xffffffff == (this->configFrameID = pImp->GetPropertyInteger(
		AI_CONFIG_IMPORT_MDC_KEYFRAME,0xffffffff)))
	{
		this->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 new ImportErrorException( "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 new ImportErrorException( "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 = (BE_NCONST MDC::Surface*)(mBuffer + pcHeader->ulOffsetSurfaces);
	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 = (const MDC::Surface*)((int8_t*)pcSurface2 + pcSurface2->ulOffsetEnd);
	}
	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 = 0xffffffff;
	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 (0xffffffff == 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;
		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 = (BE_NCONST MDC::Surface*)((int8_t*)pcSurface + pcSurface->ulOffsetEnd);
	}

	// create a flat node graph with a root node and one child for each surface
	if (!pScene->mNumMeshes)
		throw new ImportErrorException( "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)
	{
		MaterialHelper* pcMat = new MaterialHelper();
		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));
		}
	}
}