/*
---------------------------------------------------------------------------
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,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
---------------------------------------------------------------------------
*/

#include "AssimpPCH.h"

/** @file Implementation of the MD2 importer class */
#include "MD2Loader.h"
#include "MaterialSystem.h"
#include "ByteSwap.h"
#include "MD2NormalTable.h" // shouldn't be included by other units


using namespace Assimp;
using namespace Assimp::MD2;


// helper macro to determine the size of an array
#if (!defined ARRAYSIZE)
#	define ARRAYSIZE(_array) (int(sizeof(_array) / sizeof(_array[0])))
#endif 

// ------------------------------------------------------------------------------------------------
// Helper function to lookup a normal in Quake 2's precalculated table
void MD2::LookupNormalIndex(uint8_t iNormalIndex,aiVector3D& vOut)
{
	// make sure the normal index has a valid value
	if (iNormalIndex >= ARRAYSIZE(g_avNormals))
	{
		DefaultLogger::get()->warn("Index overflow in Quake II normal vector list (the "
			" LUT has only 162 entries). ");

		iNormalIndex = ARRAYSIZE(g_avNormals) - 1;
	}
	vOut = *((const aiVector3D*)(&g_avNormals[iNormalIndex]));
}


// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
MD2Importer::MD2Importer()
{
}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well 
MD2Importer::~MD2Importer()
{
}

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file. 
bool MD2Importer::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] != '2')return false;

	return true;
}
// ------------------------------------------------------------------------------------------------
// Setup configuration properties
void MD2Importer::SetupProperties(const Importer* pImp)
{
	// The AI_CONFIG_IMPORT_MD2_KEYFRAME option overrides the
	// AI_CONFIG_IMPORT_GLOBAL_KEYFRAME option.
	if(0xffffffff == (configFrameID = pImp->GetPropertyInteger(
		AI_CONFIG_IMPORT_MD2_KEYFRAME,0xffffffff)))
	{
		configFrameID = pImp->GetPropertyInteger(AI_CONFIG_IMPORT_GLOBAL_KEYFRAME,0);
	}
}
// ------------------------------------------------------------------------------------------------
// Validate the file header
void MD2Importer::ValidateHeader( )
{
	// check magic number
	if (m_pcHeader->magic != AI_MD2_MAGIC_NUMBER_BE &&
		m_pcHeader->magic != AI_MD2_MAGIC_NUMBER_LE)
	{
		char szBuffer[5];
		szBuffer[0] = ((char*)&m_pcHeader->magic)[0];
		szBuffer[1] = ((char*)&m_pcHeader->magic)[1];
		szBuffer[2] = ((char*)&m_pcHeader->magic)[2];
		szBuffer[3] = ((char*)&m_pcHeader->magic)[3];
		szBuffer[4] = '\0';

		throw new ImportErrorException("Invalid MD2 magic word: should be IDP2, the "
			"magic word found is " + std::string(szBuffer));
	}

	// check file format version
	if (m_pcHeader->version != 8)
		DefaultLogger::get()->warn( "Unsupported md2 file version. Continuing happily ...");

	// check some values whether they are valid
	if (0 == m_pcHeader->numFrames)
		throw new ImportErrorException( "Invalid md2 file: NUM_FRAMES is 0");

	if (m_pcHeader->offsetEnd > (uint32_t)fileSize)
		throw new ImportErrorException( "Invalid md2 file: File is too small");

	if (m_pcHeader->offsetSkins		+ m_pcHeader->numSkins * sizeof (MD2::Skin)			>= fileSize ||
		m_pcHeader->offsetTexCoords	+ m_pcHeader->numTexCoords * sizeof (MD2::TexCoord)	>= fileSize ||
		m_pcHeader->offsetTriangles	+ m_pcHeader->numTriangles * sizeof (MD2::Triangle)	>= fileSize ||
		m_pcHeader->offsetFrames		+ m_pcHeader->numFrames * sizeof (MD2::Frame)			>= fileSize ||
		m_pcHeader->offsetEnd			> fileSize)
	{
		throw new ImportErrorException("Invalid MD2 header: some offsets are outside the file");
	}

	if (m_pcHeader->numSkins > AI_MD2_MAX_SKINS)
		DefaultLogger::get()->warn("The model contains more skins than Quake 2 supports");
	if ( m_pcHeader->numFrames > AI_MD2_MAX_FRAMES)
		DefaultLogger::get()->warn("The model contains more frames than Quake 2 supports");
	if (m_pcHeader->numVertices > AI_MD2_MAX_VERTS)
		DefaultLogger::get()->warn("The model contains more vertices than Quake 2 supports");

	if (m_pcHeader->numFrames <= configFrameID )
		throw new ImportErrorException("The requested frame is not existing the file");

}
// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure. 
void MD2Importer::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 MD2 file " + pFile + "");

	// check whether the md3 file is large enough to contain
	// at least the file header
	fileSize = (unsigned int)file->FileSize();
	if( fileSize < sizeof(MD2::Header))
		throw new ImportErrorException( "MD2 File is too small");

	std::vector<uint8_t> mBuffer2(fileSize);
	file->Read(&mBuffer2[0], 1, fileSize);
	mBuffer = &mBuffer2[0];


	m_pcHeader = (BE_NCONST MD2::Header*)mBuffer;

#ifdef AI_BUILD_BIG_ENDIAN

	ByteSwap::Swap4(&m_pcHeader->frameSize);
	ByteSwap::Swap4(&m_pcHeader->magic);
	ByteSwap::Swap4(&m_pcHeader->numFrames);
	ByteSwap::Swap4(&m_pcHeader->numGlCommands);
	ByteSwap::Swap4(&m_pcHeader->numSkins);
	ByteSwap::Swap4(&m_pcHeader->numTexCoords);
	ByteSwap::Swap4(&m_pcHeader->numTriangles);
	ByteSwap::Swap4(&m_pcHeader->numVertices);
	ByteSwap::Swap4(&m_pcHeader->offsetEnd);
	ByteSwap::Swap4(&m_pcHeader->offsetFrames);
	ByteSwap::Swap4(&m_pcHeader->offsetGlCommands);
	ByteSwap::Swap4(&m_pcHeader->offsetSkins);
	ByteSwap::Swap4(&m_pcHeader->offsetTexCoords);
	ByteSwap::Swap4(&m_pcHeader->offsetTriangles);
	ByteSwap::Swap4(&m_pcHeader->skinHeight);
	ByteSwap::Swap4(&m_pcHeader->skinWidth);
	ByteSwap::Swap4(&m_pcHeader->version);

#endif

	ValidateHeader();

	// there won't be more than one mesh inside the file
	pScene->mNumMaterials = 1;
	pScene->mRootNode = new aiNode();
	pScene->mRootNode->mNumMeshes = 1;
	pScene->mRootNode->mMeshes = new unsigned int[1];
	pScene->mRootNode->mMeshes[0] = 0;
	pScene->mMaterials = new aiMaterial*[1];
	pScene->mMaterials[0] = new MaterialHelper();
	pScene->mNumMeshes = 1;
	pScene->mMeshes = new aiMesh*[1];

	aiMesh* pcMesh = pScene->mMeshes[0] = new aiMesh();
	pcMesh->mPrimitiveTypes = aiPrimitiveType_TRIANGLE;

	// navigate to the begin of the frame data
	BE_NCONST MD2::Frame* pcFrame = (BE_NCONST MD2::Frame*) ((uint8_t*)
		m_pcHeader + m_pcHeader->offsetFrames);

	pcFrame += configFrameID;

	// navigate to the begin of the triangle data
	MD2::Triangle* pcTriangles = (MD2::Triangle*) ((uint8_t*)
		m_pcHeader + m_pcHeader->offsetTriangles);

	// navigate to the begin of the tex coords data
	BE_NCONST MD2::TexCoord* pcTexCoords = (BE_NCONST MD2::TexCoord*) ((uint8_t*)
		m_pcHeader + m_pcHeader->offsetTexCoords);

	// navigate to the begin of the vertex data
	BE_NCONST MD2::Vertex* pcVerts = (BE_NCONST MD2::Vertex*) (pcFrame->vertices);

#ifdef AI_BUILD_BIG_ENDIAN
	for (uint32_t i = 0; i< m_pcHeader->numTriangles; ++i)
	{
		for (unsigned int p = 0; p < 3;++p)
		{
			ByteSwap::Swap2(& pcTriangles[i].textureIndices[p]);
			ByteSwap::Swap2(& pcTriangles[i].vertexIndices[p]);
		}
	}
	for (uint32_t i = 0; i < m_pcHeader->offsetTexCoords;++i)
	{
		ByteSwap::Swap2(& pcTexCoords[i].s);
		ByteSwap::Swap2(& pcTexCoords[i].t);
	}
	ByteSwap::Swap4( & pcFrame->scale[0] );
	ByteSwap::Swap4( & pcFrame->scale[1] );
	ByteSwap::Swap4( & pcFrame->scale[2] );
	ByteSwap::Swap4( & pcFrame->translate[0] );
	ByteSwap::Swap4( & pcFrame->translate[1] );
	ByteSwap::Swap4( & pcFrame->translate[2] );
#endif

	pcMesh->mNumFaces = m_pcHeader->numTriangles;
	pcMesh->mFaces = new aiFace[m_pcHeader->numTriangles];

	// allocate output storage
	pcMesh->mNumVertices = (unsigned int)pcMesh->mNumFaces*3;
	pcMesh->mVertices = new aiVector3D[pcMesh->mNumVertices];
	pcMesh->mNormals = new aiVector3D[pcMesh->mNumVertices];

	// not sure whether there are MD2 files without texture coordinates
	// NOTE: texture coordinates can be there without a texture,
	// but a texture can't be there without a valid UV channel
	if (m_pcHeader->numTexCoords && m_pcHeader->numSkins)
	{
		// navigate to the first texture associated with the mesh
		const MD2::Skin* pcSkins = (const MD2::Skin*) ((unsigned char*)m_pcHeader + 
			m_pcHeader->offsetSkins);

		const int iMode = (int)aiShadingMode_Gouraud;
		MaterialHelper* pcHelper = (MaterialHelper*)pScene->mMaterials[0];
		pcHelper->AddProperty<int>(&iMode, 1, AI_MATKEY_SHADING_MODEL);

		aiColor3D clr;
		clr.b = clr.g = clr.r = 1.0f;
		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);

		if (pcSkins->name[0])
		{
			aiString szString;
			const size_t iLen = ::strlen(pcSkins->name);
			::memcpy(szString.data,pcSkins->name,iLen);
			szString.data[iLen] = '\0';
			szString.length = iLen;

			pcHelper->AddProperty(&szString,AI_MATKEY_TEXTURE_DIFFUSE(0));
		}
		else
		{
			DefaultLogger::get()->warn("Texture file name has zero length. It will be skipped.");
		}
	}
	else
	{
		// apply a default material
		const int iMode = (int)aiShadingMode_Gouraud;
		MaterialHelper* pcHelper = (MaterialHelper*)pScene->mMaterials[0];
		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);
	}


	// now read all triangles of the first frame, apply scaling and translation
	unsigned int iCurrent = 0;

	float fDivisorU,fDivisorV;
	if (m_pcHeader->numTexCoords)
	{
		// allocate storage for texture coordinates, too
		pcMesh->mTextureCoords[0] = new aiVector3D[pcMesh->mNumVertices];
		pcMesh->mNumUVComponents[0] = 2;

		// check whether the skin width or height are zero (this would
		// cause a division through zero)
		if (!m_pcHeader->skinWidth)
		{
			DefaultLogger::get()->error("Skin width is zero but there are "
				"valid absolute texture coordinates");
			fDivisorU = 1.0f;
		}
		else fDivisorU = (float)m_pcHeader->skinWidth;
		if (!m_pcHeader->skinHeight)
		{
			DefaultLogger::get()->error("Skin height is zero but there are "
				"valid absolute texture coordinates ");
			fDivisorV = 1.0f;
		}
		else fDivisorV = (float)m_pcHeader->skinHeight;
	}

	for (unsigned int i = 0; i < (unsigned int)m_pcHeader->numTriangles;++i)
	{
		// allocate the face
		pScene->mMeshes[0]->mFaces[i].mIndices = new unsigned int[3];
		pScene->mMeshes[0]->mFaces[i].mNumIndices = 3;

		// copy texture coordinates
		// check whether they are different from the previous value at this index.
		// In this case, create a full separate set of vertices/normals/texcoords
		unsigned int iTemp = iCurrent;
		for (unsigned int c = 0; c < 3;++c,++iCurrent)
		{
			// validate vertex indices
			register unsigned int iIndex = (unsigned int)pcTriangles[i].vertexIndices[c];
			if (iIndex >= m_pcHeader->numVertices)
			{
				DefaultLogger::get()->error("MD2: Vertex index is outside the allowed range");
				iIndex = m_pcHeader->numVertices-1;
			}

			// read x,y, and z component of the vertex
			aiVector3D& vec = pcMesh->mVertices[iCurrent];

			vec.x = (float)pcVerts[iIndex].vertex[0] * pcFrame->scale[0];
			vec.x += pcFrame->translate[0];

			//  invert y 
			vec.y = (float)pcVerts[iIndex].vertex[1] * pcFrame->scale[1];
			vec.y += pcFrame->translate[1];
			vec.y *= -1.0f;

			vec.z = (float)pcVerts[iIndex].vertex[2] * pcFrame->scale[2];
			vec.z += pcFrame->translate[2];

			// read the normal vector from the precalculated normal table
			aiVector3D& vNormal = pcMesh->mNormals[iCurrent];
			LookupNormalIndex(pcVerts[iIndex].lightNormalIndex,vNormal);
			vNormal.y *= -1.0f;

			if (m_pcHeader->numTexCoords)
			{
				// validate texture coordinates
				iIndex = pcTriangles[iIndex].textureIndices[c];
				if (iIndex >= m_pcHeader->numTexCoords)
				{
					DefaultLogger::get()->error("MD2: UV index is outside the allowed range");
					iIndex = m_pcHeader->numTexCoords-1;
				}

				aiVector3D& pcOut = pcMesh->mTextureCoords[0][iCurrent];

				// the texture coordinates are absolute values but we
				// need relative values between 0 and 1
				pcOut.y = pcTexCoords[iIndex].s / fDivisorU;
				pcOut.x = pcTexCoords[iIndex].t / fDivisorV;
			}
		}
		// FIX: flip the face order for use with OpenGL
		pScene->mMeshes[0]->mFaces[i].mIndices[0] = iTemp+2;
		pScene->mMeshes[0]->mFaces[i].mIndices[1] = iTemp+1;
		pScene->mMeshes[0]->mFaces[i].mIndices[2] = iTemp+0;
	}
}
