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

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*/

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

// internal headers
#include "LWOLoader.h"
#include "MaterialSystem.h"
#include "ByteSwap.h"

// public assimp headers
#include "../include/IOStream.h"
#include "../include/IOSystem.h"
#include "../include/aiMesh.h"
#include "../include/aiScene.h"
#include "../include/aiAssert.h"
#include "../include/DefaultLogger.h"

// boost headers
#include <boost/scoped_ptr.hpp>

using namespace Assimp;


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

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

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file. 
bool LWOImporter::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] != 'l' && extension[1] != 'L')return false;
	if (extension[2] != 'w' && extension[2] != 'W')return false;
	if (extension[3] != 'o' && extension[3] != 'O')return false;

	return true;
}
// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure. 
void LWOImporter::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 LWO file " + pFile + ".");

	if((this->fileSize = (unsigned int)file->FileSize()) < 12)
		throw new ImportErrorException("LWO: The file is too small to contain the IFF header");

	// allocate storage and copy the contents of the file to a memory buffer
	std::vector< uint8_t > mBuffer(fileSize);
	file->Read( &mBuffer[0], 1, fileSize);
	this->pScene = pScene;

	// determine the type of the file
	uint32_t fileType;
	const char* sz = IFF::ReadHeader(&mBuffer[0],fileType);
	if (sz)throw new ImportErrorException(sz);

	mFileBuffer = &mBuffer[0] + 12;
	fileSize -= 12;

	// create temporary storage on the stack but store points to
	// it in the class instance. Therefoe everything will be destructed
	// properly if an exception is thrown.
	PointList _mTempPoints;		
	mTempPoints = &_mTempPoints;
	FaceList _mFaces;			
	mFaces = &_mFaces;
	TagList _mTags;				
	mTags = &_mTags;
	TagMappingTable _mMapping;	
	mMapping = &_mMapping;
	SurfaceList _mSurfaces;		
	mSurfaces = &_mSurfaces;

	// old lightwave file format (prior to v6)
	if (AI_LWO_FOURCC_LWOB == fileType)this->LoadLWOBFile();

	// new lightwave format
	else if (AI_LWO_FOURCC_LWO2 == fileType)this->LoadLWO2File();

	// we don't know this format
	else 
	{
		char szBuff[5];
		szBuff[0] = (char)(fileType >> 24u);
		szBuff[1] = (char)(fileType >> 16u);
		szBuff[2] = (char)(fileType >> 8u);
		szBuff[3] = (char)(fileType);
		throw new ImportErrorException(std::string("Unknown LWO sub format: ") + szBuff);
	}
	ResolveTags();

	// now sort all faces by the surfaces assigned to them
	typedef std::vector<unsigned int> SortedRep;
	std::vector<SortedRep> pSorted(mSurfaces->size()+1);

	unsigned int i = 0;
	unsigned int iDefaultSurface = 0xffffffff;
	for (FaceList::iterator it = mFaces->begin(), end = mFaces->end();
		it != end;++it,++i)
	{
		unsigned int idx = (*it).surfaceIndex;
		if (idx >= mTags->size())
		{
			DefaultLogger::get()->warn("LWO: Invalid face surface index");
			idx = mTags->size()-1;
		}
		if(0xffffffff == (idx = _mMapping[idx]))
		{
			if (0xffffffff == iDefaultSurface)
			{
				iDefaultSurface = mSurfaces->size();
				mSurfaces->push_back(LWO::Surface());
				LWO::Surface& surf = mSurfaces->back();
				surf.mColor.r = surf.mColor.g = surf.mColor.b = 0.6f; 
			}
			idx = iDefaultSurface;
		}
		pSorted[idx].push_back(i);
	}
	if (0xffffffff == iDefaultSurface)pSorted.erase(pSorted.end()-1);

	// now generate output meshes
	for (unsigned int p = 0; p < mSurfaces->size();++p)
		if (!pSorted[p].empty())pScene->mNumMeshes++;

	if (!(pScene->mNumMaterials = pScene->mNumMeshes))
		throw new ImportErrorException("LWO: There are no meshes");

	pScene->mMeshes = new aiMesh*[pScene->mNumMeshes];
	pScene->mMaterials = new aiMaterial*[pScene->mNumMaterials];
	for (unsigned int p = 0,i = 0;i < mSurfaces->size();++i)
	{
		SortedRep& sorted = pSorted[i];
		if (sorted.empty())continue;

		// generate the mesh 
		aiMesh* mesh = pScene->mMeshes[p] = new aiMesh();
		mesh->mNumFaces = sorted.size();

		for (SortedRep::const_iterator it = sorted.begin(), end = sorted.end();
			it != end;++it)
		{
			mesh->mNumVertices += _mFaces[*it].mNumIndices;
		}

		aiVector3D* pv = mesh->mVertices = new aiVector3D[mesh->mNumVertices];
		aiFace* pf = mesh->mFaces = new aiFace[mesh->mNumFaces];
		mesh->mMaterialIndex = p;

		// now convert all faces
		unsigned int vert = 0;
		for (SortedRep::const_iterator it = sorted.begin(), end = sorted.end();
			it != end;++it)
		{
			LWO::Face& face = _mFaces[*it];

			// copy all vertices
			for (unsigned int q = 0; q  < face.mNumIndices;++q)
			{
				*pv++ = _mTempPoints[face.mIndices[q]];
				face.mIndices[q] = vert++;
			}

			pf->mIndices = face.mIndices;
			pf->mNumIndices = face.mNumIndices;
			face.mIndices = NULL; // make sure it won't be deleted
			pf++;
		}

		// generate the corresponding material
		MaterialHelper* pcMat = new MaterialHelper();
		pScene->mMaterials[p] = pcMat;
		ConvertMaterial((*mSurfaces)[i],pcMat);
		++p;
	}

	// create a dummy nodegraph - the root node renders everything
	aiNode* p = pScene->mRootNode = new aiNode();
	p->mNumMeshes = pScene->mNumMeshes;
	p->mMeshes = new unsigned int[pScene->mNumMeshes];
	p->mName.Set("<LWORoot>");
	for (unsigned int i = 0; i < pScene->mNumMeshes;++i)
		p->mMeshes[i] = i;
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::ConvertMaterial(const LWO::Surface& surf,MaterialHelper* pcMat)
{
	// copy the name of the surface
	aiString st;
	st.Set(surf.mName);
	pcMat->AddProperty(&st,AI_MATKEY_NAME);

	int i = surf.bDoubleSided ? 1 : 0;
	pcMat->AddProperty<int>(&i,1,AI_MATKEY_TWOSIDED);
	
	if (surf.mSpecularValue && surf.mGlossiness)
	{
		// this is only an assumption, needs to be confirmed.
		/*if (16.0f >= surf.mGlossiness)surf.mGlossiness = 10.0f;
		else if (64.0f >= surf.mGlossiness)surf.mGlossiness = 14.0f;
		else if (256.0f >= surf.mGlossiness)surf.mGlossiness = 20.0f;
		else surf.mGlossiness = 24.0f;*/

		pcMat->AddProperty<float>(&surf.mSpecularValue,1,AI_MATKEY_SHININESS_STRENGTH);
		pcMat->AddProperty<float>(&surf.mGlossiness,1,AI_MATKEY_SHININESS);
	}

}

// ------------------------------------------------------------------------------------------------
void LWOImporter::CountVertsAndFaces(unsigned int& verts, unsigned int& faces,
	LE_NCONST uint16_t*& cursor, const uint16_t* const end, unsigned int max)
{
	while (cursor < end && max--)
	{
		uint16_t numIndices = *cursor++;
		verts += numIndices;faces++;
		cursor += numIndices;
		int16_t surface = *cursor++;
		if (surface < 0)
		{
			// there are detail polygons
			numIndices = *cursor++;
			CountVertsAndFaces(verts,faces,cursor,end,numIndices);
		}
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::CopyFaceIndices(LWOImporter::FaceList::iterator& it,
	LE_NCONST uint16_t*& cursor, 
	const uint16_t* const end,
	unsigned int max)
{
	while (cursor < end && max--)
	{
		LWO::Face& face = *it;++it;
		if(face.mNumIndices = *cursor++)
		{
			if (cursor + face.mNumIndices >= end)break;
			face.mIndices = new unsigned int[face.mNumIndices];
			for (unsigned int i = 0; i < face.mNumIndices;++i)
			{
				face.mIndices[i] = *cursor++;
				if (face.mIndices[i] >= mTempPoints->size())
				{
					face.mIndices[i] = mTempPoints->size()-1;
					DefaultLogger::get()->warn("LWO: Face index is out of range");
				}
			}
		}
		else DefaultLogger::get()->warn("LWO: Face has 0 indices");
		int16_t surface = *cursor++;
		if (surface < 0)
		{
			surface = -surface;

			// there are detail polygons
			uint16_t numPolygons = *cursor++;
			if (cursor < end)CopyFaceIndices(it,cursor,end,numPolygons);
		}
		face.surfaceIndex = surface-1;
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::ResolveTags()
{
	mMapping->resize(mTags->size(),0xffffffff);
	for (unsigned int a = 0; a  < mTags->size();++a)
	{
		for (unsigned int i = 0; i < mSurfaces->size();++i)
		{
			if ((*mTags)[a] == (*mSurfaces)[i].mName)
			{
				(*mMapping)[a] = i;
				break;
			}
		}
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::ParseString(std::string& out,unsigned int max)
{
	unsigned int iCursor = 0;
	const char* in = (const char*)mFileBuffer,*sz = in;
	while (*in)
	{
		if (++iCursor > max)
		{
			DefaultLogger::get()->warn("LWOB: Invalid file, texture name (TIMG) is too long");
			break;
		}
		++in;
	}
	unsigned int len = unsigned int (in-sz);
	out = std::string(sz,len);
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::AdjustTexturePath(std::string& out)
{
	if (::strstr(out.c_str(), "(sequence)"))
	{
		// remove the (sequence) and append 000
		DefaultLogger::get()->info("LWO: Sequence of animated texture found. It will be ignored");
		out = out.substr(0,out.length()-10) + "000";
	}
}

// ------------------------------------------------------------------------------------------------
#define AI_LWO_VALIDATE_CHUNK_LENGTH(length,name,size) \
	if (length < size) \
	{ \
		DefaultLogger::get()->warn("LWO: "#name" chunk is too small"); \
		break; \
	} \

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWOTags(unsigned int size)
{
	const char* szCur = (const char*)mFileBuffer, *szLast = szCur;
	const char* const szEnd = szLast+size;
	while (szCur < szEnd)
	{
		if (!(*szCur++))
		{
			const unsigned int len = unsigned int(szCur-szLast);
			mTags->push_back(std::string(szLast,len));
			szCur += len & 1;
			szLast = szCur;
		}
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWOBSurface(unsigned int size)
{
	LE_NCONST uint8_t* const end = mFileBuffer + size;

	uint32_t iCursor = 0;
	mSurfaces->push_back( LWO::Surface () );
	LWO::Surface& surf = mSurfaces->back();
	LWO::Texture* pTex = NULL;

	// at first we'll need to read the name of the surface
	LE_NCONST uint8_t* sz = mFileBuffer;
	while (*mFileBuffer)
	{
		if (++mFileBuffer > end)throw new ImportErrorException("LWOB: Invalid file, surface name is too long");
	}
	unsigned int len = unsigned int (mFileBuffer-sz);
	surf.mName = std::string((const char*)sz,len);
	mFileBuffer++;
	if (!(len & 1))++mFileBuffer; // skip one byte if the length of the surface name is odd
	while (true)
	{
		if (mFileBuffer + 6 > end)
			break;

		// no proper IFF header here - the chunk length is specified as int16
		uint32_t head_type		= *((LE_NCONST uint32_t*)mFileBuffer);mFileBuffer+=4;
		uint16_t head_length	= *((LE_NCONST uint16_t*)mFileBuffer);mFileBuffer+=2;
		AI_LSWAP4(head_type);
		AI_LSWAP2(head_length);
		if (mFileBuffer + head_length > end)
		{
			throw new ImportErrorException("LWOB: Invalid file, the size attribute of "
				"a surface sub chunk points behind the end of the file");
		}
		LE_NCONST uint8_t* const next = mFileBuffer+head_length;
		switch (head_type)
		{
			// diffuse color
		case AI_LWO_COLR:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head_length,COLR,3);
				surf.mColor.r = *mFileBuffer++ / 255.0f;
				surf.mColor.g = *mFileBuffer++ / 255.0f;
				surf.mColor.b = *mFileBuffer   / 255.0f;
				break;
			}
			// diffuse strength ... hopefully
		case AI_LWO_DIFF:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head_length,DIFF,2);
				AI_LSWAP2(mFileBuffer);
				surf.mDiffuseValue = *((int16_t*)mFileBuffer) / 255.0f;
				break;
			}
			// specular strength ... hopefully
		case AI_LWO_SPEC:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head_length,SPEC,2);
				AI_LSWAP2(mFileBuffer);
				surf.mSpecularValue = *((int16_t*)mFileBuffer) / 255.0f;
				break;
			}
		// transparency
		case AI_LWO_TRAN:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head_length,TRAN,2);
				AI_LSWAP2(mFileBuffer);
				surf.mTransparency = *((int16_t*)mFileBuffer) / 255.0f;
				break;
			}
		// glossiness
		case AI_LWO_GLOS:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head_length,GLOS,2);
				AI_LSWAP2(mFileBuffer);
				surf.mGlossiness = float(*((int16_t*)mFileBuffer));
				break;
			}
		// color texture
		case AI_LWO_CTEX:
			{
				pTex = &surf.mColorTexture;
				break;
			}
		// diffuse texture
		case AI_LWO_DTEX:
			{
				pTex = &surf.mDiffuseTexture;
				break;
			}
		// specular texture
		case AI_LWO_STEX:
			{
				pTex = &surf.mSpecularTexture;
				break;
			}
		// bump texture
		case AI_LWO_BTEX:
			{
				pTex = &surf.mBumpTexture;
				break;
			}
		// transparency texture
		case AI_LWO_TTEX:
			{
				pTex = &surf.mTransparencyTexture;
				break;
			}
			// texture path
		case AI_LWO_TIMG:
			{
				if (pTex)
				{
					ParseString(pTex->mFileName,head_length);	
					AdjustTexturePath(pTex->mFileName);
					mFileBuffer += pTex->mFileName.length();
				}
				else DefaultLogger::get()->warn("LWOB: TIMG tag was encuntered although "
					"there was no xTEX tag before");
				break;
			}
		// texture strength
		case AI_LWO_TVAL:
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head_length,TVAL,1);
				if (pTex)pTex->mStrength = *mFileBuffer / 255.0f;
				else DefaultLogger::get()->warn("LWOB: TVAL tag was encuntered "
					"although there was no xTEX tag before");
				break;
			}
		}
		mFileBuffer = next;
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWOBFile()
{
	LE_NCONST uint8_t* const end = mFileBuffer + fileSize;
	while (true)
	{
		if (mFileBuffer + sizeof(IFF::ChunkHeader) > end)
			break;
		LE_NCONST IFF::ChunkHeader* const head = (LE_NCONST IFF::ChunkHeader*)mFileBuffer;
		AI_LSWAP4(head->length);
		AI_LSWAP4(head->type);
		mFileBuffer += sizeof(IFF::ChunkHeader);
		if (mFileBuffer + head->length > end)
		{
			throw new ImportErrorException("LWOB: Invalid file, the size attribute of "
				"a chunk points behind the end of the file");
			break;
		}
		LE_NCONST uint8_t* const next = mFileBuffer+head->length;
		switch (head->type)
		{
			// vertex list
		case AI_LWO_PNTS:
			{
				mTempPoints->resize( head->length / 12 );
#ifndef AI_BUILD_BIG_ENDIAN
				for (unsigned int i = 0; i < head->length>>2;++i)
					ByteSwap::Swap4( mFileBuffer + (i << 2));
#endif
				::memcpy(&(*mTempPoints)[0],mFileBuffer,head->length);
				break;
			}
			// face list
		case AI_LWO_POLS:
			{
				// first find out how many faces and vertices we'll finally need
				LE_NCONST uint16_t* const end	= (LE_NCONST uint16_t*)next;
				LE_NCONST uint16_t* cursor		= (LE_NCONST uint16_t*)mFileBuffer;

#ifndef AI_BUILD_BIG_ENDIAN
				while (cursor < end)ByteSwap::Swap2(cursor++);
				cursor = (LE_NCONST uint16_t*)mFileBuffer;
#endif

				unsigned int iNumFaces = 0,iNumVertices = 0;
				CountVertsAndFaces(iNumVertices,iNumFaces,cursor,end);

				// allocate the output array and copy face indices
				if (iNumFaces)
				{
					cursor = (LE_NCONST uint16_t*)mFileBuffer;
					this->mTempPoints->resize(iNumVertices);
					this->mFaces->resize(iNumFaces);
					FaceList::iterator it = this->mFaces->begin();
					CopyFaceIndices(it,cursor,end);
				}
				break;
			}
			// list of tags
		case AI_LWO_SRFS:
			{
				LoadLWOTags(head->length);
				break;
			}

			// surface chunk
		case AI_LWO_SURF:
			{
				LoadLWOBSurface(head->length);
				break;
			}
		}
		mFileBuffer = next;
	}
}
// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWO2File()
{
}