/*
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Open Asset Import Library (ASSIMP)
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*/

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

#include "AssimpPCH.h"


#include "DXFLoader.h"
#include "ParsingUtils.h"
#include "fast_atof.h"
#include "MaterialSystem.h"


using namespace Assimp;

// AutoCAD Binary DXF<CR><LF><SUB><NULL> 
#define AI_DXF_BINARY_IDENT ("AutoCAD Binary DXF\r\n\x1a\0")
#define AI_DXF_BINARY_IDENT_LEN (24)


// color indices for DXF - 16 are supported
static aiColor4D g_aclrDxfIndexColors[] =
{
	aiColor4D (0.6f, 0.6f, 0.6f, 1.0f),
	aiColor4D (1.0f, 0.0f, 0.0f, 1.0f), // red
	aiColor4D (0.0f, 1.0f, 0.0f, 1.0f), // green
	aiColor4D (0.0f, 0.0f, 1.0f, 1.0f), // blue
	aiColor4D (0.3f, 1.0f, 0.3f, 1.0f), // light green
	aiColor4D (0.3f, 0.3f, 1.0f, 1.0f), // light blue
	aiColor4D (1.0f, 0.3f, 0.3f, 1.0f), // light red
	aiColor4D (1.0f, 0.0f, 1.0f, 1.0f), // pink
	aiColor4D (1.0f, 0.6f, 0.0f, 1.0f), // orange
	aiColor4D (0.6f, 0.3f, 0.0f, 1.0f), // dark orange
	aiColor4D (1.0f, 1.0f, 0.0f, 1.0f), // yellow
	aiColor4D (0.3f, 0.3f, 0.3f, 1.0f), // dark gray
	aiColor4D (0.8f, 0.8f, 0.8f, 1.0f), // light gray
	aiColor4D (0.0f, 00.f, 0.0f, 1.0f), // black
	aiColor4D (1.0f, 1.0f, 1.0f, 1.0f), // white
	aiColor4D (0.6f, 0.0f, 1.0f, 1.0f)  // violet
};
#define AI_DXF_NUM_INDEX_COLORS (sizeof(g_aclrDxfIndexColors)/sizeof(g_aclrDxfIndexColors[0]))

// invalid/unassigned color value
aiColor4D g_clrInvalid = aiColor4D(std::numeric_limits<float>::quiet_NaN(),0.f,0.f,1.f);

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
DXFImporter::DXFImporter()
{
	// nothing to do here
}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well 
DXFImporter::~DXFImporter()
{
	// nothing to do here
}

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file. 
bool DXFImporter::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] != 'd' && extension[1] != 'D' ||
			 extension[2] != 'x' && extension[2] != 'X' ||
			 extension[3] != 'f' && extension[3] != 'F');
}

// ------------------------------------------------------------------------------------------------
bool DXFImporter::GetNextLine()
{
	if(!SkipLine(&buffer))
		return false;
	if(!SkipSpaces(&buffer))return GetNextLine();
	return true;
}

// ------------------------------------------------------------------------------------------------
bool DXFImporter::GetNextToken()
{
	if (bRepeat)
	{
		bRepeat = false;
		return true;
	}

	SkipSpaces(&buffer);
	groupCode = strtol10s(buffer,&buffer);
	if(!GetNextLine())return false;
	
	// copy the data line to a separate buffer
	char* m = cursor, *end = &cursor[4096];
	while (!IsLineEnd ( *buffer ) && m < end)
		*m++ = *buffer++;
	
	*m = '\0';
	GetNextLine(); 
	return true;
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure. 
void DXFImporter::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 DXF file " + pFile + "");

	// read the contents of the file in a buffer
	unsigned int m = (unsigned int)file->FileSize();
	std::vector<char> buffer2(m+1);
	buffer = &buffer2[0];
	file->Read( &buffer2[0], m,1);
	buffer2[m] = '\0';

	bRepeat = false;
	mDefaultLayer = NULL;

	// check whether this is a binaray DXF file - we can't read binary DXF files :-(
	if (!strncmp(AI_DXF_BINARY_IDENT,buffer,AI_DXF_BINARY_IDENT_LEN))
		throw new ImportErrorException("DXF: Binary files are not supported at the moment");

	// now get all lines of the file
	while (GetNextToken())
	{
		if (2 == groupCode)
		{
			// ENTITIES and BLOCKS sections - skip the whole rest, no need to waste our time with them
			if (!::strcmp(cursor,"ENTITIES") || !::strcmp(cursor,"BLOCKS"))
				if (!ParseEntities())break; else bRepeat = true;

			// other sections - skip them to make sure there will be no name conflicts
			else
			{
				while (GetNextToken())
				{
					if (!groupCode && !::strcmp(cursor,"ENDSEC"))break;
				}
			}
		}
		// print comment strings
		else if (999 == groupCode)
		{
			DefaultLogger::get()->info(std::string( cursor ));
		}
		else if (!groupCode && !::strcmp(cursor,"EOF"))
			break;
	}

	// find out how many valud layers we have
	for (std::vector<LayerInfo>::const_iterator it = mLayers.begin(),end = mLayers.end();
		it != end;++it)
	{
		if (!(*it).vPositions.empty())++pScene->mNumMeshes;
	}

	if (!pScene->mNumMeshes)
		throw new ImportErrorException("DXF: this file contains no 3d data");

	pScene->mMeshes = new aiMesh*[ pScene->mNumMeshes ];
	m = 0;
	for (std::vector<LayerInfo>::const_iterator it = mLayers.begin(),end = mLayers.end();
		it != end;++it)
	{
		if ((*it).vPositions.empty())continue;

		// generate the output mesh
		aiMesh* pMesh = pScene->mMeshes[m++] = new aiMesh();
		const std::vector<aiVector3D>& vPositions = (*it).vPositions;
		const std::vector<aiColor4D>& vColors = (*it).vColors;

		// check whether we need vertex colors here
		aiColor4D* clrOut;
		const aiColor4D* clr = NULL;
		for (std::vector<aiColor4D>::const_iterator it2 = (*it).vColors.begin(), end2 = (*it).vColors.end();
			 it2 != end2; ++it2)
		{
			if ((*it2).r == (*it2).r) // check against qnan
			{
				clrOut = pMesh->mColors[0] = new aiColor4D[vPositions.size()];
				for (unsigned int i = 0; i < vPositions.size();++i)
					clrOut[i] = aiColor4D(0.6f,0.6f,0.6f,1.0f);

				clr = &vColors[0];
				break;
			}
		}

		pMesh->mNumFaces = (unsigned int)vPositions.size() / 4u;
		pMesh->mFaces = new aiFace[pMesh->mNumFaces];

		aiVector3D* vpOut = pMesh->mVertices = new aiVector3D[vPositions.size()];
		const aiVector3D* vp = &vPositions[0];

		for (unsigned int i = 0; i < pMesh->mNumFaces;++i)
		{
			aiFace& face = pMesh->mFaces[i];

			// check whether we need four,three or two indices here
			if (vp[1] == vp[2])
			{
				face.mNumIndices = 2;
			}
			else if (vp[3] == vp[2])
			{
				 face.mNumIndices = 3;
			}
			else face.mNumIndices = 4;
			face.mIndices = new unsigned int[face.mNumIndices];

			for (unsigned int a = 0; a < face.mNumIndices;++a)
			{
				*vpOut++ = vp[a];
				if (clr)
				{
					if (std::numeric_limits<float>::quiet_NaN() != clr[a].r)
						*clrOut = clr[a];

					++clrOut;
				}
				face.mIndices[a] = pMesh->mNumVertices++;
			}
			vp += 4;
		}
	}

	// generate the output scene graph
	pScene->mRootNode = new aiNode();
	pScene->mRootNode->mName.Set("<DXF_ROOT>");

	if (1 == pScene->mNumMeshes)
	{
		pScene->mRootNode->mMeshes = new unsigned int[ pScene->mRootNode->mNumMeshes = 1 ];
		pScene->mRootNode->mMeshes[0] = 0;
	}
	else
	{
		pScene->mRootNode->mChildren = new aiNode*[ pScene->mRootNode->mNumChildren = pScene->mNumMeshes ];
		for (m = 0; m < pScene->mRootNode->mNumChildren;++m)
		{
			aiNode* p = pScene->mRootNode->mChildren[m] = new aiNode();
			p->mName.length = ::strlen( mLayers[m].name );
			::strcpy(p->mName.data, mLayers[m].name);

			p->mMeshes = new unsigned int[p->mNumMeshes = 1];
			p->mMeshes[0] = m;
			p->mParent = pScene->mRootNode;
		}
	}

	// generate a default material
	MaterialHelper* pcMat = new MaterialHelper();
	aiString s;
	s.Set(AI_DEFAULT_MATERIAL_NAME);
	pcMat->AddProperty(&s, AI_MATKEY_NAME);

	aiColor4D clrDiffuse(0.6f,0.6f,0.6f,1.0f);
	pcMat->AddProperty(&clrDiffuse,1,AI_MATKEY_COLOR_DIFFUSE);

	clrDiffuse = aiColor4D(1.0f,1.0f,1.0f,1.0f);
	pcMat->AddProperty(&clrDiffuse,1,AI_MATKEY_COLOR_SPECULAR);

	clrDiffuse = aiColor4D(0.05f,0.05f,0.05f,1.0f);
	pcMat->AddProperty(&clrDiffuse,1,AI_MATKEY_COLOR_AMBIENT);

	pScene->mNumMaterials = 1;
	pScene->mMaterials = new aiMaterial*[1];
	pScene->mMaterials[0] = pcMat;

	// --- everything destructs automatically ---
}

// ------------------------------------------------------------------------------------------------
bool DXFImporter::ParseEntities()
{
	while (GetNextToken())
	{
		if (!groupCode)
		{			
			if (!::strcmp(cursor,"3DFACE") || !::strcmp(cursor,"LINE") || !::strcmp(cursor,"3DLINE"))
				if (!Parse3DFace()) return false; else bRepeat = true;

			if (!::strcmp(cursor,"POLYLINE") || !::strcmp(cursor,"LWPOLYLINE"))
				if (!ParsePolyLine()) return false; else bRepeat = true;

			if (!::strcmp(cursor,"ENDSEC"))
				return true;
		}
	}
	return false;
}

// ------------------------------------------------------------------------------------------------
void DXFImporter::SetLayer(LayerInfo*& out)
{
	for (std::vector<LayerInfo>::iterator it = mLayers.begin(),end = mLayers.end();
		it != end;++it)
	{
		if (!::strcmp( (*it).name, cursor ))
		{
			out = &(*it);
			break;
		}
	}
	if (!out)
	{
		// we don't have this layer yet
		mLayers.push_back(LayerInfo());
		out = &mLayers.back();
		::strcpy(out->name,cursor);
	}
}

// ------------------------------------------------------------------------------------------------
void DXFImporter::SetDefaultLayer(LayerInfo*& out)
{
	if (!mDefaultLayer)
	{
		mLayers.push_back(LayerInfo());
		mDefaultLayer = &mLayers.back();
	}
	out = mDefaultLayer;
}

// ------------------------------------------------------------------------------------------------
bool DXFImporter::ParsePolyLine()
{
	bool ret = false;
	LayerInfo* out = NULL;

	std::vector<aiVector3D> positions;
	std::vector<aiColor4D>  colors;
	std::vector<unsigned int> indices;
	unsigned int flags = 0;

	while (GetNextToken())
	{
		switch (groupCode)
		{
		case 0:
			{
				if (!::strcmp(cursor,"VERTEX"))
				{
					aiVector3D v;aiColor4D clr(g_clrInvalid);
					unsigned int idx[4] = {0xffffffff,0xffffffff,0xffffffff,0xffffffff};
					ParsePolyLineVertex(v, clr, idx);
					if (0xffffffff == idx[0])
					{
						positions.push_back(v);
						colors.push_back(clr);
					}
					else
					{
						// check whether we have a fourth coordinate
						if (0xffffffff == idx[3])
						{
							idx[3] = idx[2];
						}

						indices.reserve(indices.size()+4);
						for (unsigned int m = 0; m < 4;++m)
							indices.push_back(idx[m]);
					}
					bRepeat = true;
				}
				else if (!::strcmp(cursor,"ENDSEQ"))
				{
					ret = true;
				}
				break;
			}

		// flags --- important that we know whether it is a polyface mesh
		case 70:
			{
				flags = strtol10(cursor);
				break;
			};

		// optional number of vertices
		case 71:
			{
				positions.reserve(strtol10(cursor));
				break;
			}

		// optional number of faces
		case 72:
			{
				indices.reserve(strtol10(cursor) * 4u);
				break;
			}

		// 8 specifies the layer
		case 8:
			{
				SetLayer(out);
				break;
			}
		}
	}
	if (!(flags & 64))
	{
		DefaultLogger::get()->warn("DXF: Only polyface meshes are currently supported");
		return ret;
	}

	if (positions.size() < 3 || indices.size() < 3)
	{
		DefaultLogger::get()->warn("DXF: Unable to parse POLYLINE element - not enough vertices");
		return ret;
	}

	// use a default layer if necessary
	if (!out)SetDefaultLayer(out);

	flags = (unsigned int)(out->vPositions.size()+indices.size());
	out->vPositions.reserve(flags);
	out->vColors.reserve(flags);

	// generate unique vertices
	for (std::vector<unsigned int>::const_iterator it = indices.begin(), end = indices.end();
		it != end; ++it)
	{
		unsigned int idx = *it;
		if (idx > positions.size())
		{
			DefaultLogger::get()->error("DXF: Polyface mesh index os out of range");
			idx = (unsigned int) positions.size();
		}
		out->vPositions.push_back(positions[idx-1]); // indices are one-based.
		out->vColors.push_back(colors[idx-1]); // indices are one-based.
	}

	return ret;
}

// ------------------------------------------------------------------------------------------------
bool DXFImporter::ParsePolyLineVertex(aiVector3D& out,aiColor4D& clr, unsigned int* outIdx)
{
	bool ret = false;
	while (GetNextToken())
	{
		switch (groupCode)
		{
		case 0: ret = true;break;

		// todo - handle the correct layer for the vertex
		// At the moment it is assumed that all vertices of 
		// a polyline are placed on the same global layer.

		// x position of the first corner
		case 10: out.x = fast_atof(cursor);break;

		// y position of the first corner
		case 20: out.y = -fast_atof(cursor);break;

		// z position of the first corner
		case 30: out.z = fast_atof(cursor);break;

		// POLYFACE vertex indices
		case 71: outIdx[0] = strtol10(cursor);break;
		case 72: outIdx[1] = strtol10(cursor);break;
		case 73: outIdx[2] = strtol10(cursor);break;
		case 74: outIdx[3] = strtol10(cursor);break;

		// color
		case 62: clr = g_aclrDxfIndexColors[strtol10(cursor) % AI_DXF_NUM_INDEX_COLORS]; break;
		};
		if (ret)break;
	}
	return ret;
}

// ------------------------------------------------------------------------------------------------
bool DXFImporter::Parse3DFace()
{
	bool ret = false;
	LayerInfo* out = NULL;

	aiVector3D vip[4]; // -- vectors are initialized to zero
	aiColor4D  clr(g_clrInvalid);

	// this is also used for for parsing line entities
	bool bThird = false;

	while (GetNextToken())
	{
		switch (groupCode)
		{
		case 0: ret = true;break;

		// 8 specifies the layer
		case 8:
			{
				SetLayer(out);
				break;
			}

		// x position of the first corner
		case 10: vip[0].x = fast_atof(cursor);break;

		// y position of the first corner
		case 20: vip[0].y = -fast_atof(cursor);break;

		// z position of the first corner
		case 30: vip[0].z = fast_atof(cursor);break;

		// x position of the second corner
		case 11: vip[1].x = fast_atof(cursor);break;

		// y position of the second corner
		case 21: vip[1].y = -fast_atof(cursor);break;

		// z position of the second corner
		case 31: vip[1].z = fast_atof(cursor);break;

		// x position of the third corner
		case 12: vip[2].x = fast_atof(cursor);
			bThird = true;break;

		// y position of the third corner
		case 22: vip[2].y = -fast_atof(cursor);
			bThird = true;break;

		// z position of the third corner
		case 32: vip[2].z = fast_atof(cursor);
			bThird = true;break;

		// x position of the fourth corner
		case 13: vip[3].x = fast_atof(cursor);
			bThird = true;break;

		// y position of the fourth corner
		case 23: vip[3].y = -fast_atof(cursor);
			bThird = true;break;

		// z position of the fourth corner
		case 33: vip[3].z = fast_atof(cursor);
			bThird = true;break;

		// color
		case 62: clr = g_aclrDxfIndexColors[strtol10(cursor) % AI_DXF_NUM_INDEX_COLORS]; break;
		};
		if (ret)break;
	}

	if (!bThird)vip[2] = vip[1];

	// use a default layer if necessary
	if (!out)SetDefaultLayer(out);

	// add the faces to the face list for this layer
	out->vPositions.push_back(vip[0]);
	out->vPositions.push_back(vip[1]);
	out->vPositions.push_back(vip[2]);
	out->vPositions.push_back(vip[3]); // might be equal to the third

	for (unsigned int i = 0; i < 4;++i)
		out->vColors.push_back(clr);
	return ret;
}