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

Copyright (c) 2006-2012, assimp team

All rights reserved.

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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
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* 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 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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*/

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

#include "AssimpPCH.h"
#ifndef ASSIMP_BUILD_NO_STL_IMPORTER

// internal headers
#include "STLLoader.h"
#include "ParsingUtils.h"
#include "fast_atof.h"

using namespace Assimp;

namespace {
static const aiImporterDesc desc = {
	"Stereolithography (STL) Importer",
	"",
	"",
	"",
	aiImporterFlags_SupportTextFlavour | aiImporterFlags_SupportBinaryFlavour,
	0,
	0,
	0,
	0,
	"stl" 
};

// A valid binary STL buffer should consist of the following elements, in order:
// 1) 80 byte header
// 2) 4 byte face count
// 3) 50 bytes per face
bool IsBinarySTL(const char* buffer, unsigned int fileSize) {
	if (fileSize < 84)
		return false;

	const uint32_t faceCount = *reinterpret_cast<const uint32_t*>(buffer + 80);
	const uint32_t expectedBinaryFileSize = faceCount * 50 + 84;

	return expectedBinaryFileSize == fileSize;
}

// An ascii STL buffer will begin with "solid NAME", where NAME is optional.
// Note: The "solid NAME" check is necessary, but not sufficient, to determine
// if the buffer is ASCII; a binary header could also begin with "solid NAME".
bool IsAsciiSTL(const char* buffer, unsigned int fileSize) {
	if (IsBinarySTL(buffer, fileSize))
		return false;

	if (fileSize < 5)
		return false;

	return strncmp(buffer, "solid", 5) == 0;
}
} // namespace

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

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

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file. 
bool STLImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool checkSig) const
{
	const std::string extension = GetExtension(pFile);

	if (extension == "stl")
		return true;
	else if (!extension.length() || checkSig)	{
		if (!pIOHandler)
			return true;
		const char* tokens[] = {"STL","solid"};
		return SearchFileHeaderForToken(pIOHandler,pFile,tokens,2);
	}
	return false;
}

// ------------------------------------------------------------------------------------------------
const aiImporterDesc* STLImporter::GetInfo () const
{
	return &desc;
}

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

	fileSize = (unsigned int)file->FileSize();

	// allocate storage and copy the contents of the file to a memory buffer
	// (terminate it with zero)
	std::vector<char> mBuffer2;
	TextFileToBuffer(file.get(),mBuffer2);

	this->pScene = pScene;
	this->mBuffer = &mBuffer2[0];

	// the default vertex color is white
	clrColorDefault.r = clrColorDefault.g = clrColorDefault.b = clrColorDefault.a = 1.0f;

	// allocate one mesh
	pScene->mNumMeshes = 1;
	pScene->mMeshes = new aiMesh*[1];
	aiMesh* pMesh = pScene->mMeshes[0] = new aiMesh();
	pMesh->mMaterialIndex = 0;

	// allocate a single node
	pScene->mRootNode = new aiNode();
	pScene->mRootNode->mNumMeshes = 1;
	pScene->mRootNode->mMeshes = new unsigned int[1];
	pScene->mRootNode->mMeshes[0] = 0;

	bool bMatClr = false;

	if (IsBinarySTL(mBuffer, fileSize)) {
		bMatClr = LoadBinaryFile();
	} else if (IsAsciiSTL(mBuffer, fileSize)) {
		LoadASCIIFile();
	} else {
		throw DeadlyImportError( "Failed to determine STL storage representation for " + pFile + ".");
	}

	// now copy faces
	pMesh->mFaces = new aiFace[pMesh->mNumFaces];
	for (unsigned int i = 0, p = 0; i < pMesh->mNumFaces;++i)	{

		aiFace& face = pMesh->mFaces[i];
		face.mIndices = new unsigned int[face.mNumIndices = 3];
		for (unsigned int o = 0; o < 3;++o,++p) {
			face.mIndices[o] = p;
		}
	}

	// create a single default material - everything white, as we have vertex colors
	aiMaterial* pcMat = new aiMaterial();
	aiString s;
	s.Set(AI_DEFAULT_MATERIAL_NAME);
	pcMat->AddProperty(&s, AI_MATKEY_NAME);

	aiColor4D clrDiffuse(1.0f,1.0f,1.0f,1.0f);
	if (bMatClr) {
		clrDiffuse = clrColorDefault;
	}
	pcMat->AddProperty(&clrDiffuse,1,AI_MATKEY_COLOR_DIFFUSE);
	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;
}
// ------------------------------------------------------------------------------------------------
// Read an ASCII STL file
void STLImporter::LoadASCIIFile()
{
	aiMesh* pMesh = pScene->mMeshes[0];

	const char* sz = mBuffer + 5; // skip the "solid"
	SkipSpaces(&sz);
	const char* szMe = sz;
	while (!::IsSpaceOrNewLine(*sz)) {
		sz++;
	}

	size_t temp;
	// setup the name of the node
	if ((temp = (size_t)(sz-szMe)))	{

		pScene->mRootNode->mName.length = temp;
		memcpy(pScene->mRootNode->mName.data,szMe,temp);
		pScene->mRootNode->mName.data[temp] = '\0';
	}
	else pScene->mRootNode->mName.Set("<STL_ASCII>");

	// try to guess how many vertices we could have
	// assume we'll need 160 bytes for each face
	pMesh->mNumVertices = ( pMesh->mNumFaces = std::max(1u,fileSize / 160u )) * 3;
	pMesh->mVertices = new aiVector3D[pMesh->mNumVertices];
	pMesh->mNormals  = new aiVector3D[pMesh->mNumVertices];
	
	unsigned int curFace = 0, curVertex = 3;
	for ( ;; )
	{
		// go to the next token
		if(!SkipSpacesAndLineEnd(&sz))
		{
			// seems we're finished although there was no end marker
			DefaultLogger::get()->warn("STL: unexpected EOF. \'endsolid\' keyword was expected");
			break;
		}
		// facet normal -0.13 -0.13 -0.98
		if (!strncmp(sz,"facet",5) && IsSpaceOrNewLine(*(sz+5)))	{

			if (3 != curVertex) {
				DefaultLogger::get()->warn("STL: A new facet begins but the old is not yet complete");
			}
			if (pMesh->mNumFaces == curFace)	{
				ai_assert(pMesh->mNumFaces != 0);

				// need to resize the arrays, our size estimate was wrong
				unsigned int iNeededSize = (unsigned int)(sz-mBuffer) / pMesh->mNumFaces;
				if (iNeededSize <= 160)iNeededSize >>= 1; // prevent endless looping
				unsigned int add = (unsigned int)((mBuffer+fileSize)-sz) / iNeededSize;
				add += add >> 3; // add 12.5% as buffer
				iNeededSize = (pMesh->mNumFaces + add)*3;
				aiVector3D* pv = new aiVector3D[iNeededSize];
				memcpy(pv,pMesh->mVertices,pMesh->mNumVertices*sizeof(aiVector3D));
				delete[] pMesh->mVertices;
				pMesh->mVertices = pv;
				pv = new aiVector3D[iNeededSize];
				memcpy(pv,pMesh->mNormals,pMesh->mNumVertices*sizeof(aiVector3D));
				delete[] pMesh->mNormals;
				pMesh->mNormals = pv;

				pMesh->mNumVertices = iNeededSize;
				pMesh->mNumFaces += add;
			}
			aiVector3D* vn = &pMesh->mNormals[curFace++*3];

			sz += 6;
			curVertex = 0;
			SkipSpaces(&sz);
			if (strncmp(sz,"normal",6))	{
				DefaultLogger::get()->warn("STL: a facet normal vector was expected but not found");
			}
			else
			{
				sz += 7;
				SkipSpaces(&sz);
				sz = fast_atoreal_move<float>(sz, (float&)vn->x ); 
				SkipSpaces(&sz);
				sz = fast_atoreal_move<float>(sz, (float&)vn->y ); 
				SkipSpaces(&sz);
				sz = fast_atoreal_move<float>(sz, (float&)vn->z ); 
				*(vn+1) = *vn;
				*(vn+2) = *vn;
			}
		}
		// vertex 1.50000 1.50000 0.00000
		else if (!strncmp(sz,"vertex",6) && ::IsSpaceOrNewLine(*(sz+6)))
		{
			if (3 == curVertex)	{
				DefaultLogger::get()->error("STL: a facet with more than 3 vertices has been found");
			}
			else
			{
				sz += 7;
				SkipSpaces(&sz);
				aiVector3D* vn = &pMesh->mVertices[(curFace-1)*3 + curVertex++];
				sz = fast_atoreal_move<float>(sz, (float&)vn->x ); 
				SkipSpaces(&sz);
				sz = fast_atoreal_move<float>(sz, (float&)vn->y ); 
				SkipSpaces(&sz);
				sz = fast_atoreal_move<float>(sz, (float&)vn->z ); 
			}
		}
		else if (!::strncmp(sz,"endsolid",8))	{
			// finished!
			break;
		}
		// else skip the whole identifier
		else while (!::IsSpaceOrNewLine(*sz)) {
			++sz;
		}
	}

	if (!curFace)	{
		pMesh->mNumFaces = 0;
		throw DeadlyImportError("STL: ASCII file is empty or invalid; no data loaded");
	}
	pMesh->mNumFaces = curFace;
	pMesh->mNumVertices = curFace*3;
	// we are finished!
}

// ------------------------------------------------------------------------------------------------
// Read a binary STL file
bool STLImporter::LoadBinaryFile()
{
	// skip the first 80 bytes
	if (fileSize < 84) {
		throw DeadlyImportError("STL: file is too small for the header");
	}
	bool bIsMaterialise = false;

	// search for an occurence of "COLOR=" in the header
	const char* sz2 = (const char*)mBuffer;
	const char* const szEnd = sz2+80;
	while (sz2 < szEnd)	{

		if ('C' == *sz2++ && 'O' == *sz2++ && 'L' == *sz2++ &&
			'O' == *sz2++ && 'R' == *sz2++ && '=' == *sz2++)	{

			// read the default vertex color for facets
			bIsMaterialise = true;
			DefaultLogger::get()->info("STL: Taking code path for Materialise files");
			clrColorDefault.r = (*sz2++) / 255.0f;
			clrColorDefault.g = (*sz2++) / 255.0f;
			clrColorDefault.b = (*sz2++) / 255.0f;
			clrColorDefault.a = (*sz2++) / 255.0f;
			break;
		}
	}
	const unsigned char* sz = (const unsigned char*)mBuffer + 80;

	// now read the number of facets
	aiMesh* pMesh = pScene->mMeshes[0];
	pScene->mRootNode->mName.Set("<STL_BINARY>");

	pMesh->mNumFaces = *((uint32_t*)sz);
	sz += 4;

	if (fileSize < 84 + pMesh->mNumFaces*50) {
		throw DeadlyImportError("STL: file is too small to hold all facets");
	}

	if (!pMesh->mNumFaces) {
		throw DeadlyImportError("STL: file is empty. There are no facets defined");
	}

	pMesh->mNumVertices = pMesh->mNumFaces*3;

	aiVector3D* vp,*vn;
	vp = pMesh->mVertices = new aiVector3D[pMesh->mNumVertices];
	vn = pMesh->mNormals = new aiVector3D[pMesh->mNumVertices];

	for (unsigned int i = 0; i < pMesh->mNumFaces;++i)	{

		// NOTE: Blender sometimes writes empty normals ... this is not
		// our fault ... the RemoveInvalidData helper step should fix that
		*vn = *((aiVector3D*)sz);
		sz += sizeof(aiVector3D);
		*(vn+1) = *vn;
		*(vn+2) = *vn;
		vn += 3;

		*vp++ = *((aiVector3D*)sz);
		sz += sizeof(aiVector3D);

		*vp++ = *((aiVector3D*)sz);
		sz += sizeof(aiVector3D);

		*vp++ = *((aiVector3D*)sz);
		sz += sizeof(aiVector3D);

		uint16_t color = *((uint16_t*)sz);
		sz += 2;

		if (color & (1 << 15))
		{
			// seems we need to take the color
			if (!pMesh->mColors[0])
			{
				pMesh->mColors[0] = new aiColor4D[pMesh->mNumVertices];
				for (unsigned int i = 0; i <pMesh->mNumVertices;++i)
					*pMesh->mColors[0]++ = this->clrColorDefault;
				pMesh->mColors[0] -= pMesh->mNumVertices;

				DefaultLogger::get()->info("STL: Mesh has vertex colors");
			}
			aiColor4D* clr = &pMesh->mColors[0][i*3];
			clr->a = 1.0f;
			if (bIsMaterialise) // this is reversed
			{
				clr->r = (color & 0x31u) / 31.0f;
				clr->g = ((color & (0x31u<<5))>>5u) / 31.0f;
				clr->b = ((color & (0x31u<<10))>>10u) / 31.0f;
			}
			else
			{
				clr->b = (color & 0x31u) / 31.0f;
				clr->g = ((color & (0x31u<<5))>>5u) / 31.0f;
				clr->r = ((color & (0x31u<<10))>>10u) / 31.0f;
			}
			// assign the color to all vertices of the face
			*(clr+1) = *clr;
			*(clr+2) = *clr;
		}
	}
	if (bIsMaterialise && !pMesh->mColors[0])
	{
		// use the color as diffuse material color
		return true;
	}
	return false;
}

#endif // !! ASSIMP_BUILD_NO_STL_IMPORTER