/*
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Open Asset Import Library (ASSIMP)
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/** @file  MS3DLoader.cpp
 *  @brief Implementation of the Ms3D importer class.
 *  Written against http://chumbalum.swissquake.ch/ms3d/ms3dspec.txt
 */

#include "AssimpPCH.h"
#ifndef ASSIMP_BUILD_NO_MS3D_IMPORTER

// internal headers
#include "MS3DLoader.h"
#include "StreamReader.h"
using namespace Assimp;

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
MS3DImporter::MS3DImporter()
{}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well 
MS3DImporter::~MS3DImporter()
{}

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file. 
bool MS3DImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool checkSig) const
{
	// first call - simple extension check
	const std::string extension = GetExtension(pFile);
	if (extension == "ms3d") {
		return true;
	}

	// second call - check for magic identifiers
	else if (!extension.length() || checkSig)	{
		if (!pIOHandler) {
			return true;
		}
		const char* tokens[] = {"MS3D000000"};
		return SearchFileHeaderForToken(pIOHandler,pFile,tokens,1);
	}
	return false;
}

// ------------------------------------------------------------------------------------------------
void MS3DImporter::GetExtensionList(std::set<std::string>& extensions)
{
	extensions.insert("ms3d");
}

// ------------------------------------------------------------------------------------------------
void ReadColor(StreamReaderLE& stream, aiColor4D& ambient)
{
	// aiColor4D is packed on gcc, implicit binding to float& fails therefore.
	// But I guess casting is fine (it could cause alignment faults on some
	// architectures in general, but we're not touched because aiColor4D
	// should be properly aligned & packed due to its uniform structure)
	stream >> (float&)ambient.r >> (float&)ambient.g >> (float&)ambient.b >> (float&)ambient.a;
}

// ------------------------------------------------------------------------------------------------
void ReadVector(StreamReaderLE& stream, aiVector3D& pos)
{
	// See note in ReadColor()
	stream >> (float&)pos.x >> (float&)pos.y >> (float&)pos.z;
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure. 
void MS3DImporter::InternReadFile( const std::string& pFile, 
	aiScene* pScene, IOSystem* pIOHandler)
{
	StreamReaderLE stream(pIOHandler->Open(pFile,"rb"));

	// CanRead() should have done this already
	char head[10];
	int32_t version;


	// 1 ------------ read into temporary data structures mirroring the original file

	stream.CopyAndAdvance(head,10);
	stream >> version;
	if (strncmp(head,"MS3D000000",10)) {
		throw new ImportErrorException("Not a MS3D file, magic string MS3D000000 not found: "+pFile);
	}

	if (version != 4) {
		throw new ImportErrorException("MS3D: Unsupported file format version, 4 was expected");
	}

	uint16_t verts;
	stream >> verts;

	std::vector<TempVertex> vertices(verts);
	for (unsigned int i = 0; i < verts; ++i) {
		TempVertex& v = vertices[i];

		stream.IncPtr(1);
		ReadVector(stream,v.pos);
		v.bone_id = static_cast<unsigned int>(stream.GetI1()); // signed in original spec !! intentional bit hack.
		v.ref_cnt = static_cast<unsigned int>(stream.GetI1());
	}

	uint16_t tris;
	stream >> tris;

	std::vector<TempTriangle> triangles(tris);
	for (unsigned int i = 0;i < tris; ++i) {
		TempTriangle& t = triangles[i];

		stream.IncPtr(2);
		for (unsigned int i = 0; i < 3; ++i) {
			t.indices[i] = static_cast<unsigned int>(stream.GetI2());
		}

		for (unsigned int i = 0; i < 3; ++i) {
			ReadVector(stream,t.normals[i]);
		}

		for (unsigned int i = 0; i < 3; ++i) {
			stream >> (float&)(t.uv[i].x); // see note in ReadColor()
		}
		for (unsigned int i = 0; i < 3; ++i) {
			stream >> (float&)(t.uv[i].y);
		}

		t.sg    = static_cast<unsigned int>(stream.GetI1()); 
		t.group = static_cast<unsigned int>(stream.GetI1()); 
	}

	uint16_t grp;
	stream >> grp;

	bool need_default = false;
	std::vector<TempGroup> groups(grp);
	for (unsigned int i = 0;i < grp; ++i) {
		TempGroup& t = groups[i];

		stream.IncPtr(1);
		stream.CopyAndAdvance(t.name,32);

		t.name[32] = '\0';
		uint16_t num;
		stream >> num;

		t.triangles.resize(num);
		for (unsigned int i = 0; i < num; ++i) {
			t.triangles[i] = static_cast<unsigned int>(stream.GetI2()); 
		}
		t.mat = static_cast<unsigned int>(stream.GetI1()); 
		if (t.mat == 0xff) {
			need_default = true;
		}
	}

	uint16_t mat;
	stream >> mat;

	std::vector<TempMaterial> materials(mat);
	for (unsigned int i = 0;i < mat; ++i) {
		TempMaterial& t = materials[i];

		stream.CopyAndAdvance(t.name,32);
		t.name[32] = '\0';

		ReadColor(stream,t.ambient);
		ReadColor(stream,t.diffuse);
		ReadColor(stream,t.specular);
		ReadColor(stream,t.emissive);
		stream >> t.shininess  >> t.transparency;

		stream.IncPtr(1);

		stream.CopyAndAdvance(t.texture,128);
		t.texture[128] = '\0';

		stream.CopyAndAdvance(t.alphamap,128);
		t.alphamap[128] = '\0';
	}


	// 2 ------------ convert to proper aiXX data structures

	if (need_default && materials.size()) {
		DefaultLogger::get()->warn("MS3D: Found group with no material assigned, spawning default material");
		// if one of the groups has no material assigned, but there are other 
		// groups with materials, a default material needs to be added (
		// scenepreprocessor adds a default material only if nummat==0).
		materials.push_back(TempMaterial());
		TempMaterial& m = materials.back();

		strcpy(m.name,"<MS3D_DefaultMat>");
		m.diffuse = aiColor4D(0.6f,0.6f,0.6f,1.0);
		m.transparency = 1.f;
		m.shininess = 0.f;

		for (unsigned int i = 0; i < groups.size(); ++i) {
			TempGroup& g = groups[i];
			if (g.mat == 0xff) {
				g.mat = materials.size()-1;
			}
		}
	}

	// convert materials to our generic key-value dict-alike
	if (materials.size()) {
		pScene->mMaterials = new aiMaterial*[pScene->mNumMaterials=static_cast<unsigned int>(materials.size())];
		for (unsigned int i = 0; i < pScene->mNumMaterials; ++i) {

			MaterialHelper* mo = new MaterialHelper();
			pScene->mMaterials[i] = mo;

			const TempMaterial& mi = materials[i];

			aiString tmp;
			if (0[mi.alphamap]) {
				tmp = aiString(mi.alphamap);
				mo->AddProperty(&tmp,AI_MATKEY_TEXTURE_OPACITY(0));
			}
			if (0[mi.texture]) {
				tmp = aiString(mi.texture);
				mo->AddProperty(&tmp,AI_MATKEY_TEXTURE_DIFFUSE(0));
			}
			if (0[mi.name]) {
				tmp = aiString(mi.name);
				mo->AddProperty(&tmp,AI_MATKEY_NAME);
			}

			mo->AddProperty(&mi.ambient,1,AI_MATKEY_COLOR_AMBIENT);
			mo->AddProperty(&mi.diffuse,1,AI_MATKEY_COLOR_DIFFUSE);
			mo->AddProperty(&mi.specular,1,AI_MATKEY_COLOR_SPECULAR);
			mo->AddProperty(&mi.emissive,1,AI_MATKEY_COLOR_EMISSIVE);

			mo->AddProperty(&mi.shininess,1,AI_MATKEY_SHININESS);
			mo->AddProperty(&mi.transparency,1,AI_MATKEY_OPACITY);

			const int sm = mi.shininess>0.f?aiShadingMode_Phong:aiShadingMode_Gouraud;
			mo->AddProperty(&sm,1,AI_MATKEY_SHADING_MODEL);
		}
	}

	// convert groups to meshes
	if (groups.empty()) {
		throw new ImportErrorException("MS3D: Didn't get any group records, file is malformed");
	}

	pScene->mMeshes = new aiMesh*[pScene->mNumMeshes=static_cast<unsigned int>(groups.size())];
	for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
	
		aiMesh* m = pScene->mMeshes[i] = new aiMesh();
		const TempGroup& g = groups[i];

		if (pScene->mNumMaterials && g.mat > pScene->mNumMaterials) {
			throw new ImportErrorException("MS3D: Encountered invalid material index, file is malformed");
		} // no error if no materials at all - scenepreprocessor adds one then

		m->mMaterialIndex  = g.mat;
		m->mPrimitiveTypes = aiPrimitiveType_TRIANGLE; 

		m->mFaces = new aiFace[m->mNumFaces = g.triangles.size()];
		m->mNumVertices = m->mNumFaces*3;

		// storage for vertices - verbose format, as requested by the postprocessing pipeline
		m->mVertices = new aiVector3D[m->mNumVertices];
		m->mNormals  = new aiVector3D[m->mNumVertices];
		m->mTextureCoords[0] = new aiVector3D[m->mNumVertices];
		m->mNumUVComponents[0] = 2;

		for (unsigned int i = 0,n = 0; i < m->mNumFaces; ++i) {
			aiFace& f = m->mFaces[i];
			if (g.triangles[i]>triangles.size()) {
				throw new ImportErrorException("MS3D: Encountered invalid triangle index, file is malformed");
			}

			TempTriangle& t = triangles[g.triangles[i]];
			f.mIndices = new unsigned int[f.mNumIndices=3];
			
			for (unsigned int i = 0; i < 3; ++i,++n) {
				if (t.indices[i]>vertices.size()) {
					throw new ImportErrorException("MS3D: Encountered invalid vertex index, file is malformed");
				}

				// collect vertex components
				m->mVertices[n] = vertices[t.indices[i]].pos;

				m->mNormals[n] = t.normals[i];
				m->mTextureCoords[0][n] = aiVector3D(t.uv[i].x,t.uv[i].y,0.0);
				f.mIndices[i] = n;
			}
		}
	}

	// ... add dummy nodes under a single root, each holding a reference to one
	// mesh. If we didn't do this, we'd loose the group name.
	aiNode* rt = pScene->mRootNode = new aiNode("<MS3DRoot>");
	rt->mChildren = new aiNode*[rt->mNumChildren=pScene->mNumMeshes];

	for (unsigned int i = 0; i < rt->mNumChildren; ++i) {
		aiNode* nd = rt->mChildren[i] = new aiNode();

		const TempGroup& g = groups[i];
		nd->mName = aiString(g.name);
		nd->mParent = rt;

		nd->mMeshes = new unsigned int[nd->mNumMeshes = 1];
		nd->mMeshes[0] = i;
	}
}

#endif