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

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All rights reserved.

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  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
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  derived from this software without specific prior
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
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*/

/** @file  FBXConverter.cpp
 *  @brief Implementation of the FBX DOM -> aiScene converter
 */
#include "AssimpPCH.h"

#ifndef ASSIMP_BUILD_NO_FBX_IMPORTER

#include "FBXParser.h"
#include "FBXConverter.h"
#include "FBXDocument.h"
#include "FBXUtil.h"
#include "FBXProperties.h"
#include "FBXImporter.h"

namespace Assimp {
namespace FBX {

	using namespace Util;

namespace {

/** Dummy class to encapsulate the conversion process */
class Converter
{

public:

	Converter(aiScene* out, const Document& doc)
		: out(out) 
		, doc(doc)
	{
		//ConvertRootNode();

		// hack to process all meshes
		BOOST_FOREACH(const ObjectMap::value_type& v,doc.Objects()) {

			const Object* ob = v.second->Get();
			if(!ob) {
				continue;
			}
			const MeshGeometry* geo = dynamic_cast<const MeshGeometry*>(ob);
			if(geo) {
				ConvertMesh(*geo);
			}
		}

		// dummy root node
		out->mRootNode = new aiNode();
		out->mRootNode->mNumMeshes = static_cast<unsigned int>(meshes.size());
		out->mRootNode->mMeshes = new unsigned int[meshes.size()];
		for(unsigned int i = 0; i < out->mRootNode->mNumMeshes; ++i) {
			out->mRootNode->mMeshes[i] = i;
		}

		TransferDataToScene();
	}


	~Converter()
	{
		std::for_each(meshes.begin(),meshes.end(),Util::delete_fun<aiMesh>());
		std::for_each(materials.begin(),materials.end(),Util::delete_fun<aiMaterial>());
	}


private:

	// ------------------------------------------------------------------------------------------------
	// find scene root and trigger recursive scene conversion
	void ConvertRootNode() 
	{

	}


	// ------------------------------------------------------------------------------------------------
	// MeshGeometry -> aiMesh
	void ConvertMesh(const MeshGeometry& mesh)
	{
		const std::vector<aiVector3D>& vertices = mesh.GetVertices();
		const std::vector<unsigned int>& faces = mesh.GetFaceIndexCounts();
		if(vertices.empty() || faces.empty()) {
			return;
		}

		aiMesh* out_mesh = new aiMesh();
		meshes.push_back(out_mesh);

		sourceMeshes.push_back(&mesh);

		// copy vertices
		out_mesh->mNumVertices = static_cast<size_t>(vertices.size());
		out_mesh->mVertices = new aiVector3D[vertices.size()];
		std::copy(vertices.begin(),vertices.end(),out_mesh->mVertices);

		// generate dummy faces
		out_mesh->mNumFaces = static_cast<size_t>(faces.size());
		aiFace* fac = out_mesh->mFaces = new aiFace[faces.size()]();

		unsigned int cursor = 0;
		BOOST_FOREACH(unsigned int pcount, faces) {
			aiFace& f = *fac++;
			f.mNumIndices = pcount;
			f.mIndices = new unsigned int[pcount];
			switch(pcount) 
			{
				case 1:
					out_mesh->mPrimitiveTypes |= aiPrimitiveType_POINT;
					break;
				case 2:
					out_mesh->mPrimitiveTypes |= aiPrimitiveType_LINE;
					break;
				case 3:
					out_mesh->mPrimitiveTypes |= aiPrimitiveType_TRIANGLE;
					break;
				default:
					out_mesh->mPrimitiveTypes |= aiPrimitiveType_POLYGON;
					break;
			}
			for (unsigned int i = 0; i < pcount; ++i) {
				f.mIndices[i] = cursor++;
			}
		}

		// copy normals
		const std::vector<aiVector3D>& normals = mesh.GetVertices();
		if(normals.size()) {
			ai_assert(normals.size() == vertices.size());

			out_mesh->mNormals = new aiVector3D[vertices.size()];
			std::copy(normals.begin(),normals.end(),out_mesh->mNormals);
		}

		// copy tangents - assimp requires both tangents and bitangents (binormals)
		// to be present, or neither of them. Compute binormals from normals
		// and tangents if needed.
		const std::vector<aiVector3D>& tangents = mesh.GetTangents();
		const std::vector<aiVector3D>* binormals = &mesh.GetBinormals();

		if(tangents.size()) {
			std::vector<aiVector3D> tempBinormals;
			if (!binormals->size()) {
				if (normals.size()) {
					tempBinormals.resize(normals.size());
					for (unsigned int i = 0; i < tangents.size(); ++i) {
						tempBinormals[i] = normals[i] ^ tangents[i];
					}

					binormals = &tempBinormals;
				}
				else {
					binormals = NULL;	
				}
			}

			if(binormals) {
				ai_assert(tangents.size() == vertices.size() && binormals->size() == vertices.size());

				out_mesh->mTangents = new aiVector3D[vertices.size()];
				std::copy(tangents.begin(),tangents.end(),out_mesh->mTangents);

				out_mesh->mBitangents = new aiVector3D[vertices.size()];
				std::copy(binormals->begin(),binormals->end(),out_mesh->mBitangents);
			}
		}

		// copy texture coords
		for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i) {
			const std::vector<aiVector2D>& uvs = mesh.GetTextureCoords(i);
			if(uvs.empty()) {
				break;
			}

			aiVector3D* out_uv = out_mesh->mTextureCoords[i] = new aiVector3D[vertices.size()];
			BOOST_FOREACH(const aiVector2D& v, uvs) {
				*out_uv++ = aiVector3D(v.x,v.y,0.0f);
			}

			out_mesh->mNumUVComponents[i] = 2;
		}

		// copy vertex colors
		for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_COLOR_SETS; ++i) {
			const std::vector<aiColor4D>& colors = mesh.GetVertexColors(i);
			if(colors.empty()) {
				break;
			}

			out_mesh->mColors[i] = new aiColor4D[vertices.size()];
			std::copy(colors.begin(),colors.end(),out_mesh->mColors[i]);
		}
	}


	// ------------------------------------------------------------------------------------------------
	// Material -> aiMaterial
	void ConvertMaterial(const Material& material)
	{
		const PropertyTable& props = material.Props();

		// generate empty output material
		aiMaterial* out_mat = new aiMaterial();
		materials.push_back(out_mat);

		aiString str;

		// set material name
		str.Set(material.Name());
		out_mat->AddProperty(&str,AI_MATKEY_NAME);

		// shading stuff and colors
		SetShadingPropertiesCommon(out_mat,props);
	
		// texture assignments
		SetTextureProperties(out_mat,material.Textures());
	}


	// ------------------------------------------------------------------------------------------------
	void TrySetTextureProperties(aiMaterial* out_mat, const TextureMap& textures, const std::string& propName, aiTextureType target)
	{
		TextureMap::const_iterator it = textures.find(propName);
		if(it == textures.end()) {
			return;
		}

		const Texture* const tex = (*it).second;
		
		aiString path;
		path.Set(tex->RelativeFilename());

		out_mat->AddProperty(&path,_AI_MATKEY_TEXTURE_BASE,target,0);

		aiUVTransform uvTrafo;
		// XXX handle all kinds of UV transformations
		uvTrafo.mScaling = tex->UVScaling();
		uvTrafo.mTranslation = tex->UVTranslation();
		out_mat->AddProperty(&uvTrafo,1,_AI_MATKEY_UVTRANSFORM_BASE,target,0);

		const PropertyTable& props = tex->Props();

		int uvIndex = 0;

		bool ok;
		const std::string& uvSet = PropertyGet<std::string>(props,"UVSet",ok);
		if(ok) {
			// "default" is the name which usually appears in the FbxFileTexture template
			if(uvSet != "default" && uvSet.length()) {
				// this is a bit awkward - we need to find a mesh that uses this
				// material and scan its UV channels for the given UV name because
				// assimp references UV channels by index, not by name.

				// XXX: the case that UV channels may appear in different orders
				// in meshes is unhandled. A possible solution would be to sort
				// the UV channels alphabetically, but this would have the side
				// effect that the primary (first) UV channel would sometimes
				// be moved, causing trouble when users read only the first
				// UV channel and ignore UV channel assignments altogether.

				const unsigned int matIndex = std::distance(materials.begin(), 
					std::find(materials.begin(),materials.end(),out_mat)
				);

				uvIndex = -1;
				BOOST_FOREACH(const MeshGeometry* mesh,sourceMeshes) {
					ai_assert(mesh);

					const std::vector<unsigned int>& mats = mesh->GetMaterialIndices();
					if(std::find(mats.begin(),mats.end(),matIndex) == mats.end()) {
						continue;
					}

					int index = -1;
					for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i) {
						if(mesh->GetTextureCoords(i).empty()) {
							break;
						}
						const std::string& name = mesh->GetTextureCoordChannelName(i);
						if(name == uvSet) {
							index = static_cast<int>(i);
							break;
						}
					}
					if(index == -1) {
						FBXImporter::LogWarn("did not found UV channel named " + uvSet + " in a mesh using this material");
						continue;
					}

					if(uvIndex == -1) {
						uvIndex = index;
					}
					else {
						FBXImporter::LogWarn("the UV channel named " + uvSet + 
							" appears at different positions in meshes, results will be wrong");
					}
				}
			}
		}

		out_mat->AddProperty(&uvIndex,1,_AI_MATKEY_UVWSRC_BASE,target,0);
	}


	// ------------------------------------------------------------------------------------------------
	void SetTextureProperties(aiMaterial* out_mat, const TextureMap& textures)
	{
		TrySetTextureProperties(out_mat, textures, "DiffuseColor", aiTextureType_DIFFUSE);
		TrySetTextureProperties(out_mat, textures, "AmbientColor", aiTextureType_AMBIENT);
		TrySetTextureProperties(out_mat, textures, "EmissiveColor", aiTextureType_EMISSIVE);
		TrySetTextureProperties(out_mat, textures, "SpecularColor", aiTextureType_SPECULAR);
		TrySetTextureProperties(out_mat, textures, "TransparentColor", aiTextureType_OPACITY);
		TrySetTextureProperties(out_mat, textures, "ReflectionColor", aiTextureType_REFLECTION);
		TrySetTextureProperties(out_mat, textures, "DisplacementColor", aiTextureType_DISPLACEMENT);
		TrySetTextureProperties(out_mat, textures, "NormalMap", aiTextureType_NORMALS);
		TrySetTextureProperties(out_mat, textures, "Bump", aiTextureType_HEIGHT);
	}



	// ------------------------------------------------------------------------------------------------
	aiColor3D GetColorPropertyFromMaterial(const PropertyTable& props,const std::string& baseName, bool& result)
	{
		result = true;

		bool ok;
		const aiVector3D& Diffuse = PropertyGet<aiVector3D>(props,baseName,ok);
		if(ok) {
			return aiColor3D(Diffuse.x,Diffuse.y,Diffuse.z);
		}
		else {
			aiVector3D DiffuseColor = PropertyGet<aiVector3D>(props,baseName + "Color",ok);
			if(ok) {
				float DiffuseFactor = PropertyGet<float>(props,baseName + "Factor",ok);
				if(ok) {
					DiffuseColor *= DiffuseFactor;
				}

				return aiColor3D(DiffuseColor.x,DiffuseColor.y,DiffuseColor.z);
			}
		}
		result = false;
		return aiColor3D(0.0f,0.0f,0.0f);
	}


	// ------------------------------------------------------------------------------------------------
	void SetShadingPropertiesCommon(aiMaterial* out_mat, const PropertyTable& props)
	{
		// set shading properties. There are various, redundant ways in which FBX materials
		// specify their shading settings (depending on shading models, prop
		// template etc.). No idea which one is right in a particular context. 
		// Just try to make sense of it - there's no spec to verify this against, 
		// so why should we.
		bool ok;
		const aiColor3D& Diffuse = GetColorPropertyFromMaterial(props,"Diffuse",ok);
		if(ok) {
			out_mat->AddProperty(&Diffuse,1,AI_MATKEY_COLOR_EMISSIVE);
		}

		const aiColor3D& Emissive = GetColorPropertyFromMaterial(props,"Emissive",ok);
		if(ok) {
			out_mat->AddProperty(&Emissive,1,AI_MATKEY_COLOR_EMISSIVE);
		}

		const aiColor3D& Ambient = GetColorPropertyFromMaterial(props,"Ambient",ok);
		if(ok) {
			out_mat->AddProperty(&Ambient,1,AI_MATKEY_COLOR_AMBIENT);
		}

		const aiColor3D& Specular = GetColorPropertyFromMaterial(props,"Specular",ok);
		if(ok) {
			out_mat->AddProperty(&Specular,1,AI_MATKEY_COLOR_SPECULAR);
		}

		const float Opacity = PropertyGet<float>(props,"Opacity",ok);
		if(ok) {
			out_mat->AddProperty(&Opacity,1,AI_MATKEY_OPACITY);
		}

		const float Reflectivity = PropertyGet<float>(props,"Reflectivity",ok);
		if(ok) {
			out_mat->AddProperty(&Reflectivity,1,AI_MATKEY_REFLECTIVITY);
		}

		const float Shininess = PropertyGet<float>(props,"Shininess",ok);
		if(ok) {
			out_mat->AddProperty(&Shininess,1,AI_MATKEY_SHININESS_STRENGTH);
		}

		const float ShininessExponent = PropertyGet<float>(props,"ShininessExponent",ok);
		if(ok) {
			out_mat->AddProperty(&ShininessExponent,1,AI_MATKEY_SHININESS);
		}
	}


	// ------------------------------------------------------------------------------------------------
	// copy generated meshes, animations, lights, cameras and textures to the output scene
	void TransferDataToScene()
	{
		ai_assert(!out->mMeshes && !out->mNumMeshes);

		// note: the trailing () ensures initialization with NULL - not
		// many C++ users seem to know this, so pointing it out to avoid
		// confusion why this code works.
		out->mMeshes = new aiMesh*[meshes.size()]();
		out->mNumMeshes = static_cast<unsigned int>(meshes.size());

		std::swap_ranges(meshes.begin(),meshes.end(),out->mMeshes);


		if(materials.size()) {
			out->mMaterials = new aiMaterial*[materials.size()]();
			out->mNumMaterials = static_cast<unsigned int>(materials.size());

			std::swap_ranges(materials.begin(),materials.end(),out->mMaterials);
		}
	}


private:

	std::vector<aiMesh*> meshes;
	std::vector<aiMaterial*> materials;

	std::vector<const MeshGeometry*> sourceMeshes;

	aiScene* const out;
	const FBX::Document& doc;
};

} // !anon

// ------------------------------------------------------------------------------------------------
void ConvertToAssimpScene(aiScene* out, const Document& doc)
{
	Converter converter(out,doc);
}

} // !FBX
} // !Assimp

#endif