/*
Assimp2Json
Copyright (c) 2011, Alexander C. Gessler

Licensed under a 3-clause BSD license. See the LICENSE file for more information.

*/

#ifndef ASSIMP_BUILD_NO_EXPORT
#ifndef ASSIMP_BUILD_NO_ASSJSON_EXPORTER

#include <assimp/Importer.hpp>
#include <assimp/Exporter.hpp>
#include <assimp/IOStream.hpp>
#include <assimp/IOSystem.hpp>

#include <assimp/scene.h>

#include <sstream>
#include <limits>
#include <cassert>
#include <memory>

#define CURRENT_FORMAT_VERSION 100

// grab scoped_ptr from assimp to avoid a dependency on boost. 
//#include <assimp/../../code/BoostWorkaround/boost/scoped_ptr.hpp>

#include "mesh_splitter.h"


extern "C" {
#include "cencode.h"
}

namespace {
void Assimp2Json(const char*, Assimp::IOSystem*, const aiScene*, const Assimp::ExportProperties*);
}

Assimp::Exporter::ExportFormatEntry Assimp2Json_desc = Assimp::Exporter::ExportFormatEntry(
	"assimp.json",
	"Plain JSON representation of the Assimp scene data structure",
	"assimp.json",
	Assimp2Json,
	0u);

namespace {


	// small utility class to simplify serializing the aiScene to Json
class JSONWriter
{

public:

	enum {
		Flag_DoNotIndent = 0x1,
		Flag_WriteSpecialFloats = 0x2,
	};

public:

	JSONWriter(Assimp::IOStream& out, unsigned int flags = 0u)
		: out(out)
		, first()
		, flags(flags)
	{
		// make sure that all formatting happens using the standard, C locale and not the user's current locale
		buff.imbue( std::locale("C") );
	}

	~JSONWriter()
	{
		Flush();
	}

public:

	void Flush()	{
		const std::string s = buff.str();
		out.Write(s.c_str(),s.length(),1);
		buff.clear();
	}

	void PushIndent() {
		indent += '\t';
	}

	void PopIndent() {
		indent.erase(indent.end()-1);
	}

	void Key(const std::string& name) {
		AddIndentation();
		Delimit();
		buff << '\"'+name+"\": ";
	}

	template<typename Literal>
	void Element(const Literal& name) {
		AddIndentation();
		Delimit();

		LiteralToString(buff, name) << '\n';
	}

	template<typename Literal>
	void SimpleValue(const Literal& s) {
		LiteralToString(buff, s) << '\n';
	}


	void SimpleValue(const void* buffer, size_t len) {
		base64_encodestate s;
		base64_init_encodestate(&s);

		char* const out = new char[std::max(len*2, static_cast<size_t>(16u))];
		const int n = base64_encode_block(reinterpret_cast<const char*>( buffer ), static_cast<int>( len ),out,&s);
		out[n+base64_encode_blockend(out + n,&s)] = '\0';

		// base64 encoding may add newlines, but JSON strings may not contain 'real' newlines
		// (only escaped ones). Remove any newlines in out.
		for(char* cur = out; *cur; ++cur) {
			if(*cur == '\n') {
				*cur = ' ';
			}
		}


		buff << '\"' << out << "\"\n";
		delete[] out;
	} 

	void StartObj(bool is_element = false) {
		// if this appears as a plain array element, we need to insert a delimiter and we should also indent it
		if(is_element) {
			AddIndentation();
			if(!first) {
				buff << ',';
			}
		}
		first = true;
		buff << "{\n";
		PushIndent();
	}

	void EndObj() {
		PopIndent();
		AddIndentation();
		first = false;
		buff << "}\n";
	}

	void StartArray(bool is_element = false) {
		// if this appears as a plain array element, we need to insert a delimiter and we should also indent it
		if(is_element) {
			AddIndentation();
			if(!first) {
				buff << ',';
			}
		}
		first = true;
		buff << "[\n";
		PushIndent();
	}

	void EndArray() {
		PopIndent();
		AddIndentation();
		buff << "]\n";
		first = false;
	}

	void AddIndentation() {
		if(!(flags & Flag_DoNotIndent)) {
			buff << indent;
		}
	}

	void Delimit() {
		if(!first) {
			buff << ',';
		}
		else {
			buff << ' ';		
			first = false;
		}
	}

private:

	template<typename Literal>
	std::stringstream& LiteralToString(std::stringstream& stream, const Literal& s) {
		stream << s;
		return stream;
	}

	std::stringstream& LiteralToString(std::stringstream& stream, const aiString& s) {
		std::string t;

		// escape backslashes and single quotes, both would render the JSON invalid if left as is
		t.reserve(s.length);
		for(size_t i = 0; i < s.length; ++i) {
			
			if (s.data[i] == '\\' || s.data[i] == '\'' || s.data[i] == '\"') {
				t.push_back('\\');
			}

			t.push_back(s.data[i]);
		}
		stream << "\"";
		stream << t;
		stream << "\"";
		return stream;
	}

	std::stringstream& LiteralToString(std::stringstream& stream, float f) {
		if (!std::numeric_limits<float>::is_iec559) {
			// on a non IEEE-754 platform, we make no assumptions about the representation or existence
			// of special floating-point numbers. 
			stream << f;
			return stream;
		}

		// JSON does not support writing Inf/Nan
		// [RFC 4672: "Numeric values that cannot be represented as sequences of digits
		// (such as Infinity and NaN) are not permitted."]
		// Nevertheless, many parsers will accept the special keywords Infinity, -Infinity and NaN
		if (std::numeric_limits<float>::infinity() == fabs(f)) {
			if (flags & Flag_WriteSpecialFloats) {
				stream << (f < 0 ? "\"-" : "\"") + std::string( "Infinity\"" );
				return stream;
			}
		//  we should print this warning, but we can't - this is called from within a generic assimp exporter, we cannot use cerr
		//	std::cerr << "warning: cannot represent infinite number literal, substituting 0 instead (use -i flag to enforce Infinity/NaN)" << std::endl;
			stream << "0.0";
			return stream;
		}
		// f!=f is the most reliable test for NaNs that I know of
		else if (f != f) {
			if (flags & Flag_WriteSpecialFloats) {
				stream << "\"NaN\"";
				return stream;
			}
		//  we should print this warning, but we can't - this is called from within a generic assimp exporter, we cannot use cerr
		//	std::cerr << "warning: cannot represent infinite number literal, substituting 0 instead (use -i flag to enforce Infinity/NaN)" << std::endl;
			stream << "0.0";
			return stream;
		}

		stream << f;
		return stream;
	}

private: 
	Assimp::IOStream& out;
	std::string indent, newline;
	std::stringstream buff;
	bool first;

	unsigned int flags;
};


void Write(JSONWriter& out, const aiVector3D& ai, bool is_elem = true) 
{
	out.StartArray(is_elem);
	out.Element(ai.x);
	out.Element(ai.y);
	out.Element(ai.z);
	out.EndArray();
}

void Write(JSONWriter& out, const aiQuaternion& ai, bool is_elem = true) 
{
	out.StartArray(is_elem);
	out.Element(ai.w);
	out.Element(ai.x);
	out.Element(ai.y);
	out.Element(ai.z);
	out.EndArray();
}

void Write(JSONWriter& out, const aiColor3D& ai, bool is_elem = true) 
{
	out.StartArray(is_elem);
	out.Element(ai.r);
	out.Element(ai.g);
	out.Element(ai.b);
	out.EndArray();
}

void Write(JSONWriter& out, const aiMatrix4x4& ai, bool is_elem = true) 
{
	out.StartArray(is_elem);
	for(unsigned int x = 0; x < 4; ++x) {
		for(unsigned int y = 0; y < 4; ++y) {
			out.Element(ai[x][y]);
		}
	}
	out.EndArray();
}

void Write(JSONWriter& out, const aiBone& ai, bool is_elem = true)
{
	out.StartObj(is_elem);

	out.Key("name");
	out.SimpleValue(ai.mName);

	out.Key("offsetmatrix");
	Write(out,ai.mOffsetMatrix,false);

	out.Key("weights");
	out.StartArray();
	for(unsigned int i = 0; i < ai.mNumWeights; ++i) {
		out.StartArray(true);
		out.Element(ai.mWeights[i].mVertexId);
		out.Element(ai.mWeights[i].mWeight);
		out.EndArray();
	}
	out.EndArray();
	out.EndObj();
}


void Write(JSONWriter& out, const aiFace& ai, bool is_elem = true)
{
	out.StartArray(is_elem);
	for(unsigned int i = 0; i < ai.mNumIndices; ++i) {
		out.Element(ai.mIndices[i]);
	}
	out.EndArray();
}


void Write(JSONWriter& out, const aiMesh& ai, bool is_elem = true)
{
	out.StartObj(is_elem); 

	out.Key("name");
	out.SimpleValue(ai.mName);

	out.Key("materialindex");
	out.SimpleValue(ai.mMaterialIndex);

	out.Key("primitivetypes");
	out.SimpleValue(ai.mPrimitiveTypes);

	out.Key("vertices");
	out.StartArray();
	for(unsigned int i = 0; i < ai.mNumVertices; ++i) {
		out.Element(ai.mVertices[i].x);
		out.Element(ai.mVertices[i].y);
		out.Element(ai.mVertices[i].z);
	}
	out.EndArray();

	if(ai.HasNormals()) {
		out.Key("normals");
		out.StartArray();
		for(unsigned int i = 0; i < ai.mNumVertices; ++i) {
			out.Element(ai.mNormals[i].x);
			out.Element(ai.mNormals[i].y);
			out.Element(ai.mNormals[i].z);
		}
		out.EndArray();
	}

	if(ai.HasTangentsAndBitangents()) {
		out.Key("tangents");
		out.StartArray();
		for(unsigned int i = 0; i < ai.mNumVertices; ++i) {
			out.Element(ai.mTangents[i].x);
			out.Element(ai.mTangents[i].y);
			out.Element(ai.mTangents[i].z);
		}
		out.EndArray();

		out.Key("bitangents");
		out.StartArray();
		for(unsigned int i = 0; i < ai.mNumVertices; ++i) {
			out.Element(ai.mBitangents[i].x);
			out.Element(ai.mBitangents[i].y);
			out.Element(ai.mBitangents[i].z);
		}
		out.EndArray();
	}

	if(ai.GetNumUVChannels()) {
		out.Key("numuvcomponents");
		out.StartArray();
		for(unsigned int n = 0; n < ai.GetNumUVChannels(); ++n) {
			out.Element(ai.mNumUVComponents[n]);
		}
		out.EndArray();

		out.Key("texturecoords");
		out.StartArray();
		for(unsigned int n = 0; n < ai.GetNumUVChannels(); ++n) {

			const unsigned int numc = ai.mNumUVComponents[n] ? ai.mNumUVComponents[n] : 2;
			
			out.StartArray(true);
			for(unsigned int i = 0; i < ai.mNumVertices; ++i) {
				for(unsigned int c = 0; c < numc; ++c) {
					out.Element(ai.mTextureCoords[n][i][c]);
				}
			}
			out.EndArray();
		}
		out.EndArray();
	}

	if(ai.GetNumColorChannels()) {
		out.Key("colors");
		out.StartArray();
		for(unsigned int n = 0; n < ai.GetNumColorChannels(); ++n) {

			out.StartArray(true);
			for(unsigned int i = 0; i < ai.mNumVertices; ++i) {
				out.Element(ai.mColors[n][i].r);
				out.Element(ai.mColors[n][i].g);
				out.Element(ai.mColors[n][i].b);
				out.Element(ai.mColors[n][i].a);
			}
			out.EndArray();
		}
		out.EndArray();
	}

	if(ai.mNumBones) {
		out.Key("bones");
		out.StartArray();
		for(unsigned int n = 0; n < ai.mNumBones; ++n) {
			Write(out, *ai.mBones[n]);
		}
		out.EndArray();
	}


	out.Key("faces");
	out.StartArray();
	for(unsigned int n = 0; n < ai.mNumFaces; ++n) {
		Write(out, ai.mFaces[n]);
	}
	out.EndArray();

	out.EndObj();
}


void Write(JSONWriter& out, const aiNode& ai, bool is_elem = true)
{
	out.StartObj(is_elem);

	out.Key("name");
	out.SimpleValue(ai.mName);

	out.Key("transformation");
	Write(out,ai.mTransformation,false);

	if(ai.mNumMeshes) {
		out.Key("meshes");
		out.StartArray();
		for(unsigned int n = 0; n < ai.mNumMeshes; ++n) {
			out.Element(ai.mMeshes[n]);
		}
		out.EndArray();
	}

	if(ai.mNumChildren) {
		out.Key("children");
		out.StartArray();
		for(unsigned int n = 0; n < ai.mNumChildren; ++n) {
			Write(out,*ai.mChildren[n]);
		}
		out.EndArray();
	}

	out.EndObj();
}

void Write(JSONWriter& out, const aiMaterial& ai, bool is_elem = true)
{
	out.StartObj(is_elem);

	out.Key("properties");
	out.StartArray();
	for(unsigned int i = 0; i < ai.mNumProperties; ++i) {
		const aiMaterialProperty* const prop = ai.mProperties[i];
		out.StartObj(true);
		out.Key("key");
		out.SimpleValue(prop->mKey);
		out.Key("semantic");
		out.SimpleValue(prop->mSemantic);
		out.Key("index");
		out.SimpleValue(prop->mIndex);

		out.Key("type");
		out.SimpleValue(prop->mType);

		out.Key("value");
		switch(prop->mType)
		{
		case aiPTI_Float:
			if(prop->mDataLength/sizeof(float) > 1) {
				out.StartArray();
				for(unsigned int i = 0; i < prop->mDataLength/sizeof(float); ++i) {
					out.Element(reinterpret_cast<float*>(prop->mData)[i]);
				}
				out.EndArray();
			}
			else {
				out.SimpleValue(*reinterpret_cast<float*>(prop->mData));
			}
			break;

		case aiPTI_Integer:
			if(prop->mDataLength/sizeof(int) > 1) {
				out.StartArray();
				for(unsigned int i = 0; i < prop->mDataLength/sizeof(int); ++i) {
					out.Element(reinterpret_cast<int*>(prop->mData)[i]);
				}
				out.EndArray();
			}
			else {
				out.SimpleValue(*reinterpret_cast<int*>(prop->mData));
			}
			break;
		case aiPTI_String: 
			{
				aiString s;
				aiGetMaterialString(&ai,prop->mKey.data,prop->mSemantic,prop->mIndex,&s);
				out.SimpleValue(s);
			}
			break;
		case aiPTI_Buffer:
			{
				// binary data is written as series of hex-encoded octets
				out.SimpleValue(prop->mData,prop->mDataLength);
			}
			break;
		default:
			assert(false);
		}

		out.EndObj();
	}

	out.EndArray();
	out.EndObj();
}

void Write(JSONWriter& out, const aiTexture& ai, bool is_elem = true)
{
	out.StartObj(is_elem);

	out.Key("width");
	out.SimpleValue(ai.mWidth);

	out.Key("height");
	out.SimpleValue(ai.mHeight);

	out.Key("formathint");
	out.SimpleValue(aiString(ai.achFormatHint));

	out.Key("data");
	if(!ai.mHeight) {
		out.SimpleValue(ai.pcData,ai.mWidth);
	}
	else {
		out.StartArray();
		for(unsigned int y = 0; y < ai.mHeight; ++y) {
			out.StartArray(true);
			for(unsigned int x = 0; x < ai.mWidth; ++x) {
				const aiTexel& tx = ai.pcData[y*ai.mWidth+x];
				out.StartArray(true);
				out.Element(static_cast<unsigned int>(tx.r));
				out.Element(static_cast<unsigned int>(tx.g));
				out.Element(static_cast<unsigned int>(tx.b));
				out.Element(static_cast<unsigned int>(tx.a));
				out.EndArray();
			}
			out.EndArray();
		}
		out.EndArray();
	}

	out.EndObj();
}

void Write(JSONWriter& out, const aiLight& ai, bool is_elem = true)
{
	out.StartObj(is_elem);

	out.Key("name");
	out.SimpleValue(ai.mName);

	out.Key("type");
	out.SimpleValue(ai.mType);

	if(ai.mType == aiLightSource_SPOT || ai.mType == aiLightSource_UNDEFINED) {
		out.Key("angleinnercone");
		out.SimpleValue(ai.mAngleInnerCone);

		out.Key("angleoutercone");
		out.SimpleValue(ai.mAngleOuterCone);
	}

	out.Key("attenuationconstant");
	out.SimpleValue(ai.mAttenuationConstant);

	out.Key("attenuationlinear");
	out.SimpleValue(ai.mAttenuationLinear);

	out.Key("attenuationquadratic");
	out.SimpleValue(ai.mAttenuationQuadratic);

	out.Key("diffusecolor");
	Write(out,ai.mColorDiffuse,false);

	out.Key("specularcolor");
	Write(out,ai.mColorSpecular,false);

	out.Key("ambientcolor");
	Write(out,ai.mColorAmbient,false);

	if(ai.mType != aiLightSource_POINT) {
		out.Key("direction");
		Write(out,ai.mDirection,false);

	}

	if(ai.mType != aiLightSource_DIRECTIONAL) {
		out.Key("position");
		Write(out,ai.mPosition,false);
	}

	out.EndObj();
}

void Write(JSONWriter& out, const aiNodeAnim& ai, bool is_elem = true)
{
	out.StartObj(is_elem);

	out.Key("name");
	out.SimpleValue(ai.mNodeName);

	out.Key("prestate");
	out.SimpleValue(ai.mPreState);

	out.Key("poststate");
	out.SimpleValue(ai.mPostState);

	if(ai.mNumPositionKeys) {
		out.Key("positionkeys");
		out.StartArray();
		for(unsigned int n = 0; n < ai.mNumPositionKeys; ++n) {
			const aiVectorKey& pos = ai.mPositionKeys[n];
			out.StartArray(true);
			out.Element(pos.mTime);
			Write(out,pos.mValue);
			out.EndArray();
		}
		out.EndArray();
	}

	if(ai.mNumRotationKeys) {
		out.Key("rotationkeys");
		out.StartArray();
		for(unsigned int n = 0; n < ai.mNumRotationKeys; ++n) {
			const aiQuatKey& rot = ai.mRotationKeys[n];
			out.StartArray(true);
			out.Element(rot.mTime);
			Write(out,rot.mValue);
			out.EndArray();
		}
		out.EndArray();
	}

	if(ai.mNumScalingKeys) {
		out.Key("scalingkeys");
		out.StartArray();
		for(unsigned int n = 0; n < ai.mNumScalingKeys; ++n) {
			const aiVectorKey& scl = ai.mScalingKeys[n];
			out.StartArray(true);
			out.Element(scl.mTime);
			Write(out,scl.mValue);
			out.EndArray();
		}
		out.EndArray();
	}
	out.EndObj();
}

void Write(JSONWriter& out, const aiAnimation& ai, bool is_elem = true)
{
	out.StartObj(is_elem);

	out.Key("name");
	out.SimpleValue(ai.mName);

	out.Key("tickspersecond");
	out.SimpleValue(ai.mTicksPerSecond);

	out.Key("duration");
	out.SimpleValue(ai.mDuration);

	out.Key("channels");
	out.StartArray();
	for(unsigned int n = 0; n < ai.mNumChannels; ++n) {
		Write(out,*ai.mChannels[n]);
	}
	out.EndArray();
	out.EndObj();
}

void Write(JSONWriter& out, const aiCamera& ai, bool is_elem = true)
{
	out.StartObj(is_elem);

	out.Key("name");
	out.SimpleValue(ai.mName);

	out.Key("aspect");
	out.SimpleValue(ai.mAspect);

	out.Key("clipplanefar");
	out.SimpleValue(ai.mClipPlaneFar);

	out.Key("clipplanenear");
	out.SimpleValue(ai.mClipPlaneNear);

	out.Key("horizontalfov");
	out.SimpleValue(ai.mHorizontalFOV);

	out.Key("up");
	Write(out,ai.mUp,false);

	out.Key("lookat");
	Write(out,ai.mLookAt,false);

	out.EndObj();
}

void WriteFormatInfo(JSONWriter& out)
{
	out.StartObj();
	out.Key("format");
	out.SimpleValue("\"assimp2json\"");
	out.Key("version");
	out.SimpleValue(CURRENT_FORMAT_VERSION);
	out.EndObj();
}

void Write(JSONWriter& out, const aiScene& ai)
{
	out.StartObj();

	out.Key("__metadata__");
	WriteFormatInfo(out);

	out.Key("rootnode");
	Write(out,*ai.mRootNode, false);

	out.Key("flags");
	out.SimpleValue(ai.mFlags);

	if(ai.HasMeshes()) {
		out.Key("meshes");
		out.StartArray();
		for(unsigned int n = 0; n < ai.mNumMeshes; ++n) {
			Write(out,*ai.mMeshes[n]);
		}
		out.EndArray();
	}

	if(ai.HasMaterials()) {
		out.Key("materials");
		out.StartArray();
		for(unsigned int n = 0; n < ai.mNumMaterials; ++n) {
			Write(out,*ai.mMaterials[n]);
		}
		out.EndArray();
	}

	if(ai.HasAnimations()) {
		out.Key("animations");
		out.StartArray();
		for(unsigned int n = 0; n < ai.mNumAnimations; ++n) {
			Write(out,*ai.mAnimations[n]);
		}
		out.EndArray();
	}

	if(ai.HasLights()) {
		out.Key("lights");
		out.StartArray();
		for(unsigned int n = 0; n < ai.mNumLights; ++n) {
			Write(out,*ai.mLights[n]);
		}
		out.EndArray();
	}

	if(ai.HasCameras()) {
		out.Key("cameras");
		out.StartArray();
		for(unsigned int n = 0; n < ai.mNumCameras; ++n) {
			Write(out,*ai.mCameras[n]);
		}
		out.EndArray();
	}

	if(ai.HasTextures()) {
		out.Key("textures");
		out.StartArray();
		for(unsigned int n = 0; n < ai.mNumTextures; ++n) {
			Write(out,*ai.mTextures[n]);
		}
		out.EndArray();
	}
	out.EndObj();
}


void ExportAssimp2Json(const char* file, Assimp::IOSystem* io, const aiScene* scene, const Assimp::ExportProperties*)
{
	std::unique_ptr<Assimp::IOStream> str(io->Open(file,"wt"));
	if(!str) {
		//throw Assimp::DeadlyExportError("could not open output file");
	}

	// get a copy of the scene so we can modify it
	aiScene* scenecopy_tmp;
	aiCopyScene(scene, &scenecopy_tmp);

	try {
		// split meshes so they fit into a 16 bit index buffer
		MeshSplitter splitter;
		splitter.SetLimit(1 << 16);
		splitter.Execute(scenecopy_tmp);

		// XXX Flag_WriteSpecialFloats is turned on by default, right now we don't have a configuration interface for exporters
		JSONWriter s(*str,JSONWriter::Flag_WriteSpecialFloats);
		Write(s,*scenecopy_tmp);

	}
	catch(...) {
		aiFreeScene(scenecopy_tmp);
		throw;
	}
	aiFreeScene(scenecopy_tmp);
}

} // 

#endif // ASSIMP_BUILD_NO_ASSJSON_EXPORTER
#endif // ASSIMP_BUILD_NO_EXPORT