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

Copyright (c) 2006-2012, assimp team

All rights reserved.

Redistribution and use of this software in source and binary forms, 
with or without modification, are permitted provided that the following 
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* 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
  following disclaimer in the documentation and/or other
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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 Exporter.cpp

Assimp export interface. While it's public interface bears many similarities
to the import interface (in fact, it is largely symmetric), the internal
implementations differs a lot. Exporters are considered stateless and are
simple callbacks which we maintain in a global list along with their
description strings.

Here we implement only the C++ interface (Assimp::Exporter).
*/

#include "AssimpPCH.h"

#ifndef ASSIMP_BUILD_NO_EXPORT

#include "DefaultIOSystem.h"
#include "BlobIOSystem.h" 
#include "SceneCombiner.h" 
#include "BaseProcess.h" 
#include "Importer.h" // need this for GetPostProcessingStepInstanceList()

#include "JoinVerticesProcess.h"
#include "MakeVerboseFormat.h"
#include "ConvertToLHProcess.h"

namespace Assimp {

// PostStepRegistry.cpp
void GetPostProcessingStepInstanceList(std::vector< BaseProcess* >& out);

// ------------------------------------------------------------------------------------------------
// Exporter worker function prototypes. Should not be necessary to #ifndef them, it's just a prototype
// do not use const, because some exporter need to convert the scene temporary
void ExportSceneCollada(const char*,IOSystem*, const aiScene*);
void ExportSceneXFile(const char*,IOSystem*, const aiScene*); 
void ExportSceneObj(const char*,IOSystem*, const aiScene*);
void ExportSceneSTL(const char*,IOSystem*, const aiScene*);
void ExportSceneSTLBinary(const char*,IOSystem*, const aiScene*);
void ExportScenePly(const char*,IOSystem*, const aiScene*);
void ExportScene3DS(const char*, IOSystem*, const aiScene*);
void ExportSceneAssbin(const char*, IOSystem*, const aiScene*);

// ------------------------------------------------------------------------------------------------
// global array of all export formats which Assimp supports in its current build
Exporter::ExportFormatEntry gExporters[] = 
{
#ifndef ASSIMP_BUILD_NO_COLLADA_EXPORTER
	Exporter::ExportFormatEntry( "collada", "COLLADA - Digital Asset Exchange Schema", "dae", &ExportSceneCollada),
#endif

#ifndef ASSIMP_BUILD_NO_FXILE_EXPORTER
	Exporter::ExportFormatEntry( "x", "X Files", "x", &ExportSceneXFile,
		aiProcess_MakeLeftHanded | aiProcess_FlipWindingOrder | aiProcess_FlipUVs),
#endif

#ifndef ASSIMP_BUILD_NO_OBJ_EXPORTER
	Exporter::ExportFormatEntry( "obj", "Wavefront OBJ format", "obj", &ExportSceneObj, 
		aiProcess_GenSmoothNormals /*| aiProcess_PreTransformVertices */),
#endif

#ifndef ASSIMP_BUILD_NO_STL_EXPORTER
	Exporter::ExportFormatEntry( "stl", "Stereolithography", "stl" , &ExportSceneSTL, 
		aiProcess_Triangulate | aiProcess_GenNormals | aiProcess_PreTransformVertices
	),
	Exporter::ExportFormatEntry( "stlb", "Stereolithography (binary)", "stl" , &ExportSceneSTLBinary, 
		aiProcess_Triangulate | aiProcess_GenNormals | aiProcess_PreTransformVertices
	),
#endif

#ifndef ASSIMP_BUILD_NO_PLY_EXPORTER
	Exporter::ExportFormatEntry( "ply", "Stanford Polygon Library", "ply" , &ExportScenePly, 
		aiProcess_PreTransformVertices
	),
#endif

#ifndef ASSIMP_BUILD_NO_3DS_EXPORTER
	Exporter::ExportFormatEntry( "3ds", "Autodesk 3DS (legacy)", "3ds" , &ExportScene3DS,
		aiProcess_Triangulate | aiProcess_SortByPType | aiProcess_JoinIdenticalVertices),
#endif

#ifndef ASSIMP_BUILD_NO_ASSBIN_EXPORTER
	Exporter::ExportFormatEntry( "assbin", "Assimp Binary", "assbin" , &ExportSceneAssbin, NULL),
#endif
};

#define ASSIMP_NUM_EXPORTERS (sizeof(gExporters)/sizeof(gExporters[0]))


class ExporterPimpl {
public:

	ExporterPimpl()
		: blob()
		, mIOSystem(new Assimp::DefaultIOSystem())
		, mIsDefaultIOHandler(true)
	{
		GetPostProcessingStepInstanceList(mPostProcessingSteps);

		// grab all builtin exporters
		mExporters.resize(ASSIMP_NUM_EXPORTERS);
		std::copy(gExporters,gExporters+ASSIMP_NUM_EXPORTERS,mExporters.begin());
	}

	~ExporterPimpl() 
	{
		delete blob;

		// Delete all post-processing plug-ins
		for( unsigned int a = 0; a < mPostProcessingSteps.size(); a++) {
			delete mPostProcessingSteps[a];
		}
	}

public:
		
	aiExportDataBlob* blob;
	boost::shared_ptr< Assimp::IOSystem > mIOSystem;
	bool mIsDefaultIOHandler;

	/** Post processing steps we can apply at the imported data. */
	std::vector< BaseProcess* > mPostProcessingSteps;

	/** Last fatal export error */
	std::string mError;

	/** Exporters, this includes those registered using #Assimp::Exporter::RegisterExporter */
	std::vector<Exporter::ExportFormatEntry> mExporters;
};


} // end of namespace Assimp





using namespace Assimp;


// ------------------------------------------------------------------------------------------------
Exporter :: Exporter() 
: pimpl(new ExporterPimpl())
{
}


// ------------------------------------------------------------------------------------------------
Exporter :: ~Exporter()
{
	FreeBlob();

	delete pimpl;
}


// ------------------------------------------------------------------------------------------------
void Exporter :: SetIOHandler( IOSystem* pIOHandler)
{
	pimpl->mIsDefaultIOHandler = !pIOHandler;
	pimpl->mIOSystem.reset(pIOHandler);
}


// ------------------------------------------------------------------------------------------------
IOSystem* Exporter :: GetIOHandler() const
{
	return pimpl->mIOSystem.get();
}


// ------------------------------------------------------------------------------------------------
bool Exporter :: IsDefaultIOHandler() const
{
	return pimpl->mIsDefaultIOHandler;
}


// ------------------------------------------------------------------------------------------------
const aiExportDataBlob* Exporter :: ExportToBlob(  const aiScene* pScene, const char* pFormatId, unsigned int )
{
	if (pimpl->blob) {
		delete pimpl->blob;
		pimpl->blob = NULL;
	}


	boost::shared_ptr<IOSystem> old = pimpl->mIOSystem;

	BlobIOSystem* blobio = new BlobIOSystem();
	pimpl->mIOSystem = boost::shared_ptr<IOSystem>( blobio );

	if (AI_SUCCESS != Export(pScene,pFormatId,blobio->GetMagicFileName())) {
		pimpl->mIOSystem = old;
		return NULL;
	}

	pimpl->blob = blobio->GetBlobChain();
	pimpl->mIOSystem = old;

	return pimpl->blob;
}


// ------------------------------------------------------------------------------------------------
bool IsVerboseFormat(const aiMesh* mesh) 
{
	// avoid slow vector<bool> specialization
	std::vector<unsigned int> seen(mesh->mNumVertices,0);
	for(unsigned int i = 0; i < mesh->mNumFaces; ++i) {
		const aiFace& f = mesh->mFaces[i];
		for(unsigned int j = 0; j < f.mNumIndices; ++j) {
			if(++seen[f.mIndices[j]] == 2) {
				// found a duplicate index
				return false;
			}
		}
	}
	return true;
}


// ------------------------------------------------------------------------------------------------
bool IsVerboseFormat(const aiScene* pScene) 
{
	for(unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
		if(!IsVerboseFormat(pScene->mMeshes[i])) {
			return false;
		}
	}
	return true;
}


// ------------------------------------------------------------------------------------------------
aiReturn Exporter :: Export( const aiScene* pScene, const char* pFormatId, const char* pPath, unsigned int pPreprocessing )
{
	ASSIMP_BEGIN_EXCEPTION_REGION();

	// when they create scenes from scratch, users will likely create them not in verbose
	// format. They will likely not be aware that there is a flag in the scene to indicate
	// this, however. To avoid surprises and bug reports, we check for duplicates in
	// meshes upfront.
	const bool is_verbose_format = !(pScene->mFlags & AI_SCENE_FLAGS_NON_VERBOSE_FORMAT) || IsVerboseFormat(pScene);

	pimpl->mError = "";
	for (size_t i = 0; i < pimpl->mExporters.size(); ++i) {
		const Exporter::ExportFormatEntry& exp = pimpl->mExporters[i];
		if (!strcmp(exp.mDescription.id,pFormatId)) {

			try {

				// Always create a full copy of the scene. We might optimize this one day, 
				// but for now it is the most pragmatic way.
				aiScene* scenecopy_tmp;
				SceneCombiner::CopyScene(&scenecopy_tmp,pScene);

				std::auto_ptr<aiScene> scenecopy(scenecopy_tmp);
				const ScenePrivateData* const priv = ScenePriv(pScene);

				// steps that are not idempotent, i.e. we might need to run them again, usually to get back to the
				// original state before the step was applied first. When checking which steps we don't need
				// to run, those are excluded.
				const unsigned int nonIdempotentSteps = aiProcess_FlipWindingOrder | aiProcess_FlipUVs | aiProcess_MakeLeftHanded;

				// Erase all pp steps that were already applied to this scene
				const unsigned int pp = (exp.mEnforcePP | pPreprocessing) & ~(priv && !priv->mIsCopy
					? (priv->mPPStepsApplied & ~nonIdempotentSteps)
					: 0u);

				// If no extra postprocessing was specified, and we obtained this scene from an
				// Assimp importer, apply the reverse steps automatically.
				// TODO: either drop this, or document it. Otherwise it is just a bad surprise.
				//if (!pPreprocessing && priv) {
				//	pp |= (nonIdempotentSteps & priv->mPPStepsApplied);
				//}

				// If the input scene is not in verbose format, but there is at least postprocessing step that relies on it,
				// we need to run the MakeVerboseFormat step first.
				bool must_join_again = false;
				if (!is_verbose_format) {
					
					bool verbosify = false;
					for( unsigned int a = 0; a < pimpl->mPostProcessingSteps.size(); a++) {
						BaseProcess* const p = pimpl->mPostProcessingSteps[a];

						if (p->IsActive(pp) && p->RequireVerboseFormat()) {
							verbosify = true;
							break;
						}
					}

					if (verbosify || (exp.mEnforcePP & aiProcess_JoinIdenticalVertices)) {
						DefaultLogger::get()->debug("export: Scene data not in verbose format, applying MakeVerboseFormat step first");

						MakeVerboseFormatProcess proc;
						proc.Execute(scenecopy.get());

						if(!(exp.mEnforcePP & aiProcess_JoinIdenticalVertices)) {
							must_join_again = true;
						}
					}
				}

				if (pp) {
					// the three 'conversion' steps need to be executed first because all other steps rely on the standard data layout
					{
						FlipWindingOrderProcess step;
						if (step.IsActive(pp)) {
							step.Execute(scenecopy.get());
						}
					}
					
					{
						FlipUVsProcess step;
						if (step.IsActive(pp)) {
							step.Execute(scenecopy.get());
						}
					}

					{
						MakeLeftHandedProcess step;
						if (step.IsActive(pp)) {
							step.Execute(scenecopy.get());
						}
					}

					// dispatch other processes
					for( unsigned int a = 0; a < pimpl->mPostProcessingSteps.size(); a++) {
						BaseProcess* const p = pimpl->mPostProcessingSteps[a];

						if (p->IsActive(pp) 
							&& !dynamic_cast<FlipUVsProcess*>(p) 
							&& !dynamic_cast<FlipWindingOrderProcess*>(p) 
							&& !dynamic_cast<MakeLeftHandedProcess*>(p)) {

							p->Execute(scenecopy.get());
						}
					}
					ScenePrivateData* const privOut = ScenePriv(scenecopy.get());
					ai_assert(privOut);

					privOut->mPPStepsApplied |= pp;
				}

				if(must_join_again) {
					JoinVerticesProcess proc;
					proc.Execute(scenecopy.get());
				}

				exp.mExportFunction(pPath,pimpl->mIOSystem.get(),scenecopy.get());
			}
			catch (DeadlyExportError& err) {
				pimpl->mError = err.what();
				return AI_FAILURE;
			}
			return AI_SUCCESS;
		}
	}

	pimpl->mError = std::string("Found no exporter to handle this file format: ") + pFormatId;
	ASSIMP_END_EXCEPTION_REGION(aiReturn);
	return AI_FAILURE;
}


// ------------------------------------------------------------------------------------------------
const char* Exporter :: GetErrorString() const
{
	return pimpl->mError.c_str();
}


// ------------------------------------------------------------------------------------------------
void Exporter :: FreeBlob( )
{
	delete pimpl->blob;
	pimpl->blob = NULL;

	pimpl->mError = "";
}


// ------------------------------------------------------------------------------------------------
const aiExportDataBlob* Exporter :: GetBlob() const 
{
	return pimpl->blob;
}


// ------------------------------------------------------------------------------------------------
const aiExportDataBlob* Exporter :: GetOrphanedBlob() const 
{
	const aiExportDataBlob* tmp = pimpl->blob;
	pimpl->blob = NULL;
	return tmp;
}


// ------------------------------------------------------------------------------------------------
size_t Exporter :: GetExportFormatCount() const 
{
	return pimpl->mExporters.size();
}

// ------------------------------------------------------------------------------------------------
const aiExportFormatDesc* Exporter :: GetExportFormatDescription( size_t pIndex ) const 
{
	if (pIndex >= GetExportFormatCount()) {
		return NULL;
	}
	
	// Return from static storage if the requested index is built-in.
	if (pIndex < sizeof(gExporters) / sizeof(gExporters[0])) {
		return &gExporters[pIndex].mDescription;
	}

	return &pimpl->mExporters[pIndex].mDescription;
}

// ------------------------------------------------------------------------------------------------
aiReturn Exporter :: RegisterExporter(const ExportFormatEntry& desc)
{
	BOOST_FOREACH(const ExportFormatEntry& e, pimpl->mExporters) {
		if (!strcmp(e.mDescription.id,desc.mDescription.id)) {
			return aiReturn_FAILURE;
		}
	}

	pimpl->mExporters.push_back(desc);
	return aiReturn_SUCCESS;
}


// ------------------------------------------------------------------------------------------------
void Exporter :: UnregisterExporter(const char* id)
{
	for(std::vector<ExportFormatEntry>::iterator it = pimpl->mExporters.begin(); it != pimpl->mExporters.end(); ++it) {
		if (!strcmp((*it).mDescription.id,id)) {
			pimpl->mExporters.erase(it);
			break;
		}
	}
}

#endif // !ASSIMP_BUILD_NO_EXPORT