/*
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*/

/** @file  BlenderModifier.cpp
 *  @brief Implementation of some blender modifiers (i.e subdivision, mirror).
 */
#include "AssimpPCH.h"

#ifndef ASSIMP_BUILD_NO_BLEND_IMPORTER
#include "BlenderModifier.h"
#include "SceneCombiner.h"
#include "Subdivision.h"

#include <functional>

using namespace Assimp;
using namespace Assimp::Blender;

template <typename T> BlenderModifier* god() {
	return new T();
}

// add all available modifiers here
typedef BlenderModifier* (*fpCreateModifier)();
static const fpCreateModifier creators[] = {
		&god<BlenderModifier_Mirror>,
		&god<BlenderModifier_Subdivision>,

		NULL // sentinel
};

// ------------------------------------------------------------------------------------------------
// just testing out some new macros to simplify logging
#define ASSIMP_LOG_WARN_F(string,...)\
	DefaultLogger::get()->warn((Formatter::format(string),__VA_ARGS__))

#define ASSIMP_LOG_ERROR_F(string,...)\
	DefaultLogger::get()->error((Formatter::format(string),__VA_ARGS__))

#define ASSIMP_LOG_DEBUG_F(string,...)\
	DefaultLogger::get()->debug((Formatter::format(string),__VA_ARGS__))

#define ASSIMP_LOG_INFO_F(string,...)\
	DefaultLogger::get()->info((Formatter::format(string),__VA_ARGS__))


#define ASSIMP_LOG_WARN(string)\
	DefaultLogger::get()->warn(string)

#define ASSIMP_LOG_ERROR(string)\
	DefaultLogger::get()->error(string)

#define ASSIMP_LOG_DEBUG(string)\
	DefaultLogger::get()->debug(string)

#define ASSIMP_LOG_INFO(string)\
	DefaultLogger::get()->info(string)


// ------------------------------------------------------------------------------------------------
struct SharedModifierData : ElemBase
{
	ModifierData modifier;
};

// ------------------------------------------------------------------------------------------------
void BlenderModifierShowcase::ApplyModifiers(aiNode& out, ConversionData& conv_data, const Scene& in, const Object& orig_object ) 
{
	size_t cnt = 0u, ful = 0u;

	// NOTE: this cast is potentially unsafe by design, so we need to perform type checks before
	// we're allowed to dereference the pointers without risking to crash. We might still be
	// invoking UB btw - we're assuming that the ModifierData member of the respective modifier
	// structures is at offset sizeof(vftable) with no padding.
	const SharedModifierData* cur = boost::static_pointer_cast<const SharedModifierData> ( orig_object.modifiers.first.get() );
	for (; cur; cur =  boost::static_pointer_cast<const SharedModifierData> ( cur->modifier.next.get() ), ++ful) {
		ai_assert(cur->dna_type);

		const Structure* s = conv_data.db.dna.Get( cur->dna_type );
		if (!s) {
			ASSIMP_LOG_WARN_F("BlendModifier: could not resolve DNA name: ",cur->dna_type);
			continue;
		}

		// this is a common trait of all XXXMirrorData structures in BlenderDNA
		const Field* f = s->Get("modifier");
		if (!f || f->offset != 0) {
			ASSIMP_LOG_WARN("BlendModifier: expected a `modifier` member at offset 0");
			continue;
		}

		s = conv_data.db.dna.Get( f->type );
		if (!s || s->name != "ModifierData") {
			ASSIMP_LOG_WARN("BlendModifier: expected a ModifierData structure as first member");
			continue;
		}

		// now, we can be sure that we should be fine to dereference *cur* as
		// ModifierData (with the above note).
		const ModifierData& dat = cur->modifier;

		const fpCreateModifier* curgod = creators;
		std::vector< BlenderModifier* >::iterator curmod = cached_modifiers->begin(), endmod = cached_modifiers->end();

		for (;*curgod;++curgod,++curmod) { // allocate modifiers on the fly
			if (curmod == endmod) {
				cached_modifiers->push_back((*curgod)());

				endmod = cached_modifiers->end();
				curmod = endmod-1;
			}

			BlenderModifier* const modifier = *curmod;
			if(modifier->IsActive(dat)) {
				modifier->DoIt(out,conv_data,*boost::static_pointer_cast<const ElemBase>(cur),in,orig_object);
				cnt++;

				curgod = NULL;
				break;
			}
		}
		if (curgod) {
			ASSIMP_LOG_WARN_F("Couldn't find a handler for modifier: ",dat.name);
		}
	}

	// Even though we managed to resolve some or all of the modifiers on this
	// object, we still can't say whether our modifier implementations were
	// able to fully do their job.
	if (ful) {
		ASSIMP_LOG_DEBUG_F("BlendModifier: found handlers for ",cnt," of ",ful," modifiers on `",orig_object.id.name,
			"`, check log messages above for errors");
	}
}



// ------------------------------------------------------------------------------------------------
bool BlenderModifier_Mirror :: IsActive (const ModifierData& modin)
{
	return modin.type == ModifierData::eModifierType_Mirror;
}

// ------------------------------------------------------------------------------------------------
void  BlenderModifier_Mirror :: DoIt(aiNode& out, ConversionData& conv_data,  const ElemBase& orig_modifier, 
	const Scene& /*in*/,
	const Object& orig_object ) 
{
	// hijacking the ABI, see the big note in BlenderModifierShowcase::ApplyModifiers()
	const MirrorModifierData& mir = static_cast<const MirrorModifierData&>(orig_modifier);
	ai_assert(mir.modifier.type == ModifierData::eModifierType_Mirror);

	conv_data.meshes->reserve(conv_data.meshes->size() + out.mNumMeshes);

	// XXX not entirely correct, mirroring on two axes results in 4 distinct objects in blender ...

	// take all input meshes and clone them
	for (unsigned int i = 0; i < out.mNumMeshes; ++i) {
		aiMesh* mesh;
		SceneCombiner::Copy(&mesh,conv_data.meshes[out.mMeshes[i]]);

		const float xs = mir.flag & MirrorModifierData::Flags_AXIS_X ? -1.f : 1.f;
		const float ys = mir.flag & MirrorModifierData::Flags_AXIS_Y ? -1.f : 1.f;
		const float zs = mir.flag & MirrorModifierData::Flags_AXIS_Z ? -1.f : 1.f;

		if (mir.mirror_ob) {
			const aiVector3D center( mir.mirror_ob->obmat[3][0],mir.mirror_ob->obmat[3][1],mir.mirror_ob->obmat[3][2] );
			for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
				aiVector3D& v = mesh->mVertices[i];
		
				v.x = center.x + xs*(center.x - v.x);
				v.y = center.y + ys*(center.y - v.y);
				v.z = center.z + zs*(center.z - v.z);
			}
		}
		else {
			for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
				aiVector3D& v = mesh->mVertices[i];
				v.x *= xs;v.y *= ys;v.z *= zs;
			}
		}

		if (mesh->mNormals) {
			for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
				aiVector3D& v = mesh->mNormals[i];
				v.x *= xs;v.y *= ys;v.z *= zs;
			}
		}

		if (mesh->mTangents) {
			for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
				aiVector3D& v = mesh->mTangents[i];
				v.x *= xs;v.y *= ys;v.z *= zs;
			}
		}

		if (mesh->mBitangents) {
			for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
				aiVector3D& v = mesh->mBitangents[i];
				v.x *= xs;v.y *= ys;v.z *= zs;
			}
		}

		const float us = mir.flag & MirrorModifierData::Flags_MIRROR_U ? -1.f : 1.f;
		const float vs = mir.flag & MirrorModifierData::Flags_MIRROR_V ? -1.f : 1.f;

		for (unsigned int n = 0; mesh->HasTextureCoords(n); ++n) {
			for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
				aiVector3D& v = mesh->mTextureCoords[n][i];
				v.x *= us;v.y *= vs;
			}
		}

		conv_data.meshes->push_back(mesh);
	}
	unsigned int* nind = new unsigned int[out.mNumMeshes*2];

	std::copy(out.mMeshes,out.mMeshes+out.mNumMeshes,nind);
	std::transform(out.mMeshes,out.mMeshes+out.mNumMeshes,nind+out.mNumMeshes,
		std::bind1st(std::plus< unsigned int >(),out.mNumMeshes));

	delete[] out.mMeshes;
	out.mMeshes = nind;
	out.mNumMeshes *= 2;

	ASSIMP_LOG_INFO_F("BlendModifier: Applied the `Mirror` modifier to `",
		orig_object.id.name,"`");
}




// ------------------------------------------------------------------------------------------------
bool BlenderModifier_Subdivision :: IsActive (const ModifierData& modin)
{
	return modin.type == ModifierData::eModifierType_Subsurf;
}

// ------------------------------------------------------------------------------------------------
void  BlenderModifier_Subdivision :: DoIt(aiNode& out, ConversionData& conv_data,  const ElemBase& orig_modifier, 
	const Scene& /*in*/,
	const Object& orig_object ) 
{
	// hijacking the ABI, see the big note in BlenderModifierShowcase::ApplyModifiers()
	const SubsurfModifierData& mir = static_cast<const SubsurfModifierData&>(orig_modifier);
	ai_assert(mir.modifier.type == ModifierData::eModifierType_Subsurf);

	Subdivider::Algorithm algo;
	switch (mir.subdivType) 
	{
	case SubsurfModifierData::TYPE_CatmullClarke:
		algo = Subdivider::CATMULL_CLARKE;
		break;

	case SubsurfModifierData::TYPE_Simple:
		ASSIMP_LOG_WARN("BlendModifier: The `SIMPLE` subdivision algorithm is not currently implemented, using Catmull-Clarke");
		algo = Subdivider::CATMULL_CLARKE;
		break;

	default:
		ASSIMP_LOG_WARN_F("BlendModifier: Unrecognized subdivision algorithm: ",mir.subdivType);
		return;
	};

	boost::scoped_ptr<Subdivider> subd(Subdivider::Create(algo));
	ai_assert(subd);

	aiMesh** const meshes = &conv_data.meshes[conv_data.meshes->size() - out.mNumMeshes];
	boost::scoped_array<aiMesh*> tempmeshes(new aiMesh*[out.mNumMeshes]());

	subd->Subdivide(meshes,out.mNumMeshes,tempmeshes.get(),std::max( mir.renderLevels, mir.levels ),true);
	std::copy(tempmeshes.get(),tempmeshes.get()+out.mNumMeshes,meshes);

	ASSIMP_LOG_INFO_F("BlendModifier: Applied the `Subdivision` modifier to `",
		orig_object.id.name,"`");
}

#endif