/*
 * -----------------------------------------------------------------------------
 * This source file is part of OGRE
 * (Object-oriented Graphics Rendering Engine)
 * For the latest info, see http://www.ogre3d.org/
 *
 * Copyright (c) 2000-2014 Torus Knot Software Ltd
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 * -----------------------------------------------------------------------------
 */

#ifndef _Lod0Stripifier_H__
#define _Lod0Stripifier_H__

#include "OgreLodPrerequisites.h"
#include "OgreMesh.h"
#include "OgreSubMesh.h"
#include "OgreKeyFrame.h"
#include "OgreHardwareBufferManager.h"

namespace Ogre
{
	class Lod0Stripifier
	{
	public:
		Lod0Stripifier();
		~Lod0Stripifier();
		bool StripLod0Vertices(const MeshPtr& mesh, bool stableVertexOrder = false);

	private:
		struct RemapInfo;
		void generateRemapInfo(const MeshPtr& mesh, bool stableVertexOrder);
		static void performIndexDataRemap(HardwareBufferManagerBase* pHWBufferManager, IndexData* indexData, const RemapInfo& remapInfo);
		static void performVertexDataRemap(HardwareBufferManagerBase* pHWBufferManager, VertexData* vertexData, const RemapInfo& remapInfo);
		static HardwareVertexBufferSharedPtr getRemappedVertexBuffer(HardwareBufferManagerBase* pHWBufferManager, const HardwareVertexBufferSharedPtr& vb, size_t srcStart, size_t srcCount, const RemapInfo& remapInfo);
		template<class MeshOrSubmesh> static void performBoneAssignmentRemap(MeshOrSubmesh* m, const RemapInfo& remapInfo);
		static void performPoseRemap(Pose* pose, const RemapInfo& remapInfo);
		static void performAnimationTrackRemap(HardwareBufferManagerBase* pHWBufferManager, VertexAnimationTrack* track, const RemapInfo& remapInfo);

	private:
		std::vector<RemapInfo>		remapInfos;	// 0 for shared geometry, 1+ for submesh index + 1
	};


	// Implementation ------------------------------------------------------------------------------------

	struct Lod0Stripifier::RemapInfo
	{
		RemapInfo() : usedCount(0) { }
		void prepare(size_t originalSize) { usedCount = 0; indexMap.resize(originalSize, UnusedIdx); }
		template<typename IDX> void markUsedIndices(IDX* indices, size_t indexCount)
		{
			for(IDX *idx = indices, *idx_end = idx + indexCount; idx < idx_end; ++idx)
				if(indexMap[*idx] == UnusedIdx)
					indexMap[*idx] = usedCount++;
		}
		void renumerate()
		{
			usedCount = 0;
			for(size_t idx = 0, idx_end = indexMap.size(); idx < idx_end; ++idx)
				if(indexMap[idx] != UnusedIdx)
					indexMap[idx] = usedCount++;
		}
		bool nothingToStrip() const { return usedCount == indexMap.size(); }
		HardwareIndexBuffer::IndexType minimalIndexType() const { return usedCount < 0xFFFF ? HardwareIndexBuffer::IT_16BIT : HardwareIndexBuffer::IT_32BIT; }

	public:
		enum{ UnusedIdx = (unsigned)-1 };
		std::vector<unsigned> indexMap;	// returns new index if indexed by old index, or UnusedIdx
		unsigned usedCount;
	};

	inline Lod0Stripifier::Lod0Stripifier()
	{
	}
	inline Lod0Stripifier::~Lod0Stripifier()
	{
	}

	inline void Lod0Stripifier::generateRemapInfo(const MeshPtr& mesh, bool stableVertexOrder)
	{
		size_t submeshCount = mesh->getNumSubMeshes();
		remapInfos.resize(1 + submeshCount);
		remapInfos[0].prepare(mesh->sharedVertexData ? mesh->sharedVertexData->vertexCount : 0);
		for(ushort i = 0; i < submeshCount; i++)
		{
			const SubMesh* submesh = mesh->getSubMesh(i);
			remapInfos[1 + i].prepare(submesh->useSharedVertices ? 0 : submesh->vertexData->vertexCount);

			RemapInfo& remapInfo = remapInfos[submesh->useSharedVertices ? 0 : 1 + i];

			for(int lod = mesh->getNumLodLevels() - 1; lod > 0; --lod) // intentionally skip lod0, visit in reverse order to improve vertex locality for high lods
			{
				IndexData *lodIndexData = submesh->mLodFaceList[lod - 1];
				void* ptr = lodIndexData->indexBuffer->lock(
					lodIndexData->indexStart * lodIndexData->indexBuffer->getIndexSize(),
					lodIndexData->indexCount * lodIndexData->indexBuffer->getIndexSize(),
					HardwareBuffer::HBL_READ_ONLY);

				if(lodIndexData->indexBuffer->getType() == HardwareIndexBuffer::IT_32BIT)
					remapInfo.markUsedIndices((uint32*)ptr, lodIndexData->indexCount);
				else
					remapInfo.markUsedIndices((uint16*)ptr, lodIndexData->indexCount);

				lodIndexData->indexBuffer->unlock();
			}

			if(stableVertexOrder)
				remapInfos[1 + i].renumerate();
		}
		if(stableVertexOrder)
			remapInfos[0].renumerate();
	}

	inline void Lod0Stripifier::performIndexDataRemap(HardwareBufferManagerBase* pHWBufferManager, IndexData* indexData, const RemapInfo& remapInfo)
	{
		if(remapInfo.nothingToStrip())
			return;

		size_t indexCount = indexData->indexCount;
		HardwareIndexBuffer::IndexType indexType = indexData->indexBuffer->getType();
		HardwareIndexBuffer::IndexType newIndexType = remapInfo.minimalIndexType();
		HardwareIndexBufferSharedPtr newIndexBuffer = 
			pHWBufferManager->createIndexBuffer(
			newIndexType, indexCount, indexData->indexBuffer->getUsage(), indexData->indexBuffer->hasShadowBuffer());

		void* pSrc = indexData->indexBuffer->lock(
			indexData->indexStart * indexData->indexBuffer->getIndexSize(),
			indexData->indexCount * indexData->indexBuffer->getIndexSize(),
			HardwareBuffer::HBL_READ_ONLY);
		void* pDst = newIndexBuffer->lock(HardwareBuffer::HBL_DISCARD);

		if(indexType == HardwareIndexBuffer::IT_32BIT && newIndexType == HardwareIndexBuffer::IT_32BIT)
		{
			uint32 *pSrc32 = (uint32*)pSrc, *pDst32 = (uint32*)pDst;
			for(size_t i = 0; i < indexCount; ++i)
				pDst32[i] = remapInfo.indexMap[pSrc32[i]];
		}
		else if(indexType == HardwareIndexBuffer::IT_32BIT && newIndexType == HardwareIndexBuffer::IT_16BIT)
		{
			uint32 *pSrc32 = (uint32*)pSrc; uint16 *pDst16 = (uint16*)pDst;
			for(size_t i = 0; i < indexCount; ++i)
				pDst16[i] = (uint16)remapInfo.indexMap[pSrc32[i]];
		}
		else if(indexType == HardwareIndexBuffer::IT_16BIT && newIndexType == HardwareIndexBuffer::IT_32BIT)
		{
			uint16 *pSrc16 = (uint16*)pSrc; uint32 *pDst32 = (uint32*)pDst;
			for(size_t i = 0; i < indexCount; ++i)
				pDst32[i] = remapInfo.indexMap[pSrc16[i]];
		}
		else // indexType == HardwareIndexBuffer::IT_16BIT && newIndexType == HardwareIndexBuffer::IT_16BIT
		{
			uint16 *pSrc16 = (uint16*)pSrc, *pDst16 = (uint16*)pDst;
			for(size_t i = 0; i < indexCount; ++i)
				pDst16[i] = (uint16)remapInfo.indexMap[pSrc16[i]];
		}

		indexData->indexBuffer->unlock();
		newIndexBuffer->unlock();

		indexData->indexBuffer = newIndexBuffer;
		indexData->indexStart = 0;
	}

	inline void Lod0Stripifier::performVertexDataRemap(HardwareBufferManagerBase* pHWBufferManager, VertexData* vertexData, const RemapInfo& remapInfo)
	{
		if(remapInfo.nothingToStrip())
			return;

		// Copy vertex buffers in turn
		typedef std::map<HardwareVertexBufferSharedPtr, HardwareVertexBufferSharedPtr> VBMap;
		VBMap alreadyProcessed; // prevent duplication of the same buffer bound under several indices
		const VertexBufferBinding::VertexBufferBindingMap& bindings = vertexData->vertexBufferBinding->getBindings();
		VertexBufferBinding::VertexBufferBindingMap::const_iterator vbi, vbend;
		for(vbi = bindings.begin(), vbend = bindings.end(); vbi != vbend; ++vbi)
		{
			HardwareVertexBufferSharedPtr srcbuf = vbi->second;
			VBMap::iterator it = alreadyProcessed.find(srcbuf);
			if(it != alreadyProcessed.end())
			{
				vertexData->vertexBufferBinding->setBinding(vbi->first, it->second);
				continue;
			}

			HardwareVertexBufferSharedPtr dstbuf = getRemappedVertexBuffer(pHWBufferManager, srcbuf, vertexData->vertexStart, vertexData->vertexCount, remapInfo);
			vertexData->vertexBufferBinding->setBinding(vbi->first, dstbuf);
			alreadyProcessed[srcbuf] = dstbuf;
		}

		vertexData->vertexStart = 0;
		vertexData->vertexCount = remapInfo.usedCount;

		vertexData->hardwareShadowVolWBuffer = HardwareVertexBufferSharedPtr(); // TODO: check this
		vertexData->hwAnimationDataList.clear(); // TODO: check this
		vertexData->hwAnimDataItemsUsed = 0; // TODO: check this
	}

	inline HardwareVertexBufferSharedPtr Lod0Stripifier::getRemappedVertexBuffer(HardwareBufferManagerBase* pHWBufferManager,
		const HardwareVertexBufferSharedPtr& srcbuf, size_t srcStart, size_t srcCount, const RemapInfo& remapInfo)
	{
		assert(!remapInfo.nothingToStrip());

		size_t vertexSize = srcbuf->getVertexSize();
		HardwareVertexBufferSharedPtr dstbuf =
			pHWBufferManager->createVertexBuffer(
			vertexSize, remapInfo.usedCount, srcbuf->getUsage(), srcbuf->hasShadowBuffer());

		char* pSrc = (char*)srcbuf->lock(srcStart * vertexSize, srcCount * vertexSize, HardwareBuffer::HBL_READ_ONLY);
		char* pDst = (char*)dstbuf->lock(HardwareBuffer::HBL_DISCARD);

		for(size_t oldIdx = 0, oldIdxEnd = remapInfo.indexMap.size(); oldIdx < oldIdxEnd; ++oldIdx)
		{
			unsigned newIdx = remapInfo.indexMap[oldIdx];
			if(newIdx != RemapInfo::UnusedIdx)
				memcpy(pDst + newIdx * vertexSize, pSrc + oldIdx * vertexSize, vertexSize);
		}

		srcbuf->unlock();
		dstbuf->unlock();
		return dstbuf;
	}

	template<class MeshOrSubmesh>
	inline void Lod0Stripifier::performBoneAssignmentRemap(MeshOrSubmesh* m, const RemapInfo& remapInfo)
	{
		if(remapInfo.nothingToStrip() || m->getBoneAssignments().empty())
			return;

		Mesh::VertexBoneAssignmentList tmp = m->getBoneAssignments();
		m->clearBoneAssignments();
		for(Mesh::VertexBoneAssignmentList::const_iterator it = tmp.begin(), it_end = tmp.end(); it != it_end; ++it)
		{
			VertexBoneAssignment vba = it->second;
			unsigned newIdx = remapInfo.indexMap[vba.vertexIndex];
			if(newIdx != RemapInfo::UnusedIdx)
			{
				vba.vertexIndex = newIdx;
				m->addBoneAssignment(vba);
			}
		}
	}

	inline void Lod0Stripifier::performPoseRemap(Pose* pose, const RemapInfo& remapInfo)
	{
		if(remapInfo.nothingToStrip() || (pose->getVertexOffsets().empty() && pose->getNormals().empty()))
			return;

		Pose::VertexOffsetMap vv = pose->getVertexOffsets();
		Pose::NormalsMap nn = pose->getNormals();
		pose->clearVertices();
		for(Pose::VertexOffsetMap::const_iterator vit = vv.begin(), vit_end = vv.end(); vit != vit_end; ++vit)
		{
			unsigned newIdx = remapInfo.indexMap[vit->first];
			if(newIdx != RemapInfo::UnusedIdx)
			{
				if(pose->getIncludesNormals())
					pose->addVertex(newIdx, vit->second, nn[vit->first]);
				else
					pose->addVertex(newIdx, vit->second);
			}
		}
	}

	inline void Lod0Stripifier::performAnimationTrackRemap(HardwareBufferManagerBase* pHWBufferManager, VertexAnimationTrack* track, const RemapInfo& remapInfo)
	{
		if(remapInfo.nothingToStrip())
			return;

		if(track->getAnimationType() == VAT_MORPH)
		{
			for(unsigned short i = 0; i < track->getNumKeyFrames(); ++i)
			{
				VertexMorphKeyFrame* kf = track->getVertexMorphKeyFrame(i);
				HardwareVertexBufferSharedPtr VB = kf->getVertexBuffer();
				kf->setVertexBuffer(getRemappedVertexBuffer(pHWBufferManager, VB, 0, VB->getNumVertices(), remapInfo));
			}
		}
	}

	inline bool Lod0Stripifier::StripLod0Vertices(const MeshPtr& mesh, bool stableVertexOrder)
	{
		// we need at least one lod level except lod0 that would be stripped
		ushort numLods = mesh->hasManualLodLevel() ? 1 : mesh->getNumLodLevels();
		if(numLods <= 1)
			return false;

		bool edgeListWasBuilt = mesh->isEdgeListBuilt();
		mesh->freeEdgeList();

		generateRemapInfo(mesh, stableVertexOrder);

		if(mesh->sharedVertexData)
			performVertexDataRemap(mesh->getHardwareBufferManager(), mesh->sharedVertexData, remapInfos[0]);
		performBoneAssignmentRemap(mesh.get(), remapInfos[0]);

		size_t submeshCount = mesh->getNumSubMeshes();
		for(size_t i = 0; i < submeshCount; i++)
		{
			SubMesh* submesh = mesh->getSubMesh(i);
			const RemapInfo& remapInfo = remapInfos[submesh->useSharedVertices ? 0 : 1 + i];

			if(!submesh->useSharedVertices)
				performVertexDataRemap(mesh->getHardwareBufferManager(), submesh->vertexData, remapInfo);
			performBoneAssignmentRemap(submesh, remapInfo);

			for(int lod = numLods - 1; lod > 0; --lod) // intentionally skip lod0
			{
				IndexData *lodIndexData = submesh->mLodFaceList[lod - 1]; // lod0 is stored separately
				performIndexDataRemap(mesh->getHardwareBufferManager(), lodIndexData, remapInfo);
			}

			OGRE_DELETE submesh->indexData;
			submesh->indexData = submesh->mLodFaceList[0];
			submesh->mLodFaceList.erase(submesh->mLodFaceList.begin());
		}

		for(ushort lod = 1; lod < numLods - 1; ++lod)
			mesh->_setLodUsage(lod, mesh->getLodLevel(ushort(lod + 1)));
		mesh->_setLodInfo(ushort(numLods - 1));


		PoseList::const_iterator it;
        for( it = mesh->getPoseList().begin(); it != mesh->getPoseList().end(); ++it)
        {
			Pose* pose = *it;
			performPoseRemap(pose, remapInfos[pose->getTarget()]);
		}

		for(unsigned short a = 0; a < mesh->getNumAnimations(); ++a)
		{
			Animation* anim = mesh->getAnimation(a);
			for (const auto& trackIt : anim->_getVertexTrackList())
			{
				performAnimationTrackRemap(mesh->getHardwareBufferManager(), trackIt.second, remapInfos[trackIt.first]);
			}
		}

		if(edgeListWasBuilt)
			mesh->buildEdgeList();

		return true;
	}
}

#endif