/** 
 * @file llvocache.h
 * @brief Cache of objects on the viewer.
 *
 * $LicenseInfo:firstyear=2003&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LL_LLVOCACHE_H
#define LL_LLVOCACHE_H

#include "lluuid.h"
#include "lldatapacker.h"
#include "lldir.h"
#include "llvieweroctree.h"
#include "llapr.h"

#include <unordered_map>

//---------------------------------------------------------------------------
// Cache entries
class LLCamera;

class LLVOCacheEntry 
:	public LLViewerOctreeEntryData
{
    LL_ALIGN_NEW
public:
	enum 
	{
		//low 16-bit state
		INACTIVE = 0x00000000,     //not visible
		IN_QUEUE = 0x00000001,     //in visible queue, object to be created
		WAITING  = 0x00000002,     //object creation request sent
		ACTIVE   = 0x00000004,      //object created, and in rendering pipeline.

		//high 16-bit state
		IN_VO_TREE = 0x00010000,    //the entry is in the object cache tree.

		LOW_BITS  = 0x0000ffff,
		HIGH_BITS = 0xffff0000
	};

	struct CompareVOCacheEntry
	{
		bool operator()(const LLVOCacheEntry* const& lhs, const LLVOCacheEntry* const& rhs) const
		{
			F32 lpa = lhs->getSceneContribution();
			F32 rpa = rhs->getSceneContribution();

			//larger pixel area first
			if(lpa > rpa)		
			{
				return true;
			}
			else if(lpa < rpa)
			{
				return false;
			}
			else
			{
				return lhs < rhs;
			}			
		}
	};

    struct ExtrasEntry
    {
        LLSD extras;
        std::string extras_raw;
    };

protected:
	~LLVOCacheEntry();
public:
	LLVOCacheEntry(U32 local_id, U32 crc, LLDataPackerBinaryBuffer &dp);
	LLVOCacheEntry(LLAPRFile* apr_file);
	LLVOCacheEntry();	

	void updateEntry(U32 crc, LLDataPackerBinaryBuffer &dp);

	void clearState(U32 state) {mState &= ~state;}
	bool hasState(U32 state)   {return mState & state;}	
	void setState(U32 state);	
	bool isState(U32 state)    {return (mState & LOW_BITS) == state;}	
	U32  getState() const      {return mState & LOW_BITS;}
	
	bool isAnyVisible(const LLVector4a& camera_origin, const LLVector4a& local_camera_origin, F32 dist_threshold);

	U32 getLocalID() const			{ return mLocalID; }
	U32 getCRC() const				{ return mCRC; }
	S32 getHitCount() const			{ return mHitCount; }
	S32 getCRCChangeCount() const	{ return mCRCChangeCount; }
	
	void calcSceneContribution(const LLVector4a& camera_origin, bool needs_update, U32 last_update, F32 dist_threshold);
	void setSceneContribution(F32 scene_contrib) {mSceneContrib = scene_contrib;}
	F32 getSceneContribution() const             { return mSceneContrib;}

	void dump() const;
	S32 writeToBuffer(U8 *data_buffer) const;
	LLDataPackerBinaryBuffer *getDP();
	void recordHit();
	void recordDupe() { mDupeCount++; }
	
	/*virtual*/ void setOctreeEntry(LLViewerOctreeEntry* entry);

	void setParentID(U32 id);
	U32  getParentID() const {return mParentID;}
	bool isChild() const {return mParentID > 0;}

	void addChild(LLVOCacheEntry* entry);
	void removeChild(LLVOCacheEntry* entry);
	void removeAllChildren();
	LLVOCacheEntry* getChild(); //remove the first child, and return it.
	S32  getNumOfChildren() const  {return mChildrenList.size();}
	
	void setBoundingInfo(const LLVector3& pos, const LLVector3& scale); //called from processing object update message	
	void updateParentBoundingInfo();
	void saveBoundingSphere();

	void setValid(BOOL valid = TRUE) {mValid = valid;}
	BOOL isValid() const {return mValid;}

	void setUpdateFlags(U32 flags) {mUpdateFlags = flags;}
	U32  getUpdateFlags() const    {return mUpdateFlags;}

	static void updateDebugSettings();
	static F32  getSquaredPixelThreshold(bool is_front);

private:
	void updateParentBoundingInfo(const LLVOCacheEntry* child);	

public:
	typedef std::map<U32, LLPointer<LLVOCacheEntry> >	   vocache_entry_map_t;
	typedef std::set<LLVOCacheEntry*>                      vocache_entry_set_t;
	typedef std::set<LLVOCacheEntry*, CompareVOCacheEntry> vocache_entry_priority_list_t;
    typedef std::unordered_map<U32, ExtrasEntry>  vocache_extras_entry_map_t;

	S32                         mLastCameraUpdated;
protected:
	U32							mLocalID;
	U32                         mParentID;
	U32							mCRC;
	U32                         mUpdateFlags; //receive from sim
	S32							mHitCount;
	S32							mDupeCount;
	S32							mCRCChangeCount;
	LLDataPackerBinaryBuffer	mDP;
	U8							*mBuffer;

	F32                         mSceneContrib; //projected scene contributuion of this object.
	U32                         mState; //high 16 bits reserved for special use.
	vocache_entry_set_t         mChildrenList; //children entries in a linked set.

	BOOL                        mValid; //if set, this entry is valid, otherwise it is invalid and will be removed.

	LLVector4a                  mBSphereCenter; //bounding sphere center
	F32                         mBSphereRadius; //bounding sphere radius

public:
	static U32					sMinFrameRange;
	static F32					sNearRadius;
	static F32					sRearFarRadius;
	static F32					sFrontPixelThreshold;
	static F32					sRearPixelThreshold;
};

class LLVOCacheGroup : public LLOcclusionCullingGroup
{
public:
	LLVOCacheGroup(OctreeNode* node, LLViewerOctreePartition* part) : LLOcclusionCullingGroup(node, part){}	

	//virtual
	void handleChildAddition(const OctreeNode* parent, OctreeNode* child);

protected:
	virtual ~LLVOCacheGroup();
};

class LLVOCachePartition : public LLViewerOctreePartition
{
public:
	LLVOCachePartition(LLViewerRegion* regionp);
    virtual ~LLVOCachePartition();

	bool addEntry(LLViewerOctreeEntry* entry);
	void removeEntry(LLViewerOctreeEntry* entry);
	/*virtual*/ S32 cull(LLCamera &camera, bool do_occlusion);
	void addOccluders(LLViewerOctreeGroup* gp);
	void resetOccluders();
	void processOccluders(LLCamera* camera);
	void removeOccluder(LLVOCacheGroup* group);

	void setCullHistory(BOOL has_new_object);

	bool isFrontCull() const {return mFrontCull;}

private:
	void selectBackObjects(LLCamera &camera, F32 projection_area_cutoff, bool use_occlusion); //select objects behind camera.

public:
	static BOOL sNeedsOcclusionCheck;

private:
	BOOL  mFrontCull; //the view frustum cull if set, otherwise is back sphere cull.
	U32   mCullHistory;
	U32   mCulledTime[LLViewerCamera::NUM_CAMERAS];
	std::set<LLVOCacheGroup*> mOccludedGroups;

	S32   mBackSlectionEnabled; //enable to select back objects if > 0.
	U32   mIdleHash;
};

//
//Note: LLVOCache is not thread-safe
//
class LLVOCache : public LLParamSingleton<LLVOCache>
{
	LLSINGLETON(LLVOCache, bool read_only);
	~LLVOCache() ;

private:
	struct HeaderEntryInfo
	{
		HeaderEntryInfo() : mIndex(0), mHandle(0), mTime(0) {}
		S32 mIndex;
		U64 mHandle ;
		U32 mTime ;
	};

	struct HeaderMetaInfo
	{
		HeaderMetaInfo() : mVersion(0), mAddressSize(0) {}

		U32 mVersion;
		U32 mAddressSize;
	};

	struct header_entry_less
	{
		bool operator()(const HeaderEntryInfo* lhs, const HeaderEntryInfo* rhs) const
		{
			if(lhs->mTime == rhs->mTime) 
			{
				return lhs < rhs ;
			}
			
			return lhs->mTime < rhs->mTime ; // older entry in front of queue (set)
		}
	};
	typedef std::set<HeaderEntryInfo*, header_entry_less> header_entry_queue_t;
	typedef std::map<U64, HeaderEntryInfo*> handle_entry_map_t;

public:
	// We need this init to be separate from constructor, since we might construct cache, purge it, then init.
	void initCache(ELLPath location, U32 size, U32 cache_version);
	void removeCache(ELLPath location, bool started = false) ;

	void readFromCache(U64 handle, const LLUUID& id, LLVOCacheEntry::vocache_entry_map_t& cache_entry_map) ;
    void readGenericExtrasFromCache(U64 handle, const LLUUID& id, LLVOCacheEntry::vocache_extras_entry_map_t& cache_extras_entry_map);

	void writeToCache(U64 handle, const LLUUID& id, const LLVOCacheEntry::vocache_entry_map_t& cache_entry_map, BOOL dirty_cache, bool removal_enabled);
    void writeGenericExtrasToCache(U64 handle, const LLUUID& id, const LLVOCacheEntry::vocache_extras_entry_map_t& cache_extras_entry_map, BOOL dirty_cache, bool removal_enabled);
	void removeEntry(U64 handle) ;

	U32 getCacheEntries() { return mNumEntries; }
	U32 getCacheEntriesMax() { return mCacheSize; }

private:
	void setDirNames(ELLPath location);	
	// determine the cache filename for the region from the region handle	
	void getObjectCacheFilename(U64 handle, std::string& filename);
	void removeFromCache(HeaderEntryInfo* entry);
	void readCacheHeader();
	void writeCacheHeader();
	void clearCacheInMemory();
	void removeCache() ;
	void removeEntry(HeaderEntryInfo* entry) ;
	void purgeEntries(U32 size);
	BOOL updateEntry(const HeaderEntryInfo* entry);
	
private:
	bool                 mEnabled;
	bool                 mInitialized ;
	bool                 mReadOnly ;
	HeaderMetaInfo       mMetaInfo;
	U32                  mCacheSize;
	U32                  mNumEntries;
	std::string          mHeaderFileName ;
	std::string          mObjectCacheDirName;
	LLVolatileAPRPool*   mLocalAPRFilePoolp ; 	
	header_entry_queue_t mHeaderEntryQueue;
	handle_entry_map_t   mHandleEntryMap;	
};

#endif