/** 
 * @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 "lldlinked.h"
#include "lldir.h"
#include "llvieweroctree.h"

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

class LLVOCacheEntry : public LLViewerOctreeEntryData
{
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.
	};

	struct CompareVOCacheEntry
	{
		bool operator()(const LLVOCacheEntry* const& lhs, const LLVOCacheEntry* const& rhs)
		{
			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;
			}			
		}
	};
protected:
	~LLVOCacheEntry();
public:
	LLVOCacheEntry(U32 local_id, U32 crc, LLDataPackerBinaryBuffer &dp);
	LLVOCacheEntry(LLAPRFile* apr_file);
	LLVOCacheEntry();	

	void setState(U32 state);
	//void clearState(U32 state) {mState &= ~state;}
	bool isState(U32 state)    {return mState == state;}
	bool hasState(U32 state)   {return mState & state;}
	U32  getState() const      {return mState;}
	
	U32 getLocalID() const			{ return mLocalID; }
	U32 getCRC() const				{ return mCRC; }
	S32 getHitCount() const			{ return mHitCount; }
	S32 getCRCChangeCount() const	{ return mCRCChangeCount; }
	S32 getMinVisFrameRange()const;	

	void calcSceneContribution(const LLVector3& camera_origin, bool needs_update, U32 last_update);
	void setSceneContribution(F32 scene_contrib) {mSceneContrib = scene_contrib;}
	F32 getSceneContribution() const             { return mSceneContrib;}

	void dump() const;
	BOOL writeToFile(LLAPRFile* apr_file) const;
	LLDataPackerBinaryBuffer *getDP(U32 crc);
	LLDataPackerBinaryBuffer *getDP();
	void recordHit();
	void recordDupe() { mDupeCount++; }
	
	void copyTo(LLVOCacheEntry* new_entry); //copy variables 
	/*virtual*/ void setOctreeEntry(LLViewerOctreeEntry* entry);

	void setParentID(U32 id) {mParentID = id;}
	U32  getParentID() const {return mParentID;}

	void addChild(LLVOCacheEntry* entry);
	LLVOCacheEntry* getChild(S32 i) {return mChildrenList[i];}
	S32  getNumOfChildren()         {return mChildrenList.size();}
	void clearChildrenList()        {mChildrenList.clear();}

	//called from processing object update message
	void setBoundingInfo(const LLVector3& pos, const LLVector3& scale);
	void updateBoundingInfo(LLVOCacheEntry* parent);

	void setTouched(BOOL touched = TRUE) {mTouched = touched;}
	BOOL isTouched() const {return mTouched;}
	
	void setUpdateFlags(U32 flags) {mUpdateFlags = flags;}
	U32  getUpdateFlags() const    {return mUpdateFlags;}

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;	

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.
	S32                         mVisFrameRange;
	S32                         mRepeatedVisCounter; //number of repeatedly visible within a short time.
	U32                         mState; //high 16 bits reserved for special use.
	std::vector<LLVOCacheEntry*> mChildrenList; //children entries in a linked set.

	BOOL                        mTouched; //if set, this entry is valid, otherwise it is invalid.
};

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

	void addEntry(LLViewerOctreeEntry* entry);
	void removeEntry(LLViewerOctreeEntry* entry);
	/*virtual*/ S32 cull(LLCamera &camera);
};

//
//Note: LLVOCache is not thread-safe
//
class LLVOCache
{
private:
	struct HeaderEntryInfo
	{
		HeaderEntryInfo() : mIndex(0), mHandle(0), mTime(0) {}
		S32 mIndex;
		U64 mHandle ;
		U32 mTime ;
	};

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

		U32 mVersion;
	};

	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;
private:
	LLVOCache() ;

public:
	~LLVOCache() ;

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

	void setReadOnly(BOOL read_only) {mReadOnly = read_only;} 

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;	

	static LLVOCache* sInstance ;
public:
	static LLVOCache* getInstance() ;
	static BOOL       hasInstance() ;	
	static void       destroyClass() ;
};

#endif