/*******************************************************************************
 * libretroshare/src/ft: ftfilecreator.cc                                      *
 *                                                                             *
 * libretroshare: retroshare core library                                      *
 *                                                                             *
 * Copyright 2008 by Retroshare Team <contact@retroshare.cc>            *
 *                                                                             *
 * This program 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, either version 3 of the          *
 * License, or (at your option) any later version.                             *
 *                                                                             *
 * This program 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 program. If not, see <https://www.gnu.org/licenses/>.       *
 *                                                                             *
 *******************************************************************************/

#include <cerrno>
#include <cstdio>
#include <sys/stat.h>

#include "ftfilecreator.h"
#include "util/rstime.h"
#include "util/rsdiscspace.h"
#include "util/rsdir.h"
#include "util/largefile_retrocompat.hpp"

#ifdef WINDOWS_SYS
#	include "util/rsstring.h"
#	include "util/rswin.h"
#endif

/*******
 * #define FILE_DEBUG 1
 ******/

#define CHUNK_MAX_AGE           120
#define MAX_FTCHUNKS_PER_PEER    20

/***********************************************************
*
*	ftFileCreator methods
*
***********************************************************/

ftFileCreator::ftFileCreator(const std::string& path, uint64_t size, const RsFileHash& hash,bool assume_availability)
	: ftFileProvider(path,size,hash), chunkMap(size,assume_availability)
{
	/* 
         * FIXME any inits to do?
         */

#ifdef FILE_DEBUG
	std::cerr << "ftFileCreator()";
	std::cerr << std::endl;
	std::cerr << "\tpath: " << path;
	std::cerr << std::endl;
	std::cerr << "\tsize: " << size;
	std::cerr << std::endl;
	std::cerr << "\thash: " << hash;
	std::cerr << std::endl;
#endif
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/
	rstime_t now = time(NULL) ;
	_creation_time = now ;

	struct stat64 buf;

	// Initialise last recv time stamp to last modification time for the partial file.
	//
#ifdef WINDOWS_SYS
	std::wstring wfullname;
	librs::util::ConvertUtf8ToUtf16(file_name, wfullname);
	if ( 0 == _wstati64(wfullname.c_str(), &buf))
#else
	if ( 0 == stat64(file_name.c_str(), &buf))
#endif
		_last_recv_time_t = buf.st_mtime ;
	else
		_last_recv_time_t = now ;

#ifdef FILE_DEBUG
	std::cerr << "Inited last modification time for hash " << hash << " to " << _last_recv_time_t << std::endl;
#endif
}

bool ftFileCreator::getFileData(const RsPeerId& peer_id,uint64_t offset, uint32_t &chunk_size, void *data, bool allow_unverified)
{
	// Only send the data if we actually have it.
	//
#ifdef FILE_DEBUG
	std::cerr << "ftFileCreator::getFileData(). Asked for offset=" << offset << ", size=" << chunk_size << std::endl ;
#endif
	bool have_it = false ;
	{
		RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

		have_it = chunkMap.isChunkAvailable(offset, chunk_size) ;

#define ENABLE_SLICES
#ifdef ENABLE_SLICES
        // try if we have data from an incomplete or not veryfied chunk
        if(!have_it && allow_unverified)
        {
            //std::map<uint64_t, ftChunk>::iterator it;
            have_it = true;
            // this map contains chunks which are currently being downloaded
            for(std::map<uint64_t,ftChunk>::iterator it=mChunks.begin(); it!=mChunks.end(); ++it)
            {
                ftChunk chunk = it->second;
                // begin of slice is in requested range
                if(chunk.offset >= offset && chunk.offset < (offset+chunk_size))
                {
                    // reduce the requested size
                    chunk_size = chunk.offset - offset;
                }
                // end of slice is in requested range
                if((chunk.offset+chunk.size) >= offset && (chunk.offset+chunk.size) < (offset+chunk_size))
                {
                    // can do nothing about this
                    have_it = false;
                }
            }
            // check if the chunk was already started to download
            // if not, we don't have it
            if(chunkMap.isChunkOutstanding(offset, chunk_size))
                have_it = false;
        }
#endif
	}
#ifdef FILE_DEBUG
	if(have_it)
		std::cerr << "ftFileCreator::getFileData(). Have it" << std::endl ;
	else
		std::cerr << "ftFileCreator::getFileData(). Don't have it" << std::endl ;
#endif

	if(have_it)
		return ftFileProvider::getFileData(peer_id,offset, chunk_size, data);
	else
		return false ;
}

rstime_t ftFileCreator::creationTimeStamp() 
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/
	return _creation_time ;
}
rstime_t ftFileCreator::lastRecvTimeStamp() 
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/
	return _last_recv_time_t ;
}

void ftFileCreator::closeFile()
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

	if(fd != NULL)
	{
#ifdef FILE_DEBUG
		std::cerr << "CLOSED FILE " << (void*)fd << " (" << file_name << ")." << std::endl ;
#endif
		fclose(fd) ;
	}

	fd = NULL ;
}

uint64_t ftFileCreator::getRecvd()
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/
	return chunkMap.getTotalReceived() ;
}

bool ftFileCreator::addFileData(uint64_t offset, uint32_t chunk_size, void *data)
{
#ifdef FILE_DEBUG
	std::cerr << "ftFileCreator::addFileData(";
	std::cerr << offset;
	std::cerr << ", " << chunk_size;
	std::cerr << ", " << data << ")";
	std::cerr << " this: " << this;
	std::cerr << std::endl;
#endif
	/* dodgey checking outside of mutex...  much check again inside FileAttrs(). */
	/* Check File is open */

	if(!RsDiscSpace::checkForDiscSpace(RS_PARTIALS_DIRECTORY))
		return false ;

	bool complete = false ;
	{
		RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

		if (fd == NULL)
			if (!locked_initializeFileAttrs())
				return false;

		/* 
		 * check its at the correct location 
		 */
		if (offset + chunk_size > mSize)
		{
			chunk_size = mSize - offset;
			std::cerr <<"Chunk Size greater than total file size, adjusting chunk size " << chunk_size << std::endl;

		}

		/* 
		 * go to the offset of the file 
		 */
		if (0 != fseeko64(this->fd, offset, SEEK_SET))
		{
			std::cerr << "ftFileCreator::addFileData() Bad fseek at offset " << offset << ", fd=" << (void*)(this->fd) << ", size=" << mSize << ", errno=" << errno << std::endl;
			return 0;
		}

		if (1 != fwrite(data, chunk_size, 1, this->fd))
		{
			std::cerr << "ftFileCreator::addFileData() Bad fwrite." << std::endl;
			std::cerr << "ERRNO: " << errno << std::endl;

			return 0;
		}

#ifdef FILE_DEBUG
		std::cerr << "ftFileCreator::addFileData() added Data...";
		std::cerr << std::endl;
		std::cerr << " pos: " << offset;
		std::cerr << std::endl;
#endif
		/* 
		 * Notify ftFileChunker about chunks received 
		 */
		locked_notifyReceived(offset,chunk_size);

		complete = chunkMap.isComplete();
	}
	if(complete)
	{
#ifdef FILE_DEBUG
		std::cerr << "ftFileCreator::addFileData() File is complete: closing" << std::endl ;
#endif
		closeFile();
	}
  
	/* 
	 * FIXME HANDLE COMPLETION HERE - Any better way?
	 */

	return 1;
}

void ftFileCreator::removeInactiveChunks()
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

#ifdef FILE_DEBUG
	std::cerr << "ftFileCreator::removeInactiveChunks(): looking for old chunks." << std::endl ;
#endif
	std::vector<ftChunk::OffsetInFile> to_remove ;

	chunkMap.removeInactiveChunks(to_remove) ;

#ifdef FILE_DEBUG
	if(!to_remove.empty())
		std::cerr << "ftFileCreator::removeInactiveChunks(): removing slice ids: " ;
#endif
	// This double loop looks costly, but it's called on very few chunks, and not often, so it's ok.
	//
	for(uint32_t i=0;i<to_remove.size();++i)
	{
#ifdef FILE_DEBUG
		std::cerr << to_remove[i] << " " ;
#endif
		for(std::map<uint64_t,ftChunk>::iterator it(mChunks.begin());it!=mChunks.end();)
			if(it->second.id == to_remove[i])
			{
				std::map<uint64_t,ftChunk>::iterator tmp(it) ;
				++it ;
				if(--*tmp->second.ref_cnt == 0)
					delete tmp->second.ref_cnt;
				--mChunksPerPeer[tmp->second.peer_id].cnt ;
				mChunks.erase(tmp) ;
			}
			else
				++it ;
	}
#ifdef FILE_DEBUG
	if(!to_remove.empty())
		std::cerr << std::endl ;
#endif
}

void ftFileCreator::removeFileSource(const RsPeerId& peer_id)
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/
#ifdef FILE_DEBUG
	std::cerr << "ftFileCreator:: removign file source " << peer_id << " from chunkmap." << std::endl ;
#endif
	chunkMap.removeFileSource(peer_id) ;
}

int ftFileCreator::locked_initializeFileAttrs()
{
#ifdef FILE_DEBUG
	std::cerr << "ftFileCreator::initializeFileAttrs() Filename: " << file_name << " this: " << this << std::endl;
#endif

	/* 
	 * check if the file exists 
	 * cant use FileProviders verion because that opens readonly.
	 */

	if (fd)
		return 1;

	/* 
	 * check if the file exists 
	 */

	{
#ifdef FILE_DEBUG
		std::cerr << "ftFileCreator::initializeFileAttrs() trying (r+b) " << file_name << " this: " << this << std::endl;
#endif
	}

	/* 
	 * attempt to open file 
	 */

	fd = RsDirUtil::rs_fopen(file_name.c_str(), "r+b");

	if (!fd)
	{
#ifdef FILE_DEBUG
		std::cerr << "ftFileCreator::initializeFileAttrs() Failed to open (r+b): ";
		std::cerr << file_name << ", errno = " << errno << std::endl;

		std::cerr << "ftFileCreator::initializeFileAttrs() opening w+b";
		std::cerr << std::endl;
#endif

		/* try opening for write */
		fd = RsDirUtil::rs_fopen(file_name.c_str(), "w+b");
		if (!fd)
		{
			std::cerr << "ftFileCreator::initializeFileAttrs()";
			std::cerr << " Failed to open (w+b): "<< file_name << ", errno = " << errno << std::endl;
			return 0;
		}
	}
#ifdef FILE_DEBUG
	std::cerr << "OPENNED FILE " << (void*)fd << " (" << file_name << "), for r/w." << std::endl ;
#endif

	return 1;
}
ftFileCreator::~ftFileCreator()
{
#ifdef FILE_DEBUG
	std::cerr << "Deleting file creator for " << file_name << std::endl;
#endif

	// Note: The file is actually closed in the parent, that is always a ftFileProvider.
	//
	/*
	 * FIXME Any cleanups specific to filecreator?
	 */
}


int ftFileCreator::locked_notifyReceived(uint64_t offset, uint32_t chunk_size) 
{
	/* ALREADY LOCKED */
#ifdef FILE_DEBUG
	std::cerr << "ftFileCreator::locked_notifyReceived( " << offset;
	std::cerr << ", " << chunk_size << " )";
	std::cerr << " this: " << this;
	std::cerr << std::endl;
#endif

	/* find the chunk */
	std::map<uint64_t, ftChunk>::iterator it = mChunks.find(offset);
	ftChunk chunk ;

	if(it == mChunks.end())
	{
		// Chunk is not found. Maybe that is because the packet is in the middle
		// of an existing chunk. This case occurs whenever a packet is lost due
		// to temporarily interrupted connection.  In such a case we split the
		// chunk. Any pending block will be re-asked to the source after 40 secs.
		//
#ifdef FILE_DEBUG
		std::cerr << "ftFileCreator::locked_notifyReceived(): Failed to match to existing chunk. A packet was probably dropped. Strategy is:" << std::endl;
		std::cerr << "  - find corresponding chunk, split it in two pieces and ask again the first part." << std::endl;

		locked_printChunkMap();
#endif
		bool found = false ;

		for(std::map<uint64_t,ftChunk>::iterator it2=mChunks.begin();it2!=mChunks.end();++it2)
			if( it2->second.offset < offset && it2->second.size+it2->second.offset >= chunk_size+offset) // found it if it started strictly after the beginning of the chunk and ends before its end.
			{
				it = it2 ;
#ifdef FILE_DEBUG
				std::cerr << "ftFileCreator::locked_notifyReceived(): Chunk found: " << it->second.offset << " to " << it->second.offset + it->second.size << std::endl;
#endif

				// 1 - split the chunk into two parts. Re-ask the first part, and keep the second part
				//     as ongoing.

				ftChunk part1( it->second );
				part1.size = offset - it->second.offset ;	// always > 0

				chunk = it->second ;		// saves the data, as it will be erased by next line
				mChunks[part1.offset] = part1;

				chunk.offset = offset ;
				chunk.size -= part1.size ;
				
				// 2 - we need to be extra careful:
				//       - the chunks will have the same id. That's potentially a problem for completing the slice
				//         we should keep a list of pending chunkIds, so as to only call chunkMap.dataReceived() when
				//         all parts are obtained.
				//       - new parts arriving in the second part cannot interfere since they should come in order.

				++(*chunk.ref_cnt) ;

#ifdef FILE_DEBUG
				std::cerr << "Created two sub chunks. Ref_cnt = " << *chunk.ref_cnt << std::endl;
				std::cerr << "       chunk1: " << part1 << std::endl;
				std::cerr << "       chunk2: " << chunk << std::endl;
#endif

				found = true ;
				break ;
			}

		if(!found)
		{
#ifdef FILE_DEBUG
			std::cerr << "ftFileCreator::locked_notifyReceived(): failed to find an active slice for " << offset << "+" << chunk_size << ", hash = " << hash << ": dropping data." << std::endl;
#endif
			return 0; /* ignoring */
		}
	}
	else
	{
		chunk = it->second;
		mChunks.erase(it);
	}

	if (chunk.size != chunk_size)
	{
		/* partial : shrink chunk */
		chunk.size -= chunk_size;
		chunk.offset += chunk_size;
		mChunks[chunk.offset] = chunk;
	}
	else if( --*chunk.ref_cnt == 0)	// notify the chunkmap that the slice is finished, and decrement the number of chunks for this peer.
	{
#ifdef FILE_DEBUG
		std::cerr << "Chunk finished and ref cnt = " << *chunk.ref_cnt << ": deleting." << std::endl;
#endif
		chunkMap.dataReceived(chunk.id) ;
		--mChunksPerPeer[chunk.peer_id].cnt ;
		delete chunk.ref_cnt ;			// delete the counter
	}
#ifdef FILE_DEBUG
	else
		std::cerr << "Chunk finished but ref cnt = " << *chunk.ref_cnt << ": not deleting." << std::endl;
#endif

	_last_recv_time_t = time(NULL) ;

	/* otherwise there is another earlier block to go
	 */

	return 1;
}

FileChunksInfo::ChunkStrategy ftFileCreator::getChunkStrategy()
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

	return chunkMap.getStrategy() ;
}
void ftFileCreator::setChunkStrategy(FileChunksInfo::ChunkStrategy s)
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

	// Let's check, for safety.
	if(s != FileChunksInfo::CHUNK_STRATEGY_STREAMING && s != FileChunksInfo::CHUNK_STRATEGY_RANDOM && s != FileChunksInfo::CHUNK_STRATEGY_PROGRESSIVE)
	{
		std::cerr << "ftFileCreator::ERROR: invalid chunk strategy " << s << "!" << " setting default value " << FileChunksInfo::CHUNK_STRATEGY_STREAMING << std::endl ;
		s = FileChunksInfo::CHUNK_STRATEGY_PROGRESSIVE ;
	}

#ifdef FILE_DEBUG
	std::cerr << "ftFileCtreator: setting chunk strategy to " << s << std::endl ;
#endif
	chunkMap.setStrategy(s) ;
}

/* Returns true if more to get 
 * But can return size = 0, if we are still waiting for the data.
 */

bool ftFileCreator::getMissingChunk(const RsPeerId& peer_id,uint32_t size_hint,uint64_t &offset, uint32_t& size,bool& source_chunk_map_needed) 
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/
#ifdef FILE_DEBUG
	std::cerr << "ffc::getMissingChunk(...,"<< size_hint << ")";
	std::cerr << " this: " << this;
	std::cerr << std::endl;
	locked_printChunkMap();
#endif
	source_chunk_map_needed = false ;
	rstime_t now = time(NULL) ;

	// 0 - is there a faulting chunk that would need to be asked again ?
	
	for(std::map<uint64_t,ftChunk>::iterator it(mChunks.begin());it!=mChunks.end();++it)
		if(it->second.ts + CHUNK_MAX_AGE < now && chunkMap.getSourceChunksInfo(peer_id)->hasData(it->second.offset,ChunkMap::CHUNKMAP_FIXED_CHUNK_SIZE))
		{
			offset = it->second.offset ;
			size   = it->second.size ;
			it->second.ts = now ;

#ifdef FILE_DEBUG
			std::cerr << "ftFileCreator::getMissingChunk(): re-asking for chunk that wasn't received: " << offset << " + " << size << std::endl;
#endif
			return true ;
		}

	// 1 - is there an ongoing 1MB chunk for which we need to take a new slice?
	//
	uint32_t& chunks_for_this_peer(mChunksPerPeer[peer_id].cnt) ;

	if(chunks_for_this_peer >= MAX_FTCHUNKS_PER_PEER)
	{
#ifdef FILE_DEBUG
		std::cerr << "ffc::getMissingChunk() too many chunks for peer " << peer_id << " for hash " << hash << ". Count = " << chunks_for_this_peer << std::endl ;
#endif
		return false ;
	}

	/* else allocate a new chunk */

	ftChunk chunk ;

	if(!chunkMap.getDataChunk(peer_id,size_hint,chunk,source_chunk_map_needed))
	{
		// No chunks are available. We brutally re-ask an ongoing chunk to another peer.

		if(chunkMap.reAskPendingChunk(peer_id,size_hint,offset,size))
			return true ;

		return false ;
	}

#ifdef FILE_DEBUG
	std::cerr << "ffc::getMissingChunk() Retrieved new chunk: " << chunk << std::endl ;
#endif

	chunk.ref_cnt = new int ;
	*chunk.ref_cnt = 1 ;
	mChunks[chunk.offset] = chunk ;

	offset = chunk.offset ;
	// cppcheck-suppress unreadVariable
	size = chunk.size ;

	++chunks_for_this_peer ;	// increase number of chunks for this peer.

	return true; /* cos more data to get */
}

void ftFileCreator::getChunkMap(FileChunksInfo& info)
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

	chunkMap.getChunksInfo(info) ;

	// add info pending requests, handled by ftFileCreator
	//
	info.pending_slices.clear();

	for(std::map<uint64_t, ftChunk>::iterator it = mChunks.begin();it!=mChunks.end();++it)
	{
		int n = it->second.id / info.chunk_size ;

		FileChunksInfo::SliceInfo si ;
		si.start = it->second.offset - n*info.chunk_size ;
		si.size = it->second.size ;
		si.peer_id = it->second.peer_id ;

		info.pending_slices[n].push_back(si) ;
	}
}

bool ftFileCreator::locked_printChunkMap()
{
#ifdef FILE_DEBUG
	std::cerr << "ftFileCreator::locked_printChunkMap()";
	std::cerr << " this: " << this;
	std::cerr << std::endl;
#endif

	/* check start point */
	std::cerr << "\tOutstanding Chunks:";
	std::cerr << std::endl;

	std::map<uint64_t, ftChunk>::iterator it;
	
	for(it = mChunks.begin(); it != mChunks.end(); ++it)
		std::cerr << "  " << it->second << std::endl ;

	std::cerr << "Active chunks per peer:" << std::endl ;
	for(std::map<RsPeerId,ZeroInitCounter>::const_iterator it(mChunksPerPeer.begin());it!=mChunksPerPeer.end();++it)
		std::cerr << "   " << it->first << "\t: " << it->second.cnt << std::endl;

	return true; 
}

void ftFileCreator::setAvailabilityMap(const CompressedChunkMap& cmap) 
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

	chunkMap.setAvailabilityMap(cmap) ;
#ifdef FILE_DEBUG
	std::cerr << "ftFileCreator: setting chunkmap for hash " << hash << ": " ;

	for(uint32_t i=0;i<cmap._map.size();++i)
		std::cerr << (void*)cmap._map[i] ;
	std::cerr << std::endl ;
#endif
}

void ftFileCreator::getAvailabilityMap(CompressedChunkMap& map) 
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

	chunkMap.getAvailabilityMap(map) ;
}

bool ftFileCreator::sourceIsComplete(const RsPeerId& peer_id)
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

	return chunkMap.getSourceChunksInfo(peer_id)->is_full ;
}

void ftFileCreator::setSourceMap(const RsPeerId& peer_id,const CompressedChunkMap& compressed_map)
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

#ifdef FILE_DEBUG
	std::cerr << "ftFileCreator:: Received source map for hash " << hash << " for source peer " << peer_id << std::endl;
#endif
	// At this point, we should cancel all file chunks that are asked to the
	// peer and which this peer actually doesn't possesses. Otherwise, the transfer may get stuck. 
	// This should be done by:
	// 	- first setting the peer availability map
	// 	- then asking the chunkmap which chunks are being downloaded, but actually shouldn't
	// 	- cancelling them in the ftFileCreator, so that they can be re-asked later to another peer.
	//
	chunkMap.setPeerAvailabilityMap(peer_id,compressed_map) ;
}

bool ftFileCreator::finished() 
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

	return chunkMap.isComplete() ;
}

bool ftFileCreator::hashReceivedData(RsFileHash& hash)
{
#ifdef FILE_DEBUG
	std::cerr << "file creator asked for hashing received data " << file_name << std::endl;
#endif

	// csoler: No mutex here please !
	//
	// This is a bit dangerous, but otherwise we might stuck the GUI for a 
	// long time. Therefore, we must pay attention not to call this function
	// at a time file_name nor hash can be modified, which is easy.
	//
	if(!finished())
	{
		std::cerr << "Transfer not finished !! This should not happen" << std::endl;
		return false ;
	}

	uint64_t tmpsize ;
	return RsDirUtil::getFileHash(file_name,hash,tmpsize) ;
}

void ftFileCreator::forceCheck()
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

	chunkMap.forceCheck(); 
}

void ftFileCreator::getSourcesList(uint32_t chunk_num,std::vector<RsPeerId>& sources)
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

	chunkMap.getSourcesList(chunk_num,sources) ;
}

void ftFileCreator::getChunksToCheck(std::vector<uint32_t>& chunks_to_ask)
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/
	
	chunkMap.getChunksToCheck(chunks_to_ask) ;
}

bool ftFileCreator::verifyChunk(uint32_t chunk_number,const Sha1CheckSum& sum)
{
	RsStackMutex stack(ftcMutex); /********** STACK LOCKED MTX ******/

	if(!locked_initializeFileAttrs() )
		return false ;

	static const uint32_t chunk_size = ChunkMap::CHUNKMAP_FIXED_CHUNK_SIZE ;
	unsigned char *buff = new unsigned char[chunk_size] ;
	uint32_t len ;

	if(fseeko64(fd,(uint64_t)chunk_number * (uint64_t)chunk_size,SEEK_SET)==0 && (len = fread(buff,1,chunk_size,fd)) > 0)
	{
		Sha1CheckSum comp = RsDirUtil::sha1sum(buff,len) ;

		if(sum == comp)
			chunkMap.setChunkCheckingResult(chunk_number,true) ;
		else
		{
			std::cerr << "Sum mismatch for chunk " << chunk_number << std::endl;
			std::cerr << "    Computed  hash = " << comp.toStdString() << std::endl;
			std::cerr << "    Reference hash = " << sum.toStdString() << std::endl;

			chunkMap.setChunkCheckingResult(chunk_number,false) ;
		}
	}
	else
	{
		printf("Chunk verification: cannot fseek!\n") ;
		chunkMap.setChunkCheckingResult(chunk_number,false) ;
	}

	delete[] buff ;
	return true ;
}