/***************************************************************************
 *   Copyright (C) 2005 by Joris Guisson                                   *
 *   joris.guisson@gmail.com                                               *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 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 General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.             *
 ***************************************************************************/
#include "cache.h"
#include <KLocalizedString>
#include <util/functions.h>
#include <util/log.h>
#include <util/fileops.h>
#include <peer/connectionlimit.h>
#include <peer/peermanager.h>
#include <torrent/torrent.h>
#include <torrent/job.h>
#include "chunk.h"
#include "cachefile.h"
#include "piecedata.h"


namespace bt
{
	bool Cache::preallocate_files = true;
	bool Cache::preallocate_fully = false;

	Cache::Cache(Torrent & tor,const QString & tmpdir,const QString & datadir)
	: tor(tor),tmpdir(tmpdir),datadir(datadir),mmap_failures(0)
	{
		if (!datadir.endsWith(bt::DirSeparator()))
			this->datadir += bt::DirSeparator();

		if (!tmpdir.endsWith(bt::DirSeparator()))
			this->tmpdir += bt::DirSeparator();
		
		preexisting_files = false;
	}


	Cache::~Cache()
	{
		cleanupPieceCache();
	}

	void Cache::cleanupPieceCache()
	{
		PieceCache::iterator i = piece_cache.begin();
		while (i != piece_cache.end())
		{
			i.value()->unload();
			++i;
		}
		piece_cache.clear();
	}


	void Cache::changeTmpDir(const QString & ndir)
	{
		tmpdir = ndir;
	}
	
	bool Cache::mappedModeAllowed()
	{
#ifndef Q_WS_WIN
		return MaxOpenFiles() - bt::PeerManager::connectionLimits().totalConnections() > 100;
#else
		return true; //there isn't a file handle limit on windows
#endif
	}
	
	Job* Cache::moveDataFiles(const QMap<TorrentFileInterface*,QString> & files)
	{
		Q_UNUSED(files);
		return 0;
	}
	
	void Cache::moveDataFilesFinished(const QMap<TorrentFileInterface*,QString> & files,Job* job)
	{
		Q_UNUSED(files);
		if(job->error())
			return;
		
		QSet<QString> mps;
		if(getMountPoints(mps))
			saveMountPoints(mps);
	}
	
	PieceData::Ptr Cache::findPiece(Chunk* c,Uint32 off,Uint32 len,bool read_only)
	{
		PieceCache::const_iterator i = piece_cache.constFind(c);
		while (i != piece_cache.constEnd() && i.key() == c)
		{
			PieceData::Ptr cp = i.value();
			if (cp->offset() == off && cp->length() == len && !(!cp->writeable() && !read_only))
				return PieceData::Ptr(cp);
			++i;
		}
		
		return PieceData::Ptr();
	}
	
	void Cache::insertPiece(Chunk* c,PieceData::Ptr p)
	{
		piece_cache.insert(c,p);
	}
	
	void Cache::clearPieces(Chunk* c)
	{
		PieceCache::iterator i = piece_cache.find(c);
		while (i != piece_cache.end() && i.key() == c)
		{
			i = piece_cache.erase(i);
		}
	}
	
	void Cache::clearPieceCache()
	{
		PieceCache::iterator i = piece_cache.begin();
		while (i != piece_cache.end())
		{
			if (!i.value()->inUse())
				i = piece_cache.erase(i);
			else
				++i;
		}
	}
	
	void Cache::checkMemoryUsage()
	{
		Uint64 mem = 0;
		Uint64 freed = 0;
		PieceCache::iterator i = piece_cache.begin();
		while (i != piece_cache.end())
		{
			if (!i.value()->inUse())
			{
				freed += i.value()->length();
				i = piece_cache.erase(i);
			}
			else
			{
				mem += i.value()->length();
				++i;
			}
		}

		if (mem || freed)
			Out(SYS_DIO|LOG_DEBUG) << "Piece cache: memory in use " << BytesToString(mem) << ", memory freed " << BytesToString(freed) << endl;
	}
	
	void Cache::saveMountPoints(const QSet<QString> & mp)
	{
		mount_points = mp;
		
		QString mp_file = tmpdir + "mount_points";
		QFile fptr(mp_file);
		if(!fptr.open(QIODevice::WriteOnly))
			throw Error(i18n("Failed to create %1: %2", mp_file, fptr.errorString()));
		
		QTextStream out(&fptr);
		for(const QString & mount_point: qAsConst(mount_points))
		{
			out << mount_point << ::endl;
		}
	}

	void Cache::loadMountPoints()
	{
		QString mp_file = tmpdir + "mount_points";
		QFile fptr(mp_file);
		if(!fptr.open(QIODevice::ReadOnly))
		{
			Out(SYS_DIO|LOG_NOTICE) << "Failed to load " << mp_file << ": " << fptr.errorString() << endl;
			
			QSet<QString> mps;
			if(getMountPoints(mps))
			{
				saveMountPoints(mps);
			}
		}
		else
		{
			mount_points.clear();
			QTextStream in(&fptr);
			while(!in.atEnd())
			{
				mount_points.insert(in.readLine());
			}
		}
	}
	
	bool Cache::isStorageMounted(QStringList& missing)
	{
		if(mount_points.isEmpty())
			return true;

		missing.clear();
		for(const QString & mount_point: qAsConst(mount_points))
		{
			if(!IsMounted(mount_point))
				missing.append(mount_point);
		}
		
		return missing.empty();
	}
}
