#	Back In Time
#	Copyright (C) 2008-2009 Oprea Dan, Bart de Koning, Richard Bailey
#
#	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.


import os
import os.path
import stat
import datetime
import gettext
import statvfs
import stat
import bz2
import pwd
import grp
import socket

import config
import configfile
import logger
import applicationinstance
import tools
import pluginmanager


_=gettext.gettext


class Snapshots:
	SNAPSHOT_VERSION = 3

	def __init__( self, cfg = None ):
		self.config = cfg
		if self.config is None:
			self.config = config.Config()

		self.clear_uid_gid_cache()
		self.clear_uid_gid_names_cache()

		self.plugin_manager = pluginmanager.PluginManager()

	def get_snapshot_id( self, date ):
		profile_id = self.config.get_current_profile()
		tag = self.config.get_tag( profile_id )
		
		if type( date ) is datetime.datetime:
			snapshot_id = date.strftime( '%Y%m%d-%H%M%S' ) + '-' + tag
			return snapshot_id

		if type( date ) is datetime.date:
			snapshot_id = date.strftime( '%Y%m%d-000000' ) + '-' + tag
			return snapshot_id

		if type( date ) is str:
			snapshot_id = date
			return snapshot_id
		
		return ""

	def get_snapshot_old_id( self, date ):
		profile_id = self.config.get_current_profile()
		
		if type( date ) is datetime.datetime:
			snapshot_id = date.strftime( '%Y%m%d-%H%M%S' )
			return snapshot_id

		if type( date ) is datetime.date:
			snapshot_id = date.strftime( '%Y%m%d-000000' )
			return snapshot_id

		if type( date ) is str:
			snapshot_id = date
			return snapshot_id
		
		return ""

	def get_snapshot_path( self, date ):
		profile_id = self.config.get_current_profile()
		path = os.path.join( self.config.get_snapshots_full_path( profile_id ), self.get_snapshot_id( date ) )
		if os.path.exists( path ):
			#print path
			return path
		other_folders = self.config.get_other_folders_paths()
		for folder in other_folders:
			path_other = os.path.join( folder, self.get_snapshot_id( date ) )
			if os.path.exists( path_other ):
				#print path_other
				return path_other
		old_path = os.path.join( self.config.get_snapshots_full_path( profile_id ), self.get_snapshot_old_id( date ) )
		if os.path.exists( path ):
			#print path
			return path
		other_folders = self.config.get_other_folders_paths()
		for folder in other_folders:
			path_other = os.path.join( folder, self.get_snapshot_old_id( date ) )
			if os.path.exists( path_other ):
				#print path_other
				return path_other				
		#print path
		return path

	def get_snapshot_info_path( self, date ):
		return os.path.join( self.get_snapshot_path( date ), 'info' )

	def get_snapshot_fileinfo_path( self, date ):
		return os.path.join( self.get_snapshot_path( date ), 'fileinfo.bz2' )

	def get_snapshot_log_path( self, snapshot_id ):
		return os.path.join( self.get_snapshot_path( snapshot_id ), 'takesnapshot.log.bz2' )

	def get_snapshot_failed_path( self, snapshot_id ):
		return os.path.join( self.get_snapshot_path( snapshot_id ), 'failed' )

	def _get_snapshot_data_path( self, snapshot_id ):
		if len( snapshot_id ) <= 1:
			return '/';
		return os.path.join( self.get_snapshot_path( snapshot_id ), 'backup' )
	
	def get_snapshot_path_to( self, snapshot_id, toPath = '/' ):
		return os.path.join( self._get_snapshot_data_path( snapshot_id ), toPath[ 1 : ] )

	def can_open_path( self, snapshot_id, full_path ):
		#full_path = self.get_snapshot_path_to( snapshot_id, path )
		if not os.path.exists( full_path ):
			return False
		if not os.path.islink( full_path ):
			return True
		base_path = self.get_snapshot_path_to( snapshot_id )
		target = os.readlink( full_path )
		target = os.path.join( os.path.abspath( os.path.dirname( full_path ) ), target )
		#print "[can_open_path] full_path %s" % full_path
		#print "[can_open_path] base_path %s" % base_path
		return target.startswith( base_path )

	def get_snapshot_display_id( self, snapshot_id ):
		if len( snapshot_id ) <= 1:
			return _('Now')
		return "%s-%s-%s %s:%s:%s" % ( snapshot_id[ 0 : 4 ], snapshot_id[ 4 : 6 ], snapshot_id[ 6 : 8 ], snapshot_id[ 9 : 11 ], snapshot_id[ 11 : 13 ], snapshot_id[ 13 : 15 ]  )
	
	def get_snapshot_display_name( self, snapshot_id ):
		display_name = self.get_snapshot_display_id( snapshot_id )
		name = self.get_snapshot_name( snapshot_id )

		if len( name ) > 0:
			display_name = display_name + ' - ' + name

		if self.is_snapshot_failed( snapshot_id ):
			display_name = display_name + " (%s)" % _("WITH ERRORS !")

		return display_name

	def get_snapshot_name( self, snapshot_id ):
		if len( snapshot_id ) <= 1: #not a snapshot
			return ''

		path = self.get_snapshot_path( snapshot_id )
		if not os.path.isdir( path ):
			return ''
		
		name = ''
		try:
			file = open( os.path.join( path, 'name' ), 'rt' )
			name = file.read()
			file.close()
		except:
			pass

		return name

	def set_snapshot_name( self, snapshot_id, name ):
		if len( snapshot_id ) <= 1: #not a snapshot
			return

		path = self.get_snapshot_path( snapshot_id )
		if not os.path.isdir( path ):
			return

		name_path = os.path.join( path, 'name' )

		#info_file = configfile.ConfigFile()
		#info_file.load( self.get_snapshot_info_path( snapshot_id ) )
		#if info_file.get_int_value( 'snapshot_version' ) == 0:
		os.system( "chmod +w \"%s\"" % path )

		try:
			file = open( name_path, 'wt' )
			file.write( name )
			file.close()
		except:
			pass

	def is_snapshot_failed( self, snapshot_id ):
		if len( snapshot_id ) <= 1: #not a snapshot
			return False

		path = self.get_snapshot_failed_path( snapshot_id )
		return os.path.isfile( path )

	def clear_take_snapshot_message( self ):
		os.system( "rm \"%s\"" % self.config.get_take_snapshot_message_file() )

	def get_take_snapshot_message( self ):
		try:
			file = open( self.config.get_take_snapshot_message_file(), 'rt' )
			items = file.read().split( '\n' )
			file.close()
		except:
			return None 

		if len( items ) < 2:
			return None

		id = 0
		try:
			id = int( items[0] )
		except:
			pass

		del items[0]
		message = '\n'.join( items )

		return( id, message )

	def set_take_snapshot_message( self, type_id, message ):
		data = str(type_id) + '\n' + message

		try:
			file = open( self.config.get_take_snapshot_message_file(), 'wt' )
			file.write( data )
			file.close()
			#logger.info( "Take snapshot message: %s" % data )
		except:
			pass

		if 1 == type_id:
			self.append_to_take_snapshot_log( '[E] ' + message, 1 )
		else:
			self.append_to_take_snapshot_log( '[I] '  + message, 3 )

	def _filter_take_snapshot_log( self, log, mode ):
		if 0 == mode:
			return log

		lines = log.split( '\n' )
		log = ''

		for line in lines:
			if line.startswith( '[' ):
				if mode == 1 and line[1] != 'E':
					continue
				elif mode == 2 and line[1] != 'C':
					continue
				elif mode == 3 and line[1] != 'I':
					continue

			log = log + line + '\n'

		return log

	def get_snapshot_log( self, snapshot_id, mode = 0, profile_id = None ):
		try:
			file = bz2.BZ2File( self.get_snapshot_log_path( snapshot_id ), 'r' )
			data = file.read()
			file.close()
			return self._filter_take_snapshot_log( data, mode )
		except:
			return ''

	def get_take_snapshot_log( self, mode = 0, profile_id = None ):
		try:
			file = open( self.config.get_take_snapshot_log_file( profile_id ), 'rt' )
			data = file.read()
			file.close()
			return self._filter_take_snapshot_log( data, mode )
		except:
			return ''

	def new_take_snapshot_log( self, date ):
		os.system( "rm \"%s\"" % self.config.get_take_snapshot_log_file() )
		self.append_to_take_snapshot_log( "========== Take snapshot (profile %s): %s ==========\n" % ( self.config.get_current_profile(), date.strftime( '%c' ) ), 1 )

	def append_to_take_snapshot_log( self, message, level ):
		if level > self.config.log_level():
			return

		try:
			file = open( self.config.get_take_snapshot_log_file(), 'at' )
			file.write( message + '\n' )
			file.close()
		except:
			pass

	def is_busy( self ):
		instance = applicationinstance.ApplicationInstance( self.config.get_take_snapshot_instance_file(), False )
		return not instance.check()

	def load_fileinfo_dict( self, snapshot_id, version = None ):
		if version is None:
			info_file = configfile.ConfigFile()
			info_file.load( self.get_snapshot_info_path( snapshot_id ) )
			version = info_file.get_int_value( 'snapshot_version' )
			info_file = None

		dict = {}

		if 0 == version:
			return file_info_dict

		fileinfo_path = self.get_snapshot_fileinfo_path( snapshot_id )
		if not os.path.exists( fileinfo_path ):
			return dict

		#try:
		fileinfo = bz2.BZ2File( fileinfo_path, 'r' )
		while True:
			line = fileinfo.readline()
			if len( line ) <= 0:
				break

			line = line[ : -1 ]
			if len( line ) <= 0:
				continue
		
			index = line.find( '/' )
			if index < 0:
				continue

			file = line[ index: ]
			if len( file ) <= 0:
				continue

			info = line[ : index ].strip()
			info = info.split( ' ' )

			if len( info ) == 3:
				dict[ file ] = [ int( info[0] ), info[1], info[2] ] #perms, user, group

		fileinfo.close()
		#except:
		#	pass

		return dict

	def clear_uid_gid_names_cache(self):
		self.user_cache = {}
		self.group_cache = {}

	def clear_uid_gid_cache(self):
		self.uid_cache = {}
		self.gid_cache = {}

	def get_uid( self, name ):
		try:
			return self.uid_cache[name]
		except:
			uid = -1
			try:
				uid = pwd.getpwnam(name).pw_uid
			except:
				pass

			self.uid_cache[name] = uid
			return uid
			
	def get_gid( self, name ):
		try:
			return self.gid_cache[name]
		except:
			gid = -1
			try:
				gid = grp.getgrnam(name).gr_gid
			except:
				pass

			self.gid_cache[name] = gid
			return gid

	def get_user_name( self, uid ):
		try:
			return self.user_cache[uid]
		except:
			name = '-'
			try:
				name = pwd.getpwuid(uid).pw_name
			except:
				pass

			self.user_cache[uid] = name
			return name
			
	def get_group_name( self, gid ):
		try:
			return self.group_cache[gid]
		except:
			name = '-'
			try:
				name = grp.getgrgid(gid).gr_name
			except:
				pass

			self.group_cache[gid] = name
			return name
			
	def _restore_path_info( self, path, dict, restore_to = "" ):
		if path not in dict:
			return

		info = dict[path]

		#restore perms
		try:
			os.chmod( restore_to + path, info[0] )
		except:
			pass

		#restore uid/gid
		uid = self.get_uid(info[1])
		gid = self.get_gid(info[2])
		
		if uid != -1 or gid != -1:
			try:
				os.chown( restore_to + path, uid, gid )
			except:
				pass

	def restore( self, snapshot_id, path, restore_to = "" ):
		if restore_to.endswith('/'):
			restore_to = restore_to[ : -1 ]

		logger.info( "Restore: %s to: %s" % (path, restore_to) )

		info_file = configfile.ConfigFile()
		info_file.load( self.get_snapshot_info_path( snapshot_id ) )

		backup_suffix = '.backup.' + datetime.date.today().strftime( '%Y%m%d' )
		#cmd = "rsync -avR --copy-unsafe-links --whole-file --backup --suffix=%s --chmod=+w %s/.%s %s" % ( backup_suffix, self.get_snapshot_path_to( snapshot_id ), path, '/' )
		cmd = tools.get_rsync_prefix( self.config )
		cmd = cmd + '-R '
		if self.config.is_backup_on_restore_enabled():
			cmd = cmd + "--backup --suffix=%s " % backup_suffix
		#cmd = cmd + '--chmod=+w '
		cmd = cmd + "\"%s.%s\" %s" % ( self.get_snapshot_path_to( snapshot_id ), path, restore_to + '/' )
		self._execute( cmd )

		#restore permissions
		logger.info( "Restore permissions" )
		file_info_dict = self.load_fileinfo_dict( snapshot_id, info_file.get_int_value( 'snapshot_version' ) )
		if len( file_info_dict ) > 0:
			#explore items
			snapshot_path_to = self.get_snapshot_path_to( snapshot_id, path ).rstrip( '/' )
			root_snapshot_path_to = self.get_snapshot_path_to( snapshot_id ).rstrip( '/' )
			all_dirs = [] #restore dir permissions after all files are done

			path_items = path.strip( '/' ).split( '/' )
			curr_path = '/'
			for path_item in path_items:
				curr_path = os.path.join( curr_path, path_item )
				all_dirs.append( curr_path )

			if not os.path.isfile( snapshot_path_to ):
				for explore_path, dirs, files in os.walk( snapshot_path_to ):
					for item in dirs:
						item_path = os.path.join( explore_path, item )[ len( root_snapshot_path_to ) : ]
						all_dirs.append( item_path )

					for item in files:
						item_path = os.path.join( explore_path, item )[ len( root_snapshot_path_to ) : ]
						self._restore_path_info( item_path, file_info_dict )

			all_dirs.reverse()
			for item_path in all_dirs:
				self._restore_path_info( item_path, file_info_dict, restore_to )

	def get_snapshots_list( self, sort_reverse = True, profile_id = None, version = None ):
		'''Returns a list with the snapshot_ids of all snapshots in the snapshots folder'''
		biglist = []

		if profile_id is None:
			profile_id = self.config.get_current_profile()

		snapshots_path = self.config.get_snapshots_full_path( profile_id, version )
		
		try:
			biglist = os.listdir( snapshots_path )
		except:
			pass

		list = []

		for item in biglist:
			if len( item ) != 15 and len( item ) != 19:
				continue
			if os.path.isdir( os.path.join( snapshots_path, item, 'backup' ) ):
				list.append( item )

		list.sort( reverse = sort_reverse )
		#print "ABC:"
		#print list

		return list
		
	def get_snapshots_and_other_list( self, sort_reverse = True ):
		'''Returns a list with the snapshot_ids, and paths, of all snapshots in the snapshots_folder and the other_folders'''

		biglist = []
		profile_id = self.config.get_current_profile()
		snapshots_path = self.config.get_snapshots_full_path( profile_id )
		snapshots_other_paths = self.config.get_other_folders_paths()
		
		try:
			biglist = os.listdir( snapshots_path )
		except:
			pass
			
		list = []

		for item in biglist:
			if len( item ) != 15 and len( item ) != 19:
				continue
			if os.path.isdir( os.path.join( snapshots_path, item, 'backup' ) ):
				#a = ( item, snapshots_path )
				list.append( item )

				
		if len( snapshots_other_paths ) > 0:	
			for folder in snapshots_other_paths:
				folderlist = []
				try:
					folderlist = os.listdir( folder )
				except:
					pass
				
				for member in folderlist:
					if len( member ) != 15 and len( member ) != 19:
						continue
					if os.path.isdir( os.path.join( folder, member,  'backup' ) ):
						#a = ( member, folder )
						list.append( member )
		
		list.sort( reverse = sort_reverse )
		return list

	def remove_snapshot( self, snapshot_id ):
		if len( snapshot_id ) <= 1:
			return

		path = self.get_snapshot_path( snapshot_id )
		#cmd = "chmod -R u+rwx \"%s\"" %  path
		cmd = "find \"%s\" -type d -exec chmod u+wx {} \\;" % path #Debian patch
		self._execute( cmd )
		cmd = "rm -rf \"%s\"" % path
		self._execute( cmd )

	def copy_snapshot( self, snapshot_id, new_folder ):
		'''Copies a known snapshot to a new location'''
		current.path = self.get_snapshot_path( snapshot_id )
		#need to implement hardlinking to existing folder -> cp newest snapshot folder, rsync -aEAXHv --delete to this folder
		cmd = "gcp -dRl \"%s\"* \"%s\"" % ( current_path, new_folder )
		logger.info( '%s is copied to folder %s' %( snapshot_id, new_folder ) )
		self._execute( cmd )

	#def _get_last_snapshot_info( self ):
	#	lines = ''
	#	dict = {}

	#	try:
	#		if os.path.exists( self.config.get_last_snapshot_info_file() ):
	#			file = open( self.config.get_last_snapshot_info_file(), 'rt' )
	#			lines = file.read()
	#			file.close()
	#	except:
	#		pass

	#	lines = lines.split( '\n' )
	#	for line in lines:
	#		line = line.strip()
	#		if len( line ) <= 0:
	#			continue
	#		fields = line.split( ':' )
	#		if len( fields ) < 6:
	#			continue

	#		dict[ fields[0] ] = datetime.datetime( int(fields[1]), int(fields[2]), int(fields[3]), int(fields[4]), int(fields[5]) )

	#	return dict

	#def _set_last_snapshot_info( self, dict ):
	#	lines = []

	#	for key, value in dict.items():
	#		lines.append( "%s:%s:%s:%s:%s:%s" % ( key, value.year, value.month, value.day, value.hour, value.minute ) )

	#	try:
	#		file = open( self.config.get_last_snapshot_info_file(), 'wt' )
	#		file.write( '\n'.join( lines ) )
	#		file.close()
	#	except:
	#		pass

	#def call_user_callback( self, args ):
	#	cmd = self.config.get_take_snapshot_user_callback()
	#	if os.path.isfile( cmd ):
	#		self._execute( 'sh ' + cmd + ' ' + args )

	def update_snapshots_location( self ):
		'''Updates to location: backintime/machine/user/profile_id'''
		if self.has_old_snapshots():
			logger.info( 'Snapshot location update flag detected' )
			logger.warning( 'Snapshot location needs update' ) 
			profiles = self.config.get_profiles()

			answer_change = self.config.question_handler( _('Back In Time changed its backup format.\n\nYour old snapshots can be moved according to this new format. OK?') )
			#print answer_change
			if answer_change == True:
				logger.info( 'Update snapshot locations' )
				#print len( profiles )
				
				if len( profiles ) == 1:
					logger.info( 'Only 1 profile found' )
					answer_same = True
				elif len( profiles ) > 1:
					answer_same = self.config.question_handler( _('%s profiles found. \n\nThe new backup format supports storage of different users and profiles on the same location. Do you want the same location for both profiles? \n\n(The program will still be able to discriminate between them)') % len( profiles ) )
				else:
					logger.warning( 'No profiles are found!' )
					self.config.notify_error( _( 'No profiles are found. Will have to update to profiles first, please restart Back In Time' ) )
					logger.info( 'Config version is %s' % str( self.get_int_value( 'config.version', 1 ) ) )
					
					if self.config.get_int_value( 'config.version', 1 ) > 1:
						self.config.set_int_value( 'config.version', 2 )
						logger.info( 'Config version set to 2' )
						return False
					
				# Moving old snapshots per profile_id
				#print answer_same
				profile_id = profiles[0]
				#print profile_id
				#old_folder = self.get_snapshots_path( profile_id )
				#print old_folder
				main_folder = self.config.get_snapshots_path( profile_id )
				old_snapshots_paths=[]
				counter = 0
				success = []
				
				for profile_id in profiles:
					#print counter
					old_snapshots_paths.append( self.config.get_snapshots_path( profile_id ) )
					#print old_snapshots_paths
					old_folder = os.path.join( self.config.get_snapshots_path( profile_id ), 'backintime' )
					#print old_folder
					if profile_id != "1" and answer_same == True:
						#print 'profile_id != 1, answer = True'
						self.config.set_snapshots_path( main_folder, profile_id )
						logger.info( 'Folder of profile %s is set to %s' %( profile_id, main_folder ) )
					else:
						self.config.set_snapshots_path( self.config.get_snapshots_path( profile_id ), profile_id )
						logger.info( 'Folder of profile %s is set to %s' %( profile_id, main_folder ) )
					new_folder = self.config.get_snapshots_full_path( profile_id )
					#print new_folder
					#snapshots_to_move = tools.get_snapshots_list_in_folder( old_folder )
					#print snapshots_to_move

					output = tools.move_snapshots_folder( old_folder, new_folder )

					snapshots_left = tools.get_snapshots_list_in_folder( old_folder )
					if output == True:
						success.append( True )
						if len( snapshots_left ) == 0:
							logger.info( 'Update was successful. Snapshots of profile %s are moved to their new location' % profile_id )
						else:
							logger.warning( 'Not all snapshots are removed from the original folder!' )
							logger.info( 'The following snapshots are still present: %s' % snapshots_left )
							logger.info( 'You could move them manually or leave them where they are now' )
					else:
						logger.warning( '%s: are not moved to their new location!' %snapshots_left )
						
						answer_unsuccessful = self.config.question_handler( _('%s\nof profile %s are not moved to their new location\nDo you want to proceed?\n(Back In Time will be able to continue taking snapshots, however the remaining snapshots will not be considered for automatic removal)\n\nIf not Back In Time will restore former settings for this profile, however cannot continue taking snapshots' %( snapshots_left, profile_id ) ) )
						if answer_unsuccessful == True:
							success.append( True )
						else:
							success.append( False )
							# restore
							logger.info( 'Restore former settings' )
							self.config.set_snapshots_path( old_snapshots_paths[counter], profile_id )
							#print self.get_snapshots_path( profile_id )
							self.config.error_handler( _('Former settings of profile %s are restored.\nBack In Time cannot continue taking new snapshots.\n\nYou can manually move the snapshots, \nif you are done restart Back In Time to proceed' %profile_id ) )
					
					counter = counter + 1
				
				#print success
				overall_success = True
				for item in success:
					if item == False:
						overall_success = False	
				if overall_success == True:
					#self.set_update_other_folders( False )
					#print self.get_update_other_folders()
					logger.info( 'Back In Time will be able to make new snapshots again!' )
					self.config.error_handler( _('Update was successful!\n\nBack In Time will continue taking snapshots again as scheduled' ) )

			elif answer_change == False:
				logger.info( 'Move refused by user' )
				logger.warning( 'Old snapshots are not taken into account by smart-remove' )
				answer_continue = self.config.question_handler( _('Are you sure you do not want to move your old snapshots?\n\n\nIf you do, you will not see these questions again next time, Back In Time will continue making snapshots again, but smart-remove cannot take your old snapshots into account any longer!\n\nIf you do not, you will be asked again next time you start Back In Time.') )
				if answer_continue == True:
					#self.set_update_other_folders( False )
					for profile_id in profiles:
						old_folder = self.config.get_snapshots_path( profile_id )
						self.config.set_snapshots_path( old_folder, profile_id )
						logger.info( 'Folder of profile %s is set to %s' %( profile_id, self.get_snapshots_path( profile_id ) ) )
					
					logger.info( 'Back In Time will be able to make new snapshots again!' )
					self.config.error_handler( _('Back In Time will continue taking snapshots again as scheduled' ) )
				else: 
					self.config.error_handler( _( 'Back In Time still cannot continue taking new snapshots.\nRestart Back In Time to see the questions again' ) )
			else:
				return False
		
	def has_old_snapshots( self ):
		return len( self.get_snapshots_list( False, None, 3 ) ) > 0

	def take_snapshot( self, force = False ):
		ret_val = False
		sleep = True

		self.plugin_manager.load_plugins( self )

		if not self.config.is_configured():
			logger.warning( 'Not configured' )
			self.plugin_manager.on_error( 1 ) #not configured
		elif self.config.is_no_on_battery_enabled() and tools.on_battery():
			logger.info( 'Deferring backup while on battery' )
			logger.warning( 'Backup not performed' )
		#elif self.config.get_update_other_folders() == True:
		elif self.has_old_snapshots():
			logger.info( 'The application needs to change the backup format. Start the GUI to proceed. (As long as you do not you will not be able to make new snapshots!)' )
			logger.warning( 'Backup not performed' )
		else:
			instance = applicationinstance.ApplicationInstance( self.config.get_take_snapshot_instance_file(), False )
			if not instance.check():
				logger.warning( 'A backup is already running' )
				self.plugin_manager.on_error( 2 ) #a backup is already running
			else:
				ret_error = False

				if self.config.is_no_on_battery_enabled () and not tools.power_status_available():
					logger.warning( 'Backups disabled on battery but power status is not available' )
								
				instance.start_application()
				logger.info( 'Lock' )

				#if not self.config.get_per_directory_schedule():
				#	force = True

				now = datetime.datetime.today()
				#if not force:
				#	now = now.replace( second = 0 )

				#include_folders, ignore_folders, dict = self._get_backup_folders( now, force )
				include_folders = self.config.get_include()

				if len( include_folders ) <= 0:
					logger.info( 'Nothing to do' )
				else:
					self.plugin_manager.on_process_begins() #take snapshot process begin
					logger.info( "on process begins" )
					self.set_take_snapshot_message( 0, '...' )
					self.new_take_snapshot_log( now )
					profile_id = self.config.get_current_profile()
					logger.info( "Profile_id: %s" % profile_id )
					
					if not self.config.can_backup( profile_id ):
						if self.plugin_manager.has_gui_plugins() and self.config.is_notify_enabled():
							for counter in xrange( 30, 0, -1 ):
								self.set_take_snapshot_message( 1, 
										_('Can\'t find snapshots folder.\nIf it is on a removable drive please plug it.' ) +
										'\n' +
										gettext.ngettext( 'Waiting %s second.', 'Waiting %s seconds.', counter ) % counter )
								os.system( 'sleep 1' )
								if self.config.can_backup():
									break

					if not self.config.can_backup( profile_id ):
						logger.warning( 'Can\'t find snapshots folder !' )
						self.plugin_manager.on_error( 3 ) #Can't find snapshots directory (is it on a removable drive ?)
					else:
						snapshot_id = self.get_snapshot_id( now )
						snapshot_path = self.get_snapshot_path( snapshot_id )
						
						if os.path.exists( snapshot_path ):
							logger.warning( "Snapshot path \"%s\" already exists" % snapshot_path )
							self.plugin_manager.on_error( 4, snapshot_id ) #This snapshots already exists
						else:
							#ret_val = self._take_snapshot( snapshot_id, now, include_folders, ignore_folders, dict, force )
							ret_val, ret_error = self._take_snapshot( snapshot_id, now, include_folders )

						if not ret_val:
							self._execute( "rm -rf \"%s\"" % snapshot_path )

							if ret_error:
								logger.error( 'Failed to take snapshot !!!' )
								self.set_take_snapshot_message( 1, _('Failed to take snapshot %s !!!') % now.strftime( '%x %H:%M:%S' ) )
								os.system( 'sleep 2' )
							else:
								logger.warning( "No new snapshot" )
						else:
							ret_error = False
					
						if not ret_error:
							self._free_space( now )
							self.set_take_snapshot_message( 0, _('Finalizing') )

					os.system( 'sleep 2' )
					sleep = False

					if ret_val:
						self.plugin_manager.on_new_snapshot( snapshot_id, snapshot_path ) #new snapshot

					self.plugin_manager.on_process_ends() #take snapshot process end

				if sleep:
					os.system( 'sleep 2' )
					sleep = False

				if not ret_error:
					self.clear_take_snapshot_message()

				instance.exit_application()
				logger.info( 'Unlock' )

		if sleep:
			os.system( 'sleep 2' ) #max 1 backup / second

		return ret_val

	def _exec_rsync_callback( self, line, params ):
		self.set_take_snapshot_message( 0, _('Take snapshot') + " (rsync: %s)" % line )

		if line.endswith( ')' ):
			if line.startswith( 'rsync:' ):
				if not line.startswith( 'rsync: chgrp ' ) and not line.startswith( 'rsync: chown ' ):
					params[0] = True
					self.set_take_snapshot_message( 1, 'Error: ' + line )

	def _exec_rsync_compare_callback( self, line, params ):
		#self.set_take_snapshot_message( 0, _('Compare with snapshot %s') % params[0] )

		if len(line) >= 13:
			if line.startswith( 'BACKINTIME: ' ):
				if line[12] != '.':
					params[1] = True
					self.append_to_take_snapshot_log( '[C] ' + line[ 12 : ], 2 )

	def _append_item_to_list( self, item, list ):
		for list_item in list:
			if item == list_item:
				return
		list.append( item )

	def _is_auto_backup_needed( self, now, last, mode ):
		#print "now: %s, last: %s, mode: %s" % ( now, last, mode )

		if self.config.NONE == mode:
			return False

		if now <= last:
			return False

		if now.year > last.year: #year changed
			return True

		if self.config.MONTH == mode: #month changed
			return now.month > last.month
		
		if self.config.WEEK == mode: #weekly
			if now.date() <= last.date():
				return False
			return now.isoweekday() == 7 #Sunday

		if now.date() > last.date(): #day changed
			return True

		if self.config.DAY == mode:
			return False

		if now.hour > last.hour: #hour changed
			return True
		
		if self.config.HOUR == mode:
			return False

		if self.config._10_MIN == mode: #every 10 minutes
			return ( int( now.minute / 10 ) ) > ( int( last.minute / 10 ) )

		if self.config._5_MIN == mode: #every 5 minutes
			return ( int( now.minute / 5 ) ) > ( int( last.minute / 5 ) )

		return False

	#def _get_backup_folders( self, now, force ):
	#	include_folders = []
	#	ignore_folders = []
	#	dict = self._get_last_snapshot_info()
	#	dict2 = {}

	#	all_include_folders = self.config.get_include()
	#	
	#	for item in all_include_folders:
	#		path = item[0]
	#		path = os.path.expanduser( path )
	#		path = os.path.abspath( path )

	#		if path in dict:
	#			dict2[ path ] = dict[ path ]

	#		if not os.path.isdir( path ):
	#			continue

	#		if not force and path in dict:
	#			if not self._is_auto_backup_needed( now, dict[path], item[1] ):
	#				ignore_folders.append( path )
	#				continue

	#		include_folders.append( path )

	#	logger.info( "Include folders: %s" % include_folders )
	#	logger.info( "Ignore folders: %s" % ignore_folders )
	#	logger.info( "Last snapshots: %s" % dict2 )

	#	return ( include_folders, ignore_folders, dict2 )

	def _create_directory( self, folder ):
		tools.make_dirs( folder )

		if not os.path.exists( folder ):
			logger.error( "Can't create folder: %s" % folder )
			self.set_take_snapshot_message( 1, _('Can\'t create folder: %s') % folder )
			os.system( 'sleep 2' ) #max 1 backup / second
			return False

		return True
	
	def _save_path_info_line( self, fileinfo, path, info ):
		fileinfo.write( "%s %s %s %s\n" % ( info[0], info[1], info[2], path ) )

	def _save_path_info( self, fileinfo, path ):
		try:
			info = os.stat( path )
			user = self.get_user_name(info.st_uid)
			group = self.get_group_name(info.st_gid)
			self._save_path_info_line( fileinfo, path, [ info.st_mode, user, group ] )
		except:
			pass

	def _take_snapshot( self, snapshot_id, now, include_folders ): # ignore_folders, dict, force ):
		self.set_take_snapshot_message( 0, _('...') )

		new_snapshot_id = 'new_snapshot'
		new_snapshot_path = self.get_snapshot_path( new_snapshot_id )
		
		if os.path.exists( new_snapshot_path ):
			#self._execute( "find \"%s\" -type d -exec chmod +w {} \;" % new_snapshot_path )
			#self._execute( "chmod -R u+rwx \"%s\"" %  new_snapshot_path )
			self._execute( "find \"%s\" -type d -exec chmod u+wx {} \\;" % new_snapshot_path ) #Debian patch
			self._execute( "rm -rf \"%s\"" % new_snapshot_path )
		
			if os.path.exists( new_snapshot_path ):
				logger.error( "Can't remove folder: %s" % new_snapshot_path )
				self.set_take_snapshot_message( 1, _('Can\'t remove folder: %s') % new_snapshot_path )
				os.system( 'sleep 2' ) #max 1 backup / second
				return [ False, True ]

		new_snapshot_path_to = self.get_snapshot_path_to( new_snapshot_id )
		
		#create exclude patterns string
		items = []
		for exclude in self.config.get_exclude():
			self._append_item_to_list( "--exclude=\"%s\"" % exclude, items )
		#for folder in ignore_folders:
		#	self._append_item_to_list( "--exclude=\"%s\"" % folder, items )
		rsync_exclude = ' '.join( items )

		#create include patterns list
		items = []
		items2 = []
		for include_folder in include_folders:
			folder = include_folder[0]

			if folder == "/":	# If / is selected as included folder it should be changed to ""
				#folder = ""	# because an extra / is added below. Patch thanks to Martin Hoefling
				self._append_item_to_list( "--include=\"/\"" , items2 )
				self._append_item_to_list( "--include=\"/**\"" , items2 )
				continue

			if include_folder[1] == 0:
				self._append_item_to_list( "--include=\"%s/**\"" % folder, items2 )
			else:
				self._append_item_to_list( "--include=\"%s\"" % folder, items2 )
				folder = os.path.split( folder )[0]

			while True:
				self._append_item_to_list( "--include=\"%s/\"" % folder, items )
				folder = os.path.split( folder )[0]
				if len( folder) <= 1:
					break

		rsync_include = ' '.join( items )
		rsync_include2 = ' '.join( items2 )

		#rsync prefix & suffix
		rsync_prefix = tools.get_rsync_prefix( self.config ) # 'rsync -aEAXH '
		rsync_exclude_backup_directory = " --exclude=\"%s\" --exclude=\"%s\" " % ( self.config.get_snapshots_path(), self.config._LOCAL_DATA_FOLDER )
		#rsync_suffix = ' --chmod=Fa-w,Da-w --delete ' + rsync_exclude_backup_directory  + rsync_include + ' ' + rsync_exclude + ' ' + rsync_include2 + ' --exclude=\"*\" / '
		rsync_suffix = ' --chmod=Du+wx ' + rsync_exclude_backup_directory  + rsync_include + ' ' + rsync_exclude + ' ' + rsync_include2 + ' --exclude=\"*\" / '

		#update dict
		#if not force:
		#	for folder in include_folders:
		#		dict[ folder ] = now
		#
		#	self._set_last_snapshot_info( dict )

		#check previous backup
		#should only contain the personal snapshots
		snapshots = self.get_snapshots_list()
		prev_snapshot_id = ''
		
		if len( snapshots ) == 0:
			snapshots = self.get_snapshots_and_other_list()

		# When there is no snapshots it takes the last snapshot from the other folders
		# It should delete the excluded folders then
		rsync_prefix = rsync_prefix + ' --delete --delete-excluded '
		
		prev_snapshot_id = ''

		if len( snapshots ) > 0:
			prev_snapshot_id = snapshots[0]
			prev_snapshot_name = self.get_snapshot_display_id( prev_snapshot_id )
			self.set_take_snapshot_message( 0, _('Compare with snapshot %s') % prev_snapshot_name )
			logger.info( "Compare with old snapshot: %s" % prev_snapshot_id )
			
			prev_snapshot_folder = self.get_snapshot_path_to( prev_snapshot_id )
			cmd = rsync_prefix + ' -i --dry-run --out-format="BACKINTIME: %i %n%L"' + rsync_suffix + '"' + prev_snapshot_folder + '"'
			params = [ prev_snapshot_folder, False ]
			#try_cmd = self._execute_output( cmd, self._exec_rsync_compare_callback, prev_snapshot_name )
			self.append_to_take_snapshot_log( '[I] ' + cmd, 3 )
			self._execute( cmd, self._exec_rsync_compare_callback, params )
			changed = params[1]

			#changed = False

			#for line in try_cmd.split( '\n' ):
			#	if len( line ) < 1:
			#		continue

			#	if line[0] != '.':
			#		changed = True
			#		break

			if not changed:
				logger.info( "Nothing changed, no back needed" )
				return [ False, False ]

			if not self._create_directory( new_snapshot_path_to ):
				return [ False, True ]
			
			self.set_take_snapshot_message( 0, _('Create hard-links') )
			logger.info( "Create hard-links" )
			
			# When schedule per included folders is enabled this did not work (cp -alb iso cp -al?)
			# This resulted in a complete rsync for the whole snapshot consuming time and space
			# The ignored folders were copied afterwards. To solve this, the whole last snapshot is now hardlinked
			# and rsync is called only for the folders that should be synced (without --delete-excluded).  
			#if force or len( ignore_folders ) == 0:

			prev_snapshot_path = self.get_snapshot_path_to( prev_snapshot_id )

			#make source snapshot folders rw to allow cp -al
			self._execute( "find \"%s\" -type d -exec chmod u+wx {} \\;" % prev_snapshot_path ) #Debian patch

			#clone snapshot
			cmd = "gcp -aRl \"%s\"* \"%s\"" % ( prev_snapshot_path, new_snapshot_path_to )
			self.append_to_take_snapshot_log( '[I] ' + cmd, 3 )
			cmd_ret_val = self._execute( cmd )
			self.append_to_take_snapshot_log( "[I] returns: %s" % cmd_ret_val, 3 )

			#make source snapshot folders read-only
			self._execute( "find \"%s\" -type d -exec chmod a-w {} \\;" % prev_snapshot_path ) #Debian patch

			#make snapshot items rw to allow xopy xattr
			self._execute( "chmod -R a+w \"%s\"" % new_snapshot_path )

			#else:
			#	for folder in include_folders:
			#		prev_path = self.get_snapshot_path_to( prev_snapshot_id, folder )
			#		new_path = self.get_snapshot_path_to( new_snapshot_id, folder )
			#		tools.make_dirs( new_path )
			#		cmd = "cp -alb \"%s\"* \"%s\"" % ( prev_path, new_path )
			#		self._execute( cmd )
		else:
			if not self._create_directory( new_snapshot_path_to ):
				return [ False, True ]

		#sync changed folders
		logger.info( "Call rsync to take the snapshot" )
		cmd = rsync_prefix + ' -v ' + rsync_suffix + '"' + new_snapshot_path_to + '"'
		self.set_take_snapshot_message( 0, _('Take snapshot') )

		params = [False]
		self.append_to_take_snapshot_log( '[I] ' + cmd, 3 )
		self._execute( cmd + ' 2>&1', self._exec_rsync_callback, params )

		has_errors = False
		if params[0]:
			if not self.config.continue_on_errors():
				self._execute( "find \"%s\" -type d -exec chmod u+wx {} \\;" % new_snapshot_path ) #Debian patch
				self._execute( "rm -rf \"%s\"" % new_snapshot_path )

				#fix previous snapshot: make read-only again
				if len( prev_snapshot_id ) > 0:
					self._execute( "chmod -R a-w \"%s\"" % self.get_snapshot_path_to( prev_snapshot_id ) )

				return [ False, True ]

			has_errors = True
			self._execute( "touch \"%s\"" % self.get_snapshot_failed_path( new_snapshot_id ) )

		#backup config file
		logger.info( 'Save config file' )
		self.set_take_snapshot_message( 0, _('Save config file ...') )
		self._execute( 'gcp %s %s' % (self.config._LOCAL_CONFIG_PATH, new_snapshot_path_to + '..') )
		
		#save permissions for sync folders
		logger.info( 'Save permissions' )
		self.set_take_snapshot_message( 0, _('Save permission ...') )

		fileinfo = bz2.BZ2File( self.get_snapshot_fileinfo_path( new_snapshot_id ), 'w' )
		path_to_explore = self.get_snapshot_path_to( new_snapshot_id ).rstrip( '/' )
		fileinfo_dict = {}

		for path, dirs, files in os.walk( path_to_explore ):
			dirs.extend( files )
			for item in dirs:
				item_path = os.path.join( path, item )[ len( path_to_explore ) : ]
				fileinfo_dict[item_path] = 1
				self._save_path_info( fileinfo, item_path )

		# We now copy on forehand, so copying afterwards is not necessary anymore
		##copy ignored folders
		#if not force and len( prev_snapshot_id ) > 0 and len( ignore_folders ) > 0:
		#	prev_fileinfo_dict = self.load_fileinfo_dict( prev_snapshot_id )
		#
		#	for folder in ignore_folders:
		#		prev_path = self.get_snapshot_path_to( prev_snapshot_id, folder )
		#		new_path = self.get_snapshot_path_to( new_snapshot_id, folder )
		#		tools.make_dirs( new_path )
		#		cmd = "cp -alb \"%s/\"* \"%s\"" % ( prev_path, new_path )
		#		self._execute( cmd )
		#
		#		if len( prev_fileinfo_dict ) > 0:
		#			#save permissions for all items to folder
		#			item_path = '/'
		#			prev_path_items = folder.strip( '/' ).split( '/' )
		#			for item in items:
		#				item_path = os.path.join( item_path, item )
		#				if item_path not in fileinfo_dict and item_path in prev_fileinfo_dict:
		#					self._save_path_info_line( fileinfo, item_path, prev_fileinfo_dict[item_path] )

		#			#save permission for all items in folder
		#			for path, dirs, files in os.walk( new_path ):
		#				dirs.extend( files )
		#				for item in dirs:
		#					item_path = os.path.join( path, item )[ len( path_to_explore ) : ]
		#					if item_path not in fileinfo_dict and item_path in prev_fileinfo_dict:
		#						self._save_path_info_line( fileinfo, item_path, prev_fileinfo_dict[item_path] )

		fileinfo.close()

		#create info file 
		logger.info( "Create info file" ) 
		machine = socket.gethostname()
		user = self.config.get_user()
		profile_id = self.config.get_current_profile()
		tag = self.config.get_tag( profile_id )
		info_file = configfile.ConfigFile()
		info_file.set_int_value( 'snapshot_version', self.SNAPSHOT_VERSION )
		info_file.set_str_value( 'snapshot_date', snapshot_id[0:15] )
		info_file.set_str_value( 'snapshot_machine', machine )
		info_file.set_str_value( 'snapshot_user', user )
		info_file.set_int_value( 'snapshot_profile_id', profile_id )
		info_file.set_int_value( 'snapshot_tag', tag )
		info_file.save( self.get_snapshot_info_path( new_snapshot_id ) )
		info_file = None
		
		#copy take snapshot log
		try:
			logfile = open( self.config.get_take_snapshot_log_file(), 'r' )
			logdata = logfile.read()
			logfile.close()

			logfile = bz2.BZ2File( self.get_snapshot_log_path( new_snapshot_id ), 'w' )
			logfile.write( logdata )
			logfile.close()
		except:
			pass

		#rename snapshot
		snapshot_path = self.get_snapshot_path( snapshot_id )
		os.system( "mv \"%s\" \"%s\"" % ( new_snapshot_path, snapshot_path ) )
		if not os.path.exists( snapshot_path ):
			logger.error( "Can't rename %s to %s" % ( new_snapshot_path, snapshot_path ) )
			self.set_take_snapshot_message( 1, _('Can\'t rename %s to %s') % ( new_snapshot_path, snapshot_path ) )
			os.system( 'sleep 2' ) #max 1 backup / second
			return [ False, True ]

		#make new snapshot read-only
		self._execute( "chmod -R a-w \"%s/backup\"" % snapshot_path )

		#fix previous snapshot: make read-only again
		if len( prev_snapshot_id ) > 0:
			self._execute( "chmod -R a-w \"%s\"" % self.get_snapshot_path_to( prev_snapshot_id ) )

		return [ True, has_errors ]

	def _smart_remove_keep_all_( self, snapshots, keep_snapshots, min_date, max_date ):
		min_id = self.get_snapshot_id( min_date )
		max_id = self.get_snapshot_id( max_date )

		logger.info( "[smart remove] keep all >= %s and < %s" % ( min_id, max_id ) )

		for snapshot_id in snapshots:
			if snapshot_id >= min_id and snapshot_id < max_id:
				if snapshot_id not in keep_snapshots:
					keep_snapshots.append( snapshot_id )

		return keep_snapshots

	def _smart_remove_keep_first_( self, snapshots, keep_snapshots, min_date, max_date ):
		min_id = self.get_snapshot_id( min_date )
		max_id = self.get_snapshot_id( max_date )

		logger.info( "[smart remove] keep first >= %s and < %s" % ( min_id, max_id ) )

		for snapshot_id in snapshots:
			if snapshot_id >= min_id and snapshot_id < max_id:
				if snapshot_id not in keep_snapshots:
					keep_snapshots.append( snapshot_id )
				break

		return keep_snapshots

	def inc_month( self, date ):
		y = date.year
		m = date.month + 1
		if m > 12:
			m = 1
			y = y + 1
		return datetime.date( y, m, 1 )

	def dec_month( self, date ):
		y = date.year
		m = date.month - 1
		if m < 1:
			m = 12
			y = y - 1
		return datetime.date( y, m, 1 )

	def smart_remove( self, now_full, keep_all, keep_one_per_day, keep_one_per_week, keep_one_per_month ):
		snapshots = self.get_snapshots_list()
		logger.info( "[smart remove] considered: %s" % snapshots )
		if len( snapshots ) <= 1:
			logger.info( "[smart remove] There is only one snapshots, so keep it" )
			return

		if now_full is None:
			now_full = datetime.datetime.today()

		now = now_full.date() 

		#keep the last snapshot
		keep_snapshots = [ snapshots[0] ]

		#keep all for the last keep_all days
		if keep_all > 0:
			keep_snapshots = self._smart_remove_keep_all_( snapshots, keep_snapshots, now - datetime.timedelta( days=keep_all-1), now + datetime.timedelta(days=1) )

		#keep one per days for the last keep_one_per_day days
		if keep_one_per_day > 0:
			d = now
			for i in xrange( 0, keep_one_per_day ):
				keep_snapshots = self._smart_remove_keep_first_( snapshots, keep_snapshots, d, d + datetime.timedelta(days=1) )
				d = d - datetime.timedelta(days=1)

		#keep one per week for the last keep_one_per_week weeks
		if keep_one_per_week > 0:
			d = now - datetime.timedelta( days = now.weekday() + 1 )
			for i in xrange( 0, keep_one_per_week ):
				keep_snapshots = self._smart_remove_keep_first_( snapshots, keep_snapshots, d, d + datetime.timedelta(days=8) )
				d = d - datetime.timedelta(days=7)

		#keep one per month for the last keep_one_per_month months
		if keep_one_per_month > 0:
			d1 = datetime.date( now.year, now.month, 1 )
			d2 = self.inc_month( d1 )
			for i in xrange( 0, keep_one_per_month ):
				keep_snapshots = self._smart_remove_keep_first_( snapshots, keep_snapshots, d1, d2 )
				d2 = d1
				d1 = self.dec_month(d1)

		#keep one per year for all years
		first_year = int(snapshots[-1][ : 4])
		for i in xrange( first_year, now.year+1 ):
			keep_snapshots = self._smart_remove_keep_first_( snapshots, keep_snapshots, datetime.date(i,1,1), datetime.date(i+1,1,1) )

		logger.info( "[smart remove] keep snapshots: %s" % keep_snapshots )

		for snapshot_id in snapshots:
			if snapshot_id in keep_snapshots:
				continue

			if self.config.get_dont_remove_named_snapshots():
				if len( self.get_snapshot_name( snapshot_id ) ) > 0:
					logger.info( "[smart remove] keep snapshot: %s, it has a name" % snapshot_id )
					continue

			logger.info( "[smart remove] remove snapshot: %s" % snapshot_id )
			self.remove_snapshot( snapshot_id )

	def _free_space( self, now ):
		#remove old backups
		if self.config.is_remove_old_snapshots_enabled():
			self.set_take_snapshot_message( 0, _('Remove old snapshots') )
			snapshots = self.get_snapshots_list( False )

			old_backup_id = self.get_snapshot_id( self.config.get_remove_old_snapshots_date() )
			logger.info( "Remove backups older than: %s" % old_backup_id[0:15] )

			while True:
				if len( snapshots ) <= 1:
					break

				if snapshots[0] >= old_backup_id:
					break

				if self.config.get_dont_remove_named_snapshots():
					if len( self.get_snapshot_name( snapshots[0] ) ) > 0:
						del snapshots[0]
						continue

				self.remove_snapshot( snapshots[0] )
				del snapshots[0]

		#smart remove
		smart_remove, keep_all, keep_one_per_day, keep_one_per_week, keep_one_per_month = self.config.get_smart_remove()
		if smart_remove:
			self.set_take_snapshot_message( 0, _('Smart remove') )
			self.smart_remove( now, keep_all, keep_one_per_day, keep_one_per_week, keep_one_per_month )

		#try to keep min free space
		if self.config.is_min_free_space_enabled():
			self.set_take_snapshot_message( 0, _('Try to keep min free space') )

			min_free_space = self.config.get_min_free_space_in_mb()

			logger.info( "Keep min free disk space: %s Mb" % min_free_space )

			snapshots = self.get_snapshots_list( False )

			while True:
				if len( snapshots ) <= 1:
					break

				info = os.statvfs( self.config.get_snapshots_path() )
				free_space = info[ statvfs.F_FRSIZE ] * info[ statvfs.F_BAVAIL ] / ( 1024 * 1024 )

				if free_space >= min_free_space:
					break

				if self.config.get_dont_remove_named_snapshots():
					if len( self.get_snapshot_name( snapshots[0] ) ) > 0:
						del snapshots[0]
						continue

				logger.info( "free disk space: %s Mb" % free_space )
				self.remove_snapshot( snapshots[0] )
				del snapshots[0]

	def _execute( self, cmd, callback = None, user_data = None ):
		ret_val = 0

		if callback is None:
			ret_val = os.system( cmd )
		else:
			pipe = os.popen( cmd, 'r' )

			while True:
				line = tools.temp_failure_retry( pipe.readline )
				if len( line ) == 0:
					break
				callback( line.strip(), user_data )

			ret_val = pipe.close()
			if ret_val is None:
				ret_val = 0

		if ret_val != 0:
			logger.warning( "Command \"%s\" returns %s" % ( cmd, ret_val ) )
		else:
			logger.info( "Command \"%s\" returns %s" % ( cmd, ret_val ) )

		return ret_val

	#def _execute_output( self, cmd, callback = None, user_data = None ):
	#	output = ''

	#	pipe = os.popen( cmd, 'r' )
	#	
	#	while True:
	#		line = tools.temp_failure_retry( pipe.readline )
	#		if len( line ) == 0:
	#			break
	#		output = output + line
	#		if not callback is None:
	#			callback( line.strip(), user_data )

	#	ret_val = pipe.close()
	#	if ret_val is None:
	#		ret_val = 0

	#	if ret_val != 0:
	#		logger.warning( "Command \"%s\" returns %s" % ( cmd, ret_val ) )
	#	else:
	#		logger.info( "Command \"%s\" returns %s" % ( cmd, ret_val ) )

	#	return output
	
	def filter_for(self, base_snapshot_id, base_path, snapshots_list, list_diff_only  = False, flag_deep_check = False):
		"return a list of available snapshots (including 'now'), eventually filtered for uniqueness"
		snapshots_filtered = []

		base_full_path = self.get_snapshot_path_to( base_snapshot_id, base_path )
		if not os.path.lexists( base_full_path ):
			return []

		all_snapshots_list = [ '/' ]
		all_snapshots_list.extend( snapshots_list )

		#links
		if os.path.islink( base_full_path ):
			targets = []

			for snapshot_id in all_snapshots_list:
				path = self.get_snapshot_path_to( snapshot_id, base_path )

				if os.path.lexists( path ) and os.path.islink( path ):
					if list_diff_only:
						target = os.readlink( path )
						if target in targets:
							continue
						targets.append( target )
					snapshots_filtered.append(snapshot_id)

			return snapshots_filtered

		#directories
		if os.path.isdir( base_full_path ):
			for snapshot_id in all_snapshots_list:
				path = self.get_snapshot_path_to( snapshot_id, base_path )

				if os.path.exists( path ) and not os.path.islink( path ) and os.path.isdir( path ):
					snapshots_filtered.append(snapshot_id)

			return snapshots_filtered

		#files
		if not list_diff_only:
			for snapshot_id in all_snapshots_list:
				path = self.get_snapshot_path_to( snapshot_id, base_path )

				if os.path.exists( path ) and not os.path.islink( path ) and os.path.isfile( path ):
					snapshots_filtered.append(snapshot_id)

			return snapshots_filtered

		# check for duplicates
		uniqueness = tools.UniquenessSet(flag_deep_check, follow_symlink = False)
		for snapshot_id in all_snapshots_list:
			path = self.get_snapshot_path_to( snapshot_id, base_path )
			if os.path.exists( path ) and not os.path.islink( path ) and os.path.isfile( path ) and uniqueness.check_for(path):  
				snapshots_filtered.append(snapshot_id)

		return snapshots_filtered


if __name__ == "__main__":
	config = config.Config()
	snapshots = Snapshots( config )
	snapshots.take_snapshot()

