import os
import os.path
import threading
import time
import gobject

try:
	import pyinotify
	hasInotify = True
except ImportError:
	hasInotify = False

if hasInotify:
	class FileMonitor(object):
		def __init__( self ):
			self.monitorId = 0
			self.wm = pyinotify.WatchManager()
			self.wdds = {}
			self.callbacks = {}
			self.notifier = pyinotify.ThreadedNotifier(self.wm, self.fileChanged)
			self.notifier.setDaemon( True )			
			self.notifier.start()
			
	
		def addMonitor( self, filename, callback, args = None ):			
			mask = pyinotify.IN_DELETE | pyinotify.IN_CREATE | pyinotify.IN_MODIFY
			mId = self.wm.add_watch( filename, mask, rec = True)[filename]
			if mId >= 0:
				self.callbacks[mId] = ( callback, args )

			return mId			
	
		def removeMonitor( self, monitorId ):
			if monitorId in self.callbacks:
				self.wm.rm_watch( monitorId )
				del self.callbacks[monitorId]
				
		def fileChanged(self, event ):
			if event.wd in self.callbacks:
	#			print event.path
				callback = self.callbacks[event.wd]
				if callback[1]:
					gobject.idle_add( callback[0], callback[1] )
				else:
					gobject.idle_add( callback[0] )
	

else:
	
	class _MonitoredFile( object ):
		def __init__( self, filename, callback, monitorId, args ):
			self.filename = filename
			self.callback = callback
			self.monitorId = monitorId
			self.args = args
			self.exists = os.path.exists( self.filename )
			if self.exists:
				self.mtime = os.stat( filename ).st_mtime
			else:
				self.mtime = 0
	
		def hasChanged( self ):
			if os.path.exists( self.filename ):
				if not self.exists:
					self.exists = True
					self.mtime = os.stat( self.filename ).st_mtime
					return True
				else:
					mtime = os.stat( self.filename ).st_mtime
					if mtime != self.mtime:
						self.mtime = mtime
						return True
			else:
				if self.exists:
					self.exists = False
					return True
	
			return False
	
	class MonitorThread(threading.Thread):
		def __init__(self, monitor):
			threading.Thread.__init__ ( self )
			self.monitor = monitor
	
		def run(self):
			while(1):
				self.monitor.checkFiles()
				time.sleep(1)
				
	
	
	class FileMonitor(object):
		def __init__( self ):
			self.monitorId = 0
			self.monitoredFiles = []
			self.monitorThread = MonitorThread( self )
			self.monitorThread.setDaemon( True )
			self.monitorThread.start()
	
		def addMonitor( self, filename, callback, args = None ):
			self.monitorId += 1
			self.monitoredFiles.append( _MonitoredFile( filename, callback, self.monitorId, args ) )
			return self.monitorId
	
		def removeMonitor( self, monitorId ):
			for monitored in self.monitoredFiles:
				if monitorId == monitored.monitorId:
					self.monitoredFiles.remove( monitored )
					break
	
		def checkFiles( self ):
			for monitored in self.monitoredFiles:
				if monitored.hasChanged():
					if monitored.args:
						gobject.idle_add( monitored.callback, monitored.args )
					else:
						gobject.idle_add( monitored.callback )
	

monitor = FileMonitor()