#!/usr/bin/python

import os
import os.path
import threading
import time
from gi.repository import GLib

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 ):
            try:
                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 )
            except Exception, detail:
                mId = 0                
            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]:
                    GLib.idle_add( callback[0], callback[1] )
                else:
                    GLib.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:
                        GLib.idle_add( monitored.callback, monitored.args )
                    else:
                        GLib.idle_add( monitored.callback )


monitor = FileMonitor()