import time
from watchdog.events                            import FileSystemEventHandler
from watchdog.observers                         import Observer
from watchdog.observers.read_directory_changes  import \
    WindowsApiEmitter, DEFAULT_OBSERVER_TIMEOUT, BaseObserver

class _Logger_ : pass

class WindowsApiEmitterExceptionHandling (WindowsApiEmitter, _Logger_) :
    
    Exception = None

    def run (self, * args, ** kw) :
        try :
            super ().run (* args, ** kw)
        except Exception as err :
            WindowsApiEmitterExceptionHandling.Exception = err
    # end def run
            
# end class WindowsApiEmitterExceptionHandling
            
class WindowsApiObserverExcpetionHandler (Observer, _Logger_) :

    def __init__ (self, timeout = DEFAULT_OBSERVER_TIMEOUT) :
        BaseObserver.__init__ \
            ( self
            , emitter_class = WindowsApiEmitterExceptionHandling
            , timeout       = timeout
            )
    # end def __init__
        
    @classmethod
    def Start_Directory_Watcher (cls, handler, ** kw) :
        L          = cls.L
        retry_wait = kw.pop ("RETRY_SLEEP", 1)
        while True :
            try :
                observer        = WindowsApiObserverExcpetionHandler    ()
                observer.schedule (handler, handler.directory, ** kw)
                observer.start    ()
                L.info ("Directory watching for %s started", handler.directory)
                return observer
            except Exception as e :
                if getattr (e, "errno", None) == 2 :
                    L.error       ("%s does not exists, retry", handler.directory)
                    observer.stop ()
                    time.sleep    (retry_wait)
                else :
                    raise
    # end def Start_Directory_Watcher
    
# end class WindowsApiObserverExcpetionHandler

class Directory_Handler (FileSystemEventHandler, _Logger_) :
    
    def __init__ (self, directory) :
        super ().__init__ ()
        self.directory = directory
    # end def __init__
    
    def on_any_event (self, event):
        self.L.debug ("%s %s", event.event_type, event.src_path)
        if event.event_type == 'deleted' and event.src_path == self.directory :
            WindowsApiEmitterExceptionHandling.Exception = \
                f"Directory has been deleted {self.directory}"
        #if event.event_type == 'created' :
        #    try:
        #        fileBase = os.path.basename(event.src_path).split('.')[0]
        #        filePath = os.path.dirname(event.src_path)                                                                          (fileBase,filePath))
        #    except Exception as e:
        #        pass

        # if event.is_directory:
        #     return None
        #
        # elif event.event_type == 'created':
        #     # Take any action here when a file is first created.
        #     print(datetime.datetime.now())
        #     print("Received created event - %s." % event.src_path)
        #
        # elif event.event_type == 'modified':
        #     # Taken any action here when a file is modified.
        #     print(datetime.datetime.now())
        #     print("Received modified event - %s." % event.src_path)
        #
        # else:
        #     print(event.event_type,event.src_path)
    # end def on_any_event
        
# end class Directory_Handler
        
if __name__ == "__main__" :
    from    App_State import App_State
    import  time
    import  os

    cmd = App_State.Add_Logging_Attributes ().parse_args ()
    L = _Logger_.L = App_State.Setup_Logging (cmd)
    L.info ("PID_ %d", os.getpid ())
    def start_watching (path) :
        return WindowsApiObserverExcpetionHandler.Start_Directory_Watcher \
            (Directory_Handler, path)
    # end def start_watching
    
    path        = r"k:\glueck\watch-me"
    observer    = None
    try:
        observer = start_watching (path)
        while True:
            time.sleep (1)
            if WindowsApiEmitterExceptionHandling.Exception :
                App_State.L.exception \
                    (str (WindowsApiEmitterExceptionHandling.Exception))
                WindowsApiEmitterExceptionHandling.Exception = None
                if observer :
                    observer.stop  ()
                    observer = start_watching (path)
    finally :
        if observer :
            observer.stop ()
            observer.join ()