import sys
sys.path.insert(0, "..")

try:
    from IPython import embed
except ImportError:
    import code

    def embed():
        vars = globals()
        vars.update(locals())
        shell = code.InteractiveConsole(vars)
        shell.interact()


from opcua import Client


class SubHandler(object):

    """
    Subscription Handler. To receive events from server for a subscription
    data_change and event methods are called directly from receiving thread.
    Do not do expensive, slow or network operation there. Create another
    thread if you need to do such a thing
    """
    def event_notification(self, event):
        print("New event recived: ", event)


if __name__ == "__main__":

    client = Client("opc.tcp://localhost:4840/freeopcua/server/")
    # client = Client("opc.tcp://admin@localhost:4840/freeopcua/server/") #connect using a user
    try:
        client.connect()

        # Client has a few methods to get proxy to UA nodes that should always be in address space such as Root or Objects
        root = client.get_root_node()
        print("Objects node is: ", root)

        # Now getting a variable node using its browse path
        obj = root.get_child(["0:Objects", "2:MyObject"])
        print("MyObject is: ", obj)

        myevent = root.get_child(["0:Types", "0:EventTypes", "0:BaseEventType", "2:MyFirstEvent"])
        print("MyFirstEventType is: ", myevent)

        msclt = SubHandler()
        sub = client.create_subscription(100, msclt)
        handle = sub.subscribe_events(obj, myevent)

        embed()
        sub.unsubscribe(handle)
        sub.delete()
    finally:
        client.disconnect()