from engine import Engine
import dbus

_DBUS_SERVICE = "org.tutorius.Service"
_DBUS_PATH = "org/tutorius/Service"
_DBUS_SERVICE_IFACE = "org.tutorius.Service"

class Service(dbus.service.Object):
    """
    Global tutorius entry point to control the whole system
    """

    def __init__(self):
        bus = dbus.SessionBus()
        bus_name = dbus.service.BusName(_DBUS_SERVICE, bus=bus)
        dbus.service.Object.__init__(self, bus_name, _DBUS_PATH)

        self._engine = Engine()

    def start(self):
        """ Start the service itself
        """
        # For the moment there is nothing to do
        pass


    @dbus.service.method(_DBUS_SERVICE_IFACE,
                          in_signature="s", out_signature="") 
    def launch(self, tutorialID):
	""" Launch a tutorial 
            @param tutorialID unique tutorial identifier used to retrieve it from the disk
        """
        self._engine.launch(tutorialID)

    @dbus.service.method(_DBUS_SERVICE_IFACE,
                          in_signature="", out_signature="") 
    def stop(self):
        """ Stop the current tutorial
        """
        self._engine.stop()

    @dbus.service.method(_DBUS_SERVICE_IFACE,
                          in_signature="", out_signature="") 
    def pause(self):
        """ Interrupt the current tutorial and save its state in the journal
        """
        self._engine.pause()

class ServiceProxy:
    """ Proxy to connect to the Service object, abstracting the DBus interface"""

    def __init__(self):
        bus = dbus.SessionBus()
        self._object = bus.get_object(_DBUS_SERVICE,_DBUS_PATH)
        self._service = dbus.Interface(self._object, _DBUS_SERVICE_IFACE)

    def launch(self, tutorialID):
        self._service.launch(tutorialID)

    def stop(self):
        self._service.stop()

    def pause(self):
        self._service.pause()