import dbus
import gobject

DBUS_SERVICE = "org.laptop.Clipboard"
DBUS_INTERFACE = "org.laptop.Clipboard"
DBUS_PATH = "/org/laptop/Clipboard"

class ClipboardService(gobject.GObject):

    __gsignals__ = {
        'object-added': (gobject.SIGNAL_RUN_FIRST, gobject.TYPE_NONE,
                        ([str, str, str])),
        'object-deleted': (gobject.SIGNAL_RUN_FIRST, gobject.TYPE_NONE,
                        ([str])),
        'object-state-changed': (gobject.SIGNAL_RUN_FIRST, gobject.TYPE_NONE,
                        ([str, int])),
    }
    
    def __init__(self):
        gobject.GObject.__init__(self)
        
        self._dbus_service = None
        bus = dbus.SessionBus()
        bus.add_signal_receiver(self._name_owner_changed_cb,
                                signal_name="NameOwnerChanged",
                                dbus_interface="org.freedesktop.DBus")
        # Try to register to ClipboardService, if we fail, we'll try later.
        try:
            self._connect_clipboard_signals()
        except dbus.DBusException, exception:
            pass
        
    def _connect_clipboard_signals(self):
        bus = dbus.SessionBus()
        proxy_obj = bus.get_object(DBUS_SERVICE, DBUS_PATH)
        self._dbus_service = dbus.Interface(proxy_obj, DBUS_SERVICE)
        self._dbus_service.connect_to_signal('object_added',
                                             self._object_added_cb)    
        self._dbus_service.connect_to_signal('object_deleted',
                                             self._object_deleted_cb)
        self._dbus_service.connect_to_signal('object_state_changed',
                                             self._object_state_changed_cb)    

    def _name_owner_changed_cb(self, name, old, new):
        if name != DBUS_SERVICE:
            return
        
        if (not old and not len(old)) and (new and len(new)):
            # ClipboardService started up
            self._connect_clipboard_signals()
            
    def _object_added_cb(self, name, mimeType, fileName):
        self.emit('object-added', name, mimeType, fileName)

    def _object_deleted_cb(self, fileName):
        self.emit('object-deleted', fileName)

    def _object_state_changed_cb(self, fileName, percent):
        self.emit('object-state-changed', fileName, percent)
    
    def add_object(self, name, mimeType, fileName):
        self._dbus_service.add_object(name, mimeType, fileName)

    def delete_object(self, fileName):
        self._dbus_service.delete_object(fileName)
    
    def set_object_state(self, fileName, percent):
        self._dbus_service.set_object_state(fileName, percent)

_clipboard_service = None
def get_instance():
    global _clipboard_service
    if not _clipboard_service:
        _clipboard_service = ClipboardService()
    return _clipboard_service