initial_state = dict(
    instrument_list={},
    connection_list={},
)


class ActionTypes(object):
    # Initiate update of instrument list. For every instrument, ADD_INSTRUMENT is triggered
    UPDATE_LIST = 'instrument_manager/UPDATE_LIST'
    # Add an instrument to the instrument list.
    ADD_INSTRUMENT = 'instrument_manager/ADD_INSTRUMENT'
    # Try to connect an instrument. On success, trigger ADD_CONNECTION.
    CONNECT = 'instrument_manager/CONNECT'
    # Add an instrument from the instrument list to the connection list.
    ADD_CONNECTION = 'instrument_manager/ADD_CONNECTION'
    # Try to disconnect an instrument. On success, trigger REMOVE_CONNECTION.
    DISCONNECT = 'instrument_manager/DISCONNECT'
    # Remove a disconnected instrument from the connection list.
    REMOVE_CONNECTION = 'instrument_manager/REMOVE_CONNECTION'


class ActionCreators(object):
    @staticmethod
    def update_list():
        return dict(
            type=ActionTypes.UPDATE_LIST
        )

    @staticmethod
    def add_instrument(instrument):
        return dict(
            type=ActionTypes.ADD_INSTRUMENT,
            instrument=instrument
        )

    @staticmethod
    def connect(instrument):
        return dict(
            type=ActionTypes.CONNECT,
            id=instrument
        )

    @staticmethod
    def add_connection(instrument):
        return dict(
            type=ActionTypes.ADD_CONNECTION,
            instrument=instrument
        )

    @staticmethod
    def disconnect(instrument):
        return dict(
            type=ActionTypes.DISCONNECT,
            id=instrument
        )

    @staticmethod
    def remove_connection(instrument):
        return dict(
            type=ActionTypes.REMOVE_CONNECTION,
            id=instrument
        )


def reducer(state=None, action=None):
    if state is None:
        state = initial_state
    if not (isinstance(action, dict) and 'type' in action):
        return state
    # if action['type'] == ActionTypes.UPDATE_LIST:
    #     state = action['value']
    # elif action['type'] == ActionTypes.CONNECT:
    #     state += 1
    # elif action['type'] == ActionTypes.DISCONNECT:
    #     state -= 1
    return state


if __name__ == '__main__':
    import unittest

    unittest.main()