Add FSMAwareEventHandler which keeps track of FSM state

lib/tfw/__init__.py

@@ -1,7 +1,7 @@
 # Copyright (C) 2018 Avatao.com Innovative Learning Kft.
 # All Rights Reserved. See LICENSE file for details.
 
-from .event_handler_base import EventHandlerBase, TriggeredEventHandler, BroadcastingEventHandler
+from .event_handler_base import EventHandlerBase, FSMAwareEventHandler, BroadcastingEventHandler
 from .fsm_base import FSMBase
 from .linear_fsm import LinearFSM
 from .yaml_fsm import YamlFSM

lib/tfw/event_handler_base.py

@@ -107,20 +107,38 @@ class EventHandlerBase(ABC):
         pass
 
 
-class TriggeredEventHandler(EventHandlerBase, ABC):
+class FSMAwareEventHandler(EventHandlerBase, ABC):
     # pylint: disable=abstract-method
     """
-    Abstract base class for EventHandlers which are only triggered in case
-    TFWServer has successfully triggered an FSM step defined in __init__.
+    Abstract base class for EventHandlers which automatically
+    keep track of the state of the TFW FSM.
     """
-    def __init__(self, key, trigger):
+    def __init__(self, key):
         super().__init__(key)
-        self.trigger = trigger
+        self.subscribe('fsm_update')
+        self.fsm_state = None
 
     def dispatch_handling(self, message):
-        if message.get('trigger') == self.trigger:
+        if message['key'] == 'fsm_update':
+            self._handle_fsm_update(message)
+        else:
             return super().dispatch_handling(message)
-        return None
+
+    def _handle_fsm_update(self, message):
+        try:
+            new_state = message['data']['current_state']
+            trigger = message['data']['last_trigger']
+            if self.fsm_state != new_state:
+                self.handle_fsm_step(self.fsm_state, new_state, trigger)
+            self.fsm_state = new_state
+        except KeyError:
+            LOG.error('Invalid fsm_update message received!')
+
+    def handle_fsm_step(self, from_state, to_state, trigger):
+        """
+        Called in case the TFW FSM has stepped.
+        """
+        pass
 
 
 class BroadcastingEventHandler(EventHandlerBase, ABC):