Add timer restart and stop triggers

Restarting and stopping timers from the API was not allowed. This
commit adds api/timer/{id}/[stop|restart]/ triggers that can be
posted to through the REST-API to start/stop timers.

Signed-off-by: Paul Konstantin Gerke <paulkgerke@craftware.info>

api/tests.py

@@ -398,6 +398,34 @@ class TimerAPITestCase(TestBase.BabyBuddyAPITestCaseBase):
         self.assertEqual(response.status_code, status.HTTP_200_OK)
         self.assertEqual(response.data, entry)
     
+    def test_start_stop_timer(self):
+        endpoint = '{}{}/'.format(self.endpoint, 1)
+        response = self.client.get(endpoint)
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertFalse(response.data["active"])
+        
+        response = self.client.post(f"{endpoint}restart/")
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+
+        response = self.client.get(endpoint)
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertTrue(response.data["active"])
+
+        # Restart twice fails
+        response = self.client.post(f"{endpoint}restart/")
+        self.assertEqual(response.status_code, status.HTTP_412_PRECONDITION_FAILED)
+        
+        response = self.client.post(f"{endpoint}stop/")
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        
+        response = self.client.get(endpoint)
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertFalse(response.data["active"])
+
+        # Stopping twice fails
+        response = self.client.post(f"{endpoint}stop/")
+        self.assertEqual(response.status_code, status.HTTP_412_PRECONDITION_FAILED)
+
 
 class TummyTimeAPITestCase(TestBase.BabyBuddyAPITestCaseBase):
     endpoint = reverse('api:tummytime-list')

api/views.py

@@ -1,5 +1,7 @@
 # -*- coding: utf-8 -*-
-from rest_framework import viewsets
+from rest_framework import viewsets, status
+from rest_framework.decorators import action
+from rest_framework.response import Response
 
 from core import models
 
@@ -49,6 +51,40 @@ class TimerViewSet(viewsets.ModelViewSet):
     serializer_class = serializers.TimerSerializer
     filterset_class = filters.TimerFilter
 
+    def __timer_operation(self, pk, func):
+        try:
+            timer = models.Timer.objects.get(pk=pk)
+            return func(timer)
+        except models.Timer.DoesNotExist:
+            return Response(
+                {"detail": "timer does not exist"},
+                status=status.HTTP_404_NOT_FOUND
+            )
+
+    @action(detail=True, methods=['post'])
+    def stop(self, request, pk=None):
+        def do_stop(timer):
+            if not timer.active:
+                return Response(
+                    {"detail": "timer already stopped"},
+                    status=status.HTTP_412_PRECONDITION_FAILED
+                )
+            timer.stop()
+            return Response({"detail": "timer stopped"})
+        return self.__timer_operation(pk, do_stop)
+
+    @action(detail=True, methods=['post'])
+    def restart(self, request, pk=None):
+        def do_restart(timer):
+            if timer.active:
+                return Response(
+                    {"detail": "timer already active"},
+                    status=status.HTTP_412_PRECONDITION_FAILED
+                )
+            timer.restart()
+            return Response({"detail": "timer restarted"})
+        return self.__timer_operation(pk, do_restart)
+
 
 class TummyTimeViewSet(TimerFieldSupportMixin, viewsets.ModelViewSet):
     queryset = models.TummyTime.objects.all()