Add broadcasts to the dashboard

Shows current and previous broadcasts. Does not add a page for viewing
an individual broadcast.

Broadcasts are split into live and previous.

Draft broadcasts are excluded from the dashboard.

app/models/broadcast_message.py

@@ -4,7 +4,7 @@ from notifications_utils.broadcast_areas import broadcast_area_libraries
 from notifications_utils.template import BroadcastPreviewTemplate
 from orderedset import OrderedSet
 
-from app.models import JSONModel
+from app.models import JSONModel, ModelList
 from app.notify_client.broadcast_message_api_client import (
     broadcast_message_api_client,
 )
@@ -24,7 +24,6 @@ class BroadcastMessage(JSONModel):
         'personalisation',
         'starts_at',
         'finishes_at',
-        'status',
         'created_at',
         'approved_at',
         'cancelled_at',
@@ -57,6 +56,12 @@ class BroadcastMessage(JSONModel):
             *self._dict['areas']
         )
 
+    @property
+    def initial_area_names(self):
+        return [
+            area.name for area in self.areas
+        ][:10]
+
     @property
     def polygons(self):
         return broadcast_area_libraries.get_polygons_for_areas_lat_long(
@@ -72,6 +77,16 @@ class BroadcastMessage(JSONModel):
         )
         return BroadcastPreviewTemplate(response['data'])
 
+    @property
+    def status(self):
+        if (
+            self._dict['status']
+            and self._dict['status'] == 'broadcasting'
+            and self.finishes_at < datetime.utcnow().isoformat()
+        ):
+            return 'completed'
+        return self._dict['status']
+
     def add_areas(self, *new_areas):
         broadcast_message_api_client.update_broadcast_message(
             broadcast_message_id=self.id,
@@ -109,3 +124,14 @@ class BroadcastMessage(JSONModel):
             broadcast_message_id=self.id,
             service_id=self.service_id,
         )
+
+
+class BroadcastMessages(ModelList):
+
+    model = BroadcastMessage
+    client_method = broadcast_message_api_client.get_broadcast_messages
+
+    def with_status(self, *statuses):
+        return [
+            broadcast for broadcast in self if broadcast.status in statuses
+        ]