Send simple polygons to API along with areas

When creating broadcast message, or updating it.
We want to send simple polygons to API so we can
later relay them to the broadcast provider.

Test that update broadcast message sends polygons correctly

app/models/broadcast_message.py

@@ -62,9 +62,7 @@ class BroadcastMessage(JSONModel):
 
     @property
     def areas(self):
-        return broadcast_area_libraries.get_areas(
+        return self.get_areas(areas=self._dict['areas'])
-            *self._dict['areas']
-        )
 
     @property
     def initial_area_names(self):
@@ -82,14 +80,7 @@ class BroadcastMessage(JSONModel):
 
     @cached_property
     def simple_polygons(self):
-        polygons = Polygons(
+        return self.get_simple_polygons(areas=self.areas)
-            list(itertools.chain(*(
-                area.simple_polygons for area in self.areas
-            )))
-        )
-        # If we’ve added multiple areas then we need to re-simplify the
-        # combined shapes to keep the point count down
-        return polygons.smooth.simplify if len(self.areas) > 1 else polygons
 
     @property
     def template(self):
@@ -122,16 +113,35 @@ class BroadcastMessage(JSONModel):
     def cancelled_by(self):
         return User.from_id(self.cancelled_by_id)
 
+    def get_areas(self, areas):
+        return broadcast_area_libraries.get_areas(
+            *areas
+        )
+
+    def get_simple_polygons(self, areas):
+        polygons = Polygons(
+            list(itertools.chain(*(
+                area.simple_polygons for area in areas
+            )))
+        )
+        # If we’ve added multiple areas then we need to re-simplify the
+        # combined shapes to keep the point count down
+        return polygons.smooth.simplify if len(areas) > 1 else polygons
+
     def add_areas(self, *new_areas):
-        self._update(areas=list(OrderedSet(
+        areas = list(OrderedSet(
             self._dict['areas'] + list(new_areas)
-        )))
+        ))
+        simple_polygons = self.get_simple_polygons(areas=self.get_areas(areas=areas))
+        self._update(areas=areas, simple_polygons=simple_polygons.as_coordinate_pairs_lat_long)
 
     def remove_area(self, area_to_remove):
-        self._update(areas=[
+        areas = [
             area for area in self._dict['areas']
             if area != area_to_remove
-        ])
+        ]
+        simple_polygons = self.get_simple_polygons(areas=self.get_areas(areas=areas))
+        self._update(areas=areas, simple_polygons=simple_polygons.as_coordinate_pairs_lat_long)
 
     def _set_status_to(self, status):
         broadcast_message_api_client.update_broadcast_message_status(

tests/app/main/views/test_broadcast.py

@@ -1,5 +1,6 @@
 import json
 import uuid
+from collections import namedtuple
 from functools import partial
 
 import pytest
@@ -495,8 +496,14 @@ def test_add_broadcast_area(
     mock_get_draft_broadcast_message,
     mock_update_broadcast_message,
     fake_uuid,
+    mocker
 ):
     service_one['permissions'] += ['broadcast']
+    polygon_class = namedtuple("polygon_class", ["as_coordinate_pairs_lat_long"])
+    coordinates = [[50.1, 0.1], [50.2, 0.2], [50.3, 0.2]]
+    polygons = polygon_class(as_coordinate_pairs_lat_long=coordinates)
+    mocker.patch('app.models.broadcast_message.BroadcastMessage.get_simple_polygons', return_value=polygons)
+
     client_request.post(
         '.choose_broadcast_area',
         service_id=SERVICE_ONE_ID,
@@ -510,7 +517,7 @@ def test_add_broadcast_area(
         service_id=SERVICE_ONE_ID,
         broadcast_message_id=fake_uuid,
         data={
-            'areas': ['ctry19-E92000001', 'ctry19-S92000003', 'ctry19-W92000004']
+            'areas': ['ctry19-E92000001', 'ctry19-S92000003', 'ctry19-W92000004'], 'simple_polygons': coordinates
         },
     )
 
@@ -543,8 +550,14 @@ def test_add_broadcast_sub_area(
     fake_uuid,
     post_data,
     expected_selected,
+    mocker
 ):
     service_one['permissions'] += ['broadcast']
+    polygon_class = namedtuple("polygon_class", ["as_coordinate_pairs_lat_long"])
+    coordinates = [[50.1, 0.1], [50.2, 0.2], [50.3, 0.2]]
+    polygons = polygon_class(as_coordinate_pairs_lat_long=coordinates)
+    mocker.patch('app.models.broadcast_message.BroadcastMessage.get_simple_polygons', return_value=polygons)
+
     client_request.post(
         '.choose_broadcast_sub_area',
         service_id=SERVICE_ONE_ID,
@@ -557,6 +570,7 @@ def test_add_broadcast_sub_area(
         service_id=SERVICE_ONE_ID,
         broadcast_message_id=fake_uuid,
         data={
+            'simple_polygons': coordinates,
             'areas': [
                 # These two areas are on the broadcast already
                 'ctry19-E92000001',
@@ -572,8 +586,14 @@ def test_remove_broadcast_area_page(
     mock_get_draft_broadcast_message,
     mock_update_broadcast_message,
     fake_uuid,
+    mocker,
 ):
     service_one['permissions'] += ['broadcast']
+    polygon_class = namedtuple("polygon_class", ["as_coordinate_pairs_lat_long"])
+    coordinates = [[50.1, 0.1], [50.2, 0.2], [50.3, 0.2]]
+    polygons = polygon_class(as_coordinate_pairs_lat_long=coordinates)
+    mocker.patch('app.models.broadcast_message.BroadcastMessage.get_simple_polygons', return_value=polygons)
+
     client_request.get(
         '.remove_broadcast_area',
         service_id=SERVICE_ONE_ID,
@@ -590,6 +610,7 @@ def test_remove_broadcast_area_page(
         service_id=SERVICE_ONE_ID,
         broadcast_message_id=fake_uuid,
         data={
+            'simple_polygons': coordinates,
             'areas': ['ctry19-S92000003']
         },
     )