notifs: Live-update state of whether realm has enabled notifications

Making sure that when the realm goes from disabling to enabling
notifications, we clear out the state of whether the user has
dismissed the banner on the home screen -- just like we do when the
/register response informs us of this change. That's so that if
notifications become disabled again, a new banner will be shown.

Fixes: zulip#5805

src/account/__tests__/accountsReducer-test.js

@@ -15,6 +15,7 @@ import { ZulipVersion } from '../../utils/zulipVersion';
 
 import * as eg from '../../__tests__/lib/exampleData';
 import { identityOfAccount } from '../accountMisc';
+import { EventTypes } from '../../api/eventTypes';
 
 describe('accountsReducer', () => {
   describe('REGISTER_COMPLETE', () => {
@@ -219,4 +220,69 @@ describe('accountsReducer', () => {
       ).toEqual(prevState);
     });
   });
+
+  describe('EventTypes.realm, op update_dict', () => {
+    const stateWithDismissedNotice = [
+      { ...eg.plusReduxState.accounts[0], lastDismissedServerPushSetupNotice: new Date() },
+    ];
+    const stateWithoutDismissedNotice = [
+      { ...eg.plusReduxState.accounts[0], lastDismissedServerPushSetupNotice: null },
+    ];
+
+    const eventCommon = { id: 0, type: EventTypes.realm, op: 'update_dict', property: 'default' };
+
+    test('data.push_notifications_enabled is true, on state with dismissed notice', () => {
+      expect(
+        accountsReducer(stateWithDismissedNotice, {
+          type: EVENT,
+          event: { ...eventCommon, data: { push_notifications_enabled: true } },
+        }),
+      ).toEqual(stateWithoutDismissedNotice);
+    });
+
+    test('data.push_notifications_enabled is true, on state without dismissed notice', () => {
+      expect(
+        accountsReducer(stateWithoutDismissedNotice, {
+          type: EVENT,
+          event: { ...eventCommon, data: { push_notifications_enabled: true } },
+        }),
+      ).toEqual(stateWithoutDismissedNotice);
+    });
+
+    test('data.push_notifications_enabled is false, on state with dismissed notice', () => {
+      expect(
+        accountsReducer(stateWithDismissedNotice, {
+          type: EVENT,
+          event: { ...eventCommon, data: { push_notifications_enabled: false } },
+        }),
+      ).toEqual(stateWithDismissedNotice);
+    });
+
+    test('data.push_notifications_enabled is false, on state without dismissed notice', () => {
+      expect(
+        accountsReducer(stateWithoutDismissedNotice, {
+          type: EVENT,
+          event: { ...eventCommon, data: { push_notifications_enabled: false } },
+        }),
+      ).toEqual(stateWithoutDismissedNotice);
+    });
+
+    test('data.push_notifications_enabled is absent, on state with dismissed notice', () => {
+      expect(
+        accountsReducer(stateWithDismissedNotice, {
+          type: EVENT,
+          event: { ...eventCommon, data: {} },
+        }),
+      ).toEqual(stateWithDismissedNotice);
+    });
+
+    test('data.push_notifications_enabled is absent, on state without dismissed notice', () => {
+      expect(
+        accountsReducer(stateWithoutDismissedNotice, {
+          type: EVENT,
+          event: { ...eventCommon, data: {} },
+        }),
+      ).toEqual(stateWithoutDismissedNotice);
+    });
+  });
 });

src/account/accountsReducer.js

@@ -151,6 +151,20 @@ export default (state: AccountsState = initialState, action: Action): AccountsSt
             zulipFeatureLevel: zulip_feature_level,
           });
         }
+        case EventTypes.realm: {
+          if (event.op === 'update_dict') {
+            return updateActiveAccount(state, {
+              lastDismissedServerPushSetupNotice:
+                event.data.push_notifications_enabled === true
+                  ? null
+                  : state[0].lastDismissedServerPushSetupNotice,
+            });
+          }
+
+          // (We've converted any `op: 'update'` events to
+          //   `op: 'update_dict'` events near the edge.)
+          return state;
+        }
         default:
           return state;
       }

src/realm/__tests__/realmReducer-test.js

@@ -530,6 +530,14 @@ describe('realmReducer', () => {
         check(Moderators, Members);
         check(Moderators, Nobody);
       });
+
+      describe('pushNotificationsEnabled / push_notifications_enabled', () => {
+        const check = mkCheck('pushNotificationsEnabled', 'push_notifications_enabled');
+        check(true, true);
+        check(true, false);
+        check(false, true);
+        check(false, false);
+      });
     });
   });
 });

src/realm/realmReducer.js

@@ -285,6 +285,9 @@ export default (
             if (data.email_address_visibility !== undefined) {
               result.emailAddressVisibility = data.email_address_visibility;
             }
+            if (data.push_notifications_enabled !== undefined) {
+              result.pushNotificationsEnabled = data.push_notifications_enabled;
+            }
 
             return result;
           }