notif: Create group summary notification

Make use of Group Summary Notifications to group notifications
based on different realms and also display the respective group
label (which is currently the realm URL).

See:
  https://developer.android.com/develop/ui/views/notifications/group#group-summary

This change is a port of implementation in zulip-mobile:
  https://github.com/zulip/zulip-mobile/blob/6d5d56d175644cd0cdf47f3cd30ffadf6756bbdc/android/app/src/main/java/com/zulipmobile/notifications/NotificationUiManager.kt#L299-L382

Fixes: #569
Fixes: #571

Author: rajveermalviya

lib/notifications/display.dart

@@ -89,7 +89,7 @@ class NotificationDisplayManager {
     }
   }
 
-  static void _onMessageFcmMessage(MessageFcmMessage data, Map<String, dynamic> dataJson) {
+  static Future<void> _onMessageFcmMessage(MessageFcmMessage data, Map<String, dynamic> dataJson) async {
     assert(debugLog('notif message content: ${data.content}'));
     final zulipLocalizations = GlobalLocalizations.zulipLocalizations;
     final title = switch (data.recipient) {
@@ -103,13 +103,16 @@ class NotificationDisplayManager {
       FcmMessageDmRecipient() =>
         data.senderFullName,
     };
-    final conversationKey = _conversationKey(data);
-    ZulipBinding.instance.androidNotificationHost.notify(
+    final groupKey = _groupKey(data);
+    final conversationKey = _conversationKey(data, groupKey);
+
+    await ZulipBinding.instance.androidNotificationHost.notify(
       // TODO the notification ID can be constant, instead of matching requestCode
       //   (This is a legacy of `flutter_local_notifications`.)
       id: notificationIdAsHashOf(conversationKey),
       tag: conversationKey,
       channelId: NotificationChannelManager.kChannelId,
+      groupKey: groupKey,
 
       contentTitle: title,
       contentText: data.content,
@@ -140,6 +143,21 @@ class NotificationDisplayManager {
         //   (This is a legacy of `flutter_local_notifications`.)
         ),
     );
+
+    await ZulipBinding.instance.androidNotificationHost.notify(
+      id: notificationIdAsHashOf(groupKey),
+      channelId: NotificationChannelManager.kChannelId,
+      tag: groupKey,
+      groupKey: groupKey,
+      isGroupSummary: true,
+      color: kZulipBrandColor.value,
+      // TODO vary notification icon for debug
+      smallIconResourceName: 'zulip_notification', // This name must appear in keep.xml too: https://github.com/zulip/zulip-flutter/issues/528
+      inboxStyle: InboxStyle(
+        // TODO(#570) Show organization name, not URL
+        summaryText: data.realmUri.toString()),
+      autoCancel: true,
+    );
   }
 
   /// A notification ID, derived as a hash of the given string key.
@@ -157,8 +175,7 @@ class NotificationDisplayManager {
       | ((bytes[3] & 0x7f) << 24);
   }
 
-  static String _conversationKey(MessageFcmMessage data) {
-    final groupKey = _groupKey(data);
+  static String _conversationKey(MessageFcmMessage data, String groupKey) {
     final conversation = switch (data.recipient) {
       FcmMessageStreamRecipient(:var streamId, :var topic) => 'stream:$streamId:$topic',
       FcmMessageDmRecipient(:var allRecipientIds) => 'dm:${allRecipientIds.join(',')}',

test/notifications/display_test.dart

@@ -111,24 +111,49 @@ void main() {
       required String expectedTagComponent,
     }) {
       final expectedTag = '${data.realmUri}|${data.userId}|$expectedTagComponent';
+      final expectedGroupKey = '${data.realmUri}|${data.userId}';
       final expectedId =
         NotificationDisplayManager.notificationIdAsHashOf(expectedTag);
       const expectedIntentFlags =
         PendingIntentFlag.immutable | PendingIntentFlag.updateCurrent;
-      check(testBinding.androidNotificationHost.takeNotifyCalls()).single
-        ..id.equals(expectedId)
-        ..tag.equals(expectedTag)
-        ..channelId.equals(NotificationChannelManager.kChannelId)
-        ..contentTitle.equals(expectedTitle)
-        ..contentText.equals(data.content)
-        ..color.equals(kZulipBrandColor.value)
-        ..smallIconResourceName.equals('zulip_notification')
-        ..extras.isNull()
-        ..contentIntent.which((it) => it.isNotNull()
-          ..requestCode.equals(expectedId)
-          ..flags.equals(expectedIntentFlags)
-          ..intentPayload.equals(jsonEncode(data.toJson()))
-        );
+
+      check(testBinding.androidNotificationHost.takeNotifyCalls())
+        ..length.equals(2)
+        ..containsInOrder([
+          (Subject<AndroidNotificationHostApiNotifyCall> it) => it
+            ..id.equals(expectedId)
+            ..tag.equals(expectedTag)
+            ..channelId.equals(NotificationChannelManager.kChannelId)
+            ..contentTitle.equals(expectedTitle)
+            ..contentText.equals(data.content)
+            ..color.equals(kZulipBrandColor.value)
+            ..smallIconResourceName.equals('zulip_notification')
+            ..extras.isNull()
+            ..groupKey.equals(expectedGroupKey)
+            ..isGroupSummary.isNull()
+            ..inboxStyle.isNull()
+            ..autoCancel.isNull()
+            ..contentIntent.which((it) => it.isNotNull()
+              ..requestCode.equals(expectedId)
+              ..flags.equals(expectedIntentFlags)
+              ..intentPayload.equals(jsonEncode(data.toJson()))),
+          (Subject<AndroidNotificationHostApiNotifyCall> it) => it
+            ..id.equals(NotificationDisplayManager.notificationIdAsHashOf(expectedGroupKey))
+            ..tag.equals(expectedGroupKey)
+            ..channelId.equals(NotificationChannelManager.kChannelId)
+            ..contentTitle.isNull()
+            ..contentText.isNull()
+            ..color.equals(kZulipBrandColor.value)
+            ..smallIconResourceName.equals('zulip_notification')
+            ..extras.isNull()
+            ..groupKey.equals(expectedGroupKey)
+            ..isGroupSummary.equals(true)
+            ..inboxStyle.which((it) => it.isNotNull()
+              ..summaryText.equals(data.realmUri.toString())
+            )
+            ..autoCancel.equals(true)
+            ..contentIntent.isNull()
+        ]);
     }
 
     Future<void> checkNotifications(FakeAsync async, MessageFcmMessage data, {
@@ -376,10 +401,18 @@ extension on Subject<AndroidNotificationHostApiNotifyCall> {
   Subject<String?> get contentTitle => has((x) => x.contentTitle, 'contentTitle');
   Subject<Map<String?, String?>?> get extras => has((x) => x.extras, 'extras');
   Subject<String?> get smallIconResourceName => has((x) => x.smallIconResourceName, 'smallIconResourceName');
+  Subject<String?> get groupKey => has((x) => x.groupKey, 'groupKey');
+  Subject<bool?> get isGroupSummary => has((x) => x.isGroupSummary, 'isGroupSummary');
+  Subject<InboxStyle?> get inboxStyle => has((x) => x.inboxStyle, 'inboxStyle');
+  Subject<bool?> get autoCancel => has((x) => x.autoCancel, 'autoCancel');
 }
 
 extension on Subject<PendingIntent> {
   Subject<int> get requestCode => has((x) => x.requestCode, 'requestCode');
   Subject<String> get intentPayload => has((x) => x.intentPayload, 'intentPayload');
   Subject<int> get flags => has((x) => x.flags, 'flags');
 }
+
+extension on Subject<InboxStyle> {
+  Subject<String> get summaryText => has((x) => x.summaryText, 'summaryText');
+}