inbox: Add label for archived channels in headers

Design inspired by the web version.

Fixes #800

Author: chimnayajith

assets/l10n/app_en.arb

@@ -375,6 +375,10 @@
   "@unknownChannelName": {
     "description": "Replacement name for channel when it cannot be found in the store."
   },
+  "channelArchivedLabel": "(archived)",
+  "@channelArchivedLabel": {
+    "description": "Label shown next to an archived channel's name in headers."
+  },
   "composeBoxTopicHintText": "Topic",
   "@composeBoxTopicHintText":  {
     "description": "Hint text for topic input widget in compose box."

lib/generated/l10n/zulip_localizations.dart

@@ -603,6 +603,12 @@ abstract class ZulipLocalizations {
   /// **'(unknown channel)'**
   String get unknownChannelName;
 
+  /// Label shown next to an archived channel's name in headers.
+  ///
+  /// In en, this message translates to:
+  /// **'(archived)'**
+  String get channelArchivedLabel;
+
   /// Hint text for topic input widget in compose box.
   ///
   /// In en, this message translates to:

lib/generated/l10n/zulip_localizations_ar.dart

@@ -295,6 +295,9 @@ class ZulipLocalizationsAr extends ZulipLocalizations {
   @override
   String get unknownChannelName => '(unknown channel)';
 
+  @override
+  String get channelArchivedLabel => '(archived)';
+
   @override
   String get composeBoxTopicHintText => 'Topic';
 

lib/generated/l10n/zulip_localizations_en.dart

@@ -295,6 +295,9 @@ class ZulipLocalizationsEn extends ZulipLocalizations {
   @override
   String get unknownChannelName => '(unknown channel)';
 
+  @override
+  String get channelArchivedLabel => '(archived)';
+
   @override
   String get composeBoxTopicHintText => 'Topic';
 

lib/generated/l10n/zulip_localizations_ja.dart

@@ -295,6 +295,9 @@ class ZulipLocalizationsJa extends ZulipLocalizations {
   @override
   String get unknownChannelName => '(unknown channel)';
 
+  @override
+  String get channelArchivedLabel => '(archived)';
+
   @override
   String get composeBoxTopicHintText => 'Topic';
 

lib/generated/l10n/zulip_localizations_nb.dart

@@ -295,6 +295,9 @@ class ZulipLocalizationsNb extends ZulipLocalizations {
   @override
   String get unknownChannelName => '(unknown channel)';
 
+  @override
+  String get channelArchivedLabel => '(archived)';
+
   @override
   String get composeBoxTopicHintText => 'Topic';
 

lib/generated/l10n/zulip_localizations_pl.dart

@@ -295,6 +295,9 @@ class ZulipLocalizationsPl extends ZulipLocalizations {
   @override
   String get unknownChannelName => '(nieznany kanał)';
 
+  @override
+  String get channelArchivedLabel => '(archived)';
+
   @override
   String get composeBoxTopicHintText => 'Wątek';
 

lib/generated/l10n/zulip_localizations_ru.dart

@@ -295,6 +295,9 @@ class ZulipLocalizationsRu extends ZulipLocalizations {
   @override
   String get unknownChannelName => '(unknown channel)';
 
+  @override
+  String get channelArchivedLabel => '(archived)';
+
   @override
   String get composeBoxTopicHintText => 'Тема';
 

lib/generated/l10n/zulip_localizations_sk.dart

@@ -295,6 +295,9 @@ class ZulipLocalizationsSk extends ZulipLocalizations {
   @override
   String get unknownChannelName => '(unknown channel)';
 
+  @override
+  String get channelArchivedLabel => '(archived)';
+
   @override
   String get composeBoxTopicHintText => 'Topic';
 

lib/widgets/action_sheet.dart

@@ -230,19 +230,22 @@ void showTopicActionSheet(BuildContext context, {
   final pageContext = PageRoot.contextOf(context);
 
   final store = PerAccountStoreWidget.of(pageContext);
+  final channel = store.streams[channelId];
   final subscription = store.subscriptions[channelId];
 
   final optionButtons = <ActionSheetMenuItemButton>[];
 
+  final isChannelArchived = channel?.isArchived == true;
   // TODO(server-7): simplify this condition away
   final supportsUnmutingTopics = store.zulipFeatureLevel >= 170;
   // TODO(server-8): simplify this condition away
   final supportsFollowingTopics = store.zulipFeatureLevel >= 219;
 
   final visibilityOptions = <UserTopicVisibilityPolicy>[];
   final visibilityPolicy = store.topicVisibilityPolicy(channelId, topic);
-  if (subscription == null) {
-    // Not subscribed to the channel; there is no user topic change to be made.
+  if (subscription == null || isChannelArchived) {
+    // Not subscribed to the channel or the channel is archived;
+    // there is no user topic change to be made.
   } else if (!subscription.isMuted) {
     // Channel is subscribed and not muted.
     switch (visibilityPolicy) {
@@ -306,7 +309,8 @@ void showTopicActionSheet(BuildContext context, {
   //   limit for editing topics).
   if (someMessageIdInTopic != null
       // ignore: unnecessary_null_comparison // null topic names soon to be enabled
-      && topic.displayName != null) {
+      && topic.displayName != null
+      && !isChannelArchived) {
     optionButtons.add(ResolveUnresolveButton(pageContext: pageContext,
       topic: topic,
       someMessageIdInTopic: someMessageIdInTopic));
@@ -564,14 +568,19 @@ void showMessageActionSheet({required BuildContext context, required Message mes
   final messageListPage = MessageListPage.ancestorOf(pageContext);
   final isComposeBoxOffered = messageListPage.composeBoxController != null;
 
+  bool isInArchivedChannel = false;
+  if (message is StreamMessage) {
+    final channel = store.streams[message.streamId];
+    isInArchivedChannel = channel?.isArchived == true;
+  }
   final isMessageRead = message.flags.contains(MessageFlag.read);
   final markAsUnreadSupported = store.zulipFeatureLevel >= 155; // TODO(server-6)
   final showMarkAsUnreadButton = markAsUnreadSupported && isMessageRead;
 
   final optionButtons = [
     ReactionButtons(message: message, pageContext: pageContext),
     StarButton(message: message, pageContext: pageContext),
-    if (isComposeBoxOffered)
+    if (isComposeBoxOffered && !isInArchivedChannel)
       QuoteAndReplyButton(message: message, pageContext: pageContext),
     if (showMarkAsUnreadButton)
       MarkAsUnreadButton(message: message, pageContext: pageContext),