FEATURE: Improving thread list item and header (#21749)

* Moved the settings cog from thread list to thread and
  put it in a new header component
* Remove thread original message component, no longer needed
  and the list item and thread indicator styles/content
  will be quite different
* Start adding content (unread indicator etc.) to the thread
  list item and changing structure to be more like designs
* Serialize the last thread reply when opening the thread index,
  show in list and update with message bus

plugins/chat/app/models/chat/message.rb

@@ -146,6 +146,12 @@ module Chat
       PrettyText.excerpt(cooked, max_length)
     end
 
+    def censored_excerpt(rich: false, max_length: 50)
+      WordWatcher.censor(
+        rich ? rich_excerpt(max_length: max_length) : excerpt(max_length: max_length),
+      )
+    end
+
     def cooked_for_excerpt
       (cooked.blank? && uploads.present?) ? "<p>#{uploads.first.original_filename}</p>" : cooked
     end

plugins/chat/app/models/chat/thread.rb

@@ -23,6 +23,7 @@ module Chat
              primary_key: :id,
              class_name: "Chat::Message"
     has_many :user_chat_thread_memberships
+    has_one :last_reply, -> { order("created_at DESC, id DESC") }, class_name: "Chat::Message"
 
     enum :status, { open: 0, read_only: 1, closed: 2, archived: 3 }, scopes: false
 

plugins/chat/app/serializers/chat/in_reply_to_serializer.rb

@@ -8,7 +8,7 @@ module Chat
     attributes :id, :cooked, :excerpt
 
     def excerpt
-      WordWatcher.censor(object.excerpt)
+      object.censored_excerpt
     end
 
     def user

plugins/chat/app/serializers/chat/message_serializer.rb

@@ -44,7 +44,7 @@ module Chat
     end
 
     def excerpt
-      WordWatcher.censor(object.excerpt)
+      object.censored_excerpt
     end
 
     def reactions

plugins/chat/app/serializers/chat/thread_list_serializer.rb

@@ -10,6 +10,7 @@ module Chat
           thread,
           scope: scope,
           membership: object.memberships.find { |m| m.thread_id == thread.id },
+          include_preview: true,
           root: nil,
         )
       end

plugins/chat/app/serializers/chat/thread_original_message_serializer.rb

@@ -3,7 +3,11 @@
 module Chat
   class ThreadOriginalMessageSerializer < Chat::MessageSerializer
     def excerpt
-      WordWatcher.censor(object.rich_excerpt(max_length: Chat::Thread::EXCERPT_LENGTH))
+      object.censored_excerpt(rich: true, max_length: Chat::Thread::EXCERPT_LENGTH)
+    end
+
+    def include_available_flags?
+      false
     end
 
     def include_reactions?

plugins/chat/app/serializers/chat/thread_preview_serializer.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module Chat
+  class ThreadPreviewSerializer < ApplicationSerializer
+    attributes :last_reply_created_at, :last_reply_excerpt, :last_reply_id
+
+    def last_reply_created_at
+      object.last_reply.created_at
+    end
+
+    def last_reply_id
+      object.last_reply.id
+    end
+
+    def last_reply_excerpt
+      object.last_reply.censored_excerpt
+    end
+  end
+end

plugins/chat/app/serializers/chat/thread_serializer.rb

@@ -5,7 +5,14 @@ module Chat
     has_one :original_message_user, serializer: BasicUserWithStatusSerializer, embed: :objects
     has_one :original_message, serializer: Chat::ThreadOriginalMessageSerializer, embed: :objects
 
-    attributes :id, :title, :status, :channel_id, :meta, :reply_count, :current_user_membership
+    attributes :id,
+               :title,
+               :status,
+               :channel_id,
+               :meta,
+               :reply_count,
+               :current_user_membership,
+               :preview
 
     def initialize(object, opts)
       super(object, opts)
@@ -24,6 +31,14 @@ module Chat
       object.replies_count_cache || 0
     end
 
+    def include_preview?
+      @opts[:include_preview]
+    end
+
+    def preview
+      Chat::ThreadPreviewSerializer.new(object, scope: scope, root: false).as_json
+    end
+
     def include_current_user_membership?
       @current_user_membership.present?
     end

plugins/chat/app/services/chat/lookup_channel_threads.rb

@@ -54,6 +54,7 @@ module Chat
       Chat::Thread
         .includes(
           :channel,
+          :last_reply,
           original_message_user: :user_status,
           original_message: :chat_webhook_event,
         )

plugins/chat/app/services/chat/publisher.rb

@@ -72,6 +72,9 @@ module Chat
             user_id: chat_message.user.id,
             username: chat_message.user.username,
             thread_id: chat_message.thread_id,
+            created_at: chat_message.created_at,
+            excerpt:
+              chat_message.censored_excerpt(rich: true, max_length: Chat::Thread::EXCERPT_LENGTH),
           },
           permissions(chat_channel),
         )