FEATURE: Display link with count to user's assigned messages page.

assets/javascripts/discourse/templates/user-activity-assigned.hbs

@@ -1,11 +1,18 @@
-{{#if canUnassignAll}}
-  <div class='assign-controls'>
+<div class='assign-controls'>
+  {{#if model.topic_list.assigned_messages_count}}
+    {{#link-to 'userPrivateMessages.assigned' user.model class="btn assign-messages-assigned"}}
+      {{d-icon "envelope" class="glyph"}}
+      {{i18n 'user.messages.assigned_title' count=model.topic_list.assigned_messages_count}}
+    {{/link-to}}
+  {{/if}}
+
+  {{#if canUnassignAll}}
     {{d-button
       action=(action "unassignAll")
       icon="times"
       label="discourse_assign.unassign_all.title"
       class="btn-danger"}}
-  </div>
-{{/if}}
+  {{/if}}
+</div>
 
 {{outlet}}

assets/stylesheets/assigns.scss

@@ -3,6 +3,10 @@
     display: flex;
     justify-content: flex-end;
     margin-bottom: 0.5em;
+
+    .assign-messages-assigned {
+      margin-right: 0.5em;
+    }
   }
 }
 

config/locales/client.en.yml

@@ -28,4 +28,5 @@ en:
         help: "Assign topic to yourself"
     user:
       messages:
+        assigned_title: "Assigned Messages (%{count})"
         assigned: "Assigned"

plugin.rb

@@ -123,13 +123,21 @@ after_initialize do
   end
 
   add_to_class(:topic_query, :list_private_messages_assigned) do |user|
-    list = private_messages_for(user, :all)
-    list = list.where("topics.id IN (
-        SELECT topic_id FROM topic_custom_fields WHERE name = 'assigned_to_id' AND value = ?
-    )", user.id.to_s)
+    list = private_messages_assigned_query(user)
     create_list(:private_messages, {}, list)
   end
 
+  add_to_class(:topic_query, :private_messages_assigned_query) do |user|
+    list = private_messages_for(user, :all)
+
+    list = list.where("
+      topics.id IN (
+        SELECT topic_id FROM topic_custom_fields
+        WHERE name = 'assigned_to_id'
+        AND value = ?)
+    ", user.id.to_s)
+  end
+
   add_to_class(:topic, :assigned_to_user) do
     @assigned_to_user ||
       if user_id = custom_fields["assigned_to_id"]
@@ -145,6 +153,22 @@ after_initialize do
     (SiteSetting.assigns_public || scope.is_staff?) && object.assigned_to_user
   end
 
+  add_to_serializer(:topic_list, :assigned_messages_count) do
+    TopicQuery.new(object.current_user, guardian: scope, limit: false)
+      .private_messages_assigned_query(object.current_user)
+      .count
+  end
+
+  add_to_serializer(:topic_list, 'include_assigned_messages_count?') do
+    return unless SiteSetting.assigns_public
+    options = object.instance_variable_get(:@opts)
+
+    if assigned_username = options[:assigned]&.downcase
+      assigned_username == object.current_user&.username_lower
+    end
+  end
+
+
   add_to_serializer(:topic_view, :assigned_to_user, false) do
     DiscourseAssign::Helpers.build_assigned_to_user(assigned_to_user_id, object.topic)
   end

spec/serializers/topic_list_serializer_spec.rb

@@ -0,0 +1,60 @@
+require 'rails_helper'
+
+RSpec.describe TopicListSerializer do
+  let(:user) { Fabricate(:user) }
+
+  let(:private_message_topic) do
+    Fabricate(:private_message_topic,
+      posts: [Fabricate(:post)],
+      topic_allowed_users: [
+        Fabricate.build(:topic_allowed_user, user: user)
+      ]
+    )
+  end
+
+  let(:assigned_topic) do
+    topic = Fabricate(:private_message_topic,
+      posts: [Fabricate(:post)],
+      topic_allowed_users: [
+        Fabricate.build(:topic_allowed_user, user: user)
+      ]
+    )
+
+    TopicAssigner.new(topic, user).assign(user)
+    topic
+  end
+
+  let(:guardian) { Guardian.new(user) }
+  let(:serializer) { TopicListSerializer.new(topic_list, scope: guardian) }
+
+  before do
+    SiteSetting.assign_enabled = true
+    SiteSetting.assigns_public = true
+  end
+
+  describe '#assigned_messages_count' do
+    let(:topic_list) do
+      TopicQuery.new(user, assigned: user.username).list_private_messages_assigned(user)
+    end
+
+    before do
+      assigned_topic
+    end
+
+    it 'should include right attribute' do
+      expect(serializer.as_json[:topic_list][:assigned_messages_count])
+        .to eq(1)
+    end
+
+    describe 'when assigns are not public' do
+      before do
+        SiteSetting.assigns_public = false
+      end
+
+      it 'should not include the attributes' do
+        expect(serializer.as_json[:topic_list][:assigned_messages_count])
+          .to eq(nil)
+      end
+    end
+  end
+end