UX: Display button to message group on group page.

https://meta.discourse.org/t/make-it-easier-to-send-a-message-to-groups/65065

app/assets/javascripts/discourse/controllers/group.js.es6

@@ -48,6 +48,11 @@ export default Ember.Controller.extend({
     };
   },
 
+  @computed("model.mentionable")
+  displayGroupMessageButton(mentionable) {
+    return this.currentUser && mentionable;
+  },
+
   @observes('model.user_count')
   _setMembersTabCount() {
     this.get('tabs')[0].set('count', this.get('model.user_count'));
@@ -66,5 +71,11 @@ export default Ember.Controller.extend({
 
       return canSee;
     });
+  },
+
+  actions: {
+    messageGroup() {
+      this.send('createNewMessageViaParams', this.get('model.name'));
+    }
   }
 });

app/assets/javascripts/discourse/templates/group.hbs

@@ -43,6 +43,14 @@
         {{/each}}
       {{/mobile-nav}}
 
+      {{#if displayGroupMessageButton}}
+        {{d-button
+            action="messageGroup"
+            class="btn-primary group-message-button"
+            icon="envelope"
+            label="groups.message"}}
+      {{/if}}
+
       {{group-membership-button model=model showLogin='showLogin'}}
     </div>
   </div>

app/serializers/group_show_serializer.rb

@@ -1,8 +1,8 @@
 class GroupShowSerializer < BasicGroupSerializer
-  attributes :is_group_user, :is_group_owner
+  attributes :is_group_user, :is_group_owner, :mentionable
 
   def include_is_group_user?
-    scope.authenticated?
+    authenticated?
   end
 
   def is_group_user
@@ -10,15 +10,27 @@ class GroupShowSerializer < BasicGroupSerializer
   end
 
   def include_is_group_owner?
-    scope.authenticated?
+    authenticated?
   end
 
   def is_group_owner
     scope.is_admin? || fetch_group_user&.owner
   end
 
+  def include_mentionable?
+    authenticated?
+  end
+
+  def mentionable
+    Group.mentionable(scope.user).exists?(id: object.id)
+  end
+
   private
 
+  def authenticated?
+    scope.authenticated?
+  end
+
   def fetch_group_user
     @group_user ||= object.group_users.find_by(user: scope.user)
   end

config/locales/client.en.yml

@@ -421,6 +421,7 @@ en:
       join: "Join Group"
       leave: "Leave Group"
       request: "Request to Join Group"
+      message: "Message"
       automatic_group: Automatic Group
       closed_group: Closed Group
       is_group_user: "You are a member of this group"

spec/serializers/group_show_serializer_spec.rb

@@ -1,6 +1,9 @@
 require 'rails_helper'
 
 describe GroupShowSerializer do
+  let(:user) { Fabricate(:user) }
+  let(:group) { Fabricate(:group) }
+
   context 'admin user' do
     let(:user) { Fabricate(:admin) }
     let(:group) { Fabricate(:group, users: [user]) }
@@ -14,9 +17,6 @@ describe GroupShowSerializer do
   end
 
   context 'group owner' do
-    let(:user) { Fabricate(:user) }
-    let(:group) { Fabricate(:group) }
-
     before do
       group.add_owner(user)
     end
@@ -28,4 +28,18 @@ describe GroupShowSerializer do
       expect(json[:group_show][:is_group_user]).to eq(true)
     end
   end
+
+  describe '#mentionable' do
+    let(:group) { Fabricate(:group, alias_level: Group::ALIAS_LEVELS[:everyone]) }
+
+    it 'should return the right value' do
+      json = GroupShowSerializer.new(group, scope: Guardian.new).as_json
+
+      expect(json[:group_show][:mentionable]).to eq(nil)
+
+      json = GroupShowSerializer.new(group, scope: Guardian.new(user)).as_json
+
+      expect(json[:group_show][:mentionable]).to eq(true)
+    end
+  end
 end

test/javascripts/acceptance/groups-test.js.es6

@@ -42,12 +42,13 @@ QUnit.test("Browsing Groups", assert => {
   });
 });
 
-QUnit.test("Viewing Group", assert => {
+QUnit.test("Anonymous Viewing Group", assert => {
   visit("/groups/discourse");
 
   andThen(() => {
     assert.ok(count('.avatar-flair .fa-adjust') === 1, "it displays the group's avatar flair");
     assert.ok(count('.group-members tr') > 0, "it lists group members");
+    assert.ok(count('.group-message-button') === 0, 'it does not show group message button');
   });
 
   click(".nav-pills li a[title='Activity']");
@@ -80,6 +81,20 @@ QUnit.test("Viewing Group", assert => {
   });
 });
 
+QUnit.test("User Viewing Group", assert => {
+  logIn();
+  Discourse.reset();
+
+  visit("/groups/discourse");
+
+  click('.group-message-button');
+
+  andThen(() => {
+    assert.ok(count('#reply-control') === 1, 'it opens the composer');
+    assert.equal(find('.ac-wrap .item').text(), 'discourse', 'it prefills the group name');
+  });
+});
+
 QUnit.test("Admin Viewing Group", assert => {
   logIn();
   Discourse.reset();

test/javascripts/fixtures/group-fixtures.js.es6

@@ -6,11 +6,12 @@ export default {
       "name":"discourse",
       "full_name":"Awesome Team",
       "user_count":8,
-      "alias_level":0,
+      "alias_level":99,
       "visible":true,
       "public":true,
       "flair_url": 'fa-adjust',
-      "is_group_owner":true
+      "is_group_owner":true,
+      "mentionable":true
     }
   },
   "/groups/discourse/counts.json":{