Show link to the original topic when it was deleted (#7319)

* Moved i18n keys to core. We show a links that points to the original topic when it was deleted

* Use link-to since it's more idiomatic

app/assets/javascripts/discourse/templates/components/reviewable-topic-link.hbs

@@ -7,6 +7,9 @@
   {{else if (has-block)}}
     {{yield}}
   {{else}}
-    <span class="title-text">{{i18n "topic.deleted"}}</span>
+    <span class="title-text">
+      {{i18n "review.topics.deleted"}}
+      {{link-to (i18n "review.topics.original") "topic" "-" reviewable.removed_topic_id}}
+    </span>
   {{/if}}
 </div>

app/serializers/reviewable_serializer.rb

@@ -72,7 +72,8 @@ class ReviewableSerializer < ApplicationSerializer
   end
 
   def attributes
-    data = super
+    super.tap do |data|
+      data[:removed_topic_id] = object.topic_id unless object.topic
 
       if object.target.present?
         # Automatically add the target id as a "good name" for example a target_type of `User`
@@ -83,8 +84,7 @@ class ReviewableSerializer < ApplicationSerializer
       if self.class._payload_for_serialization.present?
         data[:payload] = (object.payload || {}).slice(*self.class._payload_for_serialization)
       end
-
+    end
-    data
   end
 
   def topic_tags

config/locales/client.en.yml

@@ -404,6 +404,8 @@ en:
         topic: "Topic"
         reviewable_count: "Count"
         reported_by: "Reported by"
+        deleted: "[Topic Deleted]"
+        original: '(original topic)'
         details: "details"
         unique_users:
           one: "1 user"

spec/serializers/reviewable_serializer_spec.rb

@@ -6,7 +6,7 @@ describe ReviewableSerializer do
   let(:admin) { Fabricate(:admin) }
 
   it "serializes all the fields" do
-    json = ReviewableSerializer.new(reviewable, scope: Guardian.new(admin), root: nil).as_json
+    json = described_class.new(reviewable, scope: Guardian.new(admin), root: nil).as_json
 
     expect(json[:id]).to eq(reviewable.id)
     expect(json[:status]).to eq(reviewable.status)
@@ -15,6 +15,15 @@ describe ReviewableSerializer do
     expect(json[:category_id]).to eq(reviewable.category_id)
     expect(json[:can_edit]).to eq(true)
     expect(json[:version]).to eq(0)
+    expect(json[:removed_topic_id]).to be_nil
+  end
+
+  it 'Includes the removed topic id when the topis was deleted' do
+    reviewable.topic.trash!(admin)
+
+    json = described_class.new(reviewable.reload, scope: Guardian.new(admin), root: nil).as_json
+
+    expect(json[:removed_topic_id]).to eq reviewable.topic_id
   end
 
   it "will not throw an error when the payload is `nil`" do
@@ -22,5 +31,4 @@ describe ReviewableSerializer do
     json = ReviewableQueuedPostSerializer.new(reviewable, scope: Guardian.new(admin), root: nil).as_json
     expect(json['payload']).to be_blank
   end
-
 end