Add endpoint for fetching label template tags [SCI-7053] (#4319)

app/controllers/label_templates_controller.rb

@@ -85,6 +85,10 @@ class LabelTemplatesController < ApplicationController
     render json: { error: I18n.t('errors.general') }, status: :unprocessable_entity
   end
 
+  def template_tags
+    render json: LabelTemplates::TagService.new(current_team).tags
+  end
+
   private
 
   def check_feature_enabled

app/services/label_templates/tag_service.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+module LabelTemplates
+  class TagService
+    DEFAULT_COLUMNS = [
+      { key: :item_id, tag: '{{ITEM_ID}}' },
+      { key: :added_by, tag: '{{ADDED_BY}}' },
+      { key: :added_on, tag: '{{ADDED_ON}}' },
+      { key: :name, tag: '{{NAME}}' }
+    ].freeze
+
+    def initialize(team)
+      @team = team
+    end
+
+    def tags
+      {
+        default: DEFAULT_COLUMNS,
+        common: repository_tags.pluck(:tags).reduce(:&),
+        repository: repository_tags
+      }
+    end
+
+    private
+
+    def repository_tags
+      @repository_tags ||=
+        Repository.includes(:repository_columns).active.where(team: @team).map do |repository|
+          {
+            repository_id: repository.id,
+            repository_name: repository.name,
+            tags: repository.repository_columns.pluck(:name).map do |name|
+              {
+                key: name,
+                tag: "{{COLUMN_[#{name}]}}"
+              }
+            end
+          }
+        end
+    end
+  end
+end

config/routes.rb

@@ -53,6 +53,7 @@ Rails.application.routes.draw do
         post :duplicate
         post :delete
         get :datatable
+        get :template_tags
       end
     end