Define an endpoint to return the default affinities of a group

app/controllers/affinities_controller.rb

@@ -9,10 +9,10 @@ class AffinitiesController < ApplicationController
     overridden = @group.affinities.each_with_object({}) do |affinity, acc|
       acc[affinity.another_group(@group).id] = affinity.discomfort
     end
-    Group.where.not(id: @group.id)
-         .pluck(:id)
-         .index_with { |group_id| GroupAffinity::MAX_DISCOMFORT - (overridden[group_id] || GroupAffinity::NEUTRAL) }
-         .then { |affinities| render json: affinities }
+
+    for_each_group do |group_id|
+      overridden[group_id] || GroupAffinity::NEUTRAL
+    end
   end
 
   def bulk_update
@@ -33,8 +33,21 @@ class AffinitiesController < ApplicationController
     render json: { error: 'Invalid group ID or discomfort provided.' }, status: :bad_request
   end
 
+  def default
+    for_each_group do |group_id|
+      Tables::DiscomfortCalculator.cohesion_discomfort(id_a: @group.id, id_b: group_id).to_f
+    end
+  end
+
   private
 
+  def for_each_group
+    Group.where.not(id: @group.id)
+         .pluck(:id)
+         .index_with { |group_id| GroupAffinity::MAX_DISCOMFORT - yield(group_id) }
+         .then { |affinities| render json: affinities }
+  end
+
   def set_group
     @group = Group.find(params[:group_id])
   end

config/routes.rb

@@ -26,6 +26,7 @@ Rails.application.routes.draw do
     resources :groups, only: %i[index create update destroy] do
       resources :affinities, only: %i[index] do
         put :bulk_update, on: :collection
+        get :default, on: :collection
       end
     end
 

spec/requests/affinities_spec.rb

@@ -20,6 +20,21 @@ RSpec.describe 'affinities' do
     end
   end
 
+  path '/{slug}/groups/{group_id}/affinities/default' do
+    parameter Swagger::Schema::SLUG
+    parameter name: 'group_id', in: :path, type: :string, format: :uuid, description: 'group_id'
+
+    get('calculate default affinity') do
+      tags 'Affinities'
+      produces 'application/json'
+
+      response(200, 'successful') do
+        schema type: :object, additionalProperties: { type: :integer, minimum: 0, maximum: 2 }
+        xit
+      end
+    end
+  end
+
   path '/{slug}/groups/{group_id}/affinities/bulk_update' do
     parameter Swagger::Schema::SLUG
     parameter name: 'group_id', in: :path, type: :string, format: :uuid, description: 'group_id'