Pass remix identifier through with lesson list (#608)

## Status

- Related to
RaspberryPiFoundation/digital-editor-issues#994

## What's changed?

- Requests to list lessons now include a remix identifier if the user
has one
- Added route to show the identifier of a remix of a given project

Author: loiswells97

app/controllers/api/lessons_controller.rb

@@ -10,7 +10,10 @@ def index
       archive_scope = params[:include_archived] == 'true' ? Lesson : Lesson.unarchived
       scope = params[:school_class_id] ? archive_scope.where(school_class_id: params[:school_class_id]) : archive_scope
       ordered_scope = scope.order(created_at: :asc)
-      @lessons_with_users = ordered_scope.accessible_by(current_ability).with_users
+      accessible_lessons = ordered_scope.accessible_by(current_ability)
+      lessons_with_users = accessible_lessons.with_users
+      remixes = user_remixes(accessible_lessons)
+      @lessons_with_users_and_remixes = lessons_with_users.zip(remixes)
       render :index, formats: [:json], status: :ok
     end
 
@@ -74,6 +77,22 @@ def verify_school_class_belongs_to_school
       raise ParameterError, 'school_class_id does not correspond to school_id'
     end
 
+    def user_remixes(lessons)
+      lessons.map do |lesson|
+        next nil unless lesson&.project&.remixes&.any?
+
+        user_remix(lesson)
+      end
+    end
+
+    def user_remix(lesson)
+      lesson.project&.remixes
+            &.where(user_id: current_user.id)
+            &.accessible_by(current_ability)
+            &.order(created_at: :asc)
+            &.first
+    end
+
     def lesson_params
       base_params.merge(user_id: current_user.id)
     end

app/controllers/api/projects/remixes_controller.rb

@@ -5,7 +5,7 @@ module Projects
     class RemixesController < ApiController
       before_action :authorize_user
       load_and_authorize_resource :school, only: :index
-      before_action :load_and_authorize_remix, only: %i[show]
+      before_action :load_and_authorize_remix, only: %i[show show_identifier]
 
       def index
         projects = Project.where(remixed_from_id: project.id).accessible_by(current_ability)
@@ -17,6 +17,10 @@ def show
         render '/api/projects/show', formats: [:json]
       end
 
+      def show_identifier
+        render json: { identifier: @project.identifier }, status: :ok
+      end
+
       def create
         # Ensure we have a fallback value to prevent bad requests
         remix_origin = request.origin || request.referer

app/views/api/lessons/index.json.jbuilder

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
-json.array!(@lessons_with_users) do |lesson, user|
+json.array!(@lessons_with_users_and_remixes) do |lesson_with_user, remix|
+  lesson, user = lesson_with_user # Destructure the pair
   json.call(
     lesson,
     :id,
@@ -26,4 +27,6 @@ json.array!(@lessons_with_users) do |lesson, user|
   end
 
   json.user_name(user&.name)
+
+  json.remix_identifier(remix.identifier) if remix.present?
 end

config/routes.rb

@@ -43,7 +43,9 @@
       post :submit, on: :member, to: 'school_projects#submit'
       post :return, on: :member, to: 'school_projects#return'
       post :complete, on: :member, to: 'school_projects#complete'
-      resource :remix, only: %i[show create], controller: 'projects/remixes'
+      resource :remix, only: %i[show create], controller: 'projects/remixes' do
+        get :identifier, on: :member, to: 'projects/remixes#show_identifier'
+      end
       resources :remixes, only: %i[index], controller: 'projects/remixes'
       resource :images, only: %i[show create], controller: 'projects/images'
       resources :feedback, only: %i[index create], controller: 'feedback' do

spec/features/lesson/listing_lessons_spec.rb

@@ -210,6 +210,17 @@
       expect(data.size).to eq(1)
     end
 
+    it "includes the remix identifier when the user has remixed the lesson's project" do
+      student = create(:student, school:)
+      authenticated_in_hydra_as(student)
+      create(:class_student, school_class:, student_id: student.id)
+      student_project = create(:project, school:, lesson:, parent: lesson.project, user_id: student.id)
+
+      get('/api/lessons', headers:)
+      data = JSON.parse(response.body, symbolize_names: true)
+      expect(data.first[:remix_identifier]).to eq(student_project.identifier)
+    end
+
     it "does not include the lesson when the user is not a school-student within the lesson's class" do
       student = create(:student, school:)
       authenticated_in_hydra_as(student)

spec/requests/projects/remix_spec.rb

@@ -70,6 +70,35 @@
       end
     end
 
+    describe('#show_identifier') do
+      let!(:remixed_project) do
+        create(:project, remixed_from_id: original_project.id, user_id: authenticated_user.id)
+      end
+
+      it 'returns success response' do
+        get("/api/projects/#{original_project.identifier}/remix/identifier", headers:)
+        expect(response).to have_http_status(:ok)
+      end
+
+      it 'returns the project identifier' do
+        get("/api/projects/#{original_project.identifier}/remix/identifier", headers:)
+        expect(response.parsed_body['identifier']).to eq(remixed_project.identifier)
+      end
+
+      it 'returns 404 response if invalid project' do
+        get('/api/projects/no-such-project/remix/identifier', headers:)
+        expect(response).to have_http_status(:not_found)
+      end
+
+      it 'returns 404 if no remixed project for user' do
+        another_user = create(:owner, school:)
+        authenticated_in_hydra_as(another_user)
+
+        get("/api/projects/#{original_project.identifier}/remix/identifier", headers:)
+        expect(response).to have_http_status(:not_found)
+      end
+    end
+
     describe '#create' do
       it 'returns success response' do
         post("/api/projects/#{original_project.identifier}/remix", params: { project: project_params }, headers:)
@@ -116,6 +145,13 @@
       end
     end
 
+    describe '#show_identifier' do
+      it 'returns unauthorized' do
+        get "/api/projects/#{original_project.identifier}/remix/identifier"
+        expect(response).to have_http_status(:unauthorized)
+      end
+    end
+
     describe '#create' do
       it 'returns unauthorized' do
         post "/api/projects/#{original_project.identifier}/remix"