Scratch projects can be copied fix (#849)

## Status

- Closes
RaspberryPiFoundation/digital-editor-issues#1465


## What's changed?

The bug was that lesson copy already duplicated the lesson/project
shell, but Scratch projects also need two Scratch-specific things:

 1. scratch_component.content
 2. project-owned scratch_assets

Without those, the copied project exists, but Scratch cannot load the
project/asset data correctly.


https://github.com/user-attachments/assets/bb0aed59-69f7-4ba0-abfb-1d3ec06ad495

Author: abcampo-iry

lib/concepts/lesson/operations/create_copy.rb

@@ -5,8 +5,13 @@ class CreateCopy
     class << self
       def call(lesson:, lesson_params:)
         response = OperationResponse.new
-        response[:lesson] = build_copy(lesson, lesson_params)
-        response[:lesson].save!
+
+        Lesson.transaction do
+          response[:lesson] = build_copy(lesson, lesson_params)
+          response[:lesson].save!
+          copy_scratch_assets(lesson.project, response[:lesson].project)
+        end
+
         response
       rescue StandardError => e
         Sentry.capture_exception(e)
@@ -39,8 +44,30 @@ def build_project_copy(project, project_params)
           project_copy.components.build({ name: component.name, extension: component.extension, content: component.content })
         end
 
+        copy_scratch_component(project, project_copy)
+
         project_copy
       end
+
+      def copy_scratch_component(project, project_copy)
+        return unless project.scratch_project? && project.scratch_component
+
+        project_copy.build_scratch_component(content: project.scratch_component.content.deep_dup)
+      end
+
+      def copy_scratch_assets(project, project_copy)
+        return unless project.scratch_project?
+
+        project.scratch_assets.where(uploaded_user_id: project.user_id).find_each do |scratch_asset|
+          next unless scratch_asset.file.attached?
+
+          scratch_asset_copy = project_copy.scratch_assets.create!(
+            filename: scratch_asset.filename,
+            uploaded_user_id: project_copy.user_id
+          )
+          scratch_asset_copy.file.attach(scratch_asset.file.blob)
+        end
+      end
     end
   end
 end

spec/concepts/lesson/create_copy_spec.rb

@@ -109,6 +109,78 @@
     expect(copied_component.content).to eq(original_component.content)
   end
 
+  context 'when the project is a Scratch project' do
+    let(:copied_teacher_id) { SecureRandom.uuid }
+    let(:lesson_params) { { user_id: copied_teacher_id } }
+    let(:scratch_content) do
+      {
+        targets: [
+          {
+            isStage: true,
+            costumes: [
+              {
+                assetId: 'teacher_asset',
+                md5ext: 'teacher_asset.png',
+                dataFormat: 'png'
+              }
+            ]
+          }
+        ],
+        monitors: [],
+        extensions: [],
+        meta: {}
+      }
+    end
+
+    before do
+      lesson.project.update!(project_type: Project::Types::CODE_EDITOR_SCRATCH, locale: nil)
+      create(:scratch_component, project: lesson.project, content: scratch_content)
+    end
+
+    it 'copies the Scratch component content' do
+      response = described_class.call(lesson:, lesson_params:)
+      copied_project = response[:lesson].reload.project
+
+      expect(copied_project.scratch_component.content.to_h)
+        .to eq(scratch_content.deep_stringify_keys)
+    end
+
+    it 'copies only teacher-owned Scratch assets to the new project owner' do
+      create_scratch_asset(
+        filename: 'teacher_asset.png',
+        project: lesson.project,
+        uploaded_user_id: teacher_id,
+        body: 'teacher-body'
+      )
+      create_scratch_asset(
+        filename: 'student_asset.png',
+        project: lesson.project,
+        uploaded_user_id: SecureRandom.uuid,
+        body: 'student-body'
+      )
+
+      response = described_class.call(lesson:, lesson_params:)
+      copied_project = response[:lesson].reload.project
+      copied_asset = ScratchAsset.find_by!(
+        filename: 'teacher_asset.png',
+        project: copied_project,
+        uploaded_user_id: copied_teacher_id
+      )
+
+      visible_asset = ScratchAsset.find_visible_to_project(
+        project: copied_project,
+        user: User.new(id: SecureRandom.uuid),
+        filename: 'teacher_asset.png'
+      )
+
+      expect(copied_asset.file.download).to eq('teacher-body')
+      expect(visible_asset).to eq(copied_asset)
+      expect(
+        ScratchAsset.find_by(filename: 'student_asset.png', project: copied_project)
+      ).to be_nil
+    end
+  end
+
   context 'when creating a copy fails' do
     let(:lesson_params) { { name: ' ' } }
 
@@ -135,4 +207,10 @@
       expect(Sentry).to have_received(:capture_exception).with(kind_of(StandardError))
     end
   end
+
+  def create_scratch_asset(filename:, project:, uploaded_user_id:, body:)
+    ScratchAsset.create!(filename:, project:, uploaded_user_id:).tap do |asset|
+      asset.file.attach(io: StringIO.new(body), filename:, content_type: 'image/png')
+    end
+  end
 end