Handle project images when remixing

app/concepts/project/operation/create_remix.rb

@@ -36,6 +36,10 @@ def create_remix(original_project, params, user_id)
             proj.remixed_from_id = original_project.id
           end
 
+          original_project.images.each do |image|
+            remix.images.attach(image.blob)
+          end
+
           params[:components].each do |x|
             remix.components.build(x.slice(:name, :extension, :content, :index))
           end

lib/tasks/projects.rake

@@ -21,9 +21,9 @@ namespace :projects do
       end
 
       project_images = proj_config['IMAGES'] || []
+      delete_removed_images(project, project_images)
       project_images.each do |image_name|
-        project.images.attach(io: File.open(File.dirname(__FILE__) + "/project_components/#{dir}/#{image_name}"),
-                              filename: image_name)
+        attach_image_if_needed(project, image_name, dir)
       end
 
       project.save
@@ -38,8 +38,41 @@ def find_project(proj_config)
     project = Project.find_by(identifier: proj_config['IDENTIFIER'])
     project.name = proj_config['NAME']
     project.components.each(&:destroy)
-    project.images.purge
   end
 
   project
 end
+
+def delete_removed_images(project, images_to_attach)
+  existing_images = project.images.map { |x| x.blob.filename.to_s }
+  diff = existing_images - images_to_attach
+  return if diff.empty?
+
+  diff.each do |filename|
+    img = project.images.find { |i| i.blob.filename == filename }
+    img.purge
+  end
+end
+
+def attach_image_if_needed(project, image_name, dir)
+  existing_image = project.images.find { |i| i.blob.filename == image_name }
+
+  if existing_image
+    return if existing_image.blob.checksum == image_checksum(image_name, dir)
+
+    existing_image.purge
+  end
+  project.images.attach(io: File.open(File.dirname(__FILE__) + "/project_components/#{dir}/#{image_name}"),
+                        filename: image_name)
+end
+
+def image_checksum(image_name, dir)
+  io = File.open(File.dirname(__FILE__) + "/project_components/#{dir}/#{image_name}")
+  OpenSSL::Digest.new('MD5').tap do |checksum|
+    while (chunk = io.read(5.megabytes))
+      checksum << chunk
+    end
+
+    io.rewind
+  end.base64digest
+end

spec/concepts/project/operation/create_remix_spec.rb

@@ -6,7 +6,7 @@
   subject(:create_remix) { described_class.call(params: remix_params, user_id: user_id, original_project: original_project) }
 
   let(:user_id) { 'e0675b6c-dc48-4cd6-8c04-0f7ac05af51a' }
-  let!(:original_project) { create(:project, :with_components) }
+  let!(:original_project) { create(:project, :with_components, :with_attached_image) }
   let(:remix_params) do
     component = original_project.components.first
     {
@@ -59,6 +59,19 @@
       expect(remixed_attrs).to eq(original_attrs)
     end
 
+    it 'links remix to attached images' do
+      remixed_project = create_remix[:project]
+      expect(remixed_project.images.length).to eq(original_project.images.length)
+    end
+
+    it 'creates a new attachment' do
+      expect { create_remix }.to change(ActiveStorage::Attachment, :count).by(1)
+    end
+
+    it 'does not create a new image' do
+      expect { create_remix }.not_to change(ActiveStorage::Blob, :count)
+    end
+
     it 'creates new components' do
       expect { create_remix }.to change(Component, :count).by(1)
     end

spec/factories/project.rb

@@ -25,9 +25,11 @@
       end
     end
 
-    trait :with_attached_images do
-      after(:create) do |object|
-        object.images.attach(fixture_file_upload(Rails.root.join('spec/fixtures/test_image_1.png'), 'image/png'))
+    trait :with_attached_image do
+      after(:build) do |object|
+        object.images.attach(io: File.open(Rails.root.join('spec/fixtures/files/test_image_1.png')),
+                             filename: 'test_image',
+                             content_type: 'image/png')
       end
     end
   end

spec/models/project_spec.rb

@@ -8,6 +8,10 @@
     it { is_expected.to have_many(:children) }
     it { is_expected.to belong_to(:parent).optional(true) }
     it { is_expected.to have_many_attached(:images) }
+
+    it 'purges attached images' do
+      expect(described_class.reflect_on_attachment(:images).options[:dependent]).to eq(:purge_later)
+    end
   end
 
   describe 'identifier not nil' do