1 files changed, 92 insertions, 0 deletions
diff --git a/app/services/packages/maven/metadata/create_plugins_xml_service.rb b/app/services/packages/maven/metadata/create_plugins_xml_service.rb
new file mode 100644
index 00000000000..707a8c577ba
--- /dev/null
+++ b/app/services/packages/maven/metadata/create_plugins_xml_service.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+module Packages
+  module Maven
+    module Metadata
+      class CreatePluginsXmlService < BaseCreateXmlService
+        XPATH_PLUGIN_ARTIFACT_ID = '//plugin/artifactId'
+        XPATH_PLUGINS = '//metadata/plugins'
+        EMPTY_PLUGINS_PAYLOAD = {
+          changes_exist: true,
+          empty_plugins: true
+        }.freeze
+
+        def execute
+          return ServiceResponse.error(message: 'package not set') unless @package
+          return ServiceResponse.error(message: 'metadata_content not set') unless @metadata_content
+          return ServiceResponse.error(message: 'metadata_content is invalid') unless plugins_xml_node.present?
+          return ServiceResponse.success(payload: EMPTY_PLUGINS_PAYLOAD) if plugin_artifact_ids_from_database.empty?
+
+          changes_exist = update_plugins_list
+
+          payload = { changes_exist: changes_exist, empty_versions: false }
+          payload[:metadata_content] = xml_doc.to_xml(indent: INDENT_SPACE) if changes_exist
+
+          ServiceResponse.success(payload: payload)
+        end
+
+        private
+
+        def update_plugins_list
+          return false if plugin_artifact_ids_from_xml == plugin_artifact_ids_from_database
+
+          plugins_xml_node.children.remove
+
+          plugin_artifact_ids_from_database.each do |artifact_id|
+            plugins_xml_node.add_child(plugin_node_for(artifact_id))
+          end
+
+          true
+        end
+
+        def plugins_xml_node
+          strong_memoize(:plugins_xml_node) do
+            xml_doc.xpath(XPATH_PLUGINS)
+                   .first
+          end
+        end
+
+        def plugin_artifact_ids_from_xml
+          strong_memoize(:plugin_artifact_ids_from_xml) do
+            plugins_xml_node.xpath(XPATH_PLUGIN_ARTIFACT_ID)
+                            .map(&:content)
+          end
+        end
+
+        def plugin_artifact_ids_from_database
+          strong_memoize(:plugin_artifact_ids_from_database) do
+            package_names = plugin_artifact_ids_from_xml.map do |artifact_id|
+              "#{@package.name}/#{artifact_id}"
+            end
+
+            packages = @package.project.packages
+                                       .maven
+                                       .displayable
+                                       .with_name(package_names)
+                                       .has_version
+
+            ::Packages::Maven::Metadatum.for_package_ids(packages.select(:id))
+                                        .order_created
+                                        .pluck_app_name
+                                        .uniq
+          end
+        end
+
+        def plugin_node_for(artifact_id)
+          xml_doc.create_element('plugin').tap do |plugin_node|
+            plugin_node.add_child(xml_node('name', artifact_id))
+            plugin_node.add_child(xml_node('prefix', prefix_from(artifact_id)))
+            plugin_node.add_child(xml_node('artifactId', artifact_id))
+          end
+        end
+
+        # Maven plugin prefix generation from
+        # https://github.com/apache/maven/blob/c3dba0e5ba71ee7cbd62620f669a8c206e71b5e2/maven-plugin-api/src/main/java/org/apache/maven/plugin/descriptor/PluginDescriptor.java#L189
+        def prefix_from(artifact_id)
+          artifact_id.gsub(/-?maven-?/, '')
+                     .gsub(/-?plugin-?/, '')
+        end
+      end
+    end
+  end
+end