1 files changed, 58 insertions, 0 deletions
diff --git a/lib/gitlab/github_import/importer/milestones_importer.rb b/lib/gitlab/github_import/importer/milestones_importer.rb
new file mode 100644
index 00000000000..c53480e828a
--- /dev/null
+++ b/lib/gitlab/github_import/importer/milestones_importer.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module GithubImport
+    module Importer
+      class MilestonesImporter
+        include BulkImporting
+
+        attr_reader :project, :client, :existing_milestones
+
+        # project - An instance of `Project`
+        # client - An instance of `Gitlab::GithubImport::Client`
+        def initialize(project, client)
+          @project = project
+          @client = client
+          @existing_milestones = project.milestones.pluck(:iid).to_set
+        end
+
+        def execute
+          bulk_insert(Milestone, build_milestones)
+          build_milestones_cache
+        end
+
+        def build_milestones
+          build_database_rows(each_milestone)
+        end
+
+        def already_imported?(milestone)
+          existing_milestones.include?(milestone.number)
+        end
+
+        def build_milestones_cache
+          MilestoneFinder.new(project).build_cache
+        end
+
+        def build(milestone)
+          {
+            iid: milestone.number,
+            title: milestone.title,
+            description: milestone.description,
+            project_id: project.id,
+            state: state_for(milestone),
+            created_at: milestone.created_at,
+            updated_at: milestone.updated_at
+          }
+        end
+
+        def state_for(milestone)
+          milestone.state == 'open' ? :active : :closed
+        end
+
+        def each_milestone
+          client.milestones(project.import_source, state: 'all')
+        end
+      end
+    end
+  end
+end