Add a method named 'inactive?' to determine if a project is inactive

Inactive projects are defined as follows:

Self-managed projects with any license (Free, Premium, or Ultimate) or
GitLab SaaS projects that have a Free license where the project meets
both of the following criteria:

1. The project repository size exceeds the size threshold defined in
the instance settings.
2. The project has not had any comments, commits, MRs, new issues, or
other activity for the length of time defined in the instance settings.

app/models/project.rb

@@ -2868,6 +2868,11 @@ class Project < ApplicationRecord
     Projects::RecordTargetPlatformsWorker.perform_async(id)
   end
 
+  def inactive?
+    statistics.storage_size > ::Gitlab::CurrentSettings.inactive_projects_min_size_mb.megabytes &&
+      last_activity_at < ::Gitlab::CurrentSettings.inactive_projects_send_warning_email_after_months.months.ago
+  end
+
   private
 
   # overridden in EE

ee/app/models/ee/project.rb

@@ -867,6 +867,11 @@ module EE
       ].compact
     end
 
+    override :inactive?
+    def inactive?
+      ::Gitlab.com? && root_namespace.paid? ? false : super
+    end
+
     private
 
     def ci_minutes_usage

ee/spec/models/project_spec.rb

@@ -3338,4 +3338,35 @@ RSpec.describe Project do
       end
     end
   end
+
+  describe '#inactive?' do
+    context 'when Gitlab.com', :saas do
+      context 'when project belongs to paid namespace' do
+        before do
+          stub_application_setting(inactive_projects_min_size_mb: 5)
+          stub_application_setting(inactive_projects_send_warning_email_after_months: 24)
+        end
+
+        it 'returns false' do
+          ultimate_group = create(:group_with_plan, plan: :ultimate_plan)
+          ultimate_project = create(:project, last_activity_at: 3.years.ago, namespace: ultimate_group)
+
+          expect(ultimate_project.inactive?).to eq(false)
+        end
+      end
+
+      context 'when project belongs to free namespace' do
+        let_it_be(:no_plan_group) { create(:group_with_plan, plan: nil) }
+        let_it_be(:project) { create(:project, namespace: no_plan_group) }
+
+        it_behaves_like 'returns true if project is inactive'
+      end
+    end
+
+    context 'when not Gitlab.com' do
+      let_it_be(:project) { create(:project, name: 'test-project') }
+
+      it_behaves_like 'returns true if project is inactive'
+    end
+  end
 end

spec/models/project_spec.rb

@@ -8178,6 +8178,12 @@ RSpec.describe Project, factory_default: :keep do
     end
   end
 
+  describe '#inactive?' do
+    let_it_be(:project) { create(:project, name: 'test-project') }
+
+    it_behaves_like 'returns true if project is inactive'
+  end
+
   private
 
   def finish_job(export_job)

spec/support/shared_examples/models/project_shared_examples.rb

+# frozen_string_literal: true
+
+RSpec.shared_examples 'returns true if project is inactive' do
+  using RSpec::Parameterized::TableSyntax
+
+  where(:storage_size, :last_activity_at, :expected_result) do
+    104857  | 1.month.ago | false
+    104857  | 3.years.ago | false
+    8388600 | 1.month.ago | false
+    8388600 | 3.years.ago | true
+  end
+
+  with_them do
+    before do
+      stub_application_setting(inactive_projects_min_size_mb: 5)
+      stub_application_setting(inactive_projects_send_warning_email_after_months: 24)
+
+      project.statistics.storage_size = storage_size
+      project.last_activity_at = last_activity_at
+      project.save!
+    end
+
+    it 'returns expected result' do
+      expect(project.inactive?).to eq(expected_result)
+    end
+  end
+end