fix(invoice): Quarterly boundaries with anniversary on the 31st

app/services/subscriptions/dates/monthly_service.rb

@@ -69,11 +69,9 @@ def compute_to_date(from_date = compute_from_date)
 
         # NOTE: if subscription anniversary day is higher than the current last day of the month,
         #       subscription period, will end on the previous end of day
-        if last_day_of_month?(date) && subscription_at.day > date.day
-          date - 1.day
-        else
-          date
-        end
+        return date - 1.day if last_day_of_month?(date) && subscription_at.day > date.day
+
+        date
       end
 
       def compute_next_end_of_period

app/services/subscriptions/dates/quarterly_service.rb

@@ -39,6 +39,16 @@ def compute_duration(from_date:)
       alias compute_charges_duration compute_duration
 
       def compute_base_date
+        # NOTE: if subscription anniversary is on last day of month and current month days count
+        #       is less than month anniversary day count, we need to use the last day of the previous month
+        if subscription.anniversary? && last_day_of_month?(billing_date) && (billing_date.day < subscription_at.day)
+          if (billing_date - 3.months).end_of_month.day >= subscription_at.day
+            return (billing_date - 3.months).end_of_month.change(day: subscription_at.day)
+          end
+
+          return (billing_date - 3.months).end_of_month
+        end
+
         billing_date - 3.months
       end
 
@@ -56,7 +66,13 @@ def compute_to_date(from_date = compute_from_date)
           year += 1
         end
 
-        build_date(year, month, day)
+        date = build_date(year, month, day)
+
+        # NOTE: if subscription anniversary day is higher than the current last day of the month,
+        #       subscription period, will end on the previous end of day
+        return date - 1.day if last_day_of_month?(date) && subscription_at.day > date.day
+
+        date
       end
 
       def compute_next_end_of_period

spec/scenarios/subscriptions/billing_spec.rb

@@ -498,6 +498,51 @@
         it_behaves_like 'a subscription billing without duplicated invoices'
       end
 
+      context 'with anniversary on a 31st' do
+        let(:billing_times) do
+          [
+            DateTime.new(2023, 3, 31, 1),
+            DateTime.new(2023, 6, 30, 1),
+            DateTime.new(2023, 9, 30, 2),
+            DateTime.new(2023, 12, 31, 2),
+          ]
+        end
+
+        let(:subscription_time) { DateTime.new(2022, 12, 31) }
+
+        it_behaves_like 'a subscription billing on every billing day'
+      end
+
+      context 'with anniversary on a 30' do
+        let(:billing_times) do
+          [
+            DateTime.new(2023, 1, 30, 1),
+            DateTime.new(2023, 4, 30, 1),
+            DateTime.new(2023, 7, 30, 2),
+            DateTime.new(2023, 10, 30, 2),
+          ]
+        end
+
+        let(:subscription_time) { DateTime.new(2022, 4, 30) }
+
+        it_behaves_like 'a subscription billing on every billing day'
+      end
+
+      context 'with anniversary on a 28 of february' do
+        let(:billing_times) do
+          [
+            DateTime.new(2023, 2, 28, 1),
+            DateTime.new(2023, 5, 28, 1),
+            DateTime.new(2023, 8, 28, 2),
+            DateTime.new(2023, 11, 28, 2),
+          ]
+        end
+
+        let(:subscription_time) { DateTime.new(2022, 2, 28) }
+
+        it_behaves_like 'a subscription billing on every billing day'
+      end
+
       context 'with UTC+ timezone' do
         let(:timezone) { 'Asia/Kolkata' }
         let(:subscription_time) { DateTime.new(2023, 2, 2) }

spec/services/subscriptions/dates/quarterly_service_spec.rb

@@ -254,7 +254,16 @@
         let(:billing_at) { DateTime.parse('01 Mar 2022') }
 
         it 'returns the last day of the previous month' do
-          expect(result).to eq('2022-02-28 23:59:59 UTC')
+          expect(result).to eq('2022-02-27 23:59:59 UTC')
+        end
+
+        context 'when subscription is not the last day of the month' do
+          let(:subscription_at) { DateTime.parse('30 Jan 2022') }
+          let(:billing_at) { DateTime.parse('30 Apr 2022') }
+
+          it 'returns the last day of the month' do
+            expect(result).to eq('2022-04-29 23:59:59 UTC')
+          end
         end
       end