Add batch endpoint for instant estimate

app/controllers/api/v1/events_controller.rb

@@ -100,6 +100,20 @@ def estimate_instant_fees
         end
       end
 
+      def batch_estimate_instant_fees
+        fees = []
+        batch_params[:events].each do |create_params|
+          fees += Fees::EstimateInstantPayInAdvanceService.call!(
+            organization: current_organization,
+            params: create_params
+          ).fees
+        end
+
+        render(
+          json: {fees: fees}
+        )
+      end
+
       def estimate_fees
         result = Fees::EstimatePayInAdvanceService.call(
           organization: current_organization,

config/routes.rb

@@ -52,6 +52,7 @@
       resources :events, only: %i[create show index] do
         post :estimate_fees, on: :collection
         post :estimate_instant_fees, on: :collection
+        post :batch_estimate_instant_fees, on: :collection
       end
       resources :applied_coupons, only: %i[create index]
       resources :fees, only: %i[show update index destroy]

spec/requests/api/v1/events_controller_spec.rb

@@ -385,6 +385,54 @@
     end
   end
 
+  describe 'POST /api/v1/events/batch_estimate_instant_fees' do
+    subject do
+      post_with_token(organization, '/api/v1/events/batch_estimate_instant_fees', events: batch_params)
+    end
+
+    let(:metric) { create(:sum_billable_metric, organization:) }
+    let(:charge) { create(:percentage_charge, :pay_in_advance, plan:, billable_metric: metric, properties: {rate: '0.1', fixed_amount: '0'}) }
+
+    let(:event_params) do
+      {
+        code: metric.code,
+        organization_id: organization.id,
+        external_subscription_id: subscription.external_id,
+        transaction_id: SecureRandom.uuid,
+        properties: {
+          metric.field_name => 400
+        }
+      }
+    end
+
+    let(:batch_params) { [event_params] }
+
+    before do
+      charge
+    end
+
+    include_examples 'requires API permission', 'event', 'write'
+
+    it 'returns a success' do
+      subject
+
+      expect(response).to have_http_status(:success)
+
+      expect(json[:fees].count).to eq(1)
+
+      fee = json[:fees].first
+      expect(fee[:lago_id]).to be_nil
+      expect(fee[:lago_group_id]).to be_nil
+      expect(fee[:item][:type]).to eq('charge')
+      expect(fee[:item][:code]).to eq(metric.code)
+      expect(fee[:item][:name]).to eq(metric.name)
+      expect(fee[:amount_cents]).to eq('40.0')
+      expect(fee[:amount_currency]).to eq('EUR')
+      expect(fee[:units]).to eq('400.0')
+      expect(fee[:events_count]).to eq(1)
+    end
+  end
+
   describe 'POST /api/v1/events/estimate_instant_fees' do
     subject do
       post_with_token(organization, '/api/v1/events/estimate_instant_fees', event: event_params)