use capture! if payment is already authorized

app/models/spree/payment/processing.rb

@@ -6,14 +6,22 @@ module Spree
       def process!
         return unless validate!
 
-        purchase!
+        if response_code
+          capture!
+        else
+          purchase!
+        end
       end
 
       def process_offline!
         return unless validate!
         return if authorization_action_required?
 
-        charge_offline!
+        if response_code
+          capture!
+        else
+          charge_offline!
+        end
       end
 
       def authorize!(return_url = nil)

spec/factories/payment_factory.rb

@@ -14,7 +14,7 @@ FactoryBot.define do
     association(:source, factory: :credit_card)
     order
     state { 'checkout' }
-    response_code { '12345' }
+    response_code { nil }
 
     payment_method { FactoryBot.create(:payment_method, distributors: [distributor]) }
   end

spec/models/spree/payment_spec.rb

@@ -97,6 +97,30 @@ describe Spree::Payment do
           expect { payment.process! }.to raise_error(Spree::Core::GatewayError)
           expect(payment.state).to eq('invalid')
         end
+
+        context "the payment is already authorized" do
+          before do
+            allow(payment).to receive(:response_code) { "pi_123" }
+          end
+
+          it "should call capture instead of purchase" do
+            expect(payment).to receive(:capture!)
+            expect(payment).to_not receive(:purchase!)
+            payment.process!
+          end
+        end
+      end
+
+      context "#process_offline when payment is already authorized" do
+        before do
+          allow(payment).to receive(:response_code) { "pi_123" }
+        end
+
+        it "should call capture if the payment is already authorized" do
+          expect(payment).to receive(:capture!)
+          expect(payment).to_not receive(:purchase!)
+          payment.process!
+        end
       end
 
       context "#authorize" do