feat(s3): Stripe PSP adapter + WireMock stubs (STA-124)

fiat-on-ramp/fiat-on-ramp/src/main/java/com/stablecoin/payments/onramp/config/FallbackAdaptersConfig.java

@@ -1,20 +1,44 @@
 package com.stablecoin.payments.onramp.config;
 
+import com.stablecoin.payments.onramp.domain.port.PspGateway;
+import com.stablecoin.payments.onramp.domain.port.PspPaymentResult;
+import com.stablecoin.payments.onramp.domain.port.PspRefundResult;
 import lombok.extern.slf4j.Slf4j;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
+import java.util.UUID;
+
 /**
  * Provides fallback (dev/test) implementations of outbound ports
  * via {@code @ConditionalOnMissingBean}. Real adapters are registered
  * by provider-specific configurations under
  * {@code infrastructure/provider/<name>/}.
- *
- * <p>Adapters will be added here as domain ports are defined.
  */
 @Slf4j
 @Configuration
 public class FallbackAdaptersConfig {
 
-    // Fallback beans will be added as domain ports are implemented.
-    // Pattern: @Bean @ConditionalOnMissingBean public <Port> fallback<Port>() { ... }
+    @Bean
+    @ConditionalOnMissingBean
+    public PspGateway fallbackPspGateway() {
+        return new PspGateway() {
+            @Override
+            public PspPaymentResult initiatePayment(
+                    com.stablecoin.payments.onramp.domain.port.PspPaymentRequest request) {
+                log.warn("[FALLBACK-PSP] Using dev PSP gateway for payment collectionId={}",
+                        request.collectionId());
+                return new PspPaymentResult("dev-pi-" + UUID.randomUUID(), "succeeded");
+            }
+
+            @Override
+            public PspRefundResult initiateRefund(
+                    com.stablecoin.payments.onramp.domain.port.PspRefundRequest request) {
+                log.warn("[FALLBACK-PSP] Using dev PSP gateway for refund collectionId={}",
+                        request.collectionId());
+                return new PspRefundResult("dev-re-" + UUID.randomUUID(), "succeeded");
+            }
+        };
+    }
 }

fiat-on-ramp/fiat-on-ramp/src/main/java/com/stablecoin/payments/onramp/infrastructure/provider/stripe/StripePaymentIntentResponse.java

@@ -0,0 +1,10 @@
+package com.stablecoin.payments.onramp.infrastructure.provider.stripe;
+
+record StripePaymentIntentResponse(
+        String id,
+        String status,
+        Long amount,
+        String currency,
+        String clientSecret
+) {
+}

fiat-on-ramp/fiat-on-ramp/src/main/java/com/stablecoin/payments/onramp/infrastructure/provider/stripe/StripeProperties.java

@@ -0,0 +1,19 @@
+package com.stablecoin.payments.onramp.infrastructure.provider.stripe;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+@ConfigurationProperties(prefix = "app.psp.stripe")
+public record StripeProperties(String baseUrl, String apiKey, int timeoutSeconds) {
+
+    public StripeProperties {
+        if (baseUrl == null || baseUrl.isBlank()) {
+            baseUrl = "https://api.stripe.com";
+        }
+        if (apiKey == null || apiKey.isBlank()) {
+            apiKey = "sk_test_default";
+        }
+        if (timeoutSeconds <= 0) {
+            timeoutSeconds = 10;
+        }
+    }
+}

fiat-on-ramp/fiat-on-ramp/src/main/java/com/stablecoin/payments/onramp/infrastructure/provider/stripe/StripePspAdapter.java

@@ -0,0 +1,120 @@
+package com.stablecoin.payments.onramp.infrastructure.provider.stripe;
+
+import com.stablecoin.payments.onramp.domain.port.PspGateway;
+import com.stablecoin.payments.onramp.domain.port.PspPaymentRequest;
+import com.stablecoin.payments.onramp.domain.port.PspPaymentResult;
+import com.stablecoin.payments.onramp.domain.port.PspRefundRequest;
+import com.stablecoin.payments.onramp.domain.port.PspRefundResult;
+import io.github.resilience4j.circuitbreaker.annotation.CircuitBreaker;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+import org.springframework.http.client.JdkClientHttpRequestFactory;
+import org.springframework.stereotype.Component;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.client.RestClient;
+
+import java.net.http.HttpClient;
+import java.net.http.HttpClient.Version;
+import java.time.Duration;
+
+@Slf4j
+@Component
+@ConditionalOnProperty(name = "app.psp.provider", havingValue = "stripe")
+@EnableConfigurationProperties(StripeProperties.class)
+public class StripePspAdapter implements PspGateway {
+
+    private final RestClient restClient;
+
+    public StripePspAdapter(StripeProperties properties) {
+        var httpClient = HttpClient.newBuilder()
+                .version(Version.HTTP_1_1)
+                .connectTimeout(Duration.ofSeconds(properties.timeoutSeconds()))
+                .build();
+
+        var requestFactory = new JdkClientHttpRequestFactory(httpClient);
+        requestFactory.setReadTimeout(Duration.ofSeconds(properties.timeoutSeconds()));
+
+        this.restClient = RestClient.builder()
+                .baseUrl(properties.baseUrl())
+                .defaultHeader(HttpHeaders.AUTHORIZATION, "Bearer " + properties.apiKey())
+                .requestFactory(requestFactory)
+                .build();
+    }
+
+    @Override
+    @CircuitBreaker(name = "stripe", fallbackMethod = "initiatePaymentFallback")
+    public PspPaymentResult initiatePayment(PspPaymentRequest request) {
+        log.info("[STRIPE] Initiating payment collectionId={} amount={} currency={}",
+                request.collectionId(), request.amount().amount(), request.amount().currency());
+
+        MultiValueMap<String, String> formData = new LinkedMultiValueMap<>();
+        formData.add("amount", toMinorUnits(request));
+        formData.add("currency", request.amount().currency().toLowerCase());
+        formData.add("payment_method_types[]", "us_bank_account");
+        formData.add("confirm", "true");
+        formData.add("metadata[collection_id]", request.collectionId().toString());
+
+        var response = restClient.post()
+                .uri("/v1/payment_intents")
+                .contentType(MediaType.APPLICATION_FORM_URLENCODED)
+                .body(formData)
+                .retrieve()
+                .body(StripePaymentIntentResponse.class);
+
+        log.info("[STRIPE] Payment initiated collectionId={} pspRef={} status={}",
+                request.collectionId(), response.id(), response.status());
+
+        return new PspPaymentResult(response.id(), response.status());
+    }
+
+    @Override
+    @CircuitBreaker(name = "stripe", fallbackMethod = "initiateRefundFallback")
+    public PspRefundResult initiateRefund(PspRefundRequest request) {
+        log.info("[STRIPE] Initiating refund collectionId={} pspRef={} amount={}",
+                request.collectionId(), request.pspReference(), request.refundAmount().amount());
+
+        MultiValueMap<String, String> formData = new LinkedMultiValueMap<>();
+        formData.add("payment_intent", request.pspReference());
+        formData.add("amount", toMinorUnitsFromRefund(request));
+        formData.add("reason", "requested_by_customer");
+        formData.add("metadata[collection_id]", request.collectionId().toString());
+
+        var response = restClient.post()
+                .uri("/v1/refunds")
+                .contentType(MediaType.APPLICATION_FORM_URLENCODED)
+                .body(formData)
+                .retrieve()
+                .body(StripeRefundResponse.class);
+
+        log.info("[STRIPE] Refund initiated collectionId={} refundRef={} status={}",
+                request.collectionId(), response.id(), response.status());
+
+        return new PspRefundResult(response.id(), response.status());
+    }
+
+    @SuppressWarnings("unused")
+    private PspPaymentResult initiatePaymentFallback(PspPaymentRequest request, Exception ex) {
+        log.error("[STRIPE] Circuit breaker open — payment initiation failed collectionId={}",
+                request.collectionId(), ex);
+        throw new IllegalStateException("Stripe payment initiation unavailable", ex);
+    }
+
+    @SuppressWarnings("unused")
+    private PspRefundResult initiateRefundFallback(PspRefundRequest request, Exception ex) {
+        log.error("[STRIPE] Circuit breaker open — refund initiation failed collectionId={}",
+                request.collectionId(), ex);
+        throw new IllegalStateException("Stripe refund initiation unavailable", ex);
+    }
+
+    private String toMinorUnits(PspPaymentRequest request) {
+        return String.valueOf(request.amount().amount().movePointRight(2).longValueExact());
+    }
+
+    private String toMinorUnitsFromRefund(PspRefundRequest request) {
+        return String.valueOf(request.refundAmount().amount().movePointRight(2).longValueExact());
+    }
+}

fiat-on-ramp/fiat-on-ramp/src/main/java/com/stablecoin/payments/onramp/infrastructure/provider/stripe/StripeRefundResponse.java

@@ -0,0 +1,10 @@
+package com.stablecoin.payments.onramp.infrastructure.provider.stripe;
+
+record StripeRefundResponse(
+        String id,
+        String status,
+        Long amount,
+        String currency,
+        String paymentIntent
+) {
+}

fiat-on-ramp/fiat-on-ramp/src/main/resources/application.yml

@@ -115,6 +115,12 @@ springdoc:
 app:
   security:
     enabled: false
+  psp:
+    provider: stripe
+    stripe:
+      base-url: https://api.stripe.com
+      api-key: ${STRIPE_API_KEY:sk_test_default}
+      timeout-seconds: 10
 
 logging:
   level: