Removed the Invoice entity from the Payment Service models.

Added invoiceId as a UUID to reference invoices managed by the Invoice Service.
Maintained the paymentGateway field to identify the external payment gateway used.

payment-service/src/main/java/com/finpay/payment_service/models/Payment.java

@@ -2,6 +2,9 @@
 
 import jakarta.persistence.*;
 import lombok.*;
+import org.hibernate.annotations.CreationTimestamp;
+import org.hibernate.annotations.UpdateTimestamp;
+
 import java.math.BigDecimal;
 import java.time.LocalDateTime;
 import java.util.Set;
@@ -20,7 +23,7 @@ public class Payment {
     private UUID id;
 
     @Column(nullable = false, unique = true)
-    private String paymentReference;
+    private String paymentReference; // Unique reference for the payment
 
     @Column(nullable = false)
     private BigDecimal amount;
@@ -32,22 +35,22 @@ public class Payment {
     @Column(nullable = false)
     private PaymentStatus status;
 
-    @ManyToOne(fetch = FetchType.LAZY)
-    @JoinColumn(name = "payment_method_id")
-    private PaymentMethod paymentMethod;
+    @Column(nullable = false)
+    private UUID invoiceId; // Reference to Invoice managed by Invoice Service
 
-    @ManyToOne(fetch = FetchType.LAZY)
-    @JoinColumn(name = "payment_gateway_id")
-    private PaymentGateway paymentGateway;
+    @Column(nullable = false)
+    private String paymentGateway; // e.g., Stripe, PayPal
 
     @OneToMany(mappedBy = "payment", cascade = CascadeType.ALL, orphanRemoval = true)
     private Set<Transaction> transactions;
 
     @OneToMany(mappedBy = "payment", cascade = CascadeType.ALL, orphanRemoval = true)
     private Set<Refund> refunds;
 
-    @Column(nullable = false)
+    @CreationTimestamp
+    @Column(nullable = false, updatable = false)
     private LocalDateTime createdAt;
 
+    @UpdateTimestamp
     private LocalDateTime updatedAt;
 }