feat(events): Add payment reject audit events (#6465)

Co-authored-by: Anish Kacham <f2010091@hyderabad.bits-pilani.ac.in>

crates/router/src/core/payments/operations/payment_reject.rs

@@ -12,6 +12,7 @@ use crate::{
         errors::{self, RouterResult, StorageErrorExt},
         payments::{helpers, operations, PaymentAddress, PaymentData},
     },
+    events::audit_events::{AuditEvent, AuditEventType},
     routes::{app::ReqState, SessionState},
     services,
     types::{
@@ -209,7 +210,7 @@ impl<F: Clone> UpdateTracker<F, PaymentData<F>, PaymentsCancelRequest> for Payme
     async fn update_trackers<'b>(
         &'b self,
         state: &'b SessionState,
-        _req_state: ReqState,
+        req_state: ReqState,
         mut payment_data: PaymentData<F>,
         _customer: Option<domain::Customer>,
         storage_scheme: enums::MerchantStorageScheme,
@@ -264,6 +265,16 @@ impl<F: Clone> UpdateTracker<F, PaymentData<F>, PaymentsCancelRequest> for Payme
             )
             .await
             .to_not_found_response(errors::ApiErrorResponse::PaymentNotFound)?;
+        let error_code = payment_data.payment_attempt.error_code.clone();
+        let error_message = payment_data.payment_attempt.error_message.clone();
+        req_state
+            .event_context
+            .event(AuditEvent::new(AuditEventType::PaymentReject {
+                error_code,
+                error_message,
+            }))
+            .with(payment_data.to_event())
+            .emit();
 
         Ok((Box::new(self), payment_data))
     }

crates/router/src/events/audit_events.rs

@@ -33,6 +33,10 @@ pub enum AuditEventType {
     },
     PaymentApprove,
     PaymentCreate,
+    PaymentReject {
+        error_code: Option<String>,
+        error_message: Option<String>,
+    },
 }
 
 #[derive(Debug, Clone, Serialize)]
@@ -74,6 +78,7 @@ impl Event for AuditEvent {
             AuditEventType::PaymentUpdate { .. } => "payment_update",
             AuditEventType::PaymentApprove { .. } => "payment_approve",
             AuditEventType::PaymentCreate { .. } => "payment_create",
+            AuditEventType::PaymentReject { .. } => "payment_rejected",
         };
         format!(
             "{event_type}-{}",