Address review comments

crates/api_models/src/payments.rs

@@ -5974,6 +5974,8 @@ pub struct PaymentsConfirmIntentRequest {
 #[derive(Debug, serde::Deserialize, serde::Serialize, ToSchema)]
 #[serde(deny_unknown_fields)]
 pub struct PaymentMethodBalanceCheckRequest {
+    /// The payment method data to be used for the balance check request. It can
+    /// only be a payment method that supports checking balance e.g. gift card
     pub payment_method_data: BalanceCheckPaymentMethodData,
 }
 

crates/hyperswitch_connectors/src/connectors/adyen.rs

@@ -1250,12 +1250,13 @@ impl
         event_builder.map(|i| i.set_response_body(&response));
         router_env::logger::info!(connector_response=?response);
 
-        let currency = match data.request.currency {
-            Some(currency) => currency,
-            None => Err(errors::ConnectorError::MissingRequiredField {
+        let currency = data
+            .request
+            .currency
+            .get_required_value("currency")
+            .change_context(errors::ConnectorError::MissingRequiredField {
                 field_name: "currency",
-            })?,
-        };
+            })?;
 
         if response.balance.currency != currency {
             Ok(RouterData {

crates/hyperswitch_domain_models/src/payment_method_data.rs

@@ -711,13 +711,21 @@ impl GiftCardData {
     /// Payment Method Balance Check Flow for storing the balance
     /// data in Redis.
     ///
-    /// For PaySafeCard, it returns a static identifier "paysafecard"
-    /// as currently we don't have any unique identifier for it.
-    pub fn get_payment_method_key(&self) -> Secret<String> {
+    pub fn get_payment_method_key(
+        &self,
+    ) -> Result<Secret<String>, error_stack::Report<common_utils::errors::ValidationError>> {
         match self {
-            Self::Givex(givex) => givex.number.clone(),
-            Self::PaySafeCard {} => Secret::new("paysafecard".to_string()),
-            Self::BhnCardNetwork(bhn) => bhn.account_number.clone(),
+            Self::Givex(givex) => Ok(givex.number.clone()),
+            Self::PaySafeCard {} =>
+            // Generate a validation error here as we don't support balance check flow for it
+            {
+                Err(error_stack::Report::new(
+                    common_utils::errors::ValidationError::InvalidValue {
+                        message: "PaySafeCard doesn't support balance check flow".to_string(),
+                    },
+                ))
+            }
+            Self::BhnCardNetwork(bhn) => Ok(bhn.account_number.clone()),
         }
     }
 }

crates/hyperswitch_domain_models/src/payment_methods.rs

@@ -1204,14 +1204,14 @@ impl PaymentMethodBalanceKey {
 /// payment method to be stored in the HashMap in Redis
 #[cfg(feature = "v2")]
 #[derive(Clone, Debug, serde::Serialize)]
-pub struct PaymentMethodBalanceValue {
+pub struct PaymentMethodBalance {
     pub balance: common_utils::types::MinorUnit,
     pub currency: common_enums::Currency,
 }
 
 #[cfg(feature = "v2")]
 pub struct PaymentMethodBalanceData<'a> {
-    pub pm_balance_data: HashMap<PaymentMethodBalanceKey, PaymentMethodBalanceValue>,
+    pub pm_balance_data: HashMap<PaymentMethodBalanceKey, PaymentMethodBalance>,
     pub payment_intent_id: &'a id_type::GlobalPaymentId,
 }
 
@@ -1232,9 +1232,7 @@ impl<'a> PaymentMethodBalanceData<'a> {
         self.pm_balance_data.is_empty()
     }
 
-    pub fn get_individual_pm_balance_key_value_pairs(
-        &self,
-    ) -> Vec<(String, PaymentMethodBalanceValue)> {
+    pub fn get_individual_pm_balance_key_value_pairs(&self) -> Vec<(String, PaymentMethodBalance)> {
         self.pm_balance_data
             .iter()
             .map(|(pm_balance_key, pm_balance_value)| {

crates/router/src/core/gift_card.rs

@@ -163,17 +163,22 @@ pub async fn payments_check_gift_card_balance_core(
     let balance = gift_card_balance.balance;
     let currency = gift_card_balance.currency;
 
+    let payment_method_key = domain::GiftCardData::from(gift_card_data.clone())
+        .get_payment_method_key()
+        .change_context(errors::ApiErrorResponse::InvalidRequestData {
+            message: "Unable to get unique key for payment method".to_string(),
+        })?
+        .expose();
+
     let balance_data = domain::PaymentMethodBalanceData {
         payment_intent_id: &payment_intent.id,
         pm_balance_data: vec![(
             domain::PaymentMethodBalanceKey {
                 payment_method_type: common_enums::PaymentMethod::GiftCard,
                 payment_method_subtype: gift_card_data.get_payment_method_type(),
-                payment_method_key: domain::GiftCardData::from(gift_card_data)
-                    .get_payment_method_key()
-                    .expose(),
+                payment_method_key,
             },
-            domain::PaymentMethodBalanceValue { balance, currency },
+            domain::PaymentMethodBalance { balance, currency },
         )]
         .into_iter()
         .collect(),