feat(payments_v2): add logic to render required_fields in response of payment_method list (#8317)

Co-authored-by: hyperswitch-bot[bot] <148525504+hyperswitch-bot[bot]@users.noreply.github.com>

Author: Sakilmostak

api-reference/v2/openapi_spec_v2.json

@@ -22358,7 +22358,8 @@
             "type": "object",
             "required": [
               "payment_method_type",
-              "payment_method_subtype"
+              "payment_method_subtype",
+              "required_fields"
             ],
             "properties": {
               "payment_method_type": {
@@ -22376,12 +22377,7 @@
                 "nullable": true
               },
               "required_fields": {
-                "allOf": [
-                  {
-                    "$ref": "#/components/schemas/RequiredFieldInfo"
-                  }
-                ],
-                "nullable": true
+                "$ref": "#/components/schemas/RequiredFieldInfo"
               },
               "surcharge_details": {
                 "allOf": [

crates/api_models/src/payments.rs

@@ -7765,8 +7765,8 @@ pub struct ResponsePaymentMethodTypesForPayments {
 
     /// Required fields for the payment_method_type.
     /// This is the union of all the required fields for the payment method type enabled in all the connectors.
-    #[schema(value_type = Option<RequiredFieldInfo>)]
-    pub required_fields: Option<Vec<payment_methods::RequiredFieldInfo>>,
+    #[schema(value_type = RequiredFieldInfo)]
+    pub required_fields: Vec<payment_methods::RequiredFieldInfo>,
 
     /// surcharge details for this payment method type if exists
     #[schema(value_type = Option<SurchargeDetailsResponse>)]

crates/router/src/core/payments/payment_methods.rs

@@ -82,7 +82,7 @@ pub async fn list_payment_methods(
                 &payment_intent,
             ).await?
             .merge_and_transform()
-            .get_required_fields(RequiredFieldsInput::new())
+            .get_required_fields(RequiredFieldsInput::new(state.conf.required_fields.clone()))
             .perform_surcharge_calculation()
             .populate_pm_subtype_specific_data(&state.conf.bank_config)
             .generate_response(customer_payment_methods);
@@ -93,11 +93,41 @@ pub async fn list_payment_methods(
 }
 
 /// Container for the inputs required for the required fields
-struct RequiredFieldsInput {}
+struct RequiredFieldsInput {
+    required_fields_config: settings::RequiredFields,
+}
 
 impl RequiredFieldsInput {
-    fn new() -> Self {
-        Self {}
+    fn new(required_fields_config: settings::RequiredFields) -> Self {
+        Self {
+            required_fields_config,
+        }
+    }
+}
+
+trait GetRequiredFields {
+    fn get_required_fields(
+        &self,
+        payment_method_enabled: &hyperswitch_domain_models::merchant_connector_account::PaymentMethodsEnabledForConnector,
+    ) -> Option<&settings::RequiredFieldFinal>;
+}
+
+impl GetRequiredFields for settings::RequiredFields {
+    fn get_required_fields(
+        &self,
+        payment_method_enabled: &hyperswitch_domain_models::merchant_connector_account::PaymentMethodsEnabledForConnector,
+    ) -> Option<&settings::RequiredFieldFinal> {
+        self.0
+            .get(&payment_method_enabled.payment_method)
+            .and_then(|required_fields_for_payment_method| {
+                required_fields_for_payment_method.0.get(
+                    &payment_method_enabled
+                        .payment_methods_enabled
+                        .payment_method_subtype,
+                )
+            })
+            .map(|connector_fields| &connector_fields.fields)
+            .and_then(|connector_hashmap| connector_hashmap.get(&payment_method_enabled.connector))
     }
 }
 
@@ -170,20 +200,47 @@ struct MergedEnabledPaymentMethodTypes(Vec<MergedEnabledPaymentMethod>);
 impl MergedEnabledPaymentMethodTypes {
     fn get_required_fields(
         self,
-        _input: RequiredFieldsInput,
+        input: RequiredFieldsInput,
     ) -> RequiredFieldsForEnabledPaymentMethodTypes {
+        let required_fields_config = input.required_fields_config;
+
         let required_fields_info = self
             .0
             .into_iter()
-            .map(
-                |payment_methods_enabled| RequiredFieldsForEnabledPaymentMethod {
-                    required_field: None,
+            .map(|payment_methods_enabled| {
+                let required_fields =
+                    required_fields_config.get_required_fields(&payment_methods_enabled);
+
+                let required_fields = required_fields
+                    .map(|required_fields| {
+                        let common_required_fields = required_fields
+                            .common
+                            .iter()
+                            .flatten()
+                            .map(ToOwned::to_owned);
+
+                        // Collect mandate required fields because this is for zero auth mandates only
+                        let mandate_required_fields = required_fields
+                            .mandate
+                            .iter()
+                            .flatten()
+                            .map(ToOwned::to_owned);
+
+                        // Combine both common and mandate required fields
+                        common_required_fields
+                            .chain(mandate_required_fields)
+                            .collect::<Vec<_>>()
+                    })
+                    .unwrap_or_default();
+
+                RequiredFieldsForEnabledPaymentMethod {
+                    required_fields,
                     payment_method_type: payment_methods_enabled.payment_method_type,
                     payment_method_subtype: payment_methods_enabled.payment_method_subtype,
                     payment_experience: payment_methods_enabled.payment_experience,
                     connectors: payment_methods_enabled.connectors,
-                },
-            )
+                }
+            })
             .collect();
 
         RequiredFieldsForEnabledPaymentMethodTypes(required_fields_info)
@@ -192,7 +249,7 @@ impl MergedEnabledPaymentMethodTypes {
 
 /// Element container to hold the filtered payment methods with required fields
 struct RequiredFieldsForEnabledPaymentMethod {
-    required_field: Option<Vec<api_models::payment_methods::RequiredFieldInfo>>,
+    required_fields: Vec<api_models::payment_methods::RequiredFieldInfo>,
     payment_method_subtype: common_enums::PaymentMethodType,
     payment_method_type: common_enums::PaymentMethod,
     payment_experience: Option<Vec<common_enums::PaymentExperience>>,
@@ -228,7 +285,7 @@ impl RequiredFieldsForEnabledPaymentMethodTypes {
 
 /// Element Container to hold the filtered payment methods enabled with required fields and surcharge
 struct RequiredFieldsAndSurchargeForEnabledPaymentMethodType {
-    required_field: Option<Vec<api_models::payment_methods::RequiredFieldInfo>>,
+    required_fields: Vec<api_models::payment_methods::RequiredFieldInfo>,
     payment_method_subtype: common_enums::PaymentMethodType,
     payment_method_type: common_enums::PaymentMethod,
     payment_experience: Option<Vec<common_enums::PaymentExperience>>,
@@ -354,7 +411,7 @@ impl RequiredFieldsAndSurchargeWithExtraInfoForEnabledPaymentMethodTypes {
                     payment_method_type: payment_methods_enabled.payment_method_type,
                     payment_method_subtype: payment_methods_enabled.payment_method_subtype,
                     payment_experience: payment_methods_enabled.payment_experience,
-                    required_fields: payment_methods_enabled.required_field,
+                    required_fields: payment_methods_enabled.required_fields,
                     surcharge_details: payment_methods_enabled.surcharge,
                     extra_information: payment_methods_enabled.pm_subtype_specific_data,
                 }