feat(router): add mandates list api (#1143)

crates/router/src/core/mandate.rs

@@ -1,5 +1,6 @@
 use common_utils::{ext_traits::Encode, pii};
 use error_stack::{report, ResultExt};
+use futures::future;
 use router_env::{instrument, logger, tracing};
 use storage_models::enums as storage_enums;
 
@@ -259,6 +260,25 @@ where
     Ok(resp)
 }
 
+#[instrument(skip(state))]
+pub async fn retrieve_mandates_list(
+    state: &AppState,
+    merchant_account: storage::MerchantAccount,
+    constraints: api_models::mandates::MandateListConstraints,
+) -> RouterResponse<Vec<api_models::mandates::MandateResponse>> {
+    let mandates = state
+        .store
+        .find_mandates_by_merchant_id(&merchant_account.merchant_id, constraints)
+        .await
+        .change_context(errors::ApiErrorResponse::InternalServerError)
+        .attach_printable("Unable to retrieve mandates")?;
+    let mandates_list = future::try_join_all(mandates.into_iter().map(|mandate| {
+        mandates::MandateResponse::from_db_mandate(state, mandate, &merchant_account)
+    }))
+    .await?;
+    Ok(services::ApplicationResponse::Json(mandates_list))
+}
+
 impl ForeignTryFrom<Result<types::PaymentsResponseData, types::ErrorResponse>>
     for Option<pii::SecretSerdeValue>
 {