refactor(router): include currency conversion utility functions as Currency methods (#1790)

crates/common_enums/src/enums.rs

@@ -1,3 +1,5 @@
+use std::num::TryFromIntError;
+
 use router_derive;
 use serde::{Deserialize, Serialize};
 use utoipa::ToSchema;
@@ -289,6 +291,40 @@ pub enum Currency {
 }
 
 impl Currency {
+    /// Convert the amount to its base denomination based on Currency and return String
+    pub fn to_currency_base_unit(&self, amount: i64) -> Result<String, TryFromIntError> {
+        let amount_f64 = self.to_currency_base_unit_asf64(amount)?;
+        Ok(format!("{amount_f64:.2}"))
+    }
+
+    /// Convert the amount to its base denomination based on Currency and return f64
+    pub fn to_currency_base_unit_asf64(&self, amount: i64) -> Result<f64, TryFromIntError> {
+        let amount_f64: f64 = u32::try_from(amount)?.into();
+        let amount = if self.is_zero_decimal_currency() {
+            amount_f64
+        } else if self.is_three_decimal_currency() {
+            amount_f64 / 1000.00
+        } else {
+            amount_f64 / 100.00
+        };
+        Ok(amount)
+    }
+
+    /// Convert the amount to its base denomination based on Currency and check for zero decimal currency and return String
+    /// Paypal Connector accepts Zero and Two decimal currency but not three decimal and it should be updated as required for 3 decimal currencies.
+    /// Paypal Ref - https://developer.paypal.com/docs/reports/reference/paypal-supported-currencies/
+    pub fn to_currency_base_unit_with_zero_decimal_check(
+        &self,
+        amount: i64,
+    ) -> Result<String, TryFromIntError> {
+        let amount_f64 = self.to_currency_base_unit_asf64(amount)?;
+        if self.is_zero_decimal_currency() {
+            Ok(amount_f64.to_string())
+        } else {
+            Ok(format!("{amount_f64:.2}"))
+        }
+    }
+
     pub fn iso_4217(&self) -> &'static str {
         match *self {
             Self::AED => "784",

crates/router/src/connector/utils.rs

@@ -21,7 +21,7 @@ use crate::{
     core::errors::{self, CustomResult},
     pii::PeekInterface,
     types::{self, api, transformers::ForeignTryFrom, PaymentsCancelData, ResponseId},
-    utils::{self, OptionExt, ValueExt},
+    utils::{OptionExt, ValueExt},
 };
 
 pub fn missing_field_err(
@@ -924,7 +924,9 @@ pub fn to_currency_base_unit(
     amount: i64,
     currency: diesel_models::enums::Currency,
 ) -> Result<String, error_stack::Report<errors::ConnectorError>> {
-    utils::to_currency_base_unit(amount, currency)
+    currency
+        .to_currency_base_unit(amount)
+        .into_report()
         .change_context(errors::ConnectorError::RequestEncodingFailed)
 }
 
@@ -932,7 +934,9 @@ pub fn to_currency_base_unit_with_zero_decimal_check(
     amount: i64,
     currency: diesel_models::enums::Currency,
 ) -> Result<String, error_stack::Report<errors::ConnectorError>> {
-    utils::to_currency_base_unit_with_zero_decimal_check(amount, currency)
+    currency
+        .to_currency_base_unit_with_zero_decimal_check(amount)
+        .into_report()
         .change_context(errors::ConnectorError::RequestEncodingFailed)
 }
 
@@ -940,7 +944,9 @@ pub fn to_currency_base_unit_asf64(
     amount: i64,
     currency: diesel_models::enums::Currency,
 ) -> Result<f64, error_stack::Report<errors::ConnectorError>> {
-    utils::to_currency_base_unit_asf64(amount, currency)
+    currency
+        .to_currency_base_unit_asf64(amount)
+        .into_report()
         .change_context(errors::ConnectorError::RequestEncodingFailed)
 }
 

crates/router/src/core/payments/flows/session_flow.rs

@@ -1,11 +1,10 @@
 use api_models::payments as payment_types;
 use async_trait::async_trait;
 use common_utils::ext_traits::ByteSliceExt;
-use error_stack::{Report, ResultExt};
+use error_stack::{IntoReport, Report, ResultExt};
 
 use super::{ConstructFlowSpecificData, Feature};
 use crate::{
-    connector,
     core::{
         errors::{self, ConnectorErrorExt, RouterResult},
         payments::{self, access_token, transformers, PaymentData},
@@ -172,10 +171,11 @@ async fn create_applepay_session_token(
         let amount_info = payment_types::AmountInfo {
             label: applepay_metadata.data.payment_request_data.label,
             total_type: Some("final".to_string()),
-            amount: connector::utils::to_currency_base_unit(
+            amount: router_data
-                router_data.request.amount,
+                .request
-                router_data.request.currency,
+                .currency
-            )
+                .to_currency_base_unit(router_data.request.amount)
+                .into_report()
                 .change_context(errors::ApiErrorResponse::PreconditionFailed {
                     message: "Failed to convert currency to base unit".to_string(),
                 })?,
@@ -324,10 +324,11 @@ fn create_gpay_session_token(
             country_code: session_data.country.unwrap_or_default(),
             currency_code: router_data.request.currency,
             total_price_status: "Final".to_string(),
-            total_price: utils::to_currency_base_unit(
+            total_price: router_data
-                router_data.request.amount,
+                .request
-                router_data.request.currency,
+                .currency
-            )
+                .to_currency_base_unit(router_data.request.amount)
+                .into_report()
                 .attach_printable(
                     "Cannot convert given amount to base currency denomination".to_string(),
                 )

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

@@ -2,7 +2,7 @@ use std::{fmt::Debug, marker::PhantomData};
 
 use common_utils::fp_utils;
 use diesel_models::{ephemeral_key, payment_attempt::PaymentListFilters};
-use error_stack::ResultExt;
+use error_stack::{IntoReport, ResultExt};
 use router_env::{instrument, tracing};
 
 use super::{flows::Feature, PaymentAddress, PaymentData};
@@ -21,7 +21,7 @@ use crate::{
         storage::{self, enums},
         transformers::{ForeignFrom, ForeignInto},
     },
-    utils::{self, OptionExt, ValueExt},
+    utils::{OptionExt, ValueExt},
 };
 
 #[instrument(skip_all)]
@@ -303,11 +303,12 @@ where
         .currency
         .as_ref()
         .get_required_value("currency")?;
-    let amount = utils::to_currency_base_unit(payment_attempt.amount, *currency).change_context(
+    let amount = currency
-        errors::ApiErrorResponse::InvalidDataValue {
+        .to_currency_base_unit(payment_attempt.amount)
+        .into_report()
+        .change_context(errors::ApiErrorResponse::InvalidDataValue {
             field_name: "amount",
-        },
+        })?;
-    )?;
     let mandate_id = payment_attempt.mandate_id.clone();
     let refunds_response = if refunds.is_empty() {
         None

crates/router/src/utils.rs

@@ -129,51 +129,6 @@ impl<E> ConnectorResponseExt
     }
 }
 
-/// Convert the amount to its base denomination based on Currency and return String
-pub fn to_currency_base_unit(
-    amount: i64,
-    currency: diesel_models::enums::Currency,
-) -> Result<String, error_stack::Report<errors::ValidationError>> {
-    let amount_f64 = to_currency_base_unit_asf64(amount, currency)?;
-    Ok(format!("{amount_f64:.2}"))
-}
-
-/// Convert the amount to its base denomination based on Currency and check for zero decimal currency and return String
-/// Paypal Connector accepts Zero and Two decimal currency but not three decimal and it should be updated as required for 3 decimal currencies.
-/// Paypal Ref - https://developer.paypal.com/docs/reports/reference/paypal-supported-currencies/
-pub fn to_currency_base_unit_with_zero_decimal_check(
-    amount: i64,
-    currency: diesel_models::enums::Currency,
-) -> Result<String, error_stack::Report<errors::ValidationError>> {
-    let amount_f64 = to_currency_base_unit_asf64(amount, currency)?;
-    if currency.is_zero_decimal_currency() {
-        Ok(amount_f64.to_string())
-    } else {
-        Ok(format!("{amount_f64:.2}"))
-    }
-}
-
-/// Convert the amount to its base denomination based on Currency and return f64
-pub fn to_currency_base_unit_asf64(
-    amount: i64,
-    currency: diesel_models::enums::Currency,
-) -> Result<f64, error_stack::Report<errors::ValidationError>> {
-    let amount_u32 = u32::try_from(amount).into_report().change_context(
-        errors::ValidationError::InvalidValue {
-            message: amount.to_string(),
-        },
-    )?;
-    let amount_f64 = f64::from(amount_u32);
-    let amount = if currency.is_zero_decimal_currency() {
-        amount_f64
-    } else if currency.is_three_decimal_currency() {
-        amount_f64 / 1000.00
-    } else {
-        amount_f64 / 100.00
-    };
-    Ok(amount)
-}
-
 #[inline]
 pub fn get_payment_attempt_id(payment_id: impl std::fmt::Display, attempt_count: i16) -> String {
     format!("{payment_id}_{attempt_count}")