Refactor

apps/hellgate/src/hg_cashflow.erl

@@ -85,18 +85,13 @@ compute_postings(CF, Context, AccountMap, Opts) ->
         ?final_posting(
             construct_final_account(Source, AccountMap),
             construct_final_account(Destination, AccountMap),
-            maybe_convert_cash(ExchangeContext, compute_volume(Volume, Context)),
+            hg_currency_converter:maybe_reverse_convert_cash(ExchangeContext, compute_volume(Volume, Context)),
             Details,
             ExchangeContext
         )
      || ?posting(Source, Destination, Volume, Details) <- CF
     ].
 
-maybe_convert_cash(undefined, Cash) ->
-    Cash;
-maybe_convert_cash(ExchangeContext, Cash) ->
-    hg_currency_converter:reverse_convert_cash(ExchangeContext, Cash).
-
 -spec construct_final_account(account(), account_map()) -> final_cash_flow_account() | no_return().
 construct_final_account(AccountType, AccountMap) ->
     #domain_FinalCashFlowAccount{

apps/hellgate/src/hg_currency_converter.erl

@@ -4,62 +4,72 @@
 
 -export([convert_cash/2]).
 -export([reverse_convert_cash/2]).
+-export([maybe_convert_cash/2]).
+-export([maybe_reverse_convert_cash/2]).
+
+-export_type([exchange_context/0]).
 
 -type cash() :: dmsl_domain_thrift:'Cash'().
+-type exchange_context() :: dmsl_domain_thrift:'ExchangeContext'().
+
+-spec convert_cash(exchange_context(), cash()) -> cash().
+convert_cash(ExchangeContext, Cash) ->
+    do_convert_cash(ExchangeContext, Cash, forward).
+
+-spec reverse_convert_cash(exchange_context(), cash()) -> cash().
+reverse_convert_cash(ExchangeContext, Cash) ->
+    %% We do not use two-way exchange rates for currency pairs.
+    do_convert_cash(ExchangeContext, Cash, reverse).
 
--spec convert_cash(hg_invoice_payment:exchange_context(), cash()) -> cash().
-convert_cash(
+-spec maybe_convert_cash(exchange_context() | undefined, cash()) -> cash().
+maybe_convert_cash(undefined, Cash) ->
+    Cash;
+maybe_convert_cash(ExchangeContext, Cash) ->
+    convert_cash(ExchangeContext, Cash).
+
+-spec maybe_reverse_convert_cash(exchange_context() | undefined, cash()) -> cash().
+maybe_reverse_convert_cash(undefined, Cash) ->
+    Cash;
+maybe_reverse_convert_cash(ExchangeContext, Cash) ->
+    reverse_convert_cash(ExchangeContext, Cash).
+
+do_convert_cash(
     #domain_ExchangeContext{
+        exchange_rate = ExchangeRate,
         source_currency = SourceCurrency,
-        destination_currency = DestinationCurrency,
-        exchange_rate = ExchangeRate
-    },
-    #domain_Cash{amount = Amount, currency = #domain_CurrencyRef{symbolic_code = SourceCurrency}}
-) ->
-    %% Example:
-    %% Amount: 1000, Src: RUB, Dst: USD, Rate: {P=100, Q=1} (1 USD = 100 RUB)
-    %% ConvertedAmountRational = {1000,100}
-    %% ConvertedAmount = 10
-    #base_Rational{p = P, q = Q} = ExchangeRate,
-    RateRational = genlib_rational:new(P, Q),
-    AmountRational = genlib_rational:new(Amount),
-    ConvertedAmountRational = genlib_rational:dvd(AmountRational, RateRational),
-    Rounding = application:get_env(hellgate, exchange_rounding_method, round_half_away_from_zero),
-    ConvertedAmount = genlib_rational:round(ConvertedAmountRational, Rounding),
-    #domain_Cash{amount = ConvertedAmount, currency = #domain_CurrencyRef{symbolic_code = DestinationCurrency}};
-convert_cash(
-    #domain_ExchangeContext{
         destination_currency = DestinationCurrency
     },
-    #domain_Cash{currency = #domain_CurrencyRef{symbolic_code = DestinationCurrency}} = Cash
+    Cash,
+    Direction
 ) ->
-    %% already needed currency
-    %% skip conversion
-    Cash.
+    {InputCurrency, OutputCurrency, SkipCurrency} =
+        case Direction of
+            forward ->
+                {SourceCurrency, DestinationCurrency, DestinationCurrency};
+            reverse ->
+                {DestinationCurrency, SourceCurrency, SourceCurrency}
+        end,
+    case Cash of
+        #domain_Cash{currency = #domain_CurrencyRef{symbolic_code = SkipCurrency}} ->
+            Cash;
+        #domain_Cash{
+            amount = Amount,
+            currency = #domain_CurrencyRef{symbolic_code = InputCurrency}
+        } ->
+            convert_amount(Amount, ExchangeRate, OutputCurrency, Direction)
+    end.
 
--spec reverse_convert_cash(hg_invoice_payment:exchange_context(), cash()) -> cash().
-reverse_convert_cash(
-    #domain_ExchangeContext{
-        source_currency = SourceCurrency,
-        destination_currency = DestinationCurrency,
-        exchange_rate = ExchangeRate
-    },
-    #domain_Cash{amount = Amount, currency = #domain_CurrencyRef{symbolic_code = DestinationCurrency}}
-) ->
-    %% We do not use two-way exchange rates for currency pairs
+convert_amount(Amount, ExchangeRate, OutputCurrency, Direction) ->
     #base_Rational{p = P, q = Q} = ExchangeRate,
     RateRational = genlib_rational:new(P, Q),
     AmountRational = genlib_rational:new(Amount),
-    ReConvertedAmountRational = genlib_rational:mul(AmountRational, RateRational),
+    ConvertedAmountRational =
+        case Direction of
+            forward ->
+                genlib_rational:dvd(AmountRational, RateRational);
+            reverse ->
+                genlib_rational:mul(AmountRational, RateRational)
+        end,
     Rounding = application:get_env(hellgate, exchange_rounding_method, round_half_away_from_zero),
-    ReConvertedAmount = genlib_rational:round(ReConvertedAmountRational, Rounding),
-    #domain_Cash{amount = ReConvertedAmount, currency = #domain_CurrencyRef{symbolic_code = SourceCurrency}};
-reverse_convert_cash(
-    #domain_ExchangeContext{
-        source_currency = SourceCurrency
-    },
-    #domain_Cash{currency = #domain_CurrencyRef{symbolic_code = SourceCurrency}} = Cash
-) ->
-    %% already needed currency
-    %% skip conversion
-    Cash.
+    ConvertedAmount = genlib_rational:round(ConvertedAmountRational, Rounding),
+    #domain_Cash{amount = ConvertedAmount, currency = #domain_CurrencyRef{symbolic_code = OutputCurrency}}.

apps/hellgate/src/hg_invoice_payment.erl

@@ -238,7 +238,7 @@
     exchange_context => exchange_context()
 }.
 
--type exchange_context() :: dmsl_domain_thrift:'ExchangeContext'().
+-type exchange_context() :: hg_currency_converter:exchange_context().
 
 %%
 
@@ -3017,7 +3017,7 @@ construct_payment_info(
     PaymentInfo
 ) ->
     ExchangeContext = get_exchange_context(St),
-    {ConvertedCost, _OriginalCost} = maybe_convert_cash(ExchangeContext, Cost),
+    ConvertedCost = hg_currency_converter:maybe_convert_cash(ExchangeContext, Cost),
     PaymentInfo#proxy_provider_PaymentInfo{
         capture = construct_proxy_capture(ConvertedCost)
     };
@@ -3033,7 +3033,7 @@ construct_proxy_payment(
         domain_revision = Revision,
         payer = Payer,
         payer_session_info = PayerSessionInfo,
-        cost = Cost,
+        cost = Cost0,
         make_recurrent = MakeRecurrent,
         skip_recurrent = SkipRecurrent,
         processing_deadline = Deadline
@@ -3043,16 +3043,21 @@ construct_proxy_payment(
 ) ->
     ContactInfo = get_contact_info(Payer),
     PaymentTool = get_payer_payment_tool(Payer),
-    ExchangeContext = get_exchange_context(St),
-    {ConvertedCost, OriginalCost} = maybe_convert_cash(ExchangeContext, Cost),
+    {Cost1, OriginalCost} =
+        case get_exchange_context(St) of
+            undefined ->
+                {Cost0, undefined};
+            ExchangeContext ->
+                {hg_currency_converter:convert_cash(ExchangeContext, Cost0), Cost0}
+        end,
     #proxy_provider_InvoicePayment{
         id = ID,
         created_at = CreatedAt,
         trx = Trx,
         payment_resource = construct_payment_resource(Payer, St),
         payment_service = hg_payment_tool:get_payment_service(PaymentTool, Revision),
         payer_session_info = PayerSessionInfo,
-        cost = construct_proxy_cash(ConvertedCost),
+        cost = construct_proxy_cash(Cost1),
         original_cost = maybe_construct_proxy_cash(OriginalCost),
         contact_info = ContactInfo,
         make_recurrent = MakeRecurrent,
@@ -3144,23 +3149,6 @@ construct_proxy_capture(Cost) ->
         cost = construct_proxy_cash(Cost)
     }.
 
-maybe_convert_cash(undefined, Cost) ->
-    {Cost, undefined};
-maybe_convert_cash(
-    #domain_ExchangeContext{source_currency = PaymentCurrency} = ExchangeContext,
-    #domain_Cash{currency = #domain_CurrencyRef{symbolic_code = PaymentCurrency}} = OriginalCash
-) ->
-    ConvertedCash = hg_currency_converter:convert_cash(ExchangeContext, OriginalCash),
-    {ConvertedCash, OriginalCash}.
-
-maybe_reverse_convert_cash(undefined, Cost) ->
-    Cost;
-maybe_reverse_convert_cash(
-    #domain_ExchangeContext{destination_currency = TerminalCurrency} = ExchangeContext,
-    #domain_Cash{currency = #domain_CurrencyRef{symbolic_code = TerminalCurrency}} = TerminalCash
-) ->
-    hg_currency_converter:reverse_convert_cash(ExchangeContext, TerminalCash).
-
 %%
 
 get_party_obj(#{party := Party, party_config_ref := PartyConfigRef}) ->
@@ -3410,7 +3398,7 @@ merge_change(Change = ?cash_changed(_OldCash, NewCash), #st{} = St, Opts) ->
     ),
     Payment0 = get_payment(St),
     ExchangeContext = get_exchange_context(St),
-    ReConvertedNewCash = maybe_reverse_convert_cash(ExchangeContext, NewCash),
+    ReConvertedNewCash = hg_currency_converter:maybe_reverse_convert_cash(ExchangeContext, NewCash),
     Payment1 = Payment0#domain_InvoicePayment{changed_cost = ReConvertedNewCash},
     St#st{new_cash = ReConvertedNewCash, new_cash_provided = true, payment = Payment1};
 merge_change(Change = ?payment_rollback_started(Failure), St, Opts) ->

apps/hellgate/src/hg_invoice_payment_refund.erl

@@ -593,7 +593,7 @@ get_refund_created_at(#domain_InvoicePaymentRefund{created_at = CreatedAt}) ->
 
 construct_payment_info(PaymentInfo, Refund) ->
     ExchangeContext = get_injected_exchange_context(Refund),
-    ConvertedCash = maybe_convert_cash(ExchangeContext, cash(Refund)),
+    ConvertedCash = hg_currency_converter:maybe_convert_cash(ExchangeContext, cash(Refund)),
     PaymentInfo#proxy_provider_PaymentInfo{
         refund = #proxy_provider_InvoicePaymentRefund{
             id = id(Refund),
@@ -603,11 +603,6 @@ construct_payment_info(PaymentInfo, Refund) ->
         }
     }.
 
-maybe_convert_cash(undefined, Cash) ->
-    Cash;
-maybe_convert_cash(ExchangeContext, Cash) ->
-    hg_currency_converter:convert_cash(ExchangeContext, Cash).
-
 construct_proxy_cash(#domain_Cash{
     amount = Amount,
     currency = CurrencyRef

apps/routing/src/hg_route.erl

@@ -13,6 +13,8 @@
 -export([set_availability/3]).
 -export([set_conversion/3]).
 -export([set_priority/2]).
+-export([set_rejection_reason/2]).
+-export([set_exchange_context/2]).
 
 -export([route_data/1]).
 -export([terminal_ref/1]).
@@ -25,7 +27,7 @@
 -export([fd_score/1]).
 -export([blacklisted/1]).
 -export([rejection_reason/1]).
--export([set_rejection_reason/2]).
+-export([exchange_context/1]).
 
 -export([score/1]).
 -export([equal/2]).
@@ -52,7 +54,7 @@
     route_data := route_data(),
     pin_data => pin_data(),
     fd_overrides => fd_overrides(),
-    rejection_reason => route_rejection_reason() | undefined,
+    rejection_reason => route_rejection_reason(),
     exchange_context => hg_invoice_payment:exchange_context()
 }.
 
@@ -168,6 +170,18 @@ set_conversion(C, V, #{route_data := Data = #{fd_score := Score}} = R) ->
 set_priority(V, #{route_data := Data} = R) ->
     R#{route_data => Data#{priority => V}}.
 
+-spec set_rejection_reason(route_rejection_reason(), t()) ->
+    t().
+set_rejection_reason(Reason, R) ->
+    R#{rejection_reason => Reason}.
+
+-spec set_exchange_context(hg_invoice_payment:exchange_context() | undefined, t()) ->
+    t().
+set_exchange_context(undefined, R) ->
+    R;
+set_exchange_context(V, R) ->
+    R#{exchange_context => V}.
+
 -spec provider_ref(t()) -> provider_ref().
 provider_ref(#{provider_ref := Ref}) ->
     Ref.
@@ -216,16 +230,17 @@ blacklisted(_) ->
     0.
 
 -spec rejection_reason(t()) ->
-    route_rejection_reason().
+    route_rejection_reason() | undefined.
 rejection_reason(#{rejection_reason := V}) ->
     V;
 rejection_reason(_) ->
     undefined.
 
--spec set_rejection_reason(route_rejection_reason(), t()) ->
-    t().
-set_rejection_reason(Reason, R) ->
-    R#{rejection_reason => Reason}.
+-spec exchange_context(t()) -> hg_invoice_payment:exchange_context() | undefined.
+exchange_context(#{exchange_context := V}) ->
+    V;
+exchange_context(_) ->
+    undefined.
 
 -spec score(t()) -> score().
 score(R) ->