Adds nonce to Payout model (#439)

* Add nonce for payout authorisation.

* Renamed crypto helper to nonce helper.

Author: sipsorcery

src/NoFrixion.MoneyMoov/Extensions/CurrencyExtensions.cs

@@ -0,0 +1,42 @@
+//-----------------------------------------------------------------------------
+// Filename: CurrencyExtensions.cs
+// 
+// Description: Contains extension methods for the Currency enum.
+// 
+// Author(s):
+// Aaron Clauson ([email protected])
+// 
+// History:
+// 23 Oct 2024  Aaron Clauson   Created, Carne, Wexford, Ireland.
+// 
+// License:
+// MIT
+//-----------------------------------------------------------------------------
+
+namespace NoFrixion.MoneyMoov;
+
+public static class CurrencyExtensions
+{
+    public static string GetCurrencySymbol(this CurrencyTypeEnum currency) =>
+    currency switch
+    {
+        CurrencyTypeEnum.BTC => "₿",
+        CurrencyTypeEnum.GBP => "£",
+        CurrencyTypeEnum.EUR => "€",
+        _ => "€"
+    };
+
+    public static bool IsFiat(this CurrencyTypeEnum currency) =>
+        currency switch
+        {
+            CurrencyTypeEnum.BTC => false,
+            _ => true
+        };
+
+    public static int GetDecimalPlaces(this CurrencyTypeEnum currency) =>
+        currency switch
+        {
+            CurrencyTypeEnum.BTC => PaymentsConstants.BITCOIN_ROUNDING_DECIMAL_PLACES,
+            _ => PaymentsConstants.FIAT_ROUNDING_DECIMAL_PLACES
+        };
+}

src/NoFrixion.MoneyMoov/Extensions/PaymentAmount.cs

@@ -21,28 +21,12 @@ public static class PaymentAmount
     /// Combines the display currency symbol and amount.
     /// </summary>
     public static string DisplayCurrencyAndAmount(CurrencyTypeEnum currency, decimal amount) =>
-        GetCurrencySymbol(currency) + " " + GetDisplayAmount(currency, amount);
+        currency.GetCurrencySymbol() + " " + GetDisplayAmount(currency, amount);
 
     public static string GetDisplayAmount(CurrencyTypeEnum currency, decimal amount) =>
-        IsFiat(currency) ? amount.ToString("N2") : amount.ToString("N8");
+        currency.IsFiat() ? amount.ToString("N2") : amount.ToString("N8");
 
     public static decimal GetRoundedAmount(CurrencyTypeEnum currency, decimal amount) =>
-         Math.Round(amount, IsFiat(currency) ? PaymentsConstants.FIAT_ROUNDING_DECIMAL_PLACES : PaymentsConstants.BITCOIN_ROUNDING_DECIMAL_PLACES);
-
-    public static string GetCurrencySymbol(CurrencyTypeEnum currency) =>
-    currency switch
-    {
-        CurrencyTypeEnum.BTC => "₿",
-        CurrencyTypeEnum.GBP => "£",
-        CurrencyTypeEnum.EUR => "€",
-        _ => "€"
-    };
-
-    private static bool IsFiat(CurrencyTypeEnum currency) =>
-        currency switch
-        {
-            CurrencyTypeEnum.BTC => false,
-            _ => true
-        };
+         Math.Round(amount, currency.IsFiat() ? PaymentsConstants.FIAT_ROUNDING_DECIMAL_PLACES : PaymentsConstants.BITCOIN_ROUNDING_DECIMAL_PLACES);
 }
 

src/NoFrixion.MoneyMoov/Models/PaymentRequests/PaymentRequest.cs

@@ -301,7 +301,7 @@ public PaymentMethodTypeEnum PaymentMethodTypes
     /// <summary>
     /// Gets the symbol for the payment request currency.
     /// </summary>
-    public string DisplayCurrencySymbol() => PaymentAmount.GetCurrencySymbol(Currency);
+    public string DisplayCurrencySymbol() => Currency.GetCurrencySymbol();
 
     /// <summary>
     /// Gets the amount to display with the correct number of decimal places based on the currency type. 

src/NoFrixion.MoneyMoov/Models/Payouts/Payout.cs

@@ -389,6 +389,8 @@ public Counterparty? DestinationAccount
     /// </summary>
     public PaymentRailEnum PaymentRail { get; set; }
 
+    public string? Nonce { get; set; }
+
     public NoFrixionProblem Validate()
     {
         var context = new ValidationContext(this, serviceProvider: null, items: null);
@@ -436,10 +438,11 @@ public string GetApprovalHash()
                 ID.ToString() +
                 AccountID.ToString() +
                 Currency +
-                Math.Round(Amount, 2).ToString() +
+                Math.Round(Amount, Currency.GetDecimalPlaces()).ToString() +
                 Destination.GetApprovalHash() +
                 Scheduled.GetValueOrDefault().ToString() +
-                ScheduleDate?.ToString("o");
+                ScheduleDate?.ToString("o") +
+                (string.IsNullOrEmpty(Nonce) ? string.Empty : Nonce);
 
             return HashHelper.CreateHash(input);
         }

src/NoFrixion.MoneyMoov/NonceHelper.cs

@@ -0,0 +1,30 @@
+//-----------------------------------------------------------------------------
+// Filename: NonceHelper.cs
+// 
+// Description: Helper functions for dealing with nonces.
+//
+// Author(s):
+// Aaron Clauson ([email protected])
+// 
+// History:
+// 23 Oct 2024  Aaron Clauson   Created, Carne, Wexford, Ireland.
+// 
+// License:
+// MIT.
+//-----------------------------------------------------------------------------
+
+using System.Security.Cryptography;
+
+namespace NoFrixion.MoneyMoov;
+
+public static class NonceHelper
+{
+    public static string GenerateRandomNonce()
+    {
+        var nonce = new byte[64];
+        var random = RandomNumberGenerator.Create();
+        random.GetBytes(nonce);
+
+        return Convert.ToBase64String(nonce);
+    }
+}