Merge pull request 'Refactored PayfastService.GenerateSignature()' (#104) from payments into master

Reviewed-on: #104

LiteCharms.Features.MidrandBooks/Payments/PayfastService.cs

@@ -157,9 +157,11 @@ public sealed partial class PayfastService(IDbContextFactory<MidrandBooksDbConte
 
             string key = kvp.Key;
 
-            string encodedVal = Uri.EscapeDataString(kvp.Value.Trim());
+            // 1. Payfast requires spaces to be '+' signs. HttpUtility does this perfectly.
+            string encodedVal = HttpUtility.UrlEncode(kvp.Value.Trim());
 
-            string val = PercentEncodingRegex.Replace(encodedVal, m => m.Value.ToLowerInvariant());
+            // 2. Payfast requires all OTHER percent-encoded hex arrays to be UPPERCASE (e.g., %3A instead of %3a)
+            string val = Regex.Replace(encodedVal, "%[0-9A-Fa-f]{2}", m => m.Value.ToUpperInvariant());
 
             pfOutput.Append($"{key}={val}&");
         }
@@ -170,8 +172,9 @@ public sealed partial class PayfastService(IDbContextFactory<MidrandBooksDbConte
 
         if (!string.IsNullOrWhiteSpace(passPhrase))
         {
-            string encodedPassphrase = Uri.EscapeDataString(passPhrase.Trim());
-            string safePassphrase = PercentEncodingRegex.Replace(encodedPassphrase, m => m.Value.ToLowerInvariant());
+            // Apply the exact same encoding rule to your passphrase
+            string encodedPassphrase = HttpUtility.UrlEncode(passPhrase.Trim());
+            string safePassphrase = Regex.Replace(encodedPassphrase, "%[0-9A-Fa-f]{2}", m => m.Value.ToUpperInvariant());
 
             getString += $"&passphrase={safePassphrase}";
         }