Can select the signing key in WalletSettings

BTCPayServer/Controllers/WalletsController.cs

@@ -453,8 +453,7 @@ namespace BTCPayServer.Controllers
                         if (!_dashboard.IsFullySynched(network.CryptoCode, out var summary))
                             throw new Exception($"{network.CryptoCode}: not started or fully synched");
 
-                        var accountKey = derivationSettings.AccountKeySettings.Where(a => a.IsFullySetup()).FirstOrDefault();
-                        accountKey = accountKey ?? derivationSettings.AccountKeySettings.FirstOrDefault();
+                        var accountKey = derivationSettings.GetSigningAccountKeySettings();
                         // Some deployment does not have the AccountKeyPath set, let's fix this...
                         if (accountKey.AccountKeyPath == null)
                         {
@@ -540,12 +539,13 @@ namespace BTCPayServer.Controllers
             var derivationSchemeSettings = await GetDerivationSchemeSettings(walletId);
             if (derivationSchemeSettings == null)
                 return NotFound();
-
+            var store = (await Repository.FindStore(walletId.StoreId, GetUserId()));
             var vm = new WalletSettingsViewModel()
             {
                 Label = derivationSchemeSettings.Label,
                 DerivationScheme = derivationSchemeSettings.AccountDerivation.ToString(),
-                DerivationSchemeInput = derivationSchemeSettings.AccountOriginal
+                DerivationSchemeInput = derivationSchemeSettings.AccountOriginal,
+                SelectedSigningKey = derivationSchemeSettings.SigningKey.ToString()
             };
             vm.AccountKeys = derivationSchemeSettings.AccountKeySettings
                             .Select(e => new WalletSettingsAccountKeyViewModel()
@@ -569,6 +569,7 @@ namespace BTCPayServer.Controllers
             if (derivationScheme == null)
                 return NotFound();
             derivationScheme.Label = vm.Label;
+            derivationScheme.SigningKey = new BitcoinExtPubKey(vm.SelectedSigningKey, derivationScheme.Network.NBitcoinNetwork);
             for (int i = 0; i < derivationScheme.AccountKeySettings.Length; i++)
             {
                 derivationScheme.AccountKeySettings[i].AccountKeyPath = string.IsNullOrWhiteSpace(vm.AccountKeys[i].AccountKeyPath) ? null

BTCPayServer/DerivationSchemeSettings.cs

@@ -116,6 +116,7 @@ namespace BTCPayServer
         {
 
         }
+
         public DerivationSchemeSettings(DerivationStrategyBase derivationStrategy, BTCPayNetwork network)
         {
             if (network == null)
@@ -129,6 +130,21 @@ namespace BTCPayServer
                 AccountKey = c.GetWif(network.NBitcoinNetwork)
             }).ToArray();
         }
+
+
+        BitcoinExtPubKey _SigningKey;
+        public BitcoinExtPubKey SigningKey
+        {
+            get
+            {
+                return _SigningKey ?? AccountKeySettings?.Select(k => k.AccountKey).FirstOrDefault();
+            }
+            set
+            {
+                _SigningKey = value;
+            }
+        }
+
         [JsonIgnore]
         public BTCPayNetwork Network { get; set; }
         public string Source { get; set; }
@@ -158,6 +174,11 @@ namespace BTCPayServer
             }
         }
 
+        public AccountKeySettings GetSigningAccountKeySettings()
+        {
+            return AccountKeySettings.Single(a => a.AccountKey == SigningKey);
+        }
+
         AccountKeySettings[] _AccountKeySettings;
         public AccountKeySettings[] AccountKeySettings
         {
@@ -190,7 +211,7 @@ namespace BTCPayServer
 
         public IEnumerable<NBXplorer.Models.PSBTRebaseKeyRules> GetPSBTRebaseKeyRules()
         {
-            foreach(var accountKey in AccountKeySettings)
+            foreach (var accountKey in AccountKeySettings)
             {
                 if (accountKey.AccountKeyPath != null && accountKey.RootFingerprint is HDFingerprint fp)
                 {

BTCPayServer/Models/WalletViewModels/WalletSettingsViewModel.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
 using System.Linq;
 using System.Threading.Tasks;
 
@@ -10,6 +11,9 @@ namespace BTCPayServer.Models.WalletViewModels
         public string Label { get; set; }
         public string DerivationScheme { get; set; }
         public string DerivationSchemeInput { get; set; }
+        [Display(Name = "Is signing key")]
+        public string SelectedSigningKey { get; set; }
+        public bool IsMultiSig => AccountKeys.Count > 1;
 
         public List<WalletSettingsAccountKeyViewModel> AccountKeys { get; set; } = new List<WalletSettingsAccountKeyViewModel>();
     }

BTCPayServer/Views/Wallets/WalletSettings.cshtml

@@ -60,6 +60,13 @@
                     <input asp-for="@Model.AccountKeys[i].AccountKeyPath" class="form-control" />
                     <span asp-validation-for="@Model.AccountKeys[i].AccountKeyPath" class="text-danger"></span>
                 </div>
+                @if (Model.IsMultiSig)
+                {
+                    <div class="form-group">
+                        <label asp-for="SelectedSigningKey"></label>
+                        <input asp-for="SelectedSigningKey" type="radio" value="@Model.AccountKeys[i].AccountKey" />
+                    </div>
+                }
             }
 
             <div class="form-group">