Add ability to set default payment method for pay button (#3606)

* Add ability to set default payment method for pay button

close #3604

* Add "#nullable enable" to UIStoresController

* Add PaymentMethodOptionViewModel

* Add explicit "Use the store’s default" option

BTCPayServer/Controllers/UIPublicController.cs

@@ -67,7 +67,8 @@ namespace BTCPayServer.Controllers
                     NotificationEmail = model.NotifyEmail,
                     NotificationURL = model.ServerIpn,
                     RedirectURL = model.BrowserRedirect,
-                    FullNotifications = true
+                    FullNotifications = true,
+                    DefaultPaymentMethod = model.DefaultPaymentMethod
                 }, store, HttpContext.Request.GetAbsoluteRoot(), cancellationToken: cancellationToken);
             }
             catch (BitpayHttpException e)

BTCPayServer/Controllers/UIStoresController.cs

@@ -1,3 +1,4 @@
+#nullable enable
 using System;
 using System.Collections.Generic;
 using System.Globalization;
@@ -229,7 +230,7 @@ namespace BTCPayServer.Controllers
         }
 
         [HttpPost("{storeId}/rates")]
-        public async Task<IActionResult> Rates(RatesViewModel model, string command = null, string storeId = null, CancellationToken cancellationToken = default)
+        public async Task<IActionResult> Rates(RatesViewModel model, string? command = null, string? storeId = null, CancellationToken cancellationToken = default)
         {
             if (command == "scripting-on")
             {
@@ -243,7 +244,7 @@ namespace BTCPayServer.Controllers
             var exchanges = GetSupportedExchanges();
             model.SetExchangeRates(exchanges, model.PreferredExchange);
             model.StoreId = storeId ?? model.StoreId;
-            CurrencyPair[] currencyPairs = null;
+            CurrencyPair[]? currencyPairs = null;
             try
             {
                 currencyPairs = model.DefaultCurrencyPairs?
@@ -277,7 +278,7 @@ namespace BTCPayServer.Controllers
                     return View(model);
                 }
             }
-            RateRules rules = null;
+            RateRules? rules = null;
             if (model.ShowScripting)
             {
                 if (!RateRules.TryParse(model.Script, out rules, out var errors))
@@ -421,6 +422,29 @@ namespace BTCPayServer.Controllers
         }
 
         void SetCryptoCurrencies(CheckoutAppearanceViewModel vm, Data.StoreData storeData)
+        {
+            var choices = GetEnabledPaymentMethodChoices(storeData);
+            var chosen = GetDefaultPaymentMethodChoice(storeData);
+
+            vm.PaymentMethods = new SelectList(choices, nameof(chosen.Value), nameof(chosen.Name), chosen?.Value);
+            vm.DefaultPaymentMethod = chosen?.Value;
+        }
+
+        PaymentMethodOptionViewModel.Format[] GetEnabledPaymentMethodChoices(Data.StoreData storeData)
+        {
+            var enabled = storeData.GetEnabledPaymentIds(_NetworkProvider);
+            
+            return enabled
+                .Select(o =>
+                    new PaymentMethodOptionViewModel.Format()
+                    {
+                        Name = o.ToPrettyString(),
+                        Value = o.ToString(),
+                        PaymentId = o
+                    }).ToArray();
+        }
+
+        PaymentMethodOptionViewModel.Format? GetDefaultPaymentMethodChoice(Data.StoreData storeData)
         {
             var enabled = storeData.GetEnabledPaymentIds(_NetworkProvider);
             var defaultPaymentId = storeData.GetDefaultPaymentId();
@@ -431,17 +455,9 @@ namespace BTCPayServer.Controllers
                                 enabled.FirstOrDefault(e => e.CryptoCode == "BTC" && e.PaymentType == PaymentTypes.LightningLike) ??
                                 enabled.FirstOrDefault();
             }
-            var choices = enabled
+            var choices = GetEnabledPaymentMethodChoices(storeData);
-                .Select(o =>
+
-                    new CheckoutAppearanceViewModel.Format()
+            return defaultChoice is null ? null : choices.FirstOrDefault(c => defaultChoice.ToString().Equals(c.Value, StringComparison.OrdinalIgnoreCase));
-                    {
-                        Name = o.ToPrettyString(),
-                        Value = o.ToString(),
-                        PaymentId = o
-                    }).ToArray();
-            var chosen = defaultChoice is null ? null : choices.FirstOrDefault(c => defaultChoice.ToString().Equals(c.Value, StringComparison.OrdinalIgnoreCase));
-            vm.PaymentMethods = new SelectList(choices, nameof(chosen.Value), nameof(chosen.Name), chosen?.Value);
-            vm.DefaultPaymentMethod = chosen?.Value;
         }
 
         [HttpPost]
@@ -616,7 +632,7 @@ namespace BTCPayServer.Controllers
         }
 
         [HttpPost("{storeId}/settings")]
-        public async Task<IActionResult> GeneralSettings(GeneralSettingsViewModel model, string command = null)
+        public async Task<IActionResult> GeneralSettings(GeneralSettingsViewModel model, string? command = null)
         {
             bool needUpdate = false;
             if (CurrentStore.StoreName != model.StoreName)
@@ -747,7 +763,7 @@ namespace BTCPayServer.Controllers
                 TempData[WellKnownTempData.ErrorMessage] = "Failure to revoke this token.";
             else
                 TempData[WellKnownTempData.SuccessMessage] = "Token revoked";
-            return RedirectToAction(nameof(ListTokens), new { storeId = token.StoreId });
+            return RedirectToAction(nameof(ListTokens), new { storeId = token?.StoreId });
         }
 
         [HttpGet]
@@ -782,7 +798,7 @@ namespace BTCPayServer.Controllers
                 Id = model.PublicKey == null ? null : NBitpayClient.Extensions.BitIdExtensions.GetBitIDSIN(new PubKey(model.PublicKey).Compress())
             };
 
-            string pairingCode = null;
+            string? pairingCode = null;
             if (model.PublicKey == null)
             {
                 tokenRequest.PairingCode = await _TokenRepository.CreatePairingCodeAsync();
@@ -807,7 +823,7 @@ namespace BTCPayServer.Controllers
             });
         }
 
-        public string GeneratedPairingCode { get; set; }
+        public string? GeneratedPairingCode { get; set; }
         public WebhookSender WebhookNotificationManager { get; }
         public IDataProtector DataProtector { get; }
 
@@ -880,7 +896,7 @@ namespace BTCPayServer.Controllers
         [HttpGet]
         [Route("/api-access-request")]
         [AllowAnonymous]
-        public async Task<IActionResult> RequestPairing(string pairingCode, string selectedStore = null)
+        public async Task<IActionResult> RequestPairing(string pairingCode, string? selectedStore = null)
         {
             var userId = GetUserId();
             if (userId == null)
@@ -956,9 +972,9 @@ namespace BTCPayServer.Controllers
             }
         }
 
-        private string GetUserId()
+        private string? GetUserId()
         {
-            if (User.Identity.AuthenticationType != AuthenticationSchemes.Cookie)
+            if (User.Identity?.AuthenticationType != AuthenticationSchemes.Cookie)
                 return null;
             return _UserManager.GetUserId(User);
         }
@@ -990,6 +1006,8 @@ namespace BTCPayServer.Controllers
             {
                 Price = null,
                 Currency = storeBlob.DefaultCurrency,
+                DefaultPaymentMethod = String.Empty,
+                PaymentMethods = GetEnabledPaymentMethodChoices(store),
                 ButtonSize = 2,
                 UrlRoot = appUrl,
                 PayButtonImageUrl = appUrl + "img/paybutton/pay.svg",

BTCPayServer/Data/StoreDataExtensions.cs

@@ -38,7 +38,7 @@ namespace BTCPayServer.Data
             return paymentMethodIds;
         }
 
-        public static void SetDefaultPaymentId(this StoreData storeData, PaymentMethodId defaultPaymentId)
+        public static void SetDefaultPaymentId(this StoreData storeData, PaymentMethodId? defaultPaymentId)
         {
             storeData.DefaultCrypto = defaultPaymentId?.ToString();
         }

BTCPayServer/Models/StoreViewModels/CheckoutAppearanceViewModel.cs

@@ -2,7 +2,6 @@ using System;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
 using System.Linq;
-using BTCPayServer.Payments;
 using BTCPayServer.Services;
 using Microsoft.AspNetCore.Mvc.Rendering;
 
@@ -10,18 +9,12 @@ namespace BTCPayServer.Models.StoreViewModels
 {
     public class CheckoutAppearanceViewModel
     {
-        public class Format
-        {
-            public string Name { get; set; }
-            public string Value { get; set; }
-            public PaymentMethodId PaymentId { get; set; }
-        }
         public SelectList PaymentMethods { get; set; }
 
         public void SetLanguages(LanguageService langService, string defaultLang)
         {
             defaultLang = langService.GetLanguages().Any(language => language.Code == defaultLang) ? defaultLang : "en";
-            var choices = langService.GetLanguages().Select(o => new Format() { Name = o.DisplayName, Value = o.Code }).ToArray().OrderBy(o => o.Name);
+            var choices = langService.GetLanguages().Select(o => new PaymentMethodOptionViewModel.Format() { Name = o.DisplayName, Value = o.Code }).ToArray().OrderBy(o => o.Name);
             var chosen = choices.FirstOrDefault(f => f.Value == defaultLang) ?? choices.FirstOrDefault();
             Languages = new SelectList(choices, nameof(chosen.Value), nameof(chosen.Name), chosen);
             DefaultLang = chosen.Value;

BTCPayServer/Models/StoreViewModels/PayButtonViewModel.cs

@@ -13,6 +13,8 @@ namespace BTCPayServer.Models.StoreViewModels
         public string InvoiceId { get; set; }
         [Required]
         public string Currency { get; set; }
+        public string DefaultPaymentMethod { get; set; }
+        public PaymentMethodOptionViewModel.Format[] PaymentMethods { get; set; }
         public string CheckoutDesc { get; set; }
         public string OrderId { get; set; }
         public int ButtonSize { get; set; }

BTCPayServer/Models/StoreViewModels/PaymentMethodOptionViewModel.cs

@@ -0,0 +1,14 @@
+using BTCPayServer.Payments;
+
+namespace BTCPayServer.Models.StoreViewModels
+{
+    public class PaymentMethodOptionViewModel
+    {
+        public class Format
+        {
+            public string Name { get; set; }
+            public string Value { get; set; }
+            public PaymentMethodId PaymentId { get; set; }
+        }
+    }
+}

BTCPayServer/Views/UIStores/PayButton.cshtml

@@ -159,6 +159,13 @@
                        v-model="srvModel.currency" v-on:change="inputChanges"
                        :class="{'is-invalid': errors.has('currency') }">
             </div>
+            <div class="form-group col-md-4" v-if="!srvModel.appIdEndpoint">
+                <label class="form-label" for="defaultPaymentMethod">Default Payment Method</label>
+                <select v-model="srvModel.defaultPaymentMethod" v-on:change="inputChanges" class="form-select" id="default-payment-method">
+                    <option value="" selected>Use the store’s default</option>
+                    <option  v-for="pm in srvModel.paymentMethods" v-bind:value="pm.value">{{pm.name}}</option>
+                </select>
+            </div>
             <div class="form-group" v-if="!srvModel.appIdEndpoint">
                 <label class="form-label" for="description">Checkout Description</label>
                 <input name="checkoutDesc" type="text" class="form-control" id="description"

BTCPayServer/wwwroot/paybutton/paybutton.js

@@ -84,6 +84,7 @@ function inputChanges(event, buttonSize) {
     let priceInputName = 'price';
     let app = srvModel.appIdEndpoint? srvModel.apps.find(value => value.id === srvModel.appIdEndpoint ): null;
     let allowCurrencySelection = true;
+    let allowDefaultPaymentMethodSelection = true;
     if (app) {
         if (app.appType.toLowerCase() === 'pointofsale') {
             actionUrl = `apps/${app.id}/pos`;
@@ -97,6 +98,7 @@ function inputChanges(event, buttonSize) {
         if (actionUrl !== 'api/v1/invoices') {
             priceInputName = 'amount';
             allowCurrencySelection = false;
+            allowDefaultPaymentMethodSelection = false;
             srvModel.useModal = false;
         }
     }
@@ -150,6 +152,15 @@ function inputChanges(event, buttonSize) {
         html += addSlider(srvModel.price, srvModel.min, srvModel.max, srvModel.step, width);
         html += '  </div>\n';
     }
+
+    if (
+        allowDefaultPaymentMethodSelection &&
+        // Only add default payment method to HTML if user explicitly selected it
+        event && event.target.id === 'default-payment-method' && event.target.value !== ""
+    )
+    {
+        html += addInput("defaultPaymentMethod", srvModel.defaultPaymentMethod)
+    }
     
     html += srvModel.payButtonText
         ? `<button type="submit" class="submit" name="submit" style="min-width:${width};min-height:${height};border-radius:4px;border-style:none;background-color:#0f3b21;" title="Pay with BTCPay Server, a Self-Hosted Bitcoin Payment Processor"><span style="color:#fff">${esc(srvModel.payButtonText)}</span>\n` +