start work on payment tolerance feature

BTCPayServer/Controllers/InvoiceController.cs

@@ -98,6 +98,7 @@ namespace BTCPayServer.Controllers
             entity.ExtendedNotifications = invoice.ExtendedNotifications;
             entity.NotificationURL = notificationUri?.AbsoluteUri;
             entity.BuyerInformation = Map<Invoice, BuyerInformation>(invoice);
+            entity.PaymentTolerance = storeBlob.PaymentTolerance;
             //Another way of passing buyer info to support
             FillBuyerInfo(invoice.Buyer, entity.BuyerInformation);
             if (entity?.BuyerInformation?.BuyerEmail != null)

BTCPayServer/Controllers/StoresController.cs

@@ -431,6 +431,7 @@ namespace BTCPayServer.Controllers
             vm.MonitoringExpiration = storeBlob.MonitoringExpiration;
             vm.InvoiceExpiration = storeBlob.InvoiceExpiration;
             vm.LightningDescriptionTemplate = storeBlob.LightningDescriptionTemplate;
+            vm.PaymentTolerance = storeBlob.PaymentTolerance;
             return View(vm);
         }
 
@@ -496,6 +497,7 @@ namespace BTCPayServer.Controllers
             blob.MonitoringExpiration = model.MonitoringExpiration;
             blob.InvoiceExpiration = model.InvoiceExpiration;
             blob.LightningDescriptionTemplate = model.LightningDescriptionTemplate ?? string.Empty;
+            blob.PaymentTolerance = model.PaymentTolerance;
 
             if (StoreData.SetStoreBlob(blob))
             {

BTCPayServer/Data/StoreData.cs

@@ -247,6 +247,7 @@ namespace BTCPayServer.Data
         {
             InvoiceExpiration = 15;
             MonitoringExpiration = 60;
+            PaymentTolerance = 0;
             RequiresRefundEmail = true;
         }
         public bool NetworkFeeDisabled
@@ -326,6 +327,10 @@ namespace BTCPayServer.Data
             }
         }
 
+        [DefaultValue(0)]
+        [JsonProperty(DefaultValueHandling = DefaultValueHandling.Populate)]
+        public double PaymentTolerance { get; set; }
+
         public BTCPayServer.Rating.RateRules GetRateRules(BTCPayNetworkProvider networkProvider)
         {
             if (!RateScripting || 

BTCPayServer/HostedServices/InvoiceNotificationManager.cs

@@ -312,6 +312,7 @@ namespace BTCPayServer.HostedServices
                 {
                     if (e.Name == "invoice_expired" ||
                        e.Name == "invoice_paidInFull" ||
+                       e.Name == "invoice_paidWithinTolerance" ||
                        e.Name == "invoice_failedToConfirm" ||
                        e.Name == "invoice_markedInvalid" ||
                        e.Name == "invoice_failedToConfirm" ||

BTCPayServer/HostedServices/InvoiceWatcher.cs

@@ -96,13 +96,30 @@ namespace BTCPayServer.HostedServices
                     }
                 }
 
-                if (accounting.Paid < accounting.TotalDue && invoice.GetPayments().Count != 0 && invoice.ExceptionStatus != "paidPartial")
+                if (accounting.Paid < accounting.TotalDue && invoice.GetPayments().Count != 0)
+                {
+                    if (invoice.PaymentTolerance > 0)
+                    {
+                        var tolerantAmount = (accounting.TotalDue.Satoshi * (invoice.PaymentTolerance / 100));
+                        var minimumTotalDue = accounting.TotalDue.Satoshi - tolerantAmount;
+                        if (accounting.Paid.Satoshi >= minimumTotalDue)
+                        {
+                            context.Events.Add(new InvoiceEvent(invoice, 1003, "invoide_paidWithinTolerance"));
+                            invoice.ExceptionStatus = "paidWithinTolerance";
+                            invoice.Status = "paid";
+                        }
+                    }
+
+                    if (invoice.ExceptionStatus != "paidPartial")
                     {
                         invoice.ExceptionStatus = "paidPartial";
                         context.MarkDirty();
                     }
                 }
 
+               
+            }
+
             // Just make sure RBF did not cancelled a payment
             if (invoice.Status == "paid")
             {

BTCPayServer/Models/InvoiceResponse.cs

@@ -178,7 +178,7 @@ namespace BTCPayServer.Models
         }
 
         //"exceptionStatus":false
-        //Can be `paidPartial`, `paidOver`, or false
+        //Can be `paidPartial`, `paidOver`, `paidWithinTolerance` or false
         [JsonProperty("exceptionStatus")]
         public JToken ExceptionStatus
         {

BTCPayServer/Models/StoreViewModels/StoreViewModel.cs

@@ -85,5 +85,13 @@ namespace BTCPayServer.Models.StoreViewModels
         {
             get; set;
         } = new List<LightningNode>();
+
+        [Display(Name = "Consider the invoice paid even if the paid amount is ... % less than expected")]
+        [Range(0, 100)]
+        public double PaymentTolerance
+        {
+            get;
+            set;
+        }
     }
 }

BTCPayServer/Services/Invoices/InvoiceEntity.cs

@@ -314,6 +314,7 @@ namespace BTCPayServer.Services.Invoices
         }
         public bool ExtendedNotifications { get; set; }
         public List<InvoiceEventData> Events { get; internal set; }
+        public double PaymentTolerance { get; set; }
 
         public bool IsExpired()
         {

BTCPayServer/Views/Stores/UpdateStore.cshtml

@@ -44,6 +44,11 @@
                 <input asp-for="MonitoringExpiration" class="form-control" />
                 <span asp-validation-for="MonitoringExpiration" class="text-danger"></span>
             </div>
+            <div class="form-group">
+                <label asp-for="PaymentTolerance"></label>
+                <input asp-for="PaymentTolerance" class="form-control" />
+                <span asp-validation-for="PaymentTolerance" class="text-danger"></span>
+            </div>
             <div class="form-group">
                 <label asp-for="SpeedPolicy"></label>
                 <select asp-for="SpeedPolicy" class="form-control">