Better handle transition from paid to invalid

BTCPayServer/BTCPayServer.csproj

@@ -2,7 +2,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>netcoreapp2.0</TargetFramework>
-		<Version>1.0.0.21</Version>
+		<Version>1.0.0.22</Version>
   </PropertyGroup>
   <ItemGroup>
     <Compile Remove="Build\dockerfiles\**" />

BTCPayServer/Controllers/InvoiceController.cs

@@ -75,8 +75,9 @@ namespace BTCPayServer.Controllers
 			_FeeProvider = feeProvider ?? throw new ArgumentNullException(nameof(feeProvider));
 		}
 
-		internal async Task<DataWrapper<InvoiceResponse>> CreateInvoiceCore(Invoice invoice, StoreData store, string serverUrl, double expiryMinutes = 15)
+		internal async Task<DataWrapper<InvoiceResponse>> CreateInvoiceCore(Invoice invoice, StoreData store, string serverUrl, double expiryMinutes = 15, double monitoringMinutes = 60)
 		{
+			//TODO: expiryMinutes (time before a new invoice can become paid) and monitoringMinutes (time before a paid invoice becomes invalid)  should be configurable at store level
 			var derivationStrategy = store.DerivationStrategy;
 			var entity = new InvoiceEntity
 			{
@@ -88,6 +89,7 @@ namespace BTCPayServer.Controllers
 				notificationUri = null;
 			EmailAddressAttribute emailValidator = new EmailAddressAttribute();
 			entity.ExpirationTime = entity.InvoiceTime.AddMinutes(expiryMinutes);
+			entity.MonitoringExpiration = entity.InvoiceTime.AddMinutes(monitoringMinutes);
 			entity.OrderId = invoice.OrderId;
 			entity.ServerUrl = serverUrl;
 			entity.FullNotifications = invoice.FullNotifications;

BTCPayServer/Services/Invoices/InvoiceEntity.cs

@@ -248,6 +248,11 @@ namespace BTCPayServer.Services.Invoices
 			get;
 			set;
 		}
+		public DateTimeOffset? MonitoringExpiration
+		{
+			get;
+			set;
+		}
 
 		public bool IsExpired()
 		{

BTCPayServer/Services/Invoices/InvoiceWatcher.cs

@@ -80,7 +80,9 @@ namespace BTCPayServer.Services.Invoices
 						Logs.PayServer.LogInformation($"Invoice {invoice.Id}: {stateBefore} => {invoice.Status}");
 					}
 
-					if(invoice.Status == "complete" || invoice.Status == "invalid")
+					var expirationMonitoring = invoice.MonitoringExpiration.HasValue ? invoice.MonitoringExpiration.Value : invoice.InvoiceTime + TimeSpan.FromMinutes(60);
+					if(invoice.Status == "complete" || 
+					   ((invoice.Status == "invalid" || invoice.Status == "expired") && expirationMonitoring < DateTimeOffset.UtcNow))
 					{
 						if(await _InvoiceRepository.RemovePendingInvoice(invoice.Id).ConfigureAwait(false))
 							Logs.PayServer.LogInformation("Stopped watching invoice " + invoiceId);
@@ -106,15 +108,7 @@ namespace BTCPayServer.Services.Invoices
 		private async Task<(bool NeedSave, UTXOChanges Changes)> UpdateInvoice(UTXOChanges changes, InvoiceEntity invoice)
 		{
 			bool needSave = false;
-			
+			//Fetch unknown payments
-			if(invoice.Status == "new" && invoice.ExpirationTime < DateTimeOffset.UtcNow)
-			{
-				needSave = true;
-				invoice.Status = "expired";
-			}
-
-			if(invoice.Status == "expired" || invoice.Status == "new" || invoice.Status == "invalid")
-			{
 			var strategy = _DerivationFactory.Parse(invoice.DerivationStrategy);
 			changes = await _ExplorerClient.SyncAsync(strategy, changes, !LongPollingMode, _Cts.Token).ConfigureAwait(false);
 
@@ -135,19 +129,21 @@ namespace BTCPayServer.Services.Invoices
 			{
 				var payment = await _InvoiceRepository.AddPayment(invoice.Id, coin).ConfigureAwait(false);
 				invoice.Payments.Add(payment);
-					if(invoice.Status == "expired")
+			}
+			//////
+
+			if(invoice.Status == "new" && invoice.ExpirationTime < DateTimeOffset.UtcNow)
 			{
-						if(invoice.ExceptionStatus == null)
-							invoice.ExceptionStatus = "paidLate";
 				needSave = true;
-					}
+				invoice.Status = "expired";
-				}
 			}
 
-			if(invoice.Status == "new")
+			if(invoice.Status == "new" || invoice.Status == "expired")
 			{
 				var totalPaid = invoice.Payments.Select(p => p.Output.Value).Sum();
 				if(totalPaid >= invoice.GetTotalCryptoDue())
+				{
+					if(invoice.Status == "new")
 					{
 						invoice.Status = "paid";
 						if(invoice.FullNotifications)
@@ -157,6 +153,12 @@ namespace BTCPayServer.Services.Invoices
 						invoice.ExceptionStatus = null;
 						needSave = true;
 					}
+					else if(invoice.Status == "expired")
+					{
+						invoice.ExceptionStatus = "paidLate";
+						needSave = true;
+					}
+				}
 
 				if(totalPaid > invoice.GetTotalCryptoDue() && invoice.ExceptionStatus != "paidOver")
 				{
@@ -172,6 +174,8 @@ namespace BTCPayServer.Services.Invoices
 			}
 
 			if(invoice.Status == "paid")
+			{
+				if(!invoice.MonitoringExpiration.HasValue || invoice.MonitoringExpiration > DateTimeOffset.UtcNow)
 				{
 					var transactions = await GetPaymentsWithTransaction(invoice);
 					if(invoice.SpeedPolicy == SpeedPolicy.HighSpeed)
@@ -195,6 +199,12 @@ namespace BTCPayServer.Services.Invoices
 						needSave = true;
 					}
 				}
+				else
+				{
+					invoice.Status = "invalid";
+					needSave = true;
+				}
+			}
 
 			if(invoice.Status == "confirmed")
 			{