From 08beffb0051ff9d0e2aafef69bc0e12f827bf2e7 Mon Sep 17 00:00:00 2001
From: "nicolas.dorier" <nicolas.dorier@gmail.com>
Date: Sun, 5 Apr 2020 16:50:19 +0900
Subject: [PATCH] Make sure FindPaymentViaPolling does not requests over and
 over the same coins

---
 BTCPayServer/Payments/Bitcoin/NBXplorerListener.cs | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/BTCPayServer/Payments/Bitcoin/NBXplorerListener.cs b/BTCPayServer/Payments/Bitcoin/NBXplorerListener.cs
index e6b1b8eff..52fe3b2c0 100644
--- a/BTCPayServer/Payments/Bitcoin/NBXplorerListener.cs
+++ b/BTCPayServer/Payments/Bitcoin/NBXplorerListener.cs
@@ -320,6 +320,8 @@ namespace BTCPayServer.Payments.Bitcoin
         {
             int totalPayment = 0;
             var invoices = await _InvoiceRepository.GetPendingInvoices();
+            var coinsPerDerivationStrategy =
+                new Dictionary<DerivationStrategyBase, ReceivedCoin[]>();
             foreach (var invoiceId in invoices)
             {
                 var invoice = await _InvoiceRepository.GetInvoice(invoiceId, true);
@@ -334,8 +336,13 @@ namespace BTCPayServer.Payments.Bitcoin
                 
                 if (!invoice.Support(cryptoId))
                     continue;
-                var coins = (await wallet.GetUnspentCoins(strategy))
-                             .Where(c => invoice.AvailableAddressHashes.Contains(c.ScriptPubKey.Hash.ToString() + cryptoId))
+
+                if (!coinsPerDerivationStrategy.TryGetValue(strategy, out var coins))
+                {
+                    coins = await wallet.GetUnspentCoins(strategy);
+                    coinsPerDerivationStrategy.Add(strategy, coins);
+                }
+                coins = coins.Where(c => invoice.AvailableAddressHashes.Contains(c.ScriptPubKey.Hash.ToString() + cryptoId))
                              .ToArray();
                 foreach (var coin in coins.Where(c => !alreadyAccounted.Contains(c.OutPoint)))
                 {