From 51db6175841d24b1fdabbfb3f4f6528bfd58dc60 Mon Sep 17 00:00:00 2001
From: Kukks <evilkukka@gmail.com>
Date: Fri, 17 Apr 2020 11:55:24 +0200
Subject: [PATCH] fixes

---
 .../PayJoin/PayJoinEndpointController.cs      |  5 ++-
 BTCPayServer/Services/PayjoinClient.cs        | 33 ++++++++++++++++---
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/BTCPayServer/Payments/PayJoin/PayJoinEndpointController.cs b/BTCPayServer/Payments/PayJoin/PayJoinEndpointController.cs
index 1cad6f693..6efdc22d9 100644
--- a/BTCPayServer/Payments/PayJoin/PayJoinEndpointController.cs
+++ b/BTCPayServer/Payments/PayJoin/PayJoinEndpointController.cs
@@ -451,8 +451,11 @@ namespace BTCPayServer.Payments.PayJoin
             foreach (var selectedUtxo in selectedUTXOs.Select(o => o.Value))
             {
                 var signedInput = newPsbt.Inputs.FindIndexedInput(selectedUtxo.Outpoint);
-                signedInput.UpdateFromCoin(selectedUtxo.AsCoin());
+                var coin = selectedUtxo.AsCoin(derivationSchemeSettings.AccountDerivation);
+                signedInput.UpdateFromCoin(coin);
                 var privateKey = accountKey.Derive(selectedUtxo.KeyPath).PrivateKey;
+                //hack until UpdateFromCoin is fixed in NBitcoin when the coin is p2sh
+                signedInput.WitnessUtxo = coin.TxOut;
                 signedInput.Sign(privateKey);
                 signedInput.FinalizeInput();
                 newTx.Inputs[signedInput.Index].WitScript = newPsbt.Inputs[(int)signedInput.Index].FinalScriptWitness;
diff --git a/BTCPayServer/Services/PayjoinClient.cs b/BTCPayServer/Services/PayjoinClient.cs
index 3e617bdba..17e95dcc9 100644
--- a/BTCPayServer/Services/PayjoinClient.cs
+++ b/BTCPayServer/Services/PayjoinClient.cs
@@ -34,9 +34,9 @@ namespace BTCPayServer.Services
             if (i.WitnessUtxo.ScriptPubKey.IsScriptType(ScriptType.P2WPKH))
                 return ScriptPubKeyType.Segwit;
             if (i.WitnessUtxo.ScriptPubKey.IsScriptType(ScriptType.P2SH) &&
-                i.FinalScriptWitness.GetSigner().ScriptPubKey.IsScriptType(ScriptType.P2WPKH))
+                PayToWitPubKeyHashTemplate.Instance.ExtractWitScriptParameters(i.FinalScriptWitness) is {})
                 return ScriptPubKeyType.SegwitP2SH;
-            return null as ScriptPubKeyType?;
+            return null;
         }
     }
 
@@ -212,8 +212,33 @@ namespace BTCPayServer.Services
             if (sentAfter > sentBefore)
             {
                 var overPaying = sentAfter - sentBefore;
-                if (!newPSBT.TryGetEstimatedFeeRate(out var newFeeRate) || !newPSBT.TryGetVirtualSize(out var newVirtualSize))
-                    throw new PayjoinSenderException("The payjoin receiver did not included UTXO information to calculate fee correctly");
+               
+                //hack until GetAllCoins is fixed in NBitcoin when the coin is p2sh (redeem needs to be loaded from RedeemScript and fallback to i.FinalScriptSig extraction)
+                int newVirtualSize = 0;
+                if (type == ScriptPubKeyType.SegwitP2SH)
+                {
+                    if (!newPSBT.TryGetFee(out var fee))
+                    {
+                        throw new PayjoinSenderException("The payjoin receiver did not included UTXO information to calculate fee correctly");
+                    }
+                    var transactionBuilder = originalTx.Network.CreateTransactionBuilder();
+                    transactionBuilder.AddCoins(newPSBT.Inputs.Select(i =>i.GetCoin().ToScriptCoin(i.RedeemScript??PayToScriptHashTemplate.Instance.ExtractScriptSigParameters(i.FinalScriptSig).RedeemScript)));
+                    try
+                    {
+                        newVirtualSize = transactionBuilder.EstimateSize(newPSBT.GetGlobalTransaction(), true);
+                    }
+                    catch
+                    {
+                        throw new PayjoinSenderException("The payjoin receiver did not included UTXO information to calculate fee correctly");
+                    }
+                    
+                }
+                else
+                {
+                    if (!newPSBT.TryGetEstimatedFeeRate(out var newFeeRate) || !newPSBT.TryGetVirtualSize(out newVirtualSize))
+                        throw new PayjoinSenderException("The payjoin receiver did not included UTXO information to calculate fee correctly");
+                }
+                
                 var additionalFee = newPSBT.GetFee() - originalFee;
                 if (overPaying > additionalFee)
                     throw new PayjoinSenderException("The payjoin receiver is sending more money to himself");