Add zero inputs for transfers to own addresses

Sources/NBitcoin/DeStreamTransactionBuilder.cs

@@ -33,22 +33,46 @@ namespace NBitcoin
             // we add input with uint256.Zero hash that points to output with change
             int changeIndex = ctx.Transaction.Outputs.FindIndex(p =>
                 p.ScriptPubKey == group.ChangeScript[(int) ctx.ChangeType]);
-            
-            if (changeIndex == -1) return result;
 
-            var outPoint = new OutPoint
+            if (changeIndex != -1)
             {
-                Hash = uint256.Zero,
-                N = (uint) changeIndex
-            };
+                var outPoint = new OutPoint
+                {
+                    Hash = uint256.Zero,
+                    N = (uint) changeIndex
+                };
 
-            ctx.Transaction.AddInput(new TxIn
+                ctx.Transaction.AddInput(new TxIn
+                {
+                    PrevOut = outPoint
+                });
+
+                group.Coins.Add(outPoint, new Coin(uint256.Zero, outPoint.N,
+                    Money.Zero, group.ChangeScript[(int) ctx.ChangeType]));
+            }
+
+            foreach (var ownAddress in group.ownAddresses)
             {
-                PrevOut = outPoint
-            });
+                var ownAddressOutputIndex = ctx.Transaction.Outputs.FindIndex(p =>
+                    string.Equals(p.ScriptPubKey.GetDestinationAddress(this.Network).ToString(), ownAddress));
+                
+                if(ownAddressOutputIndex == -1 || ownAddressOutputIndex == changeIndex)
+                    continue;
+                
+                var outPoint = new OutPoint
+                {
+                    Hash = uint256.Zero,
+                    N = (uint) ownAddressOutputIndex
+                };
+
+                ctx.Transaction.AddInput(new TxIn
+                {
+                    PrevOut = outPoint
+                });
 
-            group.Coins.Add(outPoint, new Coin(uint256.Zero, outPoint.N,
-                Money.Zero, @group.ChangeScript[(int) ctx.ChangeType]));
+                group.Coins.Add(outPoint, new Coin(uint256.Zero, outPoint.N,
+                    Money.Zero, ctx.Transaction.Outputs[ownAddressOutputIndex].ScriptPubKey));
+            }
 
             return result;
         }

Sources/NBitcoin/TransactionBuilder.cs

@@ -495,6 +495,7 @@ namespace NBitcoin
             internal List<Builder> IssuanceBuilders = new List<Builder>();
             internal Dictionary<AssetId, List<Builder>> BuildersByAsset = new Dictionary<AssetId, List<Builder>>();
             internal Script[] ChangeScript = new Script[3];
+            internal IEnumerable<string> ownAddresses { get; set; }
             internal void Shuffle()
             {
                 Shuffle(this.Builders);
@@ -1074,6 +1075,12 @@ namespace NBitcoin
             return this;
         }
 
+        public TransactionBuilder SetOwnAddresses(IEnumerable<string> ownAddresses)
+        {
+            this.CurrentGroup.ownAddresses = ownAddresses;
+            return this;
+        }
+
         public TransactionBuilder SetCoinSelector(ICoinSelector selector)
         {
             if(selector == null)

Sources/Stratis.Bitcoin.Features.Wallet/DeStreamWalletTransactionHandler.cs

@@ -30,6 +30,18 @@ namespace Stratis.Bitcoin.Features.Wallet
             }
         }
 
+        protected override void InitializeTransactionBuilder(TransactionBuildContext context)
+        {
+            base.InitializeTransactionBuilder(context);
+            this.AddOwnAddresses(context);
+        }
+
+        private void AddOwnAddresses(TransactionBuildContext context)
+        {
+            context.TransactionBuilder.SetOwnAddresses(
+                (this.walletManager as IDeStreamWalletManager).GetOwnAddresses(context.AccountReference));
+        }
+
         /// <inheritdoc />
         protected override void AddFee(TransactionBuildContext context)
         {
@@ -140,6 +152,29 @@ namespace Stratis.Bitcoin.Features.Wallet
                 seedExtKey.Derive(new KeyPath(context.ChangeAddress.HdPath)).GetWif(wallet.Network);
             signingKeys.Add(changeAddressPrivateKey);
 
+            var transfersToSelf = context.Recipients.Where(p =>
+                (this.walletManager as IDeStreamWalletManager).GetOwnAddresses(context.AccountReference)
+                .Contains(p.ScriptPubKey.GetDestinationAddress(this.network).ToString()) && context.UnspentOutputs.All(q => p.ScriptPubKey != q.Address.ScriptPubKey));
+
+            foreach (var ownAddress in transfersToSelf)
+            {
+                var ownHdAddress = this.walletManager.GetAccounts(context.AccountReference.WalletName)
+                    .Single(q => q.Name == context.AccountReference.AccountName).GetCombinedAddresses()
+                    .Single(p => string.Equals(ownAddress.ScriptPubKey.GetDestinationAddress(this.network).ToString(), p.Address));
+                var ownAddressPrivateKey = seedExtKey.Derive(new KeyPath(ownHdAddress.HdPath)).GetWif(wallet.Network);
+                signingKeys.Add(ownAddressPrivateKey);
+            }
+
+//            signingKeys.UnionWith(context.Recipients.Where(p =>
+//                (this.walletManager as IDeStreamWalletManager).GetOwnAddresses(context.AccountReference)
+//                .Contains(p.ScriptPubKey.GetDestinationAddress(this.network).ToString()) &&
+//                context.UnspentOutputs.All(q => p.ScriptPubKey != q.Address.ScriptPubKey)).Select(r =>
+//                seedExtKey.Derive(new KeyPath(this.walletManager.GetAccounts(context.AccountReference.WalletName)
+//                    .Single(q => q.Name == context.AccountReference.AccountName).GetCombinedAddresses()
+//                    .Single(p =>
+//                        string.Equals(r.ScriptPubKey.GetDestinationAddress(this.network).ToString(), p.Address))
+//                    .HdPath)).GetWif(wallet.Network)));
+
             context.TransactionBuilder.AddKeys(signingKeys.ToArray());
         }