Better UX to set the xpub correctly

BTCPayServer.Tests/TestAccount.cs

@@ -82,7 +82,6 @@ namespace BTCPayServer.Tests
 
             await store.AddDerivationScheme(StoreId, new DerivationSchemeViewModel()
             {
-                DerivationSchemeFormat = "BTCPay",
                 DerivationScheme = DerivationScheme.ToString(),
                 Confirmation = true
             }, cryptoCode);

BTCPayServer.Tests/UnitTest1.cs

@@ -806,6 +806,44 @@ namespace BTCPayServer.Tests
             }
         }
 
+        [Fact]
+        public void CanParseDerivationScheme()
+        {
+            var parser = new DerivationSchemeParser(Network.TestNet, NBXplorer.ChainType.Test);
+            NBXplorer.DerivationStrategy.DerivationStrategyBase result;
+            //  Passing electrum stuff
+            // Native
+            result = parser.Parse("zpub6nL6PUGurpU3DfPDSZaRS6WshpbNc9ctCFFzrCn54cssnheM31SZJZUcFHKtjJJNhAueMbh6ptFMfy1aeiMQJr3RJ4DDt1hAPx7sMTKV48t");
+            Assert.Equal("tpubD93CJNkmGjLXnsBqE2zGDqfEh1Q8iJ8wueordy3SeWt1RngbbuxXCsqASuVWFywmfoCwUE1rSfNJbaH4cBNcbp8WcyZgPiiRSTazLGL8U9w", result.ToString());
+            // P2SH
+            result = parser.Parse("ypub6QqdH2c5z79681jUgdxjGJzGW9zpL4ryPCuhtZE4GpvrJoZqM823XQN6iSQeVbbbp2uCRQ9UgpeMcwiyV6qjvxTWVcxDn2XEAnioMUwsrQ5");
+            Assert.Equal("tpubD6NzVbkrYhZ4YWjDJUACG9E8fJx2NqNY1iynTiPKEjJrzzRKAgha3nNnwGXr2BtvCJKJHW4nmG7rRqc2AGGy2AECgt16seMyV2FZivUmaJg-[p2sh]", result.ToString());
+            result = parser.Parse("xpub661MyMwAqRbcGeVGU5e5KBcau1HHEUGf9Wr7k4FyLa8yRPNQrrVa7Ndrgg8Afbe2UYXMSL6tJBFd2JewwWASsePPLjkcJFL1tTVEs3UQ23X");
+            Assert.Equal("tpubD6NzVbkrYhZ4YSg7vGdAX6wxE8NwDrmih9SR6cK7gUtsAg37w5LfFpJgviCxC6bGGT4G3uckqH5fiV9ZLN1gm5qgQLVuymzFUR5ed7U7ksu-[legacy]", result.ToString());
+            ////////////////
+        
+            result = parser.Parse("tpubD6NzVbkrYhZ4Wc65tjhmcKdWFauAo7bGLRTxvggygkNyp6SMGutJp7iociwsinU33jyNBp1J9j2hJH5yQsayfiS3LEU2ZqXodAcnaygra8o");
+            Assert.Equal("tpubD6NzVbkrYhZ4Wc65tjhmcKdWFauAo7bGLRTxvggygkNyp6SMGutJp7iociwsinU33jyNBp1J9j2hJH5yQsayfiS3LEU2ZqXodAcnaygra8o", result.ToString());
+            parser.HintScriptPubKey = BitcoinAddress.Create("tb1q4s33amqm8l7a07zdxcunqnn3gcsjcfz3xc573l", parser.Network).ScriptPubKey;
+            result = parser.Parse("tpubD6NzVbkrYhZ4Wc65tjhmcKdWFauAo7bGLRTxvggygkNyp6SMGutJp7iociwsinU33jyNBp1J9j2hJH5yQsayfiS3LEU2ZqXodAcnaygra8o");
+            Assert.Equal("tpubD6NzVbkrYhZ4Wc65tjhmcKdWFauAo7bGLRTxvggygkNyp6SMGutJp7iociwsinU33jyNBp1J9j2hJH5yQsayfiS3LEU2ZqXodAcnaygra8o", result.ToString());
+
+            parser.HintScriptPubKey = BitcoinAddress.Create("2N2humNio3YTApSfY6VztQ9hQwDnhDvaqFQ", parser.Network).ScriptPubKey;
+            result = parser.Parse("tpubD6NzVbkrYhZ4Wc65tjhmcKdWFauAo7bGLRTxvggygkNyp6SMGutJp7iociwsinU33jyNBp1J9j2hJH5yQsayfiS3LEU2ZqXodAcnaygra8o");
+            Assert.Equal("tpubD6NzVbkrYhZ4Wc65tjhmcKdWFauAo7bGLRTxvggygkNyp6SMGutJp7iociwsinU33jyNBp1J9j2hJH5yQsayfiS3LEU2ZqXodAcnaygra8o-[p2sh]", result.ToString());
+
+            parser.HintScriptPubKey = BitcoinAddress.Create("mwD8bHS65cdgUf6rZUUSoVhi3wNQFu1Nfi", parser.Network).ScriptPubKey;
+            result = parser.Parse("tpubD6NzVbkrYhZ4Wc65tjhmcKdWFauAo7bGLRTxvggygkNyp6SMGutJp7iociwsinU33jyNBp1J9j2hJH5yQsayfiS3LEU2ZqXodAcnaygra8o");
+            Assert.Equal("tpubD6NzVbkrYhZ4Wc65tjhmcKdWFauAo7bGLRTxvggygkNyp6SMGutJp7iociwsinU33jyNBp1J9j2hJH5yQsayfiS3LEU2ZqXodAcnaygra8o-[legacy]", result.ToString());
+
+            parser.HintScriptPubKey = BitcoinAddress.Create("2N2humNio3YTApSfY6VztQ9hQwDnhDvaqFQ", parser.Network).ScriptPubKey;
+            result = parser.Parse("tpubD6NzVbkrYhZ4Wc65tjhmcKdWFauAo7bGLRTxvggygkNyp6SMGutJp7iociwsinU33jyNBp1J9j2hJH5yQsayfiS3LEU2ZqXodAcnaygra8o-[legacy]");
+            Assert.Equal("tpubD6NzVbkrYhZ4Wc65tjhmcKdWFauAo7bGLRTxvggygkNyp6SMGutJp7iociwsinU33jyNBp1J9j2hJH5yQsayfiS3LEU2ZqXodAcnaygra8o-[p2sh]", result.ToString());
+
+            result = parser.Parse("tpubD6NzVbkrYhZ4Wc65tjhmcKdWFauAo7bGLRTxvggygkNyp6SMGutJp7iociwsinU33jyNBp1J9j2hJH5yQsayfiS3LEU2ZqXodAcnaygra8o");
+            Assert.Equal("tpubD6NzVbkrYhZ4Wc65tjhmcKdWFauAo7bGLRTxvggygkNyp6SMGutJp7iociwsinU33jyNBp1J9j2hJH5yQsayfiS3LEU2ZqXodAcnaygra8o-[p2sh]", result.ToString());
+        }
+
         [Fact]
         public void InvoiceFlowThroughDifferentStatesCorrectly()
         {

BTCPayServer/Controllers/StoresController.BTCLike.cs

@@ -75,7 +75,7 @@ namespace BTCPayServer.Controllers
             {
                 if (!string.IsNullOrEmpty(vm.DerivationScheme))
                 {
-                    strategy = ParseDerivationStrategy(vm.DerivationScheme, vm.DerivationSchemeFormat, network);
+                    strategy = ParseDerivationStrategy(vm.DerivationScheme, null, network);
                     vm.DerivationScheme = strategy.ToString();
                 }
             }
@@ -86,8 +86,38 @@ namespace BTCPayServer.Controllers
                 return View(vm);
             }
 
+            if (!vm.Confirmation && strategy != null)
+                return ShowAddresses(vm, strategy);
 
-            if (vm.Confirmation || strategy == null)
+            if (vm.Confirmation && !string.IsNullOrWhiteSpace(vm.HintAddress))
+            {
+                BitcoinAddress address = null;
+                try
+                {
+                    address = BitcoinAddress.Create(vm.HintAddress, network.NBitcoinNetwork);
+                }
+                catch
+                {
+                    ModelState.AddModelError(nameof(vm.HintAddress), "Invalid hint address");
+                    return ShowAddresses(vm, strategy);
+                }
+
+                try
+                {
+                    strategy = ParseDerivationStrategy(vm.DerivationScheme, address.ScriptPubKey, network);
+                }
+                catch
+                {
+                    ModelState.AddModelError(nameof(vm.HintAddress), "Impossible to find a match with this address");
+                    return ShowAddresses(vm, strategy);
+                }
+                vm.HintAddress = "";
+                vm.StatusMessage = "Address successfully found, please verify that the rest is correct and click on \"Confirm\"";
+                ModelState.Remove(nameof(vm.HintAddress));
+                ModelState.Remove(nameof(vm.DerivationScheme));
+                return ShowAddresses(vm, strategy);
+            }
+            else
             {
                 try
                 {
@@ -105,8 +135,11 @@ namespace BTCPayServer.Controllers
                 StatusMessage = $"Derivation scheme for {network.CryptoCode} has been modified.";
                 return RedirectToAction(nameof(UpdateStore), new { storeId = storeId });
             }
-            else
+        }
+
+        private IActionResult ShowAddresses(DerivationSchemeViewModel vm, DerivationStrategy strategy)
         {
+            vm.DerivationScheme = strategy.DerivationStrategyBase.ToString();
             if (!string.IsNullOrEmpty(vm.DerivationScheme))
             {
                 var line = strategy.DerivationStrategyBase.GetLineFor(DerivationFeature.Deposit);
@@ -114,14 +147,12 @@ namespace BTCPayServer.Controllers
                 for (int i = 0; i < 10; i++)
                 {
                     var address = line.Derive((uint)i);
-                        vm.AddressSamples.Add((DerivationStrategyBase.GetKeyPath(DerivationFeature.Deposit).Derive((uint)i).ToString(), address.ScriptPubKey.GetDestinationAddress(network.NBitcoinNetwork).ToString()));
+                    vm.AddressSamples.Add((DerivationStrategyBase.GetKeyPath(DerivationFeature.Deposit).Derive((uint)i).ToString(), address.ScriptPubKey.GetDestinationAddress(strategy.Network.NBitcoinNetwork).ToString()));
                 }
             }
             vm.Confirmation = true;
             return View(vm);
         }
-        }
-
 
 
         public class GetInfoResult
@@ -219,7 +250,8 @@ namespace BTCPayServer.Controllers
                 }
                 if (command == "getxpub")
                 {
-                    var getxpubResult = await hw.GetExtPubKey(network, account); ;
+                    var getxpubResult = await hw.GetExtPubKey(network, account);
+                    ;
                     getxpubResult.CoinType = (int)(getxpubResult.KeyPath.Indexes[1] - 0x80000000);
                     result = getxpubResult;
                 }

BTCPayServer/Controllers/StoresController.cs

@@ -327,41 +327,11 @@ namespace BTCPayServer.Controllers
             });
         }
 
-        private DerivationStrategy ParseDerivationStrategy(string derivationScheme, string format, BTCPayNetwork network)
+        private DerivationStrategy ParseDerivationStrategy(string derivationScheme, Script hint, BTCPayNetwork network)
         {
-            if (format == "Electrum")
-            {
-                //Unsupported Electrum
-                //var p2wsh_p2sh = 0x295b43fU;
-                //var p2wsh = 0x2aa7ed3U;
-                Dictionary<uint, string[]> electrumMapping = new Dictionary<uint, string[]>();
-                //Source https://github.com/spesmilo/electrum/blob/9edffd17542de5773e7284a8c8a2673c766bb3c3/lib/bitcoin.py
-                var standard = 0x0488b21eU;
-                electrumMapping.Add(standard, new[] { "legacy" });
-                var p2wpkh_p2sh = 0x049d7cb2U;
-                electrumMapping.Add(p2wpkh_p2sh, new string[] { "p2sh" });
-                var p2wpkh = 0x4b24746U;
-                electrumMapping.Add(p2wpkh, Array.Empty<string>());
-
-                var data = Encoders.Base58Check.DecodeData(derivationScheme);
-                if (data.Length < 4)
-                    throw new FormatException("data.Length < 4");
-                var prefix = Utils.ToUInt32(data, false);
-                if (!electrumMapping.TryGetValue(prefix, out string[] labels))
-                    throw new FormatException("!electrumMapping.TryGetValue(prefix, out string[] labels)");
-                var standardPrefix = Utils.ToBytes(network.NBXplorerNetwork.DefaultSettings.ChainType == NBXplorer.ChainType.Main ? 0x0488b21eU : 0x043587cf, false);
-
-                for (int i = 0; i < 4; i++)
-                    data[i] = standardPrefix[i];
-
-                derivationScheme = new BitcoinExtPubKey(Encoders.Base58Check.EncodeData(data), network.NBitcoinNetwork).ToString();
-                foreach (var label in labels)
-                {
-                    derivationScheme = derivationScheme + $"-[{label}]";
-                }
-            }
-
-            return new DerivationStrategy(new DerivationStrategyFactory(network.NBitcoinNetwork).Parse(derivationScheme), network);
+            var parser = new DerivationSchemeParser(network.NBitcoinNetwork, network.DefaultSettings.ChainType);
+            parser.HintScriptPubKey = hint;
+            return new DerivationStrategy(parser.Parse(derivationScheme), network);
         }
 
         [HttpGet]

BTCPayServer/DerivationSchemeParser.cs

@@ -0,0 +1,180 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using NBitcoin;
+using NBitcoin.DataEncoders;
+using NBXplorer;
+using NBXplorer.DerivationStrategy;
+
+namespace BTCPayServer
+{
+    public class DerivationSchemeParser
+    {
+        public Network Network { get; set; }
+        public ChainType ChainType { get; set; }
+        public Script HintScriptPubKey { get; set; }
+
+        public DerivationSchemeParser(Network expectedNetwork, ChainType chainType)
+        {
+            Network = expectedNetwork;
+            ChainType = chainType;
+        }
+
+        public DerivationStrategyBase Parse(string str)
+        {
+            if (str == null)
+                throw new ArgumentNullException(nameof(str));
+            str = str.Trim();
+
+            HashSet<string> hintedLabels = new HashSet<string>();
+
+            var hintDestination = HintScriptPubKey?.GetDestination();
+            if (hintDestination != null)
+            {
+                if (hintDestination is KeyId)
+                {
+                    hintedLabels.Add("legacy");
+                }
+                if (hintDestination is ScriptId)
+                {
+                    hintedLabels.Add("p2sh");
+                }
+            }
+
+            try
+            {
+                var result = new DerivationStrategyFactory(Network).Parse(str);
+                return FindMatch(hintedLabels, result);
+            }
+            catch
+            {
+            }
+
+            Dictionary<uint, string[]> electrumMapping = new Dictionary<uint, string[]>();
+            //Source https://github.com/spesmilo/electrum/blob/9edffd17542de5773e7284a8c8a2673c766bb3c3/lib/bitcoin.py
+            var standard = 0x0488b21eU;
+            electrumMapping.Add(standard, new[] { "legacy" });
+            var p2wpkh_p2sh = 0x049d7cb2U;
+            electrumMapping.Add(p2wpkh_p2sh, new string[] { "p2sh" });
+            var p2wpkh = 0x4b24746U;
+            electrumMapping.Add(p2wpkh, Array.Empty<string>());
+
+            var parts = str.Split('-');
+            for (int i = 0; i < parts.Length; i++)
+            {
+                if (IsLabel(parts[i]))
+                {
+                    hintedLabels.Add(parts[i].Substring(1, parts[i].Length - 2).ToLowerInvariant());
+                    continue;
+                }
+                try
+                {
+                    var data = Encoders.Base58Check.DecodeData(parts[i]);
+                    if (data.Length < 4)
+                        continue;
+                    var prefix = Utils.ToUInt32(data, false);
+                    var standardPrefix = Utils.ToBytes(ChainType == NBXplorer.ChainType.Main ? 0x0488b21eU : 0x043587cf, false);
+                    for (int ii = 0; ii < 4; ii++)
+                        data[ii] = standardPrefix[ii];
+
+                    var derivationScheme = new BitcoinExtPubKey(Encoders.Base58Check.EncodeData(data), Network).ToString();
+                    electrumMapping.TryGetValue(prefix, out string[] labels);
+                    if (labels != null)
+                    {
+                        foreach (var label in labels)
+                        {
+                            hintedLabels.Add(label.ToLowerInvariant());
+                        }
+                    }
+                    parts[i] = derivationScheme;
+                }
+                catch { continue; }
+            }
+
+            if (hintDestination != null)
+            {
+                if (hintDestination is WitKeyId)
+                {
+                    hintedLabels.Remove("legacy");
+                    hintedLabels.Remove("p2sh");
+                }
+            }
+
+            str = string.Join('-', parts.Where(p => !IsLabel(p)));
+            foreach (var label in hintedLabels)
+            {
+                str = $"{str}-[{label}]";
+            }
+
+            return FindMatch(hintedLabels, new DerivationStrategyFactory(Network).Parse(str));
+        }
+
+        private DerivationStrategyBase FindMatch(HashSet<string> hintLabels, DerivationStrategyBase result)
+        {
+            var facto = new DerivationStrategyFactory(Network);
+            var firstKeyPath = new KeyPath("0/0");
+            if (HintScriptPubKey == null)
+                return result;
+            if (HintScriptPubKey == result.Derive(firstKeyPath).ScriptPubKey)
+                return result;
+
+            if (result is MultisigDerivationStrategy)
+                hintLabels.Add("keeporder");
+
+            var resultNoLabels = result.ToString();
+            resultNoLabels = string.Join('-', resultNoLabels.Split('-').Where(p => !IsLabel(p)));
+            foreach (var labels in ItemCombinations(hintLabels.ToList()))
+            {
+                var hinted = facto.Parse(resultNoLabels + '-' + string.Join('-', labels.Select(l=>$"[{l}]").ToArray()));
+                if (HintScriptPubKey == hinted.Derive(firstKeyPath).ScriptPubKey)
+                    return hinted;
+            }
+            throw new FormatException("Could not find any match");
+        }
+
+        private static bool IsLabel(string v)
+        {
+            return v.StartsWith('[') && v.EndsWith(']');
+        }
+
+        /// <summary>
+		/// Method to create lists containing possible combinations of an input list of items. This is 
+		/// basically copied from code by user "jaolho" on this thread:
+		/// http://stackoverflow.com/questions/7802822/all-possible-combinations-of-a-list-of-values
+		/// </summary>
+		/// <typeparam name="T">type of the items on the input list</typeparam>
+		/// <param name="inputList">list of items</param>
+		/// <param name="minimumItems">minimum number of items wanted in the generated combinations, 
+		///                            if zero the empty combination is included,
+		///                            default is one</param>
+		/// <param name="maximumItems">maximum number of items wanted in the generated combinations,
+		///                            default is no maximum limit</param>
+		/// <returns>list of lists for possible combinations of the input items</returns>
+		public static List<List<T>> ItemCombinations<T>(List<T> inputList, int minimumItems = 1,
+                                                        int maximumItems = int.MaxValue)
+        {
+            int nonEmptyCombinations = (int)Math.Pow(2, inputList.Count) - 1;
+            List<List<T>> listOfLists = new List<List<T>>(nonEmptyCombinations + 1);
+
+            if (minimumItems == 0)  // Optimize default case
+                listOfLists.Add(new List<T>());
+
+            for (int i = 1; i <= nonEmptyCombinations; i++)
+            {
+                List<T> thisCombination = new List<T>(inputList.Count);
+                for (int j = 0; j < inputList.Count; j++)
+                {
+                    if ((i >> j & 1) == 1)
+                        thisCombination.Add(inputList[j]);
+                }
+
+                if (thisCombination.Count >= minimumItems && thisCombination.Count <= maximumItems)
+                    listOfLists.Add(thisCombination);
+            }
+
+            return listOfLists;
+        }
+    }
+}

BTCPayServer/Models/StoreViewModels/DerivationSchemeViewModel.cs

@@ -9,20 +9,8 @@ namespace BTCPayServer.Models.StoreViewModels
 {
     public class DerivationSchemeViewModel
     {
-        class Format
-        {
-            public string Name { get; set; }
-            public string Value { get; set; }
-        }
         public DerivationSchemeViewModel()
         {
-            var btcPay = new Format { Name = "BTCPay", Value = "BTCPay" };
-            DerivationSchemeFormat = btcPay.Value;
-            DerivationSchemeFormats = new SelectList(new Format[]
-            {
-                btcPay,
-                new Format { Name = "Electrum", Value = "Electrum" },
-            }, nameof(btcPay.Value), nameof(btcPay.Name), btcPay);
         }
         public string DerivationScheme
         {
@@ -34,18 +22,12 @@ namespace BTCPayServer.Models.StoreViewModels
             get; set;
         } = new List<(string KeyPath, string Address)>();
 
-        [Display(Name = "Derivation Scheme format")]
-        public string DerivationSchemeFormat
-        {
-            get;
-            set;
-        }
-
         public string CryptoCode { get; set; }
+        [Display(Name = "Hint address")]
+        public string HintAddress { get; set; }
         public bool Confirmation { get; set; }
 
-        public SelectList DerivationSchemeFormats { get; set; }
-
         public string ServerUrl { get; set; }
+        public string StatusMessage { get; internal set; }
     }
 }

BTCPayServer/Views/Stores/AddDerivationScheme.cshtml

@@ -5,6 +5,7 @@
     ViewData.AddActivePage(BTCPayServer.Views.Stores.StoreNavPages.Index);
 }
 
+@Html.Partial("_StatusMessage", Model.StatusMessage)
 <h4>@ViewData["Title"]</h4>
 
 <div class="row">
@@ -39,10 +40,6 @@
                         </ul>
                     </div>
                 </div>
-                <div class="form-group">
-                    <label asp-for="DerivationSchemeFormat"></label>
-                    <select asp-for="DerivationSchemeFormat" asp-items="Model.DerivationSchemeFormats" class="form-control"></select>
-                </div>
                 <div class="form-group">
                     <span>BTCPay format memo</span>
                     <table class="table">
@@ -90,7 +87,6 @@
                 </div>
                 <input type="hidden" asp-for="Confirmation" />
                 <input type="hidden" asp-for="DerivationScheme" />
-                <input type="hidden" asp-for="DerivationSchemeFormat" />
                 <div class="form-group">
                     <table class="table">
                         <thead class="thead-inverse">
@@ -110,6 +106,16 @@
                         </tbody>
                     </table>
                 </div>
+
+                <div class="form-group">
+                    <h5>Wrong addresses?</h5>
+                    <span>Help us to find the correct settings by telling us the first address of your wallet</span>
+                </div>
+                <div class="form-group">
+                    <label asp-for="HintAddress"></label>
+                    <input asp-for="HintAddress" class="form-control" />
+                    <span asp-validation-for="HintAddress" class="text-danger"></span>
+                </div>
                 <button name="command" type="submit" class="btn btn-success">Confirm</button>
             }
         </form>