Automatic coin selection strategies

src/Data/DbInitializer.cs

@@ -214,7 +214,7 @@ public static void Initialize(IServiceProvider serviceProvider)
                     {
                         ChannelAdminMacaroon =
                             "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",
-                        Endpoint = Constants.ALICE_HOST, 
+                        Endpoint = Constants.ALICE_HOST,
                         Name = "Alice",
                         CreationDatetime = DateTimeOffset.UtcNow,
                         PubKey = "02dc2ae598a02fc1e9709a23b68cd51d7fa14b1132295a4d75aa4f5acd23ee9527",
@@ -240,7 +240,7 @@ public static void Initialize(IServiceProvider serviceProvider)
                     };
 
                     _ = Task.Run(() => nodeRepository.AddAsync(carol)).Result;
-                    
+
                     //Bob node from Polar (BOB) LND 0.15.5 -> check devnetwork.zip polar file
                     var bob = new Node
                     {
@@ -253,7 +253,7 @@ public static void Initialize(IServiceProvider serviceProvider)
                         Users = new List<ApplicationUser>(),
                         AutosweepEnabled = false
                     };
-                    
+
                     _ = Task.Run(() => nodeRepository.AddAsync(bob)).Result;
 
                     //Add user to the channel
@@ -262,13 +262,13 @@ public static void Initialize(IServiceProvider serviceProvider)
 
                     var carolUpdateResult = applicationDbContext.Update(adminUser);
                 }
-                
+
                 var internalWallet = applicationDbContext.InternalWallets.FirstOrDefault();
                 if (internalWallet == null)
                 {
                     //Default Internal Wallet
                     internalWallet = CreateWallet.CreateInternalWallet(logger);
-                    
+
                     applicationDbContext.Add(internalWallet);
                     applicationDbContext.SaveChanges();
                 }
@@ -280,14 +280,14 @@ public static void Initialize(IServiceProvider serviceProvider)
                         "social mango annual basic work brain economy one safe physical junk other toy valid load cook napkin maple runway island oil fan legend stem";
                     var wallet2Seed =
                         "solar goat auto bachelor chronic input twin depth fork scale divorce fury mushroom column image sauce car public artist announce treat spend jacket physical";
-        
+
                     logger?.LogInformation("Wallet 1 seed: {MnemonicString}", wallet1Seed);
                     logger?.LogInformation("Wallet 2 seed: {MnemonicString}", wallet2Seed);
-                    
+
                     var user1Key = CreateWallet.CreateUserKey("Key 1", adminUser.Id, wallet1Seed);
                     var user2Key = CreateWallet.CreateUserKey("Key 2", financeUser.Id, wallet2Seed);
-                    
-                    var testingLegacyMultisigWallet = CreateWallet.LegacyMultiSig(internalWallet, "1'", user1Key, user2Key); 
+
+                    var testingLegacyMultisigWallet = CreateWallet.LegacyMultiSig(internalWallet, "1'", user1Key, user2Key);
                     var testingMultisigWallet = CreateWallet.MultiSig(internalWallet, "0", user1Key, user2Key);
                     var testingSinglesigWallet = CreateWallet.SingleSig(internalWallet, "1");
                     var testingSingleSigBIP39Wallet = CreateWallet.BIP39Singlesig();
@@ -329,6 +329,16 @@ public static void Initialize(IServiceProvider serviceProvider)
                     minerRPC.SendToAddress(singlesigAddress, singlesigFundCoins);
                     minerRPC.SendToAddress(singleSigBIP39Address, singleSigBIP39FundCoins);
 
+                    // Create a lot of utxos and send them to the single sig wallet
+                    // Random r = new Random();
+                    // for (var i = 0; i < 1000; i++)
+                    // {
+                    //     var keypath = nbxplorerClient.GetUnused(singlesigDerivationStrategy, DerivationFeature.Deposit);
+                    //     decimal coin = r.Next(536, 10000000);
+                    //     var randomCoint = Money.Coins(coin / 100000000); //20BTC
+                    //     minerRPC.SendToAddress(keypath.Address, randomCoint);
+                    // }
+
                     //6 blocks to confirm
                     minerRPC.Generate(6);
 
@@ -368,7 +378,7 @@ public static void Initialize(IServiceProvider serviceProvider)
                     applicationDbContext.Add(testingSingleSigBIP39Wallet);
                 }
             }
-                
+
             applicationDbContext.SaveChanges();
         }
 

src/Helpers/Constants.cs

@@ -27,6 +27,7 @@ public class Constants
     public static readonly bool ENABLE_REMOTE_SIGNER;
     public static readonly bool PUSH_NOTIFICATIONS_ONESIGNAL_ENABLED;
     public static readonly bool ENABLE_HW_SUPPORT;
+    public static readonly bool NBXPLORER_ENABLE_CUSTOM_BACKEND = false;
 
     // Connections
     public static readonly string POSTGRES_CONNECTIONSTRING = "Host=localhost;Port=5432;Database=fundsmanager;Username=rw_dev;Password=rw_dev";
@@ -102,6 +103,8 @@ static Constants()
 
         ENABLE_HW_SUPPORT = Environment.GetEnvironmentVariable("ENABLE_HW_SUPPORT") != "false"; // We default to true
 
+        NBXPLORER_ENABLE_CUSTOM_BACKEND = Environment.GetEnvironmentVariable("NBXPLORER_ENABLE_CUSTOM_BACKEND") == "true";
+
         // Connections
         POSTGRES_CONNECTIONSTRING =  Environment.GetEnvironmentVariable("POSTGRES_CONNECTIONSTRING") ?? POSTGRES_CONNECTIONSTRING;
 

src/Helpers/ValidationHelper.cs

@@ -64,14 +64,16 @@ public static void ValidateUsername(ValidatorEventArgs obj, List<ApplicationUser
     public static void ValidateChannelCapacity(ValidatorEventArgs obj)
     {
         obj.Status = ValidationStatus.Success;
-        if ((long)obj.Value < Constants.MINIMUM_CHANNEL_CAPACITY_SATS)
+        var minimumChannelValue = new Money(Constants.MINIMUM_CHANNEL_CAPACITY_SATS).ToUnit(MoneyUnit.BTC);
+        var maxChannelRegtestValue = new Money(Constants.MAXIMUM_CHANNEL_CAPACITY_SATS_REGTEST).ToUnit(MoneyUnit.BTC);
+        if ((decimal)obj.Value < minimumChannelValue)
         {
-            obj.ErrorText = "The amount selected must be greater than 20.000";
+            obj.ErrorText = $"The amount selected must be greater than {minimumChannelValue:f8} BTC";
             obj.Status = ValidationStatus.Error;
         }
-        else if ((long)obj.Value > Constants.MAXIMUM_CHANNEL_CAPACITY_SATS_REGTEST && network == Network.RegTest)
+        else if ((decimal)obj.Value > maxChannelRegtestValue && network == Network.RegTest)
         {
-            obj.ErrorText = "The amount selected must be lower than 16.777.215";
+            obj.ErrorText = $"The amount selected must be lower than {maxChannelRegtestValue:f8} BTC";
             obj.Status = ValidationStatus.Error;
         }
     }

src/Pages/ChannelRequests.razor

@@ -131,15 +131,15 @@
                 </DisplayTemplate>
                 <EditTemplate>
                     <Validation Validator="@ValidationHelper.ValidateChannelCapacity" @ref="_capacityValidation">
-                        <NumericPicker TValue="long" @bind-Value="@_amount" CurrencySymbol=" SATS" CurrencySymbolPlacement="CurrencySymbolPlacement.Suffix" Disabled="@(SelectedUTXOs.Count > 0)">
+                        <NumericPicker TValue="decimal" @bind-Value="@_amount" Min="0" Decimals="8" Step="0.00001m" CurrencySymbol=" BTC" CurrencySymbolPlacement="CurrencySymbolPlacement.Suffix" Disabled="@(SelectedUTXOs.Count > 0)">
                             <Feedback>
                                 <ValidationError/>
                             </Feedback>
                         </NumericPicker>
                         <FieldHelp>
-                            @{
-                                @($"Amount in Satoshis. Minimum 20.000. Current amount: {Math.Round(PriceConversionHelper.SatToUsdConversion(_amount, _btcPrice), 2)} USD")
-                            }
+
+                            @($"Amount in Satoshis. Minimum {_minimumChannelCapacity:f8}. Current amount: {Math.Round(PriceConversionHelper.SatToUsdConversion(new Money(_amount, MoneyUnit.BTC).Satoshi, _btcPrice), 2)} USD")
+
                         </FieldHelp>
                     </Validation>
                     <div class="mb-3">
@@ -423,7 +423,8 @@
     private Node? _selectedDestNode;
     private int? _selectedWalletId;
     private string? _destNodeName;
-    private long _amount = Constants.MINIMUM_CHANNEL_CAPACITY_SATS;
+    private static readonly decimal _minimumChannelCapacity = new Money(Constants.MINIMUM_CHANNEL_CAPACITY_SATS).ToUnit(MoneyUnit.BTC);
+    private decimal _amount { get; set; } = _minimumChannelCapacity;
     private bool _selectedPrivate = false;
 
     //Validation
@@ -475,7 +476,8 @@
         _destNodeName = "";
         _selectedDestNode = null;
         _selectedPrivate = false;
-        _amount = Constants.MINIMUM_CHANNEL_CAPACITY_SATS;
+        _selectedWalletId = null;
+        _amount = _minimumChannelCapacity;
     }
 
     private async Task ResetChannelCancelModal()
@@ -578,7 +580,7 @@
                 var amount = SelectedUTXOs.Count > 0 ? SelectedUTXOsValue() : _amount;
                 var request = new ChannelOperationRequest()
                 {
-                    SatsAmount = amount,
+                    SatsAmount = new Money(amount, MoneyUnit.BTC).Satoshi,
                     RequestType = OperationRequestType.Open,
                     Description = "Created by user via Funds Manager",
                     WalletId = _selectedWalletId,
@@ -913,9 +915,9 @@
         StateHasChanged();
     }
 
-    private long SelectedUTXOsValue()
+    private decimal SelectedUTXOsValue()
     {
-        return SelectedUTXOs.Sum(x => ((Money)x.Value).Satoshi);
+        return SelectedUTXOs.Sum(x => ((Money)x.Value).ToUnit(MoneyUnit.BTC));
     }
 
     private void ClearSelectedUTXOs()

src/Pages/_Layout.cshtml

@@ -22,7 +22,7 @@
     <script src="https://cdn.onesignal.com/sdks/OneSignalSDK.js" async=""></script>
     <script>
     if ("@Constants.PUSH_NOTIFICATIONS_ONESIGNAL_ENABLED")
-    {  
+    {
         window.OneSignal = window.OneSignal || [];
         OneSignal.push(function() {
             OneSignal.init({

src/Properties/launchSettings.json

@@ -18,6 +18,7 @@
         "POSTGRES_CONNECTIONSTRING": "Host=127.0.0.1;Port=5432;Database=fundsmanager;Username=rw_dev;Password=rw_dev",
         "BITCOIN_NETWORK": "REGTEST",
         "MAXIMUM_WITHDRAWAL_BTC_AMOUNT": "21000000",
+        "NBXPLORER_ENABLE_CUSTOM_BACKEND": "true",
         "NBXPLORER_URI": "http://127.0.0.1:32838",
         "NBXPLORER_BTCRPCUSER": "polaruser",
         "NBXPLORER_BTCRPCPASSWORD": "polarpass",

src/Services/CoinSelectionService.cs

@@ -36,6 +36,17 @@ public interface ICoinSelectionService
     /// <param name="derivationStrategy"></param>
     public Task<List<UTXO>> GetAvailableUTXOsAsync(DerivationStrategyBase derivationStrategy);
 
+    /// <summary>
+    /// Gets the UTXOs for a wallet that are not locked in other transactions, but with a limit
+    /// </summary>
+    /// <param name="derivationStrategy"></param>
+    /// <param name="strategy"></param>
+    /// <param name="limit"></param>
+    /// <param name="amount"></param>
+    /// <param name="tolerance"></param>
+    /// <param name="closestTo"></param>
+    public Task<List<UTXO>> GetAvailableUTXOsAsync(DerivationStrategyBase derivationStrategy, CoinSelectionStrategy strategy, int limit, long amount, long closestTo);
+
     /// <summary>
     /// Locks the UTXOs for using in a specific transaction
     /// </summary>
@@ -121,10 +132,9 @@ public async Task<List<UTXO>> GetLockedUTXOsForRequest(IBitcoinRequest bitcoinRe
         return utxos.Confirmed.UTXOs.Where(utxo => lockedUTXOsList.Contains(utxo.Outpoint.Hash.ToString())).ToList();
     }
 
-    public async Task<List<UTXO>> GetAvailableUTXOsAsync(DerivationStrategyBase derivationStrategy)
+    private async Task<List<UTXO>> FilterUnlockedUTXOs(UTXOChanges? utxoChanges)
     {
         var lockedUTXOs = await _fmutxoRepository.GetLockedUTXOs();
-        var utxoChanges = await _nbXplorerService.GetUTXOsAsync(derivationStrategy);
         utxoChanges.RemoveDuplicateUTXOs();
 
         var availableUTXOs = new List<UTXO>();
@@ -145,6 +155,26 @@ public async Task<List<UTXO>> GetAvailableUTXOsAsync(DerivationStrategyBase deri
         return availableUTXOs;
     }
 
+    public async Task<List<UTXO>> GetAvailableUTXOsAsync(DerivationStrategyBase derivationStrategy)
+    {
+        var utxoChanges = await _nbXplorerService.GetUTXOsAsync(derivationStrategy);
+        return await FilterUnlockedUTXOs(utxoChanges);
+    }
+
+    public async Task<List<UTXO>> GetAvailableUTXOsAsync(DerivationStrategyBase derivationStrategy, CoinSelectionStrategy strategy, int limit, long amount, long closestTo)
+    {
+        UTXOChanges utxoChanges;
+        if (Constants.NBXPLORER_ENABLE_CUSTOM_BACKEND)
+        {
+            utxoChanges = await _nbXplorerService.GetUTXOsByLimitAsync(derivationStrategy, strategy, limit, amount, closestTo);
+        }
+        else
+        {
+            utxoChanges = await _nbXplorerService.GetUTXOsAsync(derivationStrategy);
+        }
+        return await FilterUnlockedUTXOs(utxoChanges);
+    }
+
     /// <summary>
     /// Gets UTXOs confirmed from the wallet of the request
     /// </summary>

src/Services/LightningService.cs

@@ -1200,7 +1200,7 @@ await foreach (var response in closeChannelResult.ResponseStream.ReadAllAsync())
             }
             catch (Exception e)
             {
-                _logger.LogError(e, "Error while getting wallet balance for wallet: {WalletId}", wallet.Id);
+                _logger.LogError(e, "Error while getting wallet address for wallet: {WalletId}", wallet.Id);
             }
 
             var result = keyPathInformation?.Address ?? null;

src/Services/NBXplorerService.cs

@@ -1,7 +1,11 @@
+using System.Text.Json;
 using FundsManager.Helpers;
+using Microsoft.AspNetCore.WebUtilities;
 using NBitcoin;
+using NBXplorer;
 using NBXplorer.DerivationStrategy;
 using NBXplorer.Models;
+using Newtonsoft.Json;
 
 namespace FundsManager.Services;
 
@@ -23,6 +27,8 @@ public interface INBXplorerService
 
     public Task<UTXOChanges> GetUTXOsAsync(DerivationStrategyBase extKey, CancellationToken cancellation = default);
 
+    public Task<UTXOChanges> GetUTXOsByLimitAsync(DerivationStrategyBase extKey, CoinSelectionStrategy strategy = CoinSelectionStrategy.SmallestFirst, int limit = 0, long amount = 0, long closestTo = 0, CancellationToken cancellation = default);
+
     public Task<GetFeeRateResult> GetFeeRateAsync(int blockCount, FeeRate fallbackFeeRate,
         CancellationToken cancellation = default);
 
@@ -63,6 +69,14 @@ public class MempoolRecommendedFees
     public int MinimumFee { get; set; }
 }
 
+[JsonConverter(typeof(System.Text.Json.Serialization.JsonStringEnumConverter))]
+public enum CoinSelectionStrategy
+{
+    SmallestFirst,
+    BiggestFirst,
+    ClosestToTargetFirst
+}
+
 /// <summary>
 /// Wrapper for the NBXplorer client to support DI
 /// </summary>
@@ -130,6 +144,45 @@ public async Task TrackAsync(TrackedSource trackedSource, CancellationToken canc
         return await client.GetUTXOsAsync(extKey, cancellation);
     }
 
+    public async Task<UTXOChanges> GetUTXOsByLimitAsync(DerivationStrategyBase extKey,
+        CoinSelectionStrategy strategy = CoinSelectionStrategy.SmallestFirst,
+        int limit = 0,
+        long amount = 0,
+        long closestTo = 0,
+        CancellationToken cancellation = default)
+    {
+        try
+        {
+            var requestUri = $"{Constants.NBXPLORER_URI}/v1/cryptos/btc/derivations/{TrackedSource.Create(extKey).DerivationStrategy}/selectutxos";
+
+            IDictionary<string, string?> keyValuePairs = new Dictionary<string, string?>();
+            keyValuePairs.Add("strategy", strategy.ToString());
+            keyValuePairs.Add("limit", limit.ToString());
+            keyValuePairs.Add("amount", amount.ToString());
+            if (strategy == CoinSelectionStrategy.ClosestToTargetFirst)
+            {
+                keyValuePairs.Add("closestTo", closestTo.ToString());
+            }
+
+            var url = QueryHelpers.AddQueryString(requestUri, keyValuePairs);
+            var response = await _httpClient.GetAsync(url, cancellation);
+
+            if (response.IsSuccessStatusCode)
+            {
+                var client = await LightningHelper.CreateNBExplorerClient();
+
+                return client.Serializer.ToObject<UTXOChanges>(await response.Content.ReadAsStringAsync().ConfigureAwait(false));
+            }
+        }
+        catch (Exception e)
+        {
+            _logger.LogError(e.ToString());
+            throw e;
+        }
+
+        return new UTXOChanges();
+    }
+
     public async Task<GetFeeRateResult> GetFeeRateAsync(int blockCount, FeeRate fallbackFeeRate,
             CancellationToken cancellation = default)
     {