Restructured the project structure back to the way it was, there's no reasonable way to split the modules

src/NadekoBot/_common/Services/Currency/CurrencyService.cs

@@ -0,0 +1,116 @@
+#nullable disable
+using LinqToDB;
+using LinqToDB.EntityFrameworkCore;
+using NadekoBot.Db;
+using NadekoBot.Db.Models;
+using NadekoBot.Services.Currency;
+
+namespace NadekoBot.Services;
+
+public sealed class CurrencyService : ICurrencyService, INService
+{
+    private readonly DbService _db;
+    private readonly ITxTracker _txTracker;
+
+    public CurrencyService(DbService db, ITxTracker txTracker)
+    {
+        _db = db;
+        _txTracker = txTracker;
+    }
+
+    public Task<IWallet> GetWalletAsync(ulong userId, CurrencyType type = CurrencyType.Default)
+    {
+        if (type == CurrencyType.Default)
+            return Task.FromResult<IWallet>(new DefaultWallet(userId, _db));
+
+        throw new ArgumentOutOfRangeException(nameof(type));
+    }
+
+    public async Task AddBulkAsync(
+        IReadOnlyCollection<ulong> userIds,
+        long amount,
+        TxData txData,
+        CurrencyType type = CurrencyType.Default)
+    {
+        if (type == CurrencyType.Default)
+        {
+            foreach (var userId in userIds)
+            {
+                var wallet = await GetWalletAsync(userId);
+                await wallet.Add(amount, txData);
+            }
+
+            return;
+        }
+
+        throw new ArgumentOutOfRangeException(nameof(type));
+    }
+
+    public async Task RemoveBulkAsync(
+        IReadOnlyCollection<ulong> userIds,
+        long amount,
+        TxData txData,
+        CurrencyType type = CurrencyType.Default)
+    {
+        if (type == CurrencyType.Default)
+        {
+            await using var ctx = _db.GetDbContext();
+            await ctx
+                .GetTable<DiscordUser>()
+                .Where(x => userIds.Contains(x.UserId))
+                .UpdateAsync(du => new()
+                {
+                    CurrencyAmount = du.CurrencyAmount >= amount
+                        ? du.CurrencyAmount - amount
+                        : 0
+                });
+            await ctx.SaveChangesAsync();
+            return;
+        }
+
+        throw new ArgumentOutOfRangeException(nameof(type));
+    }
+
+    public async Task AddAsync(
+        ulong userId,
+        long amount,
+        TxData txData)
+    {
+        var wallet = await GetWalletAsync(userId);
+        await wallet.Add(amount, txData);
+        await _txTracker.TrackAdd(amount, txData);
+    }
+
+    public async Task AddAsync(
+        IUser user,
+        long amount,
+        TxData txData)
+        => await AddAsync(user.Id, amount, txData);
+
+    public async Task<bool> RemoveAsync(
+        ulong userId,
+        long amount,
+        TxData txData)
+    {
+        if (amount == 0)
+            return true;
+
+        var wallet = await GetWalletAsync(userId);
+        var result = await wallet.Take(amount, txData);
+        if (result)
+            await _txTracker.TrackRemove(amount, txData);
+        return result;
+    }
+
+    public async Task<bool> RemoveAsync(
+        IUser user,
+        long amount,
+        TxData txData)
+        => await RemoveAsync(user.Id, amount, txData);
+
+    public async Task<IReadOnlyList<DiscordUser>> GetTopRichest(ulong ignoreId, int page = 0, int perPage = 9)
+    {
+        await using var uow = _db.GetDbContext();
+        return await uow.Set<DiscordUser>().GetTopRichest(ignoreId, page, perPage);
+    }
+}