Reworked currency service. Some features are missing

src/NadekoBot/Services/Currency/DefaultWallet.cs

@@ -0,0 +1,104 @@
+using LinqToDB;
+using LinqToDB.EntityFrameworkCore;
+using NadekoBot.Services.Database;
+using NadekoBot.Services.Database.Models;
+
+namespace NadekoBot.Services.Currency;
+
+public class DefaultWallet : IWallet
+{
+    public ulong UserId { get; }
+
+    private readonly NadekoContext _ctx;
+
+    public DefaultWallet(ulong userId, NadekoContext ctx)
+    {
+        UserId = userId;
+        _ctx = ctx;
+    }
+
+    public Task<long> GetBalance()
+        => _ctx.DiscordUser
+               .ToLinqToDBTable()
+               .Where(x => x.UserId == UserId)
+               .Select(x => x.CurrencyAmount)
+               .FirstOrDefaultAsync();
+
+    public async Task<bool> Take(long amount, Extra extra)
+    {
+        if (amount < 0)
+            throw new ArgumentOutOfRangeException(nameof(amount), "Amount to take must be non negative.");
+
+        var changed = await _ctx.DiscordUser
+                                .Where(x => x.UserId == UserId && x.CurrencyAmount >= amount)
+                                .UpdateAsync(x => new()
+                                {
+                                    CurrencyAmount = x.CurrencyAmount - amount
+                                });
+
+        if (changed == 0)
+            return false;
+
+        // todo type, subtype
+        // todo from? by?
+        await _ctx.CreateLinqToDbContext()
+                  .InsertAsync(new CurrencyTransaction()
+                  {
+                      Amount = -amount,
+                      Reason = extra.Note,
+                      UserId = UserId,
+                  });
+
+        return true;
+    }
+
+    public async Task Add(long amount, Extra extra)
+    {
+        if (amount <= 0)
+            throw new ArgumentOutOfRangeException(nameof(amount), "Amount must be greater than 0.");
+
+        await using (var tran = await _ctx.Database.BeginTransactionAsync())
+        {
+            var changed = await _ctx.DiscordUser
+                                    .UpdateAsync(x => new()
+                                    {
+                                        CurrencyAmount = x.CurrencyAmount + amount
+                                    });
+            
+            if (changed == 0)
+            {
+                await _ctx.DiscordUser
+                          .ToLinqToDBTable()
+                          .Value(x => x.UserId, UserId)
+                          .Value(x => x.Username, "Unknown")
+                          .Value(x => x.Discriminator, "????")
+                          .Value(x => x.CurrencyAmount, amount)
+                          .InsertAsync();
+            }
+
+            await tran.CommitAsync();
+        }
+
+        var ct = new CurrencyTransaction()
+        {
+            Amount = amount,
+            Reason = extra.Note,
+            UserId = UserId,
+        };
+
+        await _ctx.CreateLinqToDbContext()
+                  .InsertAsync(ct);
+    }
+
+    public void Dispose()
+    {
+        _ctx.SaveChanges();
+        _ctx.Dispose();
+    }
+    
+    public async ValueTask DisposeAsync()
+    {
+        await _ctx.SaveChangesAsync();
+        await _ctx.DisposeAsync();
+    }
+}