nadekobot/src/NadekoBot/_common/Services/Currency/DefaultWallet.cs

using LinqToDB;
using LinqToDB.EntityFrameworkCore;
using NadekoBot.Db.Models;
using Nadeko.Bot.Db.Models;

namespace NadekoBot.Services.Currency;

public class DefaultWallet : IWallet
{
    private readonly DbService _db;
    public ulong UserId { get; }

    public DefaultWallet(ulong userId, DbService db)
    {
        UserId = userId;
        _db = db;
    }

    public async Task<long> GetBalance()
    {
        await using var ctx = _db.GetDbContext();
        var userId = UserId;
        return await ctx
            .GetTable<DiscordUser>()
            .Where(x => x.UserId == userId)
            .Select(x => x.CurrencyAmount)
            .FirstOrDefaultAsync();
    }

    public async Task<bool> Take(long amount, TxData? txData)
    {
        if (amount < 0)
            throw new ArgumentOutOfRangeException(nameof(amount), "Amount to take must be non negative.");

        await using var ctx = _db.GetDbContext();

        var userId = UserId;
        var changed = await ctx
            .GetTable<DiscordUser>()
            .Where(x => x.UserId == userId && x.CurrencyAmount >= amount)
            .UpdateAsync(x => new()
            {
                CurrencyAmount = x.CurrencyAmount - amount
            });

        if (changed == 0)
            return false;

        if (txData is not null)
        {
            await ctx
                .GetTable<CurrencyTransaction>()
                .InsertAsync(() => new()
                {
                    Amount = -amount,
                    Note = txData.Note,
                    UserId = userId,
                    Type = txData.Type,
                    Extra = txData.Extra,
                    OtherId = txData.OtherId,
                    DateAdded = DateTime.UtcNow
                });
        }

        return true;
    }

    public async Task Add(long amount, TxData? txData)
    {
        if (amount <= 0)
            throw new ArgumentOutOfRangeException(nameof(amount), "Amount must be greater than 0.");

        await using var ctx = _db.GetDbContext();
        var userId = UserId;

        await using (var tran = await ctx.Database.BeginTransactionAsync())
        {
            var changed = await ctx
                .GetTable<DiscordUser>()
                .Where(x => x.UserId == userId)
                .UpdateAsync(x => new()
                {
                    CurrencyAmount = x.CurrencyAmount + amount
                });

            if (changed == 0)
            {
                await ctx
                    .GetTable<DiscordUser>()
                    .Value(x => x.UserId, userId)
                    .Value(x => x.Username, "Unknown")
                    .Value(x => x.Discriminator, "????")
                    .Value(x => x.CurrencyAmount, amount)
                    .InsertAsync();
            }

            await tran.CommitAsync();
        }

        if (txData is not null)
        {
            await ctx.GetTable<CurrencyTransaction>()
                .InsertAsync(() => new()
                {
                    Amount = amount,
                    UserId = userId,
                    Note = txData.Note,
                    Type = txData.Type,
                    Extra = txData.Extra,
                    OtherId = txData.OtherId,
                    DateAdded = DateTime.UtcNow
                });
        }
    }
}