NadekoBot/NadekoBot.Core/Modules/Gambling/Services/WaifuService.cs

using Discord;
using NadekoBot.Core.Services;
using System.Threading.Tasks;

namespace NadekoBot.Modules.Gambling.Services
{
    public class WaifuService : INService
    {
        private readonly DbService _db;
        private readonly CurrencyService _cs;

        public WaifuService(DbService db, CurrencyService cs)
        {
            _db = db;
            _cs = cs;
        }

        public async Task<bool> WaifuTransfer(IUser owner, ulong waifuId, IUser newOwner)
        {
            if (owner.Id == newOwner.Id || waifuId == newOwner.Id)
                return false;
            using (var uow = _db.UnitOfWork)
            {
                var waifu = uow.Waifus.ByWaifuUserId(waifuId);
                var ownerUser = uow.DiscordUsers.GetOrCreate(owner);

                // owner has to be the owner of the waifu
                if (waifu == null || waifu.ClaimerId != ownerUser.Id)
                    return false;

                if (!await _cs.RemoveAsync(owner.Id,
                    "Waifu Transfer",
                    waifu.Price / 10,
                    uow).ConfigureAwait(false))
                {
                    return false;
                }

                //new claimerId is the id of the new owner
                var newOwnerUser = uow.DiscordUsers.GetOrCreate(newOwner);
                waifu.ClaimerId = newOwnerUser.Id;

                await uow.CompleteAsync().ConfigureAwait(false);
            }

            return true;
        }
    }
}