ANTOOZA-BACKEND/Application/Helpers/SignupRewardGranter.cs

using Application.Abstractions.Cache;
using Application.Abstractions.Data;
using Application.Features.Config.Get;
using Domain.Entities.Common.ValueObject;
using Domain.Entities.Members.Logs;
using Domain.Entities.Wallets.ValueObject;
using Microsoft.EntityFrameworkCore;

namespace Application.Helpers;

/// <summary>
/// 가입 축하 보상 지급 (코인=Airdrop / 캐시=Adjusted / XP=MemberStats+MemberExpLog).
/// 멱등: WalletTransaction RefID "signup:{memberID}" 가 이미 존재하면 재지급하지 않는다.
/// 신규 회원 생성 지점(로컬 가입/소셜 자동가입)에서 호출하며, SaveChangesAsync 는 호출자가 수행한다.
/// </summary>
public static class SignupRewardGranter
{
    public static string RefIDFor(int memberID) => $"signup:{memberID}";

    /// <summary>
    /// 가입 보상을 대상 회원 지갑/스탯에 반영한다. 설정 비활성/전액 0 이거나 이미 지급된 경우 아무것도 하지 않는다.
    /// 지갑은 호출자 컨텍스트에서 추적 상태로 로드해 변경을 SaveChangesAsync 에 위임한다.
    /// </summary>
    public static async Task GrantAsync(IAppDbContext db, ICacheService cache, int memberID, CancellationToken ct)
    {
        if (memberID <= 0)
        {
            return;
        }

        var config = await LoadConfigAsync(db, cache, ct);
        if (config is null || !config.Enabled)
        {
            return;
        }

        var coin = config.CoinAmount;
        var cash = config.CashAmount;
        var exp = config.ExpAmount;

        if (coin <= 0 && cash <= 0 && exp <= 0)
        {
            return;
        }

        var refID = RefIDFor(memberID);

        // 멱등: 이미 가입 보상 트랜잭션이 있으면 재지급 금지
        var alreadyGranted = await db.WalletTransaction.AsNoTracking()
            .AnyAsync(c => c.RefID == refID && c.TxType == WalletTransactionType.RewardEarned, ct);

        if (alreadyGranted)
        {
            return;
        }

        // 코인/캐시 지급 (지갑 필요)
        if (coin > 0 || cash > 0)
        {
            var wallet = await db.Wallet
                .Include(c => c.Balances)
                .FirstOrDefaultAsync(c => c.MemberID == memberID, ct);

            if (wallet is not null)
            {
                if (coin > 0)
                {
                    wallet.CreditSignupReward(WalletBalanceType.Airdrop, Money.KRW(coin), "SIGNUP_REWARD", refID);
                }

                if (cash > 0)
                {
                    wallet.CreditSignupReward(WalletBalanceType.Adjusted, Money.KRW(cash), "SIGNUP_REWARD", refID);
                }
            }
        }

        // XP 지급 (MemberStats + MemberExpLog)
        if (exp > 0)
        {
            var stats = await db.MemberStats.FirstOrDefaultAsync(c => c.MemberID == memberID, ct);
            if (stats is not null)
            {
                stats.Exp += exp;
                db.MemberExpLog.Add(MemberExpLog.Create(memberID, "가입 축하 보상", exp, stats.Exp));
            }
        }
    }

    private static async Task<Domain.Entities.Common.SignupRewardConfig?> LoadConfigAsync(IAppDbContext db, ICacheService cache, CancellationToken ct)
    {
        var cached = await cache.GetAsync<Response>(CacheKeys.Config, ct);
        if (cached is not null)
        {
            return new Domain.Entities.Common.SignupRewardConfig
            {
                Enabled = cached.SignupReward.Enabled,
                CoinAmount = cached.SignupReward.CoinAmount,
                CashAmount = cached.SignupReward.CashAmount,
                ExpAmount = cached.SignupReward.ExpAmount
            };
        }

        var entity = await db.Config.AsNoTracking().OrderByDescending(c => c.ID).FirstOrDefaultAsync(ct);

        return entity?.SignupReward;
    }
}