using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Application.Abstractions.Notification;
using Domain.Entities.Common.ValueObject;
using Domain.Entities.Developers;
using Domain.Entities.Developers.ValueObject;
using Domain.Entities.Notifications.ValueObject;
using Domain.Entities.Wallets.ValueObject;
using Microsoft.EntityFrameworkCore;
using SharedKernel.Results;

namespace Application.Features.Api.V1.Purchases.Cancel;

/// <summary>
/// 게임사 결제 취소 — 등록한 앱만 가능.
/// 보류(Pending) 중 취소: 지갑 무관, 상태만 Canceled (shortfall 없음).
/// 확정(Confirmed) 후 취소: 적립 시점 회원(CreditedMemberID)의 StoreRevenue 에서 회수,
/// 잔액 부족 시 가용분만 회수하고 부족분을 ShortfallAmount 로 기록 (Admin 검토 대상).
/// </summary>
internal sealed class Handler(IAppDbContext db, INotificationService notificationService, IAdminAlertService adminAlertService) : ICommandHandler<Command, Result<Response>>
{
    public async Task<Result<Response>> Handle(Command request, CancellationToken ct)
    {
        if (string.IsNullOrWhiteSpace(request.OrderID))
        {
            return Result.Failure<Response>(Error.Problem("Purchase.OrderIDRequired", "orderID 는 필수입니다."));
        }

        if (request.Marketplace.HasValue && !Enum.IsDefined(typeof(ApiPurchaseMarketplace), request.Marketplace.Value))
        {
            return Result.Failure<Response>(Error.Problem("Purchase.MarketplaceInvalid", "marketplace 는 1(구글)~6(기타) 값이어야 합니다."));
        }

        var orderID = request.OrderID.Trim();

        var query = db.ApiPurchase.Where(c => c.ApplicationID == request.ApplicationID && c.OrderID == orderID);
        if (request.Marketplace.HasValue)
        {
            var marketplace = (ApiPurchaseMarketplace)request.Marketplace.Value;
            query = query.Where(c => c.Marketplace == marketplace);
        }

        var purchases = await query.ToListAsync(ct);

        if (purchases.Count == 0)
        {
            return Result.Failure<Response>(Error.NotFound("Purchase.NotFound", "등록된 주문을 찾을 수 없습니다."));
        }

        if (purchases.Count > 1)
        {
            return Result.Failure<Response>(Error.Problem("Purchase.AmbiguousOrderID", "여러 마켓에 동일한 orderID 가 등록되어 있습니다. marketplace 를 지정하세요."));
        }

        var purchase = purchases[0];

        if (purchase.Status == ApiPurchaseStatus.Canceled)
        {
            return Result.Failure<Response>(Error.Conflict("Purchase.AlreadyCanceled", "이미 취소된 주문입니다."));
        }

        var gameName = await db.Game.AsNoTracking().Where(c => c.ID == purchase.GameID).Select(c => c.KorName).FirstOrDefaultAsync(ct) ?? "게임";

        var wasConfirmed = purchase.Status == ApiPurchaseStatus.Confirmed;
        var recovered = 0;
        var shortfall = 0;

        if (wasConfirmed)
        {
            // 확정 후 취소 — 적립 시점 회원 지갑에서 회수
            var wallet = await db.Wallet.Include(c => c.Balances).Include(c => c.Transactions).FirstOrDefaultAsync(c => c.MemberID == purchase.CreditedMemberID, ct);

            if (wallet is null)
            {
                shortfall = purchase.CommissionAmount;
            }
            else
            {
                var available = wallet.GetBalance(WalletBalanceType.StoreRevenue).Value;
                recovered = (int)Math.Min(available, purchase.CommissionAmount);
                shortfall = purchase.CommissionAmount - recovered;

                if (recovered > 0)
                {
                    wallet.DebitApiCommissionRevoke(Money.KRW(recovered), reason: $"{gameName} 결제 취소 회수", refID: $"apipurchase:{purchase.ID}");
                }
            }
        }

        purchase.Cancel();
        db.ApiPurchaseCancel.Add(ApiPurchaseCancel.Create(purchase, wasConfirmed, recovered, shortfall));

        await db.SaveChangesAsync(ct);

        var message = wasConfirmed
            ? $"「{gameName}」 결제 취소 — 수수료 {recovered:N0}원이 회수되었습니다." + (shortfall > 0 ? $" (잔액 부족 미회수 {shortfall:N0}원)" : string.Empty)
            : $"「{gameName}」 결제 취소 — 보류 중이던 수수료 {purchase.CommissionAmount:N0}원이 취소되었습니다.";

        await notificationService.SendAsync(
            memberID: purchase.CreditedMemberID,
            type: NotificationType.ApiCommissionRevoked,
            title: "판매 수수료 취소",
            message: message,
            actionUrl: "/studio/wallet/revenue",
            relatedType: "ApiPurchase",
            relatedID: purchase.ID,
            imageUrl: null,
            ct: ct
        );

        // 운영 알림 — 활동 방 (전 건) + 미회수 발생 시 알림 방
        var cancelKind = wasConfirmed ? $"확정 회수 {recovered:N0}원" : "보류 취소";
        await adminAlertService.SendActivityAsync($"↩️ 결제 취소 — {gameName} / {purchase.OrderID} / {cancelKind}", ct);

        if (shortfall > 0)
        {
            await adminAlertService.SendAlertAsync($"🚨 미회수 발생 — {gameName} / {purchase.OrderID} / 수수료 {purchase.CommissionAmount:N0}원 중 {shortfall:N0}원 회수 실패 (회원 ID {purchase.CreditedMemberID})", ct);
        }

        return Result.Success(new Response(
            purchase.ID,
            purchase.OrderID,
            purchase.Status.ToString(),
            wasConfirmed,
            recovered,
            shortfall,
            purchase.CanceledAt!.Value
        ));
    }
}