using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Domain.Entities.Donations.ValueObject;
using Domain.Entities.Wallets.ValueObject;
using Microsoft.EntityFrameworkCore;
using SharedKernel.Results;

namespace Application.Features.Api.Studio.Wallet.GetBalance;

internal sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Result<Response>>
{
    private const int RecentLimit = 20;

    private static readonly Response Empty = new(0, 0, 0, 0, 0, []);

    public async Task<Result<Response>> Handle(Query request, CancellationToken ct)
    {
        var channel = await db.Channel.AsNoTracking().FirstOrDefaultAsync(c => c.MemberID == request.MemberID && c.IsActive, ct);
        if (channel is null)
        {
            return Result.Success(Empty);
        }

        var wallet = await db.Wallet.AsNoTracking()
            .Include(w => w.Balances)
            .FirstOrDefaultAsync(w => w.MemberID == request.MemberID, ct);

        // 출금 가능 잔액 = Donation 잔액 (M)
        var withdrawableBalance = 0;
        if (wallet is not null)
        {
            var donationBal = wallet.Balances.FirstOrDefault(b => b.Type == WalletBalanceType.Donation);
            if (donationBal is not null)
            {
                withdrawableBalance = (int)donationBal.Amount.Value;
            }
        }

        // 누적 수익 (Donation NetAmount 합계)
        var totalEarned = await db.Donation.AsNoTracking()
            .Where(d => d.ReceiverMemberID == request.MemberID && !d.IsTest)
            .SumAsync(d => d.NetAmount, ct);

        // 누적 출금 (완료된 출금)
        var totalWithdrawn = await db.WithdrawalRequest.AsNoTracking()
            .Where(w => w.MemberID == request.MemberID && w.Status == WithdrawalStatus.Completed)
            .SumAsync(w => w.NetAmount, ct);

        // 누적 판매 수수료 (채널 보상 입금 합계)
        var totalStoreCommission = await db.WalletTransaction.AsNoTracking()
            .Where(t => t.Wallet!.MemberID == request.MemberID
                && t.BalanceType == WalletBalanceType.StoreRevenue
                && t.TxType == WalletTransactionType.OrderChannelReward)
            .SumAsync(t => (int)t.Amount.Value, ct);

        // 대기 출금
        var pendingWithdrawal = await db.WithdrawalRequest.AsNoTracking()
            .Where(w => w.MemberID == request.MemberID && (w.Status == WithdrawalStatus.Pending || w.Status == WithdrawalStatus.Processing))
            .SumAsync(w => w.RequestedAmount, ct);

        // 최근 거래 통합 (Donation 잔액 + StoreRevenue 잔액)
        var recentTx = await db.WalletTransaction.AsNoTracking()
            .Where(t => t.Wallet!.MemberID == request.MemberID
                && (t.BalanceType == WalletBalanceType.Donation || t.BalanceType == WalletBalanceType.StoreRevenue))
            .OrderByDescending(t => t.CreatedAt)
            .Take(RecentLimit)
            .Select(t => new
            {
                t.ID,
                t.TxType,
                t.BalanceType,
                Amount = (int)t.Amount.Value,
                Balance = (int)t.BalanceAfter.Value,
                t.RefID,
                t.Memo,
                t.CreatedAt
            })
            .ToListAsync(ct);

        var unified = recentTx.Select(t => new UnifiedTransactionItem(
            t.ID,
            MapCategory(t.TxType, t.BalanceType),
            t.TxType.ToString(),
            t.Amount,
            t.Balance,
            t.RefID,
            t.Memo ?? "",
            t.CreatedAt
        )).ToList();

        return Result.Success(new Response(
            withdrawableBalance,
            totalEarned,
            totalWithdrawn,
            totalStoreCommission,
            pendingWithdrawal,
            unified
        ));
    }

    // 거래 카테고리 분류 — Frontend 필터 키 (전체/후원/수수료)
    private static string MapCategory(WalletTransactionType txType, WalletBalanceType balanceType) => txType switch
    {
        WalletTransactionType.DonationIn => "donation",
        WalletTransactionType.OrderChannelReward or
        WalletTransactionType.OrderRefundChannelReward or
        WalletTransactionType.WithdrawalStoreRevenue => "commission",
        _ when balanceType == WalletBalanceType.Donation => "donation",
        _ when balanceType == WalletBalanceType.StoreRevenue => "commission",
        _ => "other"
    };
}