using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Microsoft.EntityFrameworkCore;

namespace Application.Features.Admin.Payment.Toss.Confirm.Search;

public sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Response>
{
    public async Task<Response> Handle(Query request, CancellationToken ct)
    {
        var query = db.TossConfirm.AsNoTracking().Include(c => c.Member).AsQueryable();

        // 키워드 검색
        if (!string.IsNullOrWhiteSpace(request.Keyword))
        {
            query = request.Search switch
            {
                1 => query.Where(c => c.PaymentKey.Contains(request.Keyword)),
                2 => query.Where(c => c.OrderID.Contains(request.Keyword)),
                3 => query.Where(c => c.Member != null && c.Member.ID.ToString().Contains(request.Keyword)),
                4 => query.Where(c => c.Member != null && c.Member.Name != null && c.Member.Name.Contains(request.Keyword)),
                5 => query.Where(c => c.Member != null && c.Member.SID.Contains(request.Keyword)),
                _ => query
            };
        }

        // 기간 필터
        if (!string.IsNullOrWhiteSpace(request.StartAt) && DateTime.TryParse(request.StartAt, out var startAt))
        {
            query = query.Where(c => c.CreatedAt >= startAt);
        }

        if (!string.IsNullOrWhiteSpace(request.EndAt) && DateTime.TryParse(request.EndAt, out var endAt))
        {
            query = query.Where(c => c.CreatedAt <= endAt);
        }

        // 탭별 건수 (Status 필터 전)
        var counts = await query.GroupBy(c => 1).Select(c => new Response.StatusCounts
        {
            Done = c.Count(x => x.Status == "DONE"),
            WaitingDeposit = c.Count(x => x.Status == "WAITING_FOR_DEPOSIT"),
            Canceled = c.Count(x => x.Status == "CANCELED" || x.Status == "PARTIAL_CANCELED")
        }).FirstOrDefaultAsync(ct) ?? new Response.StatusCounts();

        if (!string.IsNullOrWhiteSpace(request.Status))
        {
            query = request.Status == "CANCELED"
                ? query.Where(c => c.Status == "CANCELED" || c.Status == "PARTIAL_CANCELED")
                : query.Where(c => c.Status == request.Status);
        }

        var total = await query.CountAsync(ct);
        var skip = (request.Page - 1) * request.PerPage;

        var list = await query
            .OrderByDescending(c => c.ID)
            .Skip(skip)
            .Take(request.PerPage)
            .Select(c => new
            {
                c.ID,
                c.MemberID,
                MemberEmail = c.Member != null ? c.Member.Email : string.Empty,
                MemberName = c.Member != null ? c.Member.Name : null,
                c.PaymentKey,
                c.OrderID,
                c.Amount,
                c.TotalAmount,
                c.Status,
                c.Method,
                c.ResponseCode,
                c.ResponseMessage,
                c.PaymentOrderID,
                c.CreatedAt
            })
            .ToListAsync(ct);

        // 같은 PaymentOrderID로 성공한 TossCancel 있는지 조회
        var orderIDs = list.Select(c => c.PaymentOrderID).Distinct().ToArray();

        var cancels = await db.TossCancel.AsNoTracking()
            .Where(c => orderIDs.Contains(c.PaymentOrderID) && c.ResponseCode == "SUCCESS")
            .Select(c => new { c.PaymentOrderID, c.CancelAmount })
            .ToListAsync(ct);

        var cancelByOrder = cancels.GroupBy(c => c.PaymentOrderID).ToDictionary(
            g => g.Key,
            g => g.First()
        );

        var rows = list.Select((c, idx) =>
        {
            cancelByOrder.TryGetValue(c.PaymentOrderID, out var cancel);

            return new Response.Row
            {
                Num = total - skip - idx,
                ID = c.ID,
                MemberID = c.MemberID,
                MemberEmail = c.MemberEmail,
                MemberName = c.MemberName,
                PaymentKey = c.PaymentKey,
                OrderID = c.OrderID,
                Amount = c.Amount,
                TotalAmount = c.TotalAmount,
                Status = c.Status,
                Method = c.Method,
                ResponseCode = c.ResponseCode,
                ResponseMessage = c.ResponseMessage,
                CancelledAmount = cancel?.CancelAmount,
                CreatedAt = c.CreatedAt
            };
        }).ToList();

        return new Response
        {
            Total = total,
            Counts = counts,
            List = rows
        };
    }
}