using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Domain.Entities.Common.ValueObject;
using Microsoft.EntityFrameworkCore;

namespace Application.Features.Admin.Mail.Search;

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

        if (!string.IsNullOrWhiteSpace(request.Keyword))
        {
            var keyword = request.Keyword.Trim();
            query = request.Search switch
            {
                1 => long.TryParse(keyword, out var id) ? query.Where(x => x.ID == id) : query.Where(x => false),
                2 => query.Where(x => x.ToAddress.Contains(keyword)),
                3 => query.Where(x => x.Subject.Contains(keyword)),
                4 => query.Where(x => x.Category != null && x.Category.Contains(keyword)),
                _ => query
            };
        }

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

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

        // 탭별 건수 집계 (탭 필터 적용 전)
        var counts = await query.GroupBy(c => 1).Select(c => new
        {
            Pending = c.Count(x => x.Status == MailStatus.Pending),
            Processing = c.Count(x => x.Status == MailStatus.Processing),
            Sent = c.Count(x => x.Status == MailStatus.Sent),
            Failed = c.Count(x => x.Status == MailStatus.Failed)
        }).FirstOrDefaultAsync(ct);

        var pendingCount = counts?.Pending ?? 0;
        var processingCount = counts?.Processing ?? 0;
        var sentCount = counts?.Sent ?? 0;
        var failedCount = counts?.Failed ?? 0;

        query = request.Tab switch
        {
            1 => query.Where(x => x.Status == MailStatus.Pending),
            2 => query.Where(x => x.Status == MailStatus.Processing),
            3 => query.Where(x => x.Status == MailStatus.Sent),
            4 => query.Where(x => x.Status == MailStatus.Failed),
            _ => query
        };

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

        var list = await query
            .OrderByDescending(x => x.ID)
            .Skip(skip)
            .Take(request.PerPage)
            .Select(x => new
            {
                x.ID,
                x.ToAddress,
                x.Subject,
                x.Status,
                x.RetryCount,
                x.MaxRetryCount,
                x.NextRetryAt,
                x.LastError,
                x.Category,
                x.CreatedAt,
                x.ProcessedAt,
                x.FailedAt
            })
            .ToListAsync(ct);

        var rows = list.Select((x, idx) => new Response.Row
        {
            Num = total - skip - idx,
            ID = x.ID,
            ToAddress = x.ToAddress,
            Subject = x.Subject,
            Status = (byte)x.Status,
            StatusName = x.Status.ToString(),
            RetryCount = x.RetryCount,
            MaxRetryCount = x.MaxRetryCount,
            NextRetryAt = x.NextRetryAt,
            LastError = x.LastError,
            Category = x.Category,
            CreatedAt = x.CreatedAt,
            ProcessedAt = x.ProcessedAt,
            FailedAt = x.FailedAt
        }).ToList();

        return new Response
        {
            Total = total,
            Pending = pendingCount,
            Processing = processingCount,
            Sent = sentCount,
            Failed = failedCount,
            List = rows
        };
    }
}