using CMSMicroservice.Application.Common.Interfaces;
using CMSMicroservice.Domain.Enums;
using Microsoft.EntityFrameworkCore;
using System.Globalization;

namespace CMSMicroservice.Application.CommissionCQ.Queries.GetAvailableWeeks;

public class GetAvailableWeeksQueryHandler : IRequestHandler<GetAvailableWeeksQuery, GetAvailableWeeksResponseDto>
{
    private readonly IApplicationDbContext _context;

    public GetAvailableWeeksQueryHandler(IApplicationDbContext context)
    {
        _context = context;
    }

    public async Task<GetAvailableWeeksResponseDto> Handle(
        GetAvailableWeeksQuery request, 
        CancellationToken cancellationToken)
    {
        var currentDate = DateTime.Now;
        var currentWeekNumber = GetWeekNumber(currentDate);
        
        // دریافت هفته‌های محاسبه شده از دیتابیس
        var calculatedPools = await _context.WeeklyCommissionPools
            .Where(p => p.IsCalculated)
            .OrderByDescending(p => p.WeekNumber)
            .Take(request.PastWeeksCount)
            .ToListAsync(cancellationToken);

        // دریافت لاگ‌های اجرا
        var executionLogs = await _context.WorkerExecutionLogs
            .Where(log => log.Status == WorkerExecutionStatus.Success || 
                          log.Status == WorkerExecutionStatus.Failed)
            .GroupBy(log => log.WeekNumber)
            .Select(g => new 
            { 
                WeekNumber = g.Key, 
                LastLog = g.OrderByDescending(l => l.StartedAt).First()
            })
            .ToDictionaryAsync(x => x.WeekNumber, x => x.LastLog, cancellationToken);

        var allWeeks = new List<WeekInfoDto>();
        
        // هفته جاری
        var currentWeekInfo = CreateWeekInfo(currentDate, currentWeekNumber, calculatedPools, executionLogs);
        
        // هفته‌های گذشته (12 هفته)
        var pastWeeks = new List<WeekInfoDto>();
        for (int i = 1; i <= request.PastWeeksCount; i++)
        {
            var pastDate = currentDate.AddDays(-7 * i);
            var weekNumber = GetWeekNumber(pastDate);
            pastWeeks.Add(CreateWeekInfo(pastDate, weekNumber, calculatedPools, executionLogs));
        }
        
        // هفته‌های آینده (4 هفته)
        var futureWeeks = new List<WeekInfoDto>();
        for (int i = 1; i <= request.FutureWeeksCount; i++)
        {
            var futureDate = currentDate.AddDays(7 * i);
            var weekNumber = GetWeekNumber(futureDate);
            futureWeeks.Add(CreateWeekInfo(futureDate, weekNumber, calculatedPools, executionLogs));
        }
        
        // تفکیک به calculated و pending
        var calculatedWeeks = pastWeeks.Where(w => w.IsCalculated).ToList();
        var pendingWeeks = pastWeeks.Where(w => !w.IsCalculated).ToList();
        
        return new GetAvailableWeeksResponseDto
        {
            CurrentWeek = currentWeekInfo,
            CalculatedWeeks = calculatedWeeks,
            PendingWeeks = pendingWeeks,
            FutureWeeks = futureWeeks
        };
    }

    private WeekInfoDto CreateWeekInfo(
        DateTime date, 
        string weekNumber,
        List<Domain.Entities.Commission.WeeklyCommissionPool> calculatedPools,
        Dictionary<string, Domain.Entities.Commission.WorkerExecutionLog> executionLogs)
    {
        var (startDate, endDate) = GetWeekRange(date);
        var pool = calculatedPools.FirstOrDefault(p => p.WeekNumber == weekNumber);
        var log = executionLogs.GetValueOrDefault(weekNumber);
        
        var isCalculated = pool != null && pool.IsCalculated;
        var displayText = $"{weekNumber} ({startDate:yyyy/MM/dd} - {endDate:yyyy/MM/dd})";
        
        if (isCalculated)
        {
            displayText += " ✅ محاسبه شده";
        }
        
        return new WeekInfoDto
        {
            WeekNumber = weekNumber,
            StartDate = startDate,
            EndDate = endDate,
            IsCalculated = isCalculated,
            CalculatedAt = pool?.CalculatedAt,
            LastExecutionStatus = log?.Status.ToString(),
            TotalPoolAmount = pool?.TotalPoolAmount,
            EligibleUsersCount = pool?.UserCommissionPayouts?.Count ?? 0,
            DisplayText = displayText
        };
    }

    private static string GetWeekNumber(DateTime date)
    {
        var calendar = CultureInfo.InvariantCulture.Calendar;
        var weekOfYear = calendar.GetWeekOfYear(
            date, 
            CalendarWeekRule.FirstFourDayWeek, 
            DayOfWeek.Monday);
        
        return $"{date.Year}-W{weekOfYear:D2}";
    }

    private static (DateTime startDate, DateTime endDate) GetWeekRange(DateTime date)
    {
        var dayOfWeek = (int)date.DayOfWeek;
        var daysToMonday = dayOfWeek == 0 ? 6 : dayOfWeek - 1; // اگر یکشنبه باشد، 6 روز عقب برو
        
        var startDate = date.Date.AddDays(-daysToMonday);
        var endDate = startDate.AddDays(6);
        
        return (startDate, endDate);
    }
}