using ClosedXML.Excel;
using data.RemoteData.RemoteDataBase.DAO;
using data.Repository;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;

namespace domain.UseCase
{
    public class PresenceUseCase
    {
        private readonly IPresenceRepository _presenceRepo;
        private readonly IUserRepository _userRepo;
        private readonly IGroupRepository _groupRepo;

        public PresenceUseCase(
            IPresenceRepository presenceRepo,
            IUserRepository userRepo,
            IGroupRepository groupRepo)
        {
            _presenceRepo = presenceRepo;
            _userRepo = userRepo;
            _groupRepo = groupRepo;
        }

        // Генерация посещаемости на день
        public void GenerateDailyPresence(int groupId, DateOnly date, int firstLesson, int lastLesson)
        {
            var users = _userRepo.GetUsersByGroupId(groupId);
            if (users.Count == 0) 
                throw new Exception("Группа не содержит студентов");

            var presences = new List<PresenceDAO>();
            for (int lesson = firstLesson; lesson <= lastLesson; lesson++)
            {
                presences.AddRange(users.Select(user => new PresenceDAO
                {
                    UserId = user.UserId,
                    GroupId = groupId,
                    Date = date,
                    LessonNumber = lesson,
                    IsAttendance = true
                }));
            }
            
            _presenceRepo.SavePresence(presences);
        }

        // Получение данных за день
        public List<PresenceDAO> GetDailyAttendance(int groupId, DateOnly date)
        {
            return _presenceRepo.GetPresenceByDateAndGroup(date, date, groupId)
                .OrderBy(p => p.LessonNumber)
                .ThenBy(p => p.UserId)
                .ToList();
        }

        // Экспорт в Excel
        public void ExportToExcel(int groupId)
        {
            var data = GetGroupReport(groupId);
            var path = PrepareReportFolder();
            
            using var workbook = new XLWorkbook();
            CreateWorksheets(workbook, data);
            workbook.SaveAs(Path.Combine(path, "AttendanceReport.xlsx"));
        }

        private Dictionary<string, List<RecordAtt>> GetGroupReport(int groupId)
        {
            var report = new Dictionary<string, List<RecordAtt>>();
            var group = _groupRepo.GetGroupById(groupId);
            
            if (group == null)
                throw new Exception("Группа не найдена");

            var records = _presenceRepo.GetAttendanceByGroup(groupId)
                .Select(r => new RecordAtt
                {
                    UserName = _userRepo.GetUserById(r.UserId)?.FIO ?? "Неизвестный",
                    Date = r.Date,
                    LessonNumber = r.LessonNumber,
                    Status = r.IsAttendance ? "Присутствовал" : "Отсутствовал"
                }).ToList();

            report.Add(group.Name, records);
            return report;
        }

        private string PrepareReportFolder()
        {
            var path = Path.Combine(
                Directory.GetCurrentDirectory(), 
                "Reports",
                DateTime.Now.ToString("yyyy-MM-dd"));
            
            Directory.CreateDirectory(path);
            return path;
        }

        private void CreateWorksheets(XLWorkbook workbook, Dictionary<string, List<RecordAtt>> data)
        {
            foreach (var group in data)
            {
                var ws = workbook.Worksheets.Add(group.Key);
                ws.Cell(1, 1).Value = "ФИО";
                ws.Cell(1, 2).Value = "Дата";
                ws.Cell(1, 3).Value = "Занятие";
                ws.Cell(1, 4).Value = "Статус";

                int row = 2;
                foreach (var record in group.Value)
                {
                    ws.Cell(row, 1).Value = record.UserName;
                    ws.Cell(row, 2).Value = record.Date.ToString("dd.MM.yyyy");
                    ws.Cell(row, 3).Value = record.LessonNumber;
                    ws.Cell(row, 4).Value = record.Status;
                    row++;
                }

                ws.Columns().AdjustToContents();
            }
        }
        
        public void GenerateWeeklyPresence(int groupId, DateOnly startDate, int firstLesson, int lastLesson)
        {
            for (int i = 0; i < 7; i++)
            {
                GenerateDailyPresence(groupId, startDate.AddDays(i), firstLesson, lastLesson);
            }
        }

        public void MarkAbsence(int userId, int groupId, DateOnly date, int firstLesson, int lastLesson)
        {
            var presences = _presenceRepo.GetPresence(groupId, date, userId)
                .Where(p => p.LessonNumber >= firstLesson && p.LessonNumber <= lastLesson)
                .ToList();

            foreach (var presence in presences)
            {
                presence.IsAttendance = false;
            }
    
            _presenceRepo.UpdatePresence(presences);
        }

        public List<PresenceDAO> GetCompleteGroupAttendance(int groupId)
        {
            return _presenceRepo.GetPresenceByGroup(groupId)
                .OrderBy(p => p.Date)
                .ThenBy(p => p.LessonNumber)
                .ToList();
        }

        public GroupAttendanceStats GetGeneralPresence(int groupId)
        {
            var presences = _presenceRepo.GetPresenceByGroup(groupId);
            var users = _userRepo.GetUsersByGroupId(groupId);

            return new GroupAttendanceStats
            {
                UserCount = users.Count,
                TotalLessons = presences.Select(p => p.LessonNumber).Distinct().Count(),
                AttendancePercentage = (double)presences.Count(p => p.IsAttendance) / presences.Count * 100
            };
        }
    }
}