using Zurnal.RemaDateBase.DateDao;

public class GroupAttendanceService
    {
        public class AttendanceInfo
    {
        public int TotalStudents { get; set; }
        public int TotalLessons { get; set; }
        public double AttendancePercentage { get; set; }
        public List<StudentAttendance> StudentAttendances { get; set; }
    }

    public class StudentAttendance
    {
        public string FIO { get; set; }
        public int AttendedLessons { get; set; }
        public int MissedLessons { get; set; }
        public double AttendanceRate { get; set; }
    }
        public AttendanceInfo GetGroupAttendanceInfo(GroupDao group, List<PresnceDao> presences)
        {
            var students = group.Users.ToList();
            var totalLessons = presences.Select(p => p.LessonNumber).Distinct().Count();
            var totalStudents = students.Count;

            var studentAttendances = students.Select(student =>
            {
                var studentPresences = presences.Where(p => p.userDao.Guid == student.Guid).ToList();
                var attendedLessons = studentPresences.Count(p => p.IsAttendensy);
                var missedLessons = totalLessons - attendedLessons;
                var attendanceRate = totalLessons > 0 ? (double)attendedLessons / totalLessons * 100 : 0;

                return new StudentAttendance
                {
                    FIO = student.FIO,
                    AttendedLessons = attendedLessons,
                    MissedLessons = missedLessons,
                    AttendanceRate = attendanceRate
                };
            }).ToList();

            var attendancePercentage = totalStudents > 0 ? (double)studentAttendances.Sum(s => s.AttendedLessons) / (totalStudents * totalLessons) * 100 : 0;

            return new AttendanceInfo
            {
                TotalStudents = totalStudents,
                TotalLessons = totalLessons,
                AttendancePercentage = attendancePercentage,
                StudentAttendances = studentAttendances
            };
        }
    }