using System;
using System.Collections.Generic;
using System.Linq;

namespace Zurnal.RemaDateBase.DateDao
{
    public class GroupInfo
    {
        public int TotalStudents { get; set; }
        public int TotalLessons { get; set; }
        public double AttendancePercentage { get; set; }
        public List<StudentAttendance> StudentAttendances { get; set; }

        public GroupInfo(GroupDao group)
        {
            TotalStudents = group.Users.Count();
            TotalLessons = group.Users.SelectMany(u => u.Group.Users).Count();
            AttendancePercentage = CalculateAttendancePercentage(group);
            StudentAttendances = GetStudentAttendances(group);
        }

       private double CalculateAttendancePercentage(GroupDao group)
{
    var totalAttendance = group.Users.Sum(u => u.Group.Users.Count(x => x.IsAttendensy));
    var totalClasses = group.Users.Count() * group.Users.FirstOrDefault()?.Group.Users.Count() ?? 0;
    return totalClasses > 0 ? (double)totalAttendance / totalClasses * 100 : 0;
}

        private List<StudentAttendance> GetStudentAttendances(GroupDao group)
        {
            return group.Users.Select(u => new StudentAttendance
            {
                FIO = u.FIO,
                AttendedLessons = u.Group.Users.Count(x => x.UserGuid == u.UserGuid && x.IsAttendensy),
                MissedLessons = u.Group.Users.Count(x => x.UserGuid == u.UserGuid && !x.IsAttendensy),
                AttendancePercentage = (u.Group.Users.Count(x => x.UserGuid == u.UserGuid && x.IsAttendensy) / (double)TotalLessons) * 100
            }).ToList();
        }
    }

    public class StudentAttendance
    {
        public string FIO { get; set; }
        public int AttendedLessons { get; set; }
        public int MissedLessons { get; set; }
        public double AttendancePercentage { get; set; }
    }
}