using SchoolScheduleContracts.BindingModels;
using SchoolScheduleContracts.ViewModels;
using SchoolScheduleDataModels.Enums;
using SchoolScheduleDataModels.Models;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SchoolScheduleDataBaseImplement.Models
{
	public class Student : IStudentModel
	{
		public int Id { get; private set; }
		[Required]
		public string FullName { get; private set; }
		[Required]
		public int GradeId { get; private set; }
		public virtual Grade Grade { get; set; } = new();
		private Dictionary<int, (ILessonModel, StudentStatus, int?)> _attendance = null;
		[NotMapped]
		public Dictionary<int, (ILessonModel, StudentStatus, int?)> Attendance
		{
			get
			{
				if (_attendance == null)
				{
					_attendance = Lessons.ToDictionary(recPC => recPC.LessonId, recPC =>
				   (recPC.Lesson as ILessonModel, recPC.Status, recPC.Mark));
				}
				return _attendance;
			}
		}
		[ForeignKey("StudentId")]
		public virtual List<LessonStudent> Lessons { get; set; } = new();

		public static Student Create(SchoolScheduleDataBase context, StudentBindingModel model)
		{
			return new Student()
			{
				Id = model.Id,
				FullName = model.FullName,
				GradeId = model.GradeId,
				Grade = context.Grades.First(y => y.Id == model.GradeId),
				Lessons = model.Attendance.Select(x => new LessonStudent
				{
					Lesson = context.Lessons.First(y => y.Id == x.Key),
					Status = x.Value.Item2,
					Mark = x.Value.Item3,
				}).ToList(),
			};
		}

		public void Update(SchoolScheduleDataBase context, StudentBindingModel model)
		{
			FullName = model.FullName;
			GradeId = model.GradeId;
			Grade = context.Grades.First(y => y.Id == model.GradeId);
		}

		public StudentViewModel GetViewModel => new()
		{
			Id = Id,
			FullName = FullName,
			GradeId = GradeId,
			GradeName = Grade.Year.ToString() + Grade.Letter.ToString(),
		};

		public void UpdateAttendance(SchoolScheduleDataBase context, StudentBindingModel model)
		{
			var attendance = context.LessonStudents.Where(rec => rec.StudentId == model.Id).ToList();
			if (attendance != null && attendance.Count > 0)
			{
				context.LessonStudents.RemoveRange(attendance.Where(rec
			   => !model.Attendance.ContainsKey(rec.Id)));
				context.SaveChanges();
			}
			var student = context.Students.First(x => x.Id == Id);
			foreach (var pc in model.Attendance)
			{
				context.LessonStudents.Add(new LessonStudent
				{
					Student = student,
					Lesson = context.Lessons.First(x => x.Id == pc.Key),
					Mark = pc.Value.Item3,
					Status = pc.Value.Item2,
				});
				context.SaveChanges();
			}
			_attendance = null;

		}
	}
}