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;
using TaskTrackerContracts.BindingModels;
using TaskTrackerContracts.ViewModels;
using TaskTrackerDataModels.Models;

namespace TaskTrackerDatabase.Models
{
	public class Direction : IDirectionModel
	{
		[Required]
		public int Id { get; set; }

		[Required]
		public string Name { get; set; } = string.Empty;


		private Dictionary<int, IStudentModel>? _directionStudents = null;
		[NotMapped]
		public Dictionary<int, IStudentModel> DirectionStudents
		{
			get
			{
				if (_directionStudents == null)
				{
					_directionStudents = Students
					.ToDictionary(recPC => recPC.StudentId, recPC =>
				   (recPC.Student as IStudentModel));
				}
				return _directionStudents;
			}
		}
		[ForeignKey("DirectionId")]
		public virtual List<DirectionStudent> Students { get; set; } = new();




		private Dictionary<int, ISubjectModel>? _directionSubjects = null;
		[NotMapped]
		public Dictionary<int, ISubjectModel> DirectionSubjects
		{
			get
			{
				if (_directionSubjects == null)
				{
					_directionSubjects = Subjects
					.ToDictionary(recPC => recPC.SubjectId, recPC =>
				   (recPC.Subject as ISubjectModel));
				}
				return _directionSubjects;
			}
		}
		[ForeignKey("DirectionId")]
		public virtual List<DirectionSubject> Subjects { get; set; } = new();

		public static Direction Create(TaskTrackerDatabase context, DirectionBindingModel model)
		{
			return new Direction()
			{
				Id = model.Id,
				Name = model.Name,
				Students = model.DirectionStudents.Select(x => new DirectionStudent
				{
					Student = context.Students.First(y => y.Id == x.Key)
				}).ToList(),
				Subjects = model.DirectionSubjects.Select(x => new DirectionSubject
				{
					Subject = context.Subjects.First(y => y.Id == x.Key)
				}).ToList()
			};
		}
		public void Update(DirectionBindingModel model)
		{
			Name = model.Name;
		}
		public DirectionViewModel GetViewModel => new()
		{
			Id = Id,
			Name = Name,
			DirectionStudents = DirectionStudents,
			DirectionSubjects = DirectionSubjects
		};
		public void UpdateStudents(TaskTrackerDatabase context, DirectionBindingModel model)
		{
			var directionStudents = context.DirectionStudents.Where(rec => rec.DirectionId == model.Id).ToList();
			if (directionStudents != null && DirectionStudents.Count > 0)
			{ // удалили те, которых нет в модели
				context.DirectionStudents.RemoveRange(directionStudents.Where(rec => !model.DirectionStudents.ContainsKey(rec.StudentId)));
				context.SaveChanges();
				// обновили количество у существующих записей
				foreach (var updateStudents in directionStudents)
				{
					model.DirectionStudents.Remove(updateStudents.StudentId);
				}
				context.SaveChanges();
			}
			var reinforced = context.Directions.First(x => x.Id == Id);
			foreach (var rp in model.DirectionStudents)
			{
				context.DirectionStudents.Add(new DirectionStudent
				{
					Direction = reinforced,
					Student = context.Students.First(x => x.Id == rp.Key)
				});
				context.SaveChanges();
			}
			_directionStudents = null;
		}
		public void UpdateSubjects(TaskTrackerDatabase context, DirectionBindingModel model)
		{
			var directionSubjects = context.DirectionSubjects.Where(rec => rec.DirectionId == model.Id).ToList();
			if (directionSubjects != null && DirectionSubjects.Count > 0)
			{ // удалили те, которых нет в модели
				context.DirectionSubjects.RemoveRange(directionSubjects.Where(rec => !model.DirectionSubjects.ContainsKey(rec.SubjectId)));
				context.SaveChanges();
				// обновили количество у существующих записей
				foreach (var updateSubjects in directionSubjects)
				{
					model.DirectionSubjects.Remove(updateSubjects.SubjectId);
				}
				context.SaveChanges();
			}
			var reinforced = context.Directions.First(x => x.Id == Id);
			foreach (var rp in model.DirectionSubjects)
			{
				context.DirectionSubjects.Add(new DirectionSubject
				{
					Direction = reinforced,
					Subject = context.Subjects.First(x => x.Id == rp.Key)
				});
				context.SaveChanges();
			}
			_directionSubjects = null;
		}
	}
}