CourseWork_SchoolStudyAgain/SchoolAgainStudy/SchoolAgainStudyDataBaseImplements/Models/Task.cs

using SchoolAgainStudyContracts.BindingModel;
using SchoolAgainStudyContracts.ViewModel;
using SchoolAgainStudyDataModels.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 SchoolAgainStudyDataBaseImplements.Models
{
    public class Task : ITask
    {
        [Required]
        public string Title { get; set; } = string.Empty;
        [Required]
        public DateTime DateIssue { get; set; }
        [Required]
        public DateTime DateDelivery { get; set; }
        [Required]
        public int TeacherId { get; set; }
        public string TeacherName { get; set; } = string.Empty;
        public virtual Teacher Teacher { get; set; }
        private Dictionary<int, IMaterial>? _TaskMaterials = null;
        [NotMapped]
        public Dictionary<int, IMaterial> TaskMaterials { get 
            {
                if (_TaskMaterials == null)
                {
                    _TaskMaterials = Materials
                            .ToDictionary(recPC => recPC.MaterialId, recPC => (recPC.Material as IMaterial));
                }
                return _TaskMaterials;
            } 
        } 

        public int Id { get; set; }
        [ForeignKey("TaskId")]
        public virtual List<TaskMaterial> Materials { get; set; } = new();
        [ForeignKey("TaskId")]
        public virtual List<Diy> Diys { get; set; } = new();

        public static Task Create(SchoolDataBase context, TaskBindingModel model)
        {
            return new Task()
            {
                Id = model.Id,
                Title = model.Title,
                DateIssue = model.DateIssue,
                DateDelivery = model.DateDelivery,
                TeacherId = model.TeacherId,
                TeacherName = model.TeacherName,
                Materials = model.TaskMaterials.Select(x => new TaskMaterial
                {
                    Material = context.Materials.First(y => y.Id == x.Key),
                }).ToList()
            };
        }

        public void Update(TaskBindingModel model)
        {
            Title = model.Title;
            DateIssue = model.DateIssue;
            DateDelivery = model.DateDelivery;
        }

        public TaskViewModel GetViewModel => new()
        {
            Id = Id,
            Title = Title,
            DateIssue = DateIssue,
            DateDelivery = DateDelivery,
            TeacherId = TeacherId,
            TeacherName= TeacherName,
            TaskMaterials = TaskMaterials
        };

        public void UpdateMaterials(SchoolDataBase context, TaskBindingModel model)
        {
            var taskMaterials = context.TaskMaterials.Where(rec => rec.TaskId == model.Id).ToList();
            if (taskMaterials != null && taskMaterials.Count > 0)
            {
                context.TaskMaterials.RemoveRange(taskMaterials.Where(rec => !model.TaskMaterials.ContainsKey(rec.MaterialId)));
                context.SaveChanges();

                foreach (var updateMaterial in taskMaterials)
                {
                    model.TaskMaterials.Remove(updateMaterial.MaterialId);
                }
                context.SaveChanges();
            }
            var task = context.Tasks.First(x => x.Id == Id);
            foreach (var pc in model.TaskMaterials)
            {
                context.TaskMaterials.Add(new TaskMaterial
                {
                    Task = task,
                    Material = context.Materials.First(x => x.Id == pc.Key),
                });
                context.SaveChanges();
            }
            _TaskMaterials = null;
        }
    }
}