CourseWork_SchoolStudyAgain/SchoolAgainStudy/SchoolAgainStudyDataBaseImplements/Implements/MaterialStorage.cs

using SchoolAgainStudyContracts.BindingModel;
using SchoolAgainStudyContracts.SearchModel;
using SchoolAgainStudyContracts.StorageContracts;
using SchoolAgainStudyContracts.ViewModel;
using SchoolAgainStudyDataBaseImplements.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SchoolAgainStudyDataBaseImplements.Implements
{
    public class MaterialStorage : IMaterialStorage
    {
        public List<MaterialViewModel> GetFullList()
        {
            using var context = new SchoolDataBase();
            return context.Materials
                    .Select(x => x.GetViewModel)
                    .ToList();
        }

        public List<MaterialViewModel> GetFilteredList(MaterialSearchModel model)
        {
            if (!model.TeacherId.HasValue)
            {
                return new();
            }
            using var context = new SchoolDataBase();
            return context.Materials
                    .Where(x => x.TeacherId == model.TeacherId)
                    .Select(x => x.GetViewModel)
                    .ToList();
        }

        public MaterialViewModel? GetElement(MaterialSearchModel model)
        {
            if (string.IsNullOrEmpty(model.Title) && !model.Id.HasValue)
            {
                return null;
            }
            using var context = new SchoolDataBase();
            return context.Materials
                    .FirstOrDefault(x => (!string.IsNullOrEmpty(model.Title) && x.Title == model.Title) ||
                                        (model.Id.HasValue && x.Id == model.Id))
                    ?.GetViewModel;
        }

        public MaterialViewModel? Insert(MaterialBindingModel model)
        {
            var newMaterial = Material.Create(model);
            if (newMaterial == null)
            {
                return null;
            }
            using var context = new SchoolDataBase();
            context.Materials.Add(newMaterial);
            context.SaveChanges();
            return newMaterial.GetViewModel;
        }

        public MaterialViewModel? Update(MaterialBindingModel model)
        {
            using var context = new SchoolDataBase();
            var material = context.Materials.FirstOrDefault(x => x.Id == model.Id);
            if (material == null )
            {
                return null;
            }
            material.Update(model);
            context.SaveChanges();
            return material.GetViewModel;
        }

        public MaterialViewModel? Delete(MaterialBindingModel model)
        {
            using var context = new SchoolDataBase();
            var element = context.Materials.FirstOrDefault(rec => rec.Id == model.Id);
            if (element != null )
            {
                context.Materials.Remove(element);
                context.SaveChanges();
                return element.GetViewModel;
            }
            return null;
        }
    }
}