ISEbd-22_CourseWork_University/University/BankDatabaseImplement/Models/Purchase.cs

using UniversityContracts.BindingModels;
using UniversityContracts.ViewModels;
using UniversityDataModels;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq.Expressions;
using UniversityDataModels.ProxyModels;

namespace UniversityDatabaseImplement.Models
{
    public class Purchase : IPurchaseModel
    {
        public int ClientId { get; private set; }
        public DateOnly DatePurchase { get; private set; }
        private Dictionary<int, ClassByPurchaseModel>? _cachedOperations;
        [NotMapped]
        public Dictionary<int, ClassByPurchaseModel> ClassModel => _cachedOperations ??= Class.Select(x => (ClassByPurchaseModel)x).ToDictionary(x => x.ClassId, x => x);
        [NotMapped]
        public List<CostByPurchaseModel>? CostsModel => null;
        public int Id { get; private set; }
        [Required] 
        public Client? Client { get; private set; }
        [Required] 
        public List<ClassByPurchase> Operations { get; private set; } = new();
        [Required] 
        public List<CostByPurchase> Costs { get; private set; } = new();

        public static Purchase Create(PurchaseBindingModel model)
        {
            return new Purchase()
            {
                ClientId = model.ClientId,
                Id = model.Id,
                DatePurchase = model.DatePurchase,

			};
        }
		public void Update(PurchaseBindingModel model)
		{
            DatePurchase = model.DatePurchase;
		}

        public PurchaseViewModel GetViewModel => new()
        {
            OperationsModel = OperationsModel,
            Id = Id,
            DatePurchase = DatePurchase,
            ClientId = ClientId,
            ClientPhoneNumber = Client?.PhoneNumber ?? string.Empty,

            CostViewModels = Costs?
                .Select(x => x.Cost.GetViewModel)
                .ToList() ?? new(),
            OperationViewModels = Operations?
                .Select(x => x.Operation?.GetViewModel)
                .ToList() ?? new()
        };

        public PurchaseViewModel GetViewModel2 => new()
        {
            OperationsModel = OperationsModel,
            Id = Id,
            DatePurchase = DatePurchase,
            ClientId = ClientId,
            ClientPhoneNumber = Client?.PhoneNumber ?? string.Empty,

            CostViewModels = Costs?
                .Select(x => x.Cost.GetViewModel)
                .ToList() ?? new()
        };

        public void UpdateOperations(UniversityDB context, PurchaseBindingModel model)
        {
            var oldOperations = context.OperationByPurchases.Where(x => x.PurchaseId == model.Id).ToDictionary(x => x.OperationId, x => x);
            var newOperations = model.OperationsModel.ToDictionary(
                x => x.Key,
                x => new ClassnByPurchase() 
                { 
                    OperationId = x.Key,
					PurchaseId = Id,
                    CountOperations = x.Value.CountOperations
				}
                );
              
            context.RemoveRange(oldOperations.Where(x => !newOperations.ContainsKey(x.Key)).Select(x => x.Value));
            context.AddRange   (newOperations.Where(x => !oldOperations.ContainsKey(x.Key)).Select(x => x.Value));
			oldOperations
				.Where(x => newOperations.ContainsKey(x.Key))
				.Select(x => x.Value).ToList()
				.ForEach(x => x.CountOperations = newOperations[x.OperationId].CountOperations);
			context.SaveChanges();
            _cachedOperations = null;
        }
    }
}