PIbd-23-Volkov-N.A.-ComputersShop/ComputersShop/ComputersShopFileImplement/Implements/ImplementerStorage.cs

using ComputersShopContracts.BindingModels;
using ComputersShopContracts.SearchModels;
using ComputersShopContracts.StoragesContracts;
using ComputersShopContracts.ViewModels;
using ComputersShopFileImplement.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ComputersShopFileImplement.Implements
{
    public class ImplementerStorage : IImplementerStorage
    {
        private readonly DataFileSingleton source;
        public ImplementerStorage()
        {
            source = DataFileSingleton.GetInstance();
        }
        public ImplementerViewModel? Delete(ImplementerBindingModel model)
        {
            var element = source.Implementers.FirstOrDefault(x => x.Id == model.Id);
            if (element != null)
            {
                source.Implementers.Remove(element);
                source.SaveImplementers();
                return element.GetViewModel;
            }
            return null;
        }

        public ImplementerViewModel? GetElement(ImplementerSearchModel model)
        {
            if (model.Id.HasValue)
            {
                return source.Implementers
                    .FirstOrDefault(x => (x.Id == model.Id))?.GetViewModel;
            }
            else if (!string.IsNullOrEmpty(model.ImplementerFIO) && !string.IsNullOrEmpty(model.Password))
            {
                return source.Implementers
                    .FirstOrDefault(x => (x.ImplementerFIO == model.ImplementerFIO && x.Password == model.Password))?.GetViewModel;
            }
            return new();
        }

        public List<ImplementerViewModel> GetFilteredList(ImplementerSearchModel model)
        {
            if (string.IsNullOrEmpty(model.ImplementerFIO))
            {
                return new();
            }
            return source.Implementers.Where(x =>
                x.ImplementerFIO.Contains(model.ImplementerFIO)).Select(x => x.GetViewModel).ToList();
        }

        public List<ImplementerViewModel> GetFullList()
        {
            return source.Implementers.Select(x => x.GetViewModel).ToList();
        }

        public ImplementerViewModel? Insert(ImplementerBindingModel model)
        {
            model.Id = source.Implementers.Count > 0 ? source.Implementers.Max(x => x.Id) + 1 : 1;
            var newImplementer = Implementer.Create(model);
            if (newImplementer == null)
            {
                return null;
            }
            source.Implementers.Add(newImplementer);
            source.SaveImplementers();
            return newImplementer.GetViewModel;
        }

        public ImplementerViewModel? Update(ImplementerBindingModel model)
        {
            var implementer = source.Implementers.FirstOrDefault(x => x.Id == model.Id);
            if (implementer == null)
            {
                return null;
            }
            implementer.Update(model);
            source.SaveImplementers();
            return implementer.GetViewModel;
        }
    }
}