using ComputerHardwareStoreContracts.BindingModels;
using ComputerHardwareStoreContracts.ViewModels;
using ComputerHardwareStoreDataModels.Models;
using Microsoft.EntityFrameworkCore;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace ComputerHardwareStoreDatabaseImplement.Models
{
    public class Purchase : IPurchaseModel
    {
        public int Id { get; private set; }
        [Required]
        public int VendorId { get; set; }
        [Required]
        public double Cost { get; set; }
        [Required]
        public DateTime DateCreate { get; set; } = DateTime.Now;
        private Dictionary<int, (IBuildModel, int)>? _purchaseBuilds = null;
        [NotMapped]
        public Dictionary<int, (IBuildModel, int)> PurchaseBuilds
        {
            get
            {
                if (_purchaseBuilds == null)
                {
                    _purchaseBuilds = Builds
                        .ToDictionary(op => op.BuildId, op => (op.Build as IBuildModel, op.Count));
                }
                return _purchaseBuilds;
            }
        }

        [ForeignKey("PurchaseId")]
        public virtual List<PurchaseBuild> Builds { get; set; } = new();
        private Dictionary<int, (IProductModel, int)>? _purchaseProducts = null;
        [NotMapped]
        public Dictionary<int, (IProductModel, int)> PurchaseProducts
        {
            get
            {
                if (_purchaseProducts == null)
                {
                    _purchaseProducts = Products
                        .ToDictionary(op => op.ProductId, op => (op.Product as IProductModel, op.Count));
                }
                return _purchaseProducts;
            }
        }
        [ForeignKey("PurchaseId")]
        public virtual List<PurchaseProduct> Products { get; set; } = new();

        public static Purchase Create(ComputerHardwareStoreDBContext context, PurchaseBindingModel model)
        {
            return new Purchase()
            {
                Id = model.Id,
                Cost = model.Cost,
                DateCreate = model.DateCreate,
                Builds = context.Builds
                    .Where(b => model.PurchaseBuilds.ContainsKey(b.Id))
                    .Select(b => new PurchaseBuild()
                    {
                        PurchaseId = model.Id,
                        BuildId = b.Id,
                        Build = b,
                        Count = model.PurchaseProducts[b.Id].Item2
                    }).ToList(),
                Products = context.Products
                    .Where(p => model.PurchaseProducts.ContainsKey(p.Id))
                    .Select (p => new PurchaseProduct()
                    {
                        PurchaseId = model.Id,
                        ProductId = p.Id,
                        Product = p,
                        Count = model.PurchaseProducts[p.Id].Item2
                    })
                    .ToList()
            };
        }
        public void Update(PurchaseBindingModel model)
        {
            Cost = model.Cost;

        }
        public PurchaseViewModel GetViewModel => new()
        {
            Id = Id,
            Cost = Cost,
            DateCreate = DateCreate,
            PurchaseBuilds = PurchaseBuilds,
            PurchaseProducts = PurchaseProducts
        };

        public static void UpdateBuilds(ComputerHardwareStoreDBContext context, PurchaseBindingModel model)
        {
            var productBuilds = context.PurchaseBuilds
                .Where(pc => pc.PurchaseId == model.Id)
                .ToList();
            if (productBuilds.Count != 0 && productBuilds.Count > 0)
            {
                // удалили те, которых нет в модели
                context.PurchaseBuilds
                    .Where(pc => !model.PurchaseBuilds.ContainsKey(pc.BuildId))
                    .ExecuteDelete();
                // обновили количество у существующих записей
                productBuilds
                    .ForEach(updateBuild =>
                    {
                        updateBuild.Count = model.PurchaseBuilds[updateBuild.BuildId].Item2;
                        model.PurchaseBuilds.Remove(updateBuild.BuildId);
                    });
            }
            // добавили новые
            context.PurchaseBuilds
                .AddRange(model.PurchaseBuilds.Values
                .Select(val => new PurchaseBuild()
                {
                    PurchaseId = model.Id,
                    BuildId = val.Item1.Id,
                    Count = val.Item2
                }));
            context.SaveChanges();
        }

        public static void UpdateProducts(ComputerHardwareStoreDBContext context, PurchaseBindingModel model)
        {
            var productProducts = context.PurchaseProducts
                .Where(pc => pc.PurchaseId == model.Id)
                .ToList();
            if (productProducts.Count != 0 && productProducts.Count > 0)
            {
                // удалили те, которых нет в модели
                context.PurchaseProducts
                    .Where(pc => !model.PurchaseProducts.ContainsKey(pc.ProductId))
                    .ExecuteDelete();
                // обновили количество у существующих записей
                productProducts
                    .ForEach(updateProduct =>
                    {
                        updateProduct.Count = model.PurchaseProducts[updateProduct.ProductId].Item2;
                        model.PurchaseProducts.Remove(updateProduct.ProductId);
                    });
            }
            // добавили новые
            context.PurchaseProducts
                .AddRange(model.PurchaseProducts.Values
                .Select(val => new PurchaseProduct()
                {
                    PurchaseId = model.Id,
                    ProductId = val.Item1.Id,
                    Count = val.Item2
                }));
            context.SaveChanges();
        }
    }
}