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

namespace ComputersShopFileImplement.Implements
{
    public class ShopStorage : IShopStorage
    {
        private readonly DataFileSingleton source;

        public ShopStorage()
        {
            source = DataFileSingleton.GetInstance();
        }
        public ShopViewModel? Delete(ShopBindingModel model)
        {
            var shop = source.Shops.FirstOrDefault(x => x.Id == model.Id);
            if (shop != null)
            {
                source.Shops.Remove(shop);
                source.SaveShops();
                return shop.GetViewModel;
            }
            return null;
        }

        public ShopViewModel? GetElement(ShopSearchModel model)
        {
            if (string.IsNullOrEmpty(model.ShopName) && !model.Id.HasValue)
            {
                return null;
            }
            return source.Shops
                .FirstOrDefault(x => (!string.IsNullOrEmpty(model.ShopName) && x.ShopName == model.ShopName) || (model.Id.HasValue && x.Id == model.Id))?.GetViewModel;
        }

        public List<ShopViewModel> GetFilteredList(ShopSearchModel model)
        {
            if (string.IsNullOrEmpty(model.ShopName))
            {
                return new();
            }
            return source.Shops
                .Where(x => x.ShopName.Contains(model.ShopName))
                .Select(x => x.GetViewModel)
                .ToList();
        }

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

        public ShopViewModel? Insert(ShopBindingModel model)
        {
            model.Id = source.Shops.Count > 0 ? source.Shops.Max(x => x.Id) + 1 : 1;
            var newShop = Shop.Create(model);
            if (newShop == null)
            {
                return null;
            }
            source.Shops.Add(newShop);
            source.SaveShops();
            return newShop.GetViewModel;
        }

        public bool SellComputers(IComputerModel model, int quantity)
        {
            int hasCount = source.Shops
            .SelectMany(x => x.Computers)
            .Where(pair => pair.Key == model.Id)
            .Sum(pair => pair.Value.Item2);

            if (hasCount < quantity)
                return false;

            source.Shops.ForEach(x =>
            {
                if (x.Computers.TryGetValue(model.Id, out var pair))
                {
                    if (quantity >= pair.Item2)
                    {
                        quantity -= pair.Item2;
                        x.Computers[model.Id] = (model, 0);
                    }
                    else
                    {
                        x.Computers[model.Id] = (model, pair.Item2 - quantity);
                        quantity = 0;
                    }

                    x.Update(new ShopBindingModel
                    {
                        Id = x.Id,
                        ShopAddress = x.ShopAddress,
                        Capacity = x.Capacity,
                        DateOpening = x.DateOpening,
                        ShopName = x.ShopName,
                        Computers = x.Computers
                    });
                }
            });

            source.SaveShops();
            return true;
        }

        public ShopViewModel? Update(ShopBindingModel model)
        {
            var shop = source.Shops.FirstOrDefault(x => x.Id == model.Id);
            if (shop == null)
            {
                return null;
            }
            shop.Update(model);
            source.SaveShops();
            return shop.GetViewModel;
        }
    }
}