using DinerContracts.BindingModels;
using DinerContracts.SearchModels;
using DinerContracts.StoragesContracts;
using DinerContracts.ViewModels;
using DinerFileImplement.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DinerFileImplement.Implements
{
    public class SnackStorage : ISnackStorage
    {
        private readonly DataFileSingleton _source;

        public SnackStorage()
        {
            _source = DataFileSingleton.GetInstance();
        }

        public SnackViewModel? Delete(SnackBindingModel model)
        {
            var element = _source.Snacks.FirstOrDefault(x => x.ID == model.ID);
            if (element != null) { 
                _source.Snacks.Remove(element);
                _source.SaveSnacks();
                return element.GetViewModel;
            }
            return null;
        }

        public SnackViewModel? GetElement(SnackSearchModel model)
        {
            if (string.IsNullOrEmpty(model.ProductName) && !model.ID.HasValue) { return null; }
            return _source.Snacks
                .FirstOrDefault(x => (!string.IsNullOrEmpty(model.ProductName) &&
                x.ProductName == model.ProductName) || model.ID.HasValue &&
                x.ID == model.ID)?.GetViewModel;
        }

        public List<SnackViewModel> GetFilteredList(SnackSearchModel model)
        {
            if (string.IsNullOrEmpty(model.ProductName)) { return new(); }
            return _source.Snacks.Where(x => x.ProductName.Contains(model.ProductName))
                                    .Select(x => x.GetViewModel).ToList();
        }

        public List<SnackViewModel> GetFullList()
        {
            return _source.Snacks.Select(x => x.GetViewModel).ToList(); 
        }

        public SnackViewModel? Insert(SnackBindingModel model)
        {
            model.ID = _source.Snacks.Count > 0 ? _source.Snacks.Max(x => x.ID) + 1 : 1;
            var newProduct = Snack.Create(model);
            if (newProduct == null) { return null; }
            _source.Snacks.Add(newProduct);
            _source.SaveSnacks();
            return newProduct.GetViewModel;
        }

        public SnackViewModel? Update(SnackBindingModel model)
        {
            var product = _source.Snacks.FirstOrDefault(x => x.ID == model.ID);
            if (product == null) { return null; }
            product.Update(model);
            _source.SaveSnacks();
            return product.GetViewModel;
        }
    }
}