using Contracts.BindingModels;
using Contracts.SearchModels;
using Contracts.StorageContracts;
using Contracts.ViewModels;
using DatabaseImplement.Models;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DatabaseImplement.Implements
{
    public class SaleStorage : ISaleStorage
    {
        public SaleViewModel? Delete(SaleBindingModel model)
        {
            using var context = new Database();
            var element = context.Sales
            .FirstOrDefault(rec => rec.Id == model.Id);
            if (element != null)
            {
                context.Sales.Remove(element);
                context.SaveChanges();
                return element.GetViewModel;
            }
            return null;
        }

        public SaleViewModel? GetElement(SaleSearchModel model)
        {
            if (!model.Id.HasValue)
            {
                return null;
            }
            using var context = new Database();
            return context.Sales
            .FirstOrDefault(x => (model.Id.HasValue && x.Id == model.Id))?.GetViewModel;
        }

        public List<SaleViewModel> GetFilteredList(SaleSearchModel model)
        {
            if (string.IsNullOrEmpty(model.Category))
            {
                return new();
            }
            using var context = new Database();
            return context.Sales
                .Where(x => x.Category.Contains(model.Category))
                .ToList()
                .Select(x => x.GetViewModel)
                .ToList();
        }

        public List<SaleViewModel> GetFullList()
        {
            using var context = new Database();
            return context.Sales
            .ToList()
            .Select(x => x.GetViewModel)
            .ToList();
        }

        public SaleViewModel? Insert(SaleBindingModel model)
        {
            using var context = new Database();
            var newSale = Sale.Create(context, model);
            if (newSale == null)
            {
                return null;
            }

            foreach (var product in context.Products)
            {
                if (product.Category == newSale.Category)
                {
                    product.Sale = newSale;
                    product.SaleId = newSale.Id;
                }
            }
            context.Sales.Add(newSale);
            context.SaveChanges();
            return newSale.GetViewModel;
        }

        public SaleViewModel? Update(SaleBindingModel model)
        {
            using var context = new Database();
            using var transaction = context.Database.BeginTransaction();
            try
            {
                var sale = context.Sales.FirstOrDefault(rec =>
                rec.Id == model.Id);

                if (sale == null)
                {
                    return null;
                }
                sale.Update(model);
                
                context.SaveChanges();
                transaction.Commit();
                return new();
            }
            catch
            {
                transaction.Rollback();
                throw;
            }
        }
    }
}