session-companion/SessionCompanion/SessionCompanion.Services/Services/ShopkeeperItemService.cs

using AutoMapper;
using SessionCompanion.Database.Repositories.Base;
using SessionCompanion.Database.Tables;
using SessionCompanion.Services.Base;
using SessionCompanion.Services.Interfaces;
using SessionCompanion.ViewModels.ShopkeeperItemsViewModels;
using System;
using System.Threading.Tasks;

namespace SessionCompanion.Services.Services
{
    using System.Linq;

    using Microsoft.EntityFrameworkCore;

    using SessionCompanion.Extensions.EitherType;
    using SessionCompanion.ViewModels.ApiResponses;
    using SessionCompanion.ViewModels.ShopkeeperViewModels;

    public class ShopkeeperItemService : ServiceBase<ShopkeeperItemViewModel, ShopkeeperItem>, IShopkeeperItemService
    {
        public ShopkeeperItemService(IMapper mapper, IRepository<ShopkeeperItem> repository) : base(mapper, repository)
        { }

        public async Task<Either<SuccessResponse, ErrorResponse>> GetActiveShkopkeeperWithItems(int shopkeeperId, int amount, int? weaponId, int? armorId)
        {
            try
            {
                var shopkeeperItem = await Repository.Get(c => c.ShopkeeperId.Equals(shopkeeperId) && c.WeaponId.Equals(weaponId) && c.ArmorId.Equals(armorId)).FirstOrDefaultAsync();

                if (shopkeeperItem == null)
                {
                    throw new Exception("Shopkeeper with given id's couldn't have been found");
                }

                if (shopkeeperItem.Amount - amount < 0)
                {
                    throw new Exception("Shopkeeper does not have that quantity of the item");
                }
                else if (shopkeeperItem.Amount - amount == 0)
                {
                    this.Repository.Delete(shopkeeperItem);
                    await this.Repository.Save();
                    return new SuccessResponse("Items were deducted from the shopkeeper");
                }
                else
                {
                    shopkeeperItem.Amount -= amount;
                    await this.Repository.Update(shopkeeperItem);
                    await this.Repository.Save();
                    return new SuccessResponse("Items were deducted from the shopkeeper");
                }
            }
            catch (Exception e)
            {
                return new ErrorResponse() { StatusCode = 500, Message = e.Message };
            }
        }
    }
}