using System.Threading;
using System.Linq;
using System.Threading.Tasks;
using MediatR;

namespace HN.Application
{
  public sealed class GetLinkQueryHandler : IRequestHandler<GetLinkQuery, LinkDTO>
  {
    private readonly IDbContext _context;

    public GetLinkQueryHandler(IDbContext context)
    {
      _context = context;
    }

    public Task<LinkDTO> Handle(GetLinkQuery request, CancellationToken cancellationToken)
    {
      var result = from link in _context.Links
                   where link.Id == request.Id
                   select new LinkDTO(link);

      return Task.FromResult(result.FirstOrDefault());
    }
  }
}