using System.Linq;
using System.Threading.Tasks;
using xCommons.Extensions;
using xDataService.Extensions;
using xDataService.Interfaces;
using xModels.Base;

namespace xDataService.Providers {
    public class XIntKeyGenerator<TEntity> : IXKeyGenerator<TEntity, int>
        where TEntity : XBaseEntity<int> {
            public async Task<int> GenerateKey (IXBaseRepository<TEntity, int> repository) {
                //
                var items = (await repository.GetAllAsync ())
                    .OrderByDescending (nameof (XBaseEntity<int>.Id));
                var last = items
                    .FirstOrDefault ();

                //
                var result = last.IsNull () ? 1 : last.Id + 1;

                //
                return result;
            }

            public bool IsEmpty (int id) {
                //
                var result = id <= 0;

                //
                return result;
            }
        }
}