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

namespace xDataService.Providers {
    public class XGuidKeyGenerator<TEntity> : IXKeyGenerator<TEntity, Guid>
        where TEntity : XBaseEntity<Guid> {
            private readonly IXSequentialGuid sequentialGuid;

            public XGuidKeyGenerator (
                IXSequentialGuid sequentialGuid = null
            ) {
                this.sequentialGuid = sequentialGuid;
            }

            public async Task<Guid> GenerateKey (
                IXBaseRepository<TEntity, Guid> repository
            ) {
                //
                await Task.CompletedTask;

                //
                // Check if provided SequentialGuid ...
                if (sequentialGuid.IsNull ()) {
                    return Guid.NewGuid ();
                } else {
                    return sequentialGuid.Next ();
                }
            }

            public bool IsEmpty (Guid id) {
                //
                var result = id.IsNull () || id.IsDefaultGuid ();

                //
                return result;
            }
        }
}