using System; namespace HN.Domain { public sealed class Link : Votable { public Guid Id { get; } public string Url { get; } public DateTime CreatedAt { get; } public Guid CreatedBy { get; } private Link(Guid createdBy, string url) : base() { Id = Guid.NewGuid(); CreatedBy = createdBy; CreatedAt = DateTime.UtcNow; Url = url; } public static Link FromUrl(Guid posterId, string url) { return new Link(posterId, url); } public Comment AddComment(Guid userId, string content) { return new Comment(Id, userId, content); } } }