using System;
using System.Collections.Generic;
using System.Linq;

namespace HN.Domain
{
  /// <summary>
  /// Représente une entité sur laquelle on peut voter.
  /// </summary>
  public abstract class Votable
  {
    private List<Vote> _votes;
    public IReadOnlyList<Vote> Votes => _votes;

    protected Votable()
    {
      _votes = new List<Vote>();
    }

    public void Upvote(Guid userId)
    {
      UpsertUserVote(userId, VoteType.Up);
    }

    public void Downvote(Guid userId)
    {
      UpsertUserVote(userId, VoteType.Down);
    }

    private void UpsertUserVote(Guid userId, VoteType type)
    {
      var vote = _votes.SingleOrDefault(v => v.CreatedBy == userId);

      if (vote == null)
      {
        _votes.Add(new Vote(userId, type));
        return;
      }

      vote.HasType(type);
    }
  }
}