VideoTape - Video

Video.cs

public class Video : VoodooMagic {
  public static Video New(VideoId id, Title title, Date releaseDate) {
    return new Video(
      Events.NewVideo(id, title, releaseDate));
  }

  Video(object initialEvent) {
    ApplyEvent(initialEvent);
  }

  public void CorrectReleaseDate(Date corrected) {
    ApplyEvent(
      Events.CorrectedReleaseDate(_id, corrected));
  }

  // KISS, therefore, no tell don't ask ;-)
  internal string Id { get { return _id; } }

  internal Title Title { get { return _title; } }

  internal Percentage GetCheckoutDiscount() {
    if(_releaseDate.MoreThan(5.YearsAgo()) {
      return 25.Percent();
    }
    return 0.Percent();
  }

  //More behaviors here ...

  //Insert your preferred flavor of state change handlers 
  //(e.g. https://github.com/gregoryyoung/m-r)
  //(e.g. https://github.com/Lokad/lokad-iddd-sample)
}

public class VideoTape : VoodooMagic {
  public class VideoTape(Video video) {
    _video = video;
  }
  
  public void Checkout() {
    var discount = _video.GetCheckoutDiscount();
    //... continue here
    ApplyEvent(
      Events.CheckedOutVideoTape(_id, _video.Id, _video.Title, discount));
  }
}

public class VideoTapeRepository {
  public VideoTapeRepository(IEventStreamReader reader, IVideoRepository videoRepository) {
    _reader = reader;
    _videoRepository = videoRepository;
  }
  
  public VideoTape GetById(VideoTapeId id) {
    var stream = _reader.Get(new Uri(String.Format("urn:stream:VideoTape/{0}", id.Value)));
    var video = _videoRepository.GetById(ProbeStreamForVideoId(stream));
    var tape = new VideoTape(video);
    tape.LoadFromHistory(stream.Events);
    return tape;
  }

  VideoId ProbeStreamForVideoId(EventStream stream) {
    //Scan the stream for the answer to this question.
    //Could be the first event, the latest event relating to a title, etc ...
    //Safe to say it's highly contextual.
    //And yes, if you have millions of events in one stream,
    //you might wanna deal with this another way ;-)
  }
}