using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

namespace MediaContainers.Matroska;

public class MatroskaTracks : List<MatroskaTrackEntry>
{
	public void AddTrackEntry(EBMLMasterElement element)
	{
		if (element == null) { return; }
		if (element.Definition == MatroskaSpecification.Tracks)
		{
			foreach (var child in element.Children)
			{
				AddTrackEntry(child as EBMLMasterElement);
			}
		}
		else if (element.Definition == MatroskaSpecification.TrackEntry)
		{
			var entry = new MatroskaTrackEntry();
			entry.ReadFrom(element);
			Add(entry);
		}
	}

	public void CopyTo(MatroskaTracks tracks, bool shallow = false)
	{
		if (shallow)
		{
			tracks.Clear();
			for (int i = 0, j = Count; i < j; i++) { tracks.Add(this[i]); }
		}
		else
		{
			tracks.Clear();
			for (int i = 0, j = Count; i < j; i++)
			{
				var track = new MatroskaTrackEntry();
				this[i].CopyTo(track);
				tracks.Add(track);
			}
		}
	}

	public async ValueTask Write(EBMLWriter writer, CancellationToken cancellationToken = default)
	{
		await writer.BeginMasterElement(MatroskaSpecification.Tracks, cancellationToken);
		for (int i = 0; i < Count; i++) { await this[i].Write(writer, cancellationToken); }
		await writer.EndMasterElement(cancellationToken);
	}

	public EBMLMasterElement ToElement()
	{
		var tracks = new EBMLMasterElement(MatroskaSpecification.Tracks);
		foreach (var track in this) { tracks.AddChild(track.ToElement()); }
		return tracks;
	}
}