using System.Collections;
using Bmp.Core.FFMpeg.CsCorePorts.FFMpegWrap.Interops;

namespace Bmp.Core.FFMpeg.CsCoreExt
{
    public unsafe class FFMpegAttachedPicCollection : IReadOnlyList<FFMpegAttachedPic>
    {
        private readonly FFMpegAttachedPic[] _items;

        internal FFMpegAttachedPicCollection(AVFormatContext formatContext)
        {
            var pics = new List<FFMpegAttachedPic>((int)(formatContext.nb_streams - 1));

            for (var i = 0; i < formatContext.nb_streams; i++)
            {
                var stream = formatContext.streams[i];
                if ((stream->disposition & 0x0400) != 0x0400) continue; // AV_DISPOSITION_ATTACHED_PIC

                var item = new FFMpegAttachedPic(stream);

                pics.Add(item);
            }

            _items = pics.ToArray();
        }

        public IEnumerator<FFMpegAttachedPic> GetEnumerator()
        {
            var x = _items.Where(p => true);
            return x.GetEnumerator();
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }

        public int Count => _items.Length;

        public FFMpegAttachedPic this[int index] => _items[index];
    }
}