using System;

namespace MoonWorks.Video
{
	internal class VideoAV1Stream
	{
		public IntPtr Handle => handle;
		IntPtr handle;

		public bool Ended => Dav1dfile.df_eos(Handle) == 1;

		public IntPtr yDataHandle;
		public IntPtr uDataHandle;
		public IntPtr vDataHandle;
		public uint yDataLength;
		public uint uvDataLength;
		public uint yStride;
		public uint uvStride;

		public bool FrameDataUpdated { get; set; }

		bool IsDisposed;

		public VideoAV1Stream(VideoAV1 video)
		{
			if (Dav1dfile.df_fopen(video.Filename, out handle) == 0)
			{
				throw new Exception("Failed to open video file!");
			}

			Reset();
		}

		public void Reset()
		{
			lock (this)
			{
				Dav1dfile.df_reset(Handle);
				ReadNextFrame();
			}
		}

		public void ReadNextFrame()
		{
			lock (this)
			{
				if (!Ended)
				{
					if (Dav1dfile.df_readvideo(
						Handle,
						1,
						out var yDataHandle,
						out var uDataHandle,
						out var vDataHandle,
						out var yDataLength,
						out var uvDataLength,
						out var yStride,
						out var uvStride) == 1
					) {
						this.yDataHandle = yDataHandle;
						this.uDataHandle = uDataHandle;
						this.vDataHandle = vDataHandle;
						this.yDataLength = yDataLength;
						this.uvDataLength = uvDataLength;
						this.yStride = yStride;
						this.uvStride = uvStride;

						FrameDataUpdated = true;
					}
				}
			}
		}

		protected virtual void Dispose(bool disposing)
		{
			if (!IsDisposed)
			{
				if (disposing)
				{
					// dispose managed state (managed objects)
				}

				// free unmanaged resources (unmanaged objects)
				Dav1dfile.df_close(Handle);

				IsDisposed = true;
			}
		}

		~VideoAV1Stream()
		{
			Dispose(disposing: false);
		}

		public void Dispose()
		{
			// Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
			Dispose(disposing: true);
			GC.SuppressFinalize(this);
		}
	}
}