using Dashboard.Pal;

namespace Dashboard.Drawing
{
    public interface IShader : IDisposable
    {
    }

    /// <summary>
    /// Base interface for creating shader pipelines.
    /// </summary>
    public interface IShaderCreateInfo
    {
    }

    public enum BufferAccessPattern
    {
        /// <summary>
        /// No hint given. Not recommended.
        /// </summary>
        DontCare,

        /// <summary>
        /// For buffers which have a long lifetime, but the contents are initialized once.
        /// </summary>
        Static,

        /// <summary>
        /// For buffers which have a long lifetime, but the contents can be updated every frame.
        /// </summary>
        Stream,

        /// <summary>
        /// For buffers which have a short lifetime, used for streaming resources to the graphics hardware.
        /// </summary>
        Upload,

        /// <summary>
        /// For buffers which have a short lifetime, used for streaming resources from the graphics hardware.
        /// </summary>
        Download,
    }

    public interface IBuffer : IDisposable
    {
        public BufferAccessPattern AccessPattern { get; }
        public long Size { get; }

        void Reallocate(long newSize);
        Span<T> Map<T>(long offset, int count = -1) where T : unmanaged;
        void Unmap();
        void Read<T>(long offset, Span<T> span) where T : unmanaged;
        void Write<T>(long offset, ReadOnlySpan<T> span) where T : unmanaged;
    }

    /// <summary>
    /// This extension provides direct access to the backend rendering pipeline without writing with a higher level
    /// abstraction than the rendering backend.
    /// </summary>
    public interface IDirectRendering : IDeviceContextExtension
    {
        public IShader CreatePipeline<T>(T createInfo) where T : IShaderCreateInfo;
        public IBuffer CreateBuffer(BufferAccessPattern pattern, long size);

        void Draw(DrawCall drawCall);
    }
}