using OpenTK.Graphics.OpenGL;
using Ryujinx.Graphics.GAL;
using System;

namespace Ryujinx.Graphics.OpenGL.Image
{
    class TextureBuffer : TextureBase, ITexture
    {
        private Renderer _renderer;
        private int _bufferOffset;
        private int _bufferSize;
        private int _bufferCount;

        private BufferHandle _buffer;

        public TextureBuffer(Renderer renderer, TextureCreateInfo info) : base(info)
        {
            _renderer = renderer;
        }

        public void CopyTo(ITexture destination, int firstLayer, int firstLevel)
        {
            throw new NotSupportedException();
        }

        public void CopyTo(ITexture destination, int srcLayer, int dstLayer, int srcLevel, int dstLevel)
        {
            throw new NotSupportedException();
        }

        public void CopyTo(ITexture destination, Extents2D srcRegion, Extents2D dstRegion, bool linearFilter)
        {
            throw new NotSupportedException();
        }

        public ITexture CreateView(TextureCreateInfo info, int firstLayer, int firstLevel)
        {
            throw new NotSupportedException();
        }

        public ReadOnlySpan<byte> GetData()
        {
            return Buffer.GetData(_renderer, _buffer, _bufferOffset, _bufferSize);
        }

        public void SetData(ReadOnlySpan<byte> data)
        {
            Buffer.SetData(_buffer, _bufferOffset, data.Slice(0, Math.Min(data.Length, _bufferSize)));
        }

        public void SetData(ReadOnlySpan<byte> data, int layer, int level)
        {
            throw new NotSupportedException();
        }

        public void SetStorage(BufferRange buffer)
        {
            if (_buffer != BufferHandle.Null &&
                buffer.Offset == _bufferOffset &&
                buffer.Size == _bufferSize &&
                _renderer.BufferCount == _bufferCount)
            {
                // Only rebind the buffer when more have been created.
                return;
            }

            _buffer = buffer.Handle;
            _bufferOffset = buffer.Offset;
            _bufferSize = buffer.Size;
            _bufferCount = _renderer.BufferCount;

            Bind(0);

            SizedInternalFormat format = (SizedInternalFormat)FormatTable.GetFormatInfo(Info.Format).PixelInternalFormat;

            GL.TexBufferRange(TextureBufferTarget.TextureBuffer, format, _buffer.ToInt32(), (IntPtr)buffer.Offset, buffer.Size);
        }

        public void Dispose()
        {
            if (Handle != 0)
            {
                GL.DeleteTexture(Handle);

                Handle = 0;
            }
        }

        public void Release()
        {
            Dispose();
        }
    }
}
