using OpenTK.Graphics.OpenGL;
using Serilog;

namespace Engine.Renderer.Buffer;

public class IndexBuffer : OpenGlObject
{
    internal int Count { get; }

    public IndexBuffer(int count, BufferStorageFlags flags)
    {
        Count = count;

        GL.CreateBuffers(1, out int handle);
        Handle = handle;

        GL.NamedBufferStorage(Handle, Count * sizeof(uint), IntPtr.Zero, flags);
        
        Log.Debug("Index buffer {Handle} created with {Count} elements", Handle, Count);
    }

    public void UploadData(uint[] data)
    {
        UploadData(0, data);
    }

    public void UploadData(int offset, uint[] data)
    {
        if (offset < 0)
            throw new ArgumentException("Offset must be greater than 0");

        if (data.Length + offset > Count)
            throw new ArgumentException("Data array is too large");

        GL.NamedBufferSubData(Handle, offset, data.Length * sizeof(uint), data);
    }

    internal override void Bind()
    {
        GL.BindBuffer(BufferTarget.ElementArrayBuffer, Handle);
    }

    internal override void Unbind()
    {
        GL.BindBuffer(BufferTarget.ElementArrayBuffer, 0);
    }

    protected override void Destroy()
    {
        GL.DeleteBuffer(Handle);
    }
}