using Engine.Renderer.Pixel;
using Engine.Renderer.Texture;
using OpenTK.Graphics.OpenGL;

namespace Engine.Renderer.Framebuffer;

public class Framebuffer : OpenGlObject
{
    public int Width
    {
        get => _width;
        protected set
        {
            if (value <= 0)
                throw new ArgumentException("Width must be greater than 0");

            _width = value;
        }
    }

    public int Height
    {
        get => _height;
        protected set
        {
            if (value <= 0)
                throw new ArgumentException("Height must be greater than 0");

            _height = value;
        }
    }
    
    public IConstTexture<Rgb8> Texture => _texture;
    internal Texture.Texture<Rgb8> TextureInternal => _texture;

    private int _width;
    private int _height;

    private readonly DynamicTexture<Rgb8> _texture;
    private readonly Renderbuffer _renderbuffer;

    public Framebuffer(int width, int height)
    {
        Width = width;
        Height = height;

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

        _texture = new DynamicTexture<Rgb8>(width, height);
        GL.NamedFramebufferTexture(Handle, FramebufferAttachment.ColorAttachment0, _texture.Handle, 0);

        _renderbuffer = new Renderbuffer(width, height, RenderbufferStorage.Depth24Stencil8);
        GL.NamedFramebufferRenderbuffer(Handle, FramebufferAttachment.DepthStencilAttachment,
            RenderbufferTarget.Renderbuffer, _renderbuffer.Handle);

        var status = GL.CheckNamedFramebufferStatus(Handle, FramebufferTarget.Framebuffer);
        if (status != FramebufferStatus.FramebufferComplete)
            throw new Exception($"Framebuffer is not complete: {status}");
    }

    public void Resize(int width, int height)
    {
        if (Width == width && Height == height)
            return;

        Width = width;
        Height = height;

        _texture.Resize(width, height);
        _renderbuffer.Resize(width, height);
    }

    internal override void Bind()
    {
        GL.BindFramebuffer(FramebufferTarget.Framebuffer, Handle);
    }

    internal override void Unbind()
    {
        GL.BindFramebuffer(FramebufferTarget.Framebuffer, 0);
    }

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