use crate::shaders;

pub trait RenderBackend {
  type ShaderSource;
  type DrawCommand;
  fn new() -> Self where Self: Sized;

  fn resume(&mut self, event_loop: &winit::event_loop::ActiveEventLoop);
  fn resize(&mut self, width: u32, height: u32);
  fn draw(&self, cmd: &Self::DrawCommand);
  fn suspend(&mut self);

  // // Frame
  // fn begin_frame(&mut self) -> FrameContext;
  // fn end_frame(&mut self);
  //
  // // Resources
  fn create_shader(&mut self, desc: Self::ShaderSource) -> Result<shaders::ShaderHandle, String>;
  // fn create_buffer(&mut self, data: &[u8], usage: BufferUsage) -> BufferHandle;
  // fn create_texture(&mut self, desc: TextureDescriptor) -> TextureHandle;
  //
  // // Material = shader + uniforms + textures bundled
  // fn create_material(&mut self, shader: ShaderHandle) -> MaterialHandle;
  // fn set_material_param(&mut self, material: MaterialHandle, name: &str, value: UniformValue);
}

// pub struct FrameContext<'a> {
//     backend: &'a mut dyn RenderBackend,
// }
//
// impl FrameContext<'_> {
//     pub fn draw(&mut self, mesh: &Mesh, material: MaterialHandle, transform: Mat4);
// }