let mainElt = Document.querySelectorUnsafe "#g-Layout__Main"

let isRunning = ref false

let start ~onHidden ~onEnded =
  if not !isRunning then
    let () = isRunning := true in
    let () = Element.setClassName mainElt "g-Layout__HideMain" in
    let delay = 200 in
    let _ =
      Js.Global.setTimeout
        (fun () ->
          let () = onHidden () in
          let () = Element.setClassName mainElt "" in
          let _ =
            Js.Global.setTimeout
              (fun () ->
                let () = onEnded () in
                isRunning := false)
              delay
          in
          ())
        delay
    in
    ()
  else ()