open Import

include (val Logging.sublogs logger "Wheel")

type 'a t = {
  entries : 'a Dllist.t array;
  mutable index : int;
}

let make n = {
  entries = Array.init n (fun _ -> Dllist.create ());
  index = 0;
}

let queue t =
  t.entries.(t.index)

let add t v =
  Dllist.add_r v (queue t) |> ignore

let[@tail_mod_cons] rec empty t =
  match Dllist.take_l (queue t) with
  | x -> x :: empty t
  | exception Dllist.Empty -> []

let tick t =
  t.index <- (t.index + 1) mod Array.length t.entries;
  empty t