module Make(Repr: Repr.PRINTER) = struct

  type t = Path.Point.t

  type repr =
    { path: (Repr.t)
    }

  let create_path
    : 'b -> repr
    = fun _ ->
      { path = Repr.create ()
      }

  (* Start a new path. *)
  let start
    : Path.Point.t -> repr -> repr
    = fun t {path} ->
      let path = Repr.move_to (Path.Point.get_coord t) path in
      let path = Repr.line_to (Path.Point.get_coord' t) path in
      { path
      }

  let line_to
    : Path.Point.t -> Path.Point.t -> repr -> repr
    = fun _ t {path} ->
      let path = Repr.move_to (Path.Point.get_coord t) path in
      let path = Repr.line_to (Path.Point.get_coord' t) path in
      { path
      }

  let quadratic_to
    : Path.Point.t -> Gg.v2 -> Gg.v2 -> Path.Point.t -> repr -> repr
    = fun p0 ctrl0 ctrl1 p1 { path } ->

      let path = ref path in

      let bezier =
        { Shapes.Bezier.p0 = Path.Point.get_coord p0
        ; ctrl0
        ; ctrl1
        ; p1 = Path.Point.get_coord p1
        } in

      (* Mark each point on the bezier curve. The first point is the most
         recent point  *)
      let delay =
        ((Path.Point.get_stamp p0) -. (Path.Point.get_stamp p1))
        *. 20.
      in
      for i = 0 to ((Int.of_float delay) -1) do
        let ratio = (Float.of_int i) /. delay in
        let bezier', _ = Shapes.Bezier.slice ratio bezier in

        let point = Path.Point.mix ratio bezier'.Shapes.Bezier.p1 p0 p1 in

        path := Repr.move_to (Path.Point.get_coord point) !path;
        path := Repr.line_to (Path.Point.get_coord' point) !path;
      done;

      { path = !path }

  let stop
    : repr -> repr
    = fun path -> path


  let get
    : repr -> Repr.t
    = fun {path; _} ->
      path
end