module Make(Layer: Repr.PRINTER) = struct

  type point = Path.Point.t

  type t =
    { path: (Layer.t)
    }

  type repr = Layer.t

  let create_path
    : 'b -> t
    = fun _ ->
      { path = Layer.create ()
      }

  let start
    : point -> point -> t -> t
    = fun p1 p2 { path } ->
      let path =
        Layer.move_to (Path.Point.get_coord p1) path
        |> Layer.line_to (Path.Point.get_coord p2) in
      { path
      }

  let line_to
    : (point * point) -> (point * point) -> t -> t
    = fun (_, p1) (_, p1') {path} ->
      let path = Layer.move_to (Path.Point.get_coord p1) path in
      let path = Layer.line_to (Path.Point.get_coord p1') path in
      { path
      }

  let quadratic_to
    : (point * Gg.v2 * Gg.v2 * point) -> (point * Gg.v2 * Gg.v2 * point) -> t -> t
    = fun (p0, ctrl0, ctrl1, p1) (p0',  ctrl0', ctrl1', p1') {path} ->

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

      and bezier' =
        { Shapes.Bezier.p0 = Path.Point.get_coord p0'
        ; ctrl0 = ctrl0'
        ; ctrl1 = 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))
        *. 30.
      in
      let path = ref path in
      for i = 0 to ((Int.of_float delay) ) do
        let ratio = (Float.of_int i) /. delay in
        let bezier, _ = Shapes.Bezier.slice ratio bezier
        and bezier', _ = Shapes.Bezier.slice ratio bezier'  in

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

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

      { path = !path }

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


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