open Caml_xss

let dims = ref (180, 80)

let mk_color (r, g, b) =
  (r * 257,
   g * 257,
   b * 257)

let _color0 =
  mk_color (255, 255, 255)

let _color1 =
  mk_color (120, 80, 255)

let _color2 =
  mk_color (255, 160, 26)

let _color3 =
  mk_color (20, 250, 62)

let coords_losange (x, y) =
  [ (10 + x,  0 + y, 16 + x, 10 + y);
    (16 + x, 10 + y, 10 + x, 20 + y);
    (10 + x, 20 + y,  4 + x, 10 + y);
    ( 4 + x, 10 + y, 10 + x,  0 + y); ]

module UserSaver = struct
  type state = {
    colormap: Caml_xss.colormap;
    color0: pixel;
    color1: pixel;
    color2: pixel;
    color3: pixel;
  }
  type user_calls = {
    saver_init: x_elems -> state;
    saver_draw: x_elems -> state -> int;
    saver_reshape: x_elems -> state -> int -> int -> unit;
    saver_free: x_elems -> state -> unit;
  }
  let user_saver = {
    saver_init = (fun xelms ->
      let colormap = X.default_colormap xelms in
      let color0 = X.alloc_color xelms colormap _color0 in
      let color1 = X.alloc_color xelms colormap _color1 in
      let color2 = X.alloc_color xelms colormap _color2 in
      let color3 = X.alloc_color xelms colormap _color3 in
      { colormap;
        color0;
        color1;
        color2;
        color3;
      }
    );
    saver_reshape = (fun xelms state w h ->
      dims := (w, h);
    );
    saver_free = (fun xelms state -> print_newline ());
    saver_draw = (fun xelms state ->
      X.set_foreground xelms state.color0;
      List.iter (X.draw_point xelms) [
        (20, 20); (22, 20); (24, 20)];
      X.set_foreground xelms state.color1;
      List.iter (X.draw_line xelms)
        (coords_losange (20, 30));
      X.set_foreground xelms state.color2;
      List.iter (X.draw_rectangle xelms) [
        (60, 50, 10, 10);
        (80, 60, 10, 10)];
      List.iter (X.draw_point xelms) [
        (60 + 10, 50 + 10); (80 + 10, 60 + 10)];
      X.set_foreground xelms state.color3;
      X.draw_arc xelms (40, 60, 20, 20, 0, 360*64);
      (300_000)
    );
  }
end

module SomeSaver = MakeSaver(UserSaver)