(* Minimal animation test - shows exact bytes sent *)

module K = Kgp

let solid_color_rgba ~width ~height ~r ~g ~b ~a =
  let pixels = Bytes.create (width * height * 4) in
  for i = 0 to (width * height) - 1 do
    let idx = i * 4 in
    Bytes.set pixels idx (Char.chr r);
    Bytes.set pixels (idx + 1) (Char.chr g);
    Bytes.set pixels (idx + 2) (Char.chr b);
    Bytes.set pixels (idx + 3) (Char.chr a)
  done;
  Bytes.to_string pixels

let send cmd ~data =
  print_string (K.Command.to_string cmd ~data);
  flush stdout

let () =
  let width, height = 40, 40 in  (* Smaller for faster testing *)
  let image_id = 500 in

  (* Clear any existing image *)
  send (K.Command.delete ~quiet:`Errors_only (`All_visible_and_free)) ~data:"";

  (* Step 1: Transmit base frame (red) *)
  let red_frame = solid_color_rgba ~width ~height ~r:255 ~g:0 ~b:0 ~a:255 in
  send
    (K.Command.transmit
       ~image_id
       ~format:`Rgba32
       ~width ~height
       ~quiet:`Errors_only
       ())
    ~data:red_frame;

  (* Step 2: Add frame (blue) *)
  let blue_frame = solid_color_rgba ~width ~height ~r:0 ~g:0 ~b:255 ~a:255 in
  send
    (K.Command.frame
       ~image_id
       ~format:`Rgba32
       ~width ~height
       ~frame:(K.Frame.make ~gap_ms:500 ~composition:`Overwrite ())
       ~quiet:`Errors_only
       ())
    ~data:blue_frame;

  (* Step 3: Add frame (green) *)
  let green_frame = solid_color_rgba ~width ~height ~r:0 ~g:255 ~b:0 ~a:255 in
  send
    (K.Command.frame
       ~image_id
       ~format:`Rgba32
       ~width ~height
       ~frame:(K.Frame.make ~gap_ms:500 ~composition:`Overwrite ())
       ~quiet:`Errors_only
       ())
    ~data:green_frame;

  (* Step 4: Create placement *)
  send
    (K.Command.display
       ~image_id
       ~placement:(K.Placement.make
                     ~placement_id:1
                     ~cursor:`Static
                     ())
       ~quiet:`Errors_only
       ())
    ~data:"";

  (* Step 5: Set root frame gap - IMPORTANT: root frame has no gap by default *)
  send
    (K.Command.animate ~image_id (K.Animation.set_gap ~frame:1 ~gap_ms:500))
    ~data:"";

  (* Step 6: Start animation *)
  send
    (K.Command.animate ~image_id (K.Animation.set_state ~loops:1 `Run))
    ~data:"";

  print_endline "";
  print_endline "Animation should be playing (red -> blue -> green).";
  print_endline "Press Enter to stop...";
  flush stdout;
  let _ = read_line () in

  (* Stop animation *)
  send
    (K.Command.animate ~image_id (K.Animation.set_state `Stop))
    ~data:"";

  (* Clean up *)
  send (K.Command.delete ~quiet:`Errors_only (`All_visible_and_free)) ~data:"";
  print_endline "Done."