open Brr
open Utils

type image_size =
  | Big
  | Small

let of_string = function
  | "post-image" -> Some Small
  | "post-image-big" -> Some Big
  | _ -> None

let to_string = function Small -> "post-image" | Big -> "post-image-big"

(*change postImage class to make it bigger/smaller on click*)
let image_click post_image event =
  log "image_click@\n";
  let class_jstr = Jstr.of_string "class" in
  let current_class =
    match El.at class_jstr post_image with
    | None -> failwith "no class for post_image"
    | Some c -> Jstr.to_string c
  in
  let new_class =
    match of_string current_class with
    | Some image_size -> ( match image_size with Big -> Small | Small -> Big )
    | None -> failwith "invalid image class name"
  in
  El.set_at class_jstr (Some (Jstr.of_string (to_string new_class))) post_image;
  let id =
    match El.at (Jstr.of_string "data-id") post_image with
    | None -> failwith "no data-id on post_image"
    | Some id -> Jstr.to_string id
  in
  let src =
    match new_class with
    | Small -> Format.sprintf "/img/s/%s" id
    | Big -> Format.sprintf "/img/%s" id
  in
  El.set_at (Jstr.of_string "src") (Some (Jstr.of_string src)) post_image;
  (*prevent redirect to /img/:img*)
  Ev.prevent_default event;
  Ev.stop_propagation event

let render_time date_span =
  log "render time@\n";
  let data_time =
    match El.at (Jstr.of_string "data-time") date_span with
    | None -> failwith "no attribute data-time for date element"
    | Some data_time -> Jstr.to_float data_time
  in
  let t = Unix.localtime data_time in
  let date =
    Format.sprintf "%02d-%02d-%02d %02d:%02d" (1900 + t.tm_year) (1 + t.tm_mon)
      t.tm_mday t.tm_hour t.tm_min
  in
  let inner_html = El.Prop.jstr (Jstr.of_string "innerHTML") in
  El.set_prop inner_html (Jstr.of_string date) date_span

let preview_ref = ref None

let highlighted_ref = ref None

let selected_ref = ref None

let on_hashchange _event =
  log "on hashchange";
  let frag = Jstr.to_string @@ Uri.fragment @@ Window.location G.window in
  if frag = "" then ()
  else
    match find_by_id_opt frag with
    | None -> log "fragment not found on the page"
    | Some reply ->
      let () =
        match !selected_ref with
        | None -> ()
        | Some item -> El.set_class (Jstr.of_string "selected") false item
      in
      El.set_class (Jstr.of_string "selected") true reply;
      selected_ref := Some reply

let clone_element el =
  (* TODO: how to clone with Brr? *)
  let id =
    match El.at (Jstr.of_string "id") el with
    | None -> failwith "element as no id for cloning"
    | Some id -> Jstr.to_string id
  in
  (* get reply_div as a Jv.t *)
  let original_div = Jv.get Jv.global id in
  let div = Jv.call original_div "cloneNode" [| Jv.of_bool true |] in
  ignore
  @@ Jv.call div "setAttribute"
       [| Jv.of_string "id"; Jv.of_string "floating-reply-preview" |];
  ignore
  @@ Jv.call div "setAttribute"
       [| Jv.of_string "class"; Jv.of_string "post highlight" |];

  (* append to DOM *)
  (* we needs to add it to `body` and not `original_div` or it might change the display
   * and do buggy things with mouse events on `original_div`*)
  let document = Jv.get Jv.global "document" in
  let body = Jv.get document "body" in
  ignore @@ Jv.call body "append" [| div |];
  (* go back to El *)
  match find_by_id_opt "floating-reply-preview" with
  | None -> failwith "error cloning element"
  | Some el -> el

let on_mouse_over el _event =
  log "on mouse over@\n";

  let reply_id =
    match El.at (Jstr.of_string "data-id") el with
    | None -> failwith "no data-id on element"
    | Some data_id -> Jstr.to_string data_id
  in

  match find_by_id_opt reply_id with
  | None -> failwith "error getting reply_div, this reply is not on this page"
  | Some reply_div ->
    (* check if it in view, if it is, just make it of class `highlight` *)
    let window_height =
      let window = Jv.get Jv.global "window" in
      Jv.get window "innerHeight" |> Jv.to_int
    in
    let reply_top = El.bound_y reply_div |> int_of_float in
    if reply_top < window_height - 50 && reply_top + 50 > 0 then (
      (* just highlight if reply is in viewport *)
      El.set_class (Jstr.of_string "highlight") true reply_div;
      highlighted_ref := Some reply_div )
    else
      (* copy it to make new div  `floating-reply-preview` *)
      let preview_div = clone_element reply_div in

      (* place it next to the reply-link el*)
      let top =
        let el_top = El.bound_y el in
        let h = El.bound_h preview_div in
        (* clamp to viewport *)
        let top =
          Float.min
            (el_top -. (0.5 *. h))
            (float_of_int window_height -. h -. 7.0)
        in
        let top = Float.max top 0.0 in
        top |> int_of_float |> Format.sprintf "%dpx" |> Jstr.of_string
      in
      let left =
        El.bound_x el +. El.bound_w el
        |> int_of_float |> Format.sprintf "%dpx" |> Jstr.of_string
      in
      El.set_inline_style El.Style.position (Jstr.of_string "fixed") preview_div;
      El.set_inline_style El.Style.z_index (Jstr.of_string "42") preview_div;
      El.set_inline_style El.Style.top top preview_div;
      El.set_inline_style El.Style.left left preview_div;
      (* also highlight class doesn't work if we set inline style idk why wtf css *)
      El.set_inline_style El.Style.background_color (Jstr.of_string "#9dd162")
        preview_div;

      (* set preview_div ref for on_mouse_out *)
      preview_ref := Some preview_div

let on_mouse_out _el _event =
  log "on mouse out@\n";
  (* get the `reply-preview` element, delete it if Some*)
  let () =
    match !highlighted_ref with
    | None -> ()
    | Some highlighted_div ->
      El.set_class (Jstr.of_string "highlight") false highlighted_div
  in
  match !preview_ref with
  | None -> ()
  | Some preview_div -> El.remove preview_div

let make_pretty _event =
  log "make pretty@\n";

  let dates = El.find_by_class (Jstr.of_string "date") in
  List.iter render_time dates;

  (*add event image_click to all postImage*)
  let () = add_event_to_class Ev.click "post-image" image_click in

  (*add event mouse_over/out to all reply-link *)
  let () = add_event_to_class Ev.mouseover "reply-link" on_mouse_over in
  let () = add_event_to_class Ev.mouseout "reply-link" on_mouse_out in

  (* add fragment listener to mark as selected the linked post *)
  let hashchange = Ev.Type.create (Jstr.of_string "hashchange") in
  let (_ : Ev.listener) =
    Ev.listen hashchange on_hashchange (Window.as_target G.window)
  in
  (* call hashchange on page load too *)
  on_hashchange ()

(*make pretty after page load*)
let () =
  log "add load eventlistener to make pretty@\n";
  let load = Ev.Type.create (Jstr.of_string "load") in
  let (_ : Ev.listener) =
    Ev.listen load make_pretty (Window.as_target G.window)
  in
  ()