open StdLabels
open Brr
open Brr_note
module App = Editor_app
module Js = Js_of_ocaml.Js

(** This is the attribute attached to each link and containing the node id
    pointed by the link. *)
let note_id_attribute = Jstr.v "data-note-id"

type t =
  { ev : App.event Note.event
  ; childs : El.t list
  ; ul : El.t
  ; mutable completed : bool
  ; delete_button : El.t
  }

let build : Prosemirror.t -> t =
 fun pm ->
  let delete_button =
    El.button
      ~at:At.[ class' (Jstr.v "action-button") ]
      [ El.i
          []
          ~at:
            At.
              [ class' (Jstr.v "fa")
              ; class' (Jstr.v "fa-2x")
              ; class' (Jstr.v "fa-trash")
              ]
      ]
  and home_button =
    El.button
      ~at:At.[ class' (Jstr.v "action-button") ]
      [ El.i
          []
          ~at:
            At.
              [ class' (Jstr.v "fa")
              ; class' (Jstr.v "fa-2x")
              ; class' (Jstr.v "fa-home")
              ]
      ]
  and add_button =
    El.button
      ~at:At.[ class' (Jstr.v "action-button") ]
      [ El.i
          []
          ~at:
            At.
              [ class' (Jstr.v "fa")
              ; class' (Jstr.v "fa-2x")
              ; class' (Jstr.v "fa-plus")
              ]
      ]
  and export_button =
    El.button
      ~at:At.[ class' (Jstr.v "action-button") ]
      [ El.i
          []
          ~at:
            At.
              [ class' (Jstr.v "fa")
              ; class' (Jstr.v "fa-2x")
              ; class' (Jstr.v "fa-download")
              ]
      ]
  and load_button =
    El.button
      ~at:At.[ class' (Jstr.v "action-button") ]
      [ El.i
          []
          ~at:
            At.
              [ class' (Jstr.v "fa")
              ; class' (Jstr.v "fa-2x")
              ; class' (Jstr.v "fa-upload")
              ]
      ]
  and cog_button =
    El.button
      ~at:At.[ class' (Jstr.v "action-button") ]
      [ El.i
          []
          ~at:
            At.
              [ class' (Jstr.v "fa")
              ; class' (Jstr.v "fa-2x")
              ; class' (Jstr.v "fa-cog")
              ]
      ]
  in

  (* We are waiting for event inside another event ( form validation inside
     popup creation.

     Note.E.join is used here in order to get only te popup validation. *)
  let delete_event =
    Note.E.join
      (Evr.on_el Ev.click (fun _ -> Delete_page.create ()) delete_button)
  (* Event on popup creation *)
  and add_event =
    Note.E.join (Evr.on_el Ev.click (fun _ -> Add_page.create ()) add_button)
  and export_event =
    Evr.on_el Ev.click (fun _ -> Export.create ()) export_button
  and import_event =
    Note.E.join (Evr.on_el Ev.click (fun _ -> Import.create ()) load_button)
  and cog_event =
    Evr.on_el Ev.click (fun _ -> To_markdown.create pm) cog_button
  in

  let ul = El.ul [] in

  (* Wait for a click on an existing page in order to sent the associated
     event.

     We compose the resulting event with both :
     - the home button
     - the list for all the pages presents in the sidebar

     We use the bubble property in order to listen only the [ul] element and
     not the each entry in the list. This way, there is no recursive loop
     between the redirect_handler and the dynamic generation of elements
     inside the [ul] node. *)
  let redirect_event =
    Note.E.select
      [ Evr.on_el
          Ev.click
          (fun _ -> App.dispatch (module Load_page.M) None)
          home_button
      ; Evr.on_el
          Ev.click
          (fun ev ->
            let el = Jv.Id.of_jv @@ Jv.Id.to_jv @@ Ev.target ev in
            let name = El.at note_id_attribute el in
            App.dispatch (module Load_page.M) name )
          ul
      ]
  in

  let childs =
    [ home_button
    ; add_button
    ; export_button
    ; load_button
    ; delete_button
    ; cog_button
    ; El.hr ()
    ; ul
    ]
  in

  let result_event =
    Note.E.select
      [ delete_event
      ; redirect_event
      ; add_event
      ; export_event
      ; import_event
      ; cog_event
      ]
  in

  { ev = result_event; childs; ul; delete_button; completed = false }


let get_event : t -> App.event Note.event = fun { ev; _ } -> ev

(** Collect all the notes in the cache and return them into links. *)
let get_notes _ =
  List.map (State.Storage.get_ids ()) ~f:(fun id ->
      let name_opt = (State.Storage.load (Some id))##.title in
      let name = Js.Opt.get name_opt (fun () -> id) in
      El.li
        [ El.a
            ~at:[ At.href (Jstr.v "#"); At.v note_id_attribute id ]
            [ El.txt name ]
        ] )


let complete : t -> State.t Note.signal -> El.t list =
 fun t change ->
  (* As we register some events, we have to prevent many execution of this
     function *)
  let () =
    if t.completed then raise (Failure "The action panel is already registered")
  in
  t.completed <- true;

  Elr.def_children t.ul (Note.S.map get_notes change);

  Elr.def_at
    (Jstr.v "disabled")
    (Note.S.map
       (fun state ->
         match state.State.page_id with
         | None -> Some Jstr.empty
         | Some _ -> None )
       change )
    t.delete_button;

  t.childs