open Brr
module PM = Prosemirror
module Js = Js_of_ocaml.Js
module Actions = Editor_actions

let _ =
  Js.Unsafe.global ##. PM :=
    object%js
      val commands = Js.Unsafe.js_expr {|require("prosemirror-commands")|}

      val dropcursor = Js.Unsafe.js_expr {|require("prosemirror-dropcursor")|}

      val example_setup_ =
        Js.Unsafe.js_expr {|require("prosemirror-example-setup")|}

      val gapcursor = Js.Unsafe.js_expr {|require("prosemirror-gapcursor")|}

      val history = Js.Unsafe.js_expr {|require("prosemirror-history")|}

      val inputrules = Js.Unsafe.js_expr {|require("prosemirror-inputrules")|}

      val keymap = Js.Unsafe.js_expr {|require("prosemirror-keymap")|}

      val menu = Js.Unsafe.js_expr {|require("prosemirror-menu")|}

      val model = Js.Unsafe.js_expr {|require("prosemirror-model")|}

      val schema_basic_ =
        Js.Unsafe.js_expr {|require("prosemirror-schema-basic")|}

      val schema_list_ =
        Js.Unsafe.js_expr {|require("prosemirror-schema-list")|}

      val state = Js.Unsafe.js_expr {|require("prosemirror-state")|}

      val transform = Js.Unsafe.js_expr {|require("prosemirror-transform")|}

      val view = Js.Unsafe.js_expr {|require("prosemirror-view")|}
    end


(** Load the js-zip library, with browserify *)
let zip = Js.Unsafe.js_expr {|require("jszip")|}

(** Create a new editor view

    [build_view element state] will create the editor and attach it to [element].

*)
let build_view :
    PM.t -> Jstr.t option -> El.t -> PM.View.editor_view Js.t * float =
 fun pm page_id editor ->
  (* Remove all the elements if any *)
  El.set_children editor [];

  (* TODO
     This could be improved, instead of creating a new schema, just fetch
     the node and marks from the plungin *)
  let custom_schema =
    Plugins.Footnotes.footnote_schema pm (PM.SchemaBasic.schema pm)
  in

  (* Recreate the full schema by adding all the nodes and marks from the
     plugings *)
  let specs =
    PM.Model.schema_spec
      (PM.SchemaList.add_list_nodes
         pm
         custom_schema##.spec##.nodes
         (Jstr.v "paragraph block*")
         (Some (Jstr.v "block")) )
      (Some custom_schema##.spec##.marks)
      None
  in
  let full_schema = PM.Model.schema pm specs in
  let stored_content = State.Storage.load page_id in

  (* This variable contains the last update time, either because it is
     stored, or because it is the date where we create the page. *)
  let last_backup =
    Js.Opt.get stored_content##.date (fun () -> (new%js Js.date_now)##getTime)
  in

  let props = PM.View.direct_editor_props () in
  props##.state := State.state_of_storage pm stored_content full_schema;

  (* Add the custom nodes *)
  props##.nodeViews :=
    PM.O.init [| ("footnote", Plugins.Footnotes.footnote_view pm) |];

  let view = PM.View.editor_view pm editor props in
  (view, last_backup)


module Store = struct
  type t = El.t

  let process : t -> State.t -> State.t =
   fun title_element state ->
    let title = El.prop El.Prop.value title_element in

    let new_date = (new%js Js.date_now)##getTime in
    let content_obj =
      object%js
        val content = Js.some @@ Jv.Id.to_jv (state.view##.state##toJSON ())

        val title = Js.some title

        val date = Js.some new_date
      end
    in
    let save =
      State.Storage.save
        content_obj
        state.page_id
        (* There three date here :
           - The actual date at the time we save the note
           - The date associated with the note when we loaded it first time
           - The date associated with the note at the time we want to update it

           The two last may differ if the note has been updated in another one
           tab. *)
        ~check:(fun ~previous ~update ->
          let _ = update in
          Js.Opt.case
            previous##.date
            (fun () -> true)
            (fun date ->
              (* I do not figure how the previous date could be older
                 than the last backup. It could be either :

                 - equal (if we are the only one to update it)
                 - more recent (if the content has been updated elsewhere)

                 but older shoud be a bug. *)
              let is_ok = date <= state.last_backup in
              ( if not is_ok
              then
                let open Console in
                log
                  [ Jstr.v "Last backup date is "
                  ; new%js Js.date_fromTimeValue state.last_backup
                  ; Jstr.v " but date is "
                  ; new%js Js.date_fromTimeValue date
                  ] );
              is_ok ) )
    in
    match save with
    | Ok true -> { state with last_backup = new_date }
    | Ok false ->
        Console.(log [ Jstr.v "Didn't save" ]);
        state
    | Error other ->
        (* TODO In case of error, notify the user *)
        Console.(log [ Jstr.v "Couldn't save"; other ]);
        state
end

module App = Editor_app

let app id content =
  let title_element = Document.find_el_by_id G.document (Jstr.v "title") in
  (* Check the pre-requisite *)
  match
    (title_element, Jv.is_none id, Jv.is_none content, Blog.Sidebar.get ())
  with
  | Some title, false, false, Some sidebar ->
      let () = Blog.Sidebar.clean sidebar in

      let pm = PM.v () in
      let editor : El.t = Jv.Id.of_jv id in
      (* Load the cache for the given page *)
      let page_id = State.Storage.page_id () in
      let view, last_backup = build_view pm page_id editor in

      let init_state = State.init pm view last_backup page_id in

      (* Initialize the buttons actions and get the associated events.
         At this point, the HTML element is not yet created, and cannot be
         inserted in the document.
      *)
      let side_elements = Editor_actions.build pm in
      let btn_events = Editor_actions.get_event side_elements in

      (* Create the main event loop with all the collected events *)
      let app_state =
        App.run
          ~eq:State.eq
          init_state
          (Note.E.select
             [ Brr_note.Evr.on_els
                 Ev.focusout
                 (fun _ _ -> App.dispatch (module Store) title)
                 [ editor; title ]
             ; btn_events
             ] )
      in

      (* Get the html element associated with the buttons, and add it in the
         page.

         The state event is already created, and can be given in the html
         creation in order to update the elements when the state change.
      *)
      let childs = Editor_actions.complete side_elements app_state in
      let () = El.append_children sidebar childs in
      let _ = Note.(Logr.hold (S.log app_state (fun _ -> ()))) in
      ()
  | _ ->
      Console.(error [ str "No element with id '%s' '%s' found"; id; content ])


let () =
  let open Jv in
  let editor = obj [| ("attach_prosemirror", repr app) |] in

  set global "editor" editor