open Js_of_ocaml
open Brr

let create_new_state pm pm_model pm_state mySchema content =
  let module PM = Prosemirror in

  let doc = PM.Model.(
      DOMParser.parse
        (DOMParser.from_schema pm_model mySchema)
        (Jv.Id.of_jv content)) in

  let props = PM.State.creation_prop () in
  props##.doc := Js.some doc;
  props##.plugins := Js.some (PM.example_setup pm mySchema);

  PM.State.create
    pm_state
    props

let storage_key = (Jstr.v "editor")
let prosemirror id content =
  begin match (Jv.is_none id), (Jv.is_none content) with
    | false, false ->

      let module PM = Prosemirror in
      let pm = PM.v () in

      let ( let+ ) o f = Option.iter f o
      and ( and+ ) a b =
        match a, b with
        | Some a, Some b -> Some (a, b)
        | _ -> None

      in

      let+ pm_state = J.get pm PM.state
      and+ pm_view  = J.get pm PM.view
      and+ pm_model = J.get pm PM.model
      and+ schema_basic = J.get pm PM.schema_basic
      and+ schema_list = J.get pm PM.schema_list

      in

      let _ = schema_basic
      and _ = schema_list in

      let mySchema = Js_of_ocaml.Js.Unsafe.eval_string {|new PM.model.Schema({
    nodes: PM.schema_list.addListNodes(PM.schema_basic.schema.spec.nodes, "paragraph block*", "block"),
    marks: PM.schema_basic.schema.spec.marks
  })|} in


      (* Create the initial state *)
      let storage = Brr_io.Storage.local G.window in
      let opt_data = Brr_io.Storage.get_item storage storage_key in
      let state = match opt_data with
        | None -> create_new_state pm pm_model pm_state mySchema content
        | Some contents ->
          (* Try to load from the storage *)
          begin match Json.decode contents with
            | Error _ -> create_new_state pm pm_model pm_state mySchema content
            | Ok json ->
              Console.(log [Jstr.v "Loading json"]);

              let history = PM.History.(history pm (history_prop ()) ) in
              Console.(log [history]);
              let _ = history in

              let obj = PM.State.configuration_prop () in
              obj##.plugins := Js.some (PM.example_setup pm mySchema);
              obj##.schema := mySchema;
              PM.State.fromJSON pm_state obj json
          end
      in

      let props = PM.View.direct_editor_props () in
      props##.dispatchTransaction := (Js.wrap_meth_callback (fun view transaction ->
          Console.(log [ Jstr.v "Document size went from"
                       ; transaction##.before##.content##.size ]);
          let state = view##.state##apply transaction in
          view##updateState state
        ));
      props##.state := state;


      let view = PM.View.editor_view
          pm_view
          (Jv.Id.of_jv id)
          props in


      view##setProps props;

      (* Attach an event on focus out *)
      let _out_event = Brr_note.Evr.on_el
          (Ev.focusout)
          (fun _ ->
             let contents = view##.state##toJSON () in

             let storage = Brr_io.Storage.local G.window in
             Brr_io.Storage.set_item
               storage
               storage_key
               (Json.encode @@ contents)
             |> Console.log_if_error ~use:()



          )
          (Jv.Id.of_jv id) in
      ()

    | _, _-> Console.(error [str "No element with id '%s' '%s' found"; id ; content])

  end

let () =

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

  set global "editor" editor