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

module Storage = Storage

(** This is the state for the application *)
type t =
  { editable : bool
  ; view : PM.View.editor_view Js.t
  ; last_backup: float
  ; page_id: Jstr.t option

  ; window : Brr.El.t list
  ; pm : PM.t
  }

(** Compare two states together.

    The prosemirror elemens are ignored *)
let eq s1 s2 =
  Stdlib.(==)
    ( s1.editable
    , s1.last_backup
    , s1.page_id
    , s1.window )

    ( s2.editable
    , s2.last_backup
    , s2.page_id
    , s2.window )

let set_title
  : Storage.content Js.t -> unit
  = fun content ->
    let title =
      Js.Opt.get
        content##.title
        (fun () -> Jstr.empty) in
    let title_element = Document.find_el_by_id G.document (Jstr.v "title") in
    Option.iter
      (fun el -> El.set_prop (El.Prop.value) title el)
      title_element

let state_of_storage
  : PM.t -> Storage.content Js.t -> PM.Model.schema Js.t -> PM.State.editor_state Js.t
  = fun pm content schema ->
    Js.Opt.case
      content##.content
      (fun () ->
         let obj = PM.State.creation_prop () in
         obj##.plugins := Plugins.default pm schema;
         obj##.schema := Js.some schema;
         PM.State.create pm obj)
      (fun page_content ->
         let obj = PM.State.configuration_prop () in
         obj##.plugins := Plugins.default pm schema;
         obj##.schema := Js.some schema;
         PM.State.fromJSON pm obj page_content)

let load_page
  : Jstr.t option -> t -> t
  = fun page_id state ->
    let json = Storage.load page_id in
    let editor_state = state_of_storage state.pm json state.view##.state##.schema in
    let () = state.view##updateState editor_state
    and () = set_title json in

    let last_backup =
      Js.Opt.case json##.date
        (fun () -> state.last_backup )
        (fun v -> v) in

    { state with page_id
               ; last_backup  }

let new_page
  : Jstr.t option -> title:Jstr.t -> t -> t
  = fun page_id ~title state ->
    let new_date = (new%js Js.date_now)##getTime in
    let content_obj = object%js
      val content = Js.null
      val title = Js.some title
      val date = Js.some new_date
    end in
    let editor_state = state_of_storage state.pm content_obj state.view##.state##.schema in
    let () = state.view##updateState editor_state
    and () = set_title content_obj in

    let last_backup =
      Js.Opt.case content_obj##.date
        (fun () -> state.last_backup )
        (fun v -> v) in

    { state with page_id
               ; last_backup  }


let init
  : PM.t -> PM.View.editor_view Js.t -> float -> Jstr.t option ->  t
  = fun pm view last_backup page_id ->
    { editable = true
    ; view
    ; last_backup
    ; page_id

    ; window = []
    ; pm
    }