(** The page shell: everything that surrounds a page's own content.

    Pages hand this module a {!body_data} description and receive a complete
    document. The shell decides which navigation applies, whether a toolbar is
    present, and what goes in the head — pages never assemble those themselves.
*)

(* Page identity and site settings are defined in [Components] so navigation can
   be built without depending on this module. They are re-exported here because
   callers name them [Layout.Summary], [Layout.site], and so on. *)

type page = Components.page = Summary | Commits | Files

type site = Components.site = {
  user_name : string;
  root_title : string;
  nav_logo : string;
}

let site = Components.site

type body_data = {
  title : string;  (** heading for pages that show one *)
  repo : string option;  (** [None] on the repository list and project dirs *)
  subtitle : string;
  active : page;
  toolbar : Ui.node list;
  content : Ui.node list;
  home_href : string option;  (** where the site nav's home link points *)
}

let stylesheets =
  [ "/static/styles.css"; "/static/syntax-theme.css"; "/static/readme.css" ]

let head page_title =
  Ui.document_head ~title:page_title
    ((Ui.meta_viewport :: List.map Ui.stylesheet stylesheets)
    @ [ Ui.icon "/static/git_icon.svg" ])

(* A freshly initialised repository carries git's placeholder description; treat
   it as no description at all rather than showing boilerplate. *)
let meaningful_subtitle subtitle =
  if subtitle = Resolvers.default_repo_description then "" else subtitle

(** Inside a repository only the description is shown, since the navigation
    already names the repository. Elsewhere the site identifies itself. *)
let header ~has_repo page_title subtitle =
  match (has_repo, meaningful_subtitle subtitle) with
  | true, "" -> Ui.nothing
  | true, subtitle ->
      Ui.page_banner ~id:"page-header" [ Ui.paragraph_text subtitle ]
  | false, subtitle ->
      Ui.page_banner ~id:"page-header"
        ([
           Ui.image ~class_:"site-logo" ~src:"/static/git_icon.svg" ();
           Ui.heading [ Ui.text page_title ];
         ]
        @
        if subtitle = "" then []
        else [ Ui.paragraph_text ~class_:"subtitle" subtitle ])

let footer user_name =
  let now = Unix.(time () |> localtime) in
  let year = string_of_int (now.tm_year + 1900) in
  Ui.page_footer ~class_:"site-footer"
    [
      Ui.paragraph_text ~class_:"copyright"
        (if user_name = "" then Printf.sprintf "Copyright %s" year
         else Printf.sprintf "Copyright %s %s" year user_name);
      Ui.paragraph ~class_:"validation"
        [
          Ui.text_link ~href:"https://validator.w3.org/check/referer" "Validate";
        ];
    ]

let body site page_data =
  (* The sticky toolbar shifts everything below it; the class lets CSS offset
     sticky descendants by the right amount. *)
  let body_class =
    match (page_data.repo, page_data.toolbar) with
    | Some _, _ :: _ -> Some "has-toolbar"
    | _ -> None
  in
  let navigation, toolbar, banner, compact_nav =
    match page_data.repo with
    | None ->
        ( Components.site_nav ~title:site.root_title ~logo:site.nav_logo
            ?home_href:page_data.home_href (),
          Ui.nothing,
          Ui.nothing,
          Ui.nothing )
    | Some repo ->
        ( Components.repo_nav ~active:page_data.active ~logo:site.nav_logo repo,
          Components.toolbar page_data.toolbar,
          header ~has_repo:true page_data.title page_data.subtitle,
          Components.compact_repo_nav ~active:page_data.active repo )
  in
  Ui.document_body ?class_:body_class
    [
      Ui.skip_link ~href:"#main" "Skip to content";
      navigation;
      toolbar;
      Ui.page_content ~id:"main" (banner :: page_data.content);
      compact_nav;
      footer site.user_name;
    ]

let render ?(page_title = "Ogit") site body_data =
  Ui.document ~head:(head page_title) ~body:(body site body_data) ()