(** Ogit's vocabulary of page parts.

    Where {!Ui} supplies generic building blocks, this module names the parts
    specific to a Git browser and wires them to {!Routes}, so page modules can
    describe a page without mentioning HTML or URL strings.

    Every function returns a {!Ui.node}. Nothing here performs I/O. *)

(** {1 Page identity} *)

type page =
  | Summary
  | Commits
  | Files
      (** Which repository page is being shown. Drives the [aria-current] marker
          in the navigation. *)

type site = { user_name : string; root_title : string; nav_logo : string }
(** Site-wide presentation settings, resolved once from configuration. *)

let site ~user_name ~root_title ~nav_logo = { user_name; root_title; nav_logo }

(** {1 Routes as links} *)

let url route = Routes.path_of route

(** A link to a route, with the route standing in for a hand-written URL. *)
let route_link ?class_ ?label route text =
  Ui.text_link ?class_ ?label ~href:(url route) text

(** The commit list is narrowed through query parameters, which {!Routes} does
    not model because it covers path-shaped routes only. Passing the filters
    already in effect keeps them applied as the reader pages or switches
    filters. *)
let commits_url ?filter_type ?author ?committer ?(page_number = 1) repo =
  let params =
    (if page_number > 1 then [ ("page", string_of_int page_number) ] else [])
    @ (match filter_type with Some value -> [ ("type", value) ] | None -> [])
    @ (match author with Some value -> [ ("author", value) ] | None -> [])
    @ match committer with Some value -> [ ("committer", value) ] | None -> []
  in
  let base = Printf.sprintf "/%s/commits/" repo in
  match params with
  | [] -> base
  | _ -> base ^ "?" ^ Dream.to_form_urlencoded params

(** Where a repository's clone URL lives. *)
let clone_url repo = Printf.sprintf "/%s" repo

(** {1 Navigation} *)

let page_route repo = function
  | Summary -> Routes.Repo repo
  | Commits -> Routes.Commits repo
  | Files -> Routes.Files repo

let page_name = function
  | Summary -> "Summary"
  | Commits -> "Commits"
  | Files -> "Files"

let page_link repo ~active page =
  Ui.nav_link ~current:(page = active)
    ~href:(url (page_route repo page))
    (page_name page)

(** Configured logos may be given as bare paths; make those root-relative while
    leaving absolute and data URLs alone. *)
let asset_url source =
  if
    String.starts_with ~prefix:"/" source
    || String.starts_with ~prefix:"http://" source
    || String.starts_with ~prefix:"https://" source
    || String.starts_with ~prefix:"data:" source
  then source
  else "/" ^ source

let logo ~href ~alt source =
  Ui.link ~id:"nav-logo" ~href
    [ Ui.image ~class_:"site-logo" ~alt ~src:(asset_url source) () ]

(** Top navigation away from any repository: the repository list and project
    directory pages. When [home_href] is absent the page {i is} the list, so the
    logo points outward instead of back to itself. *)
let site_nav ~title ~logo:source ?home_href () =
  let logo_href, logo_alt =
    match home_href with
    | None -> ("https://git-scm.com", "Git website")
    | Some _ -> ("/", "Repository list")
  in
  Ui.navigation ~id:"top" ~label:"Site navigation"
    [
      logo ~href:logo_href ~alt:logo_alt source;
      Ui.text_link ~id:"nav-home"
        ~href:(Option.value home_href ~default:"/")
        title;
    ]

(** Top navigation within a repository. The link list collapses behind a
    CSS-only control on narrow viewports. *)
let repo_nav ~active ~logo:source repo =
  let project_name =
    match String.split_on_char '/' repo |> List.rev with
    | last :: _ -> last
    | [] -> repo
  in
  Ui.navigation ~id:"top" ~label:"Repository navigation"
    [
      logo ~href:"/" ~alt:"Repository list" source;
      Ui.text_link ~id:"nav-home" ~href:(url (Routes.Repo repo)) project_name;
      Ui.css_toggle ~id:"nav-toggle" ~toggle_class:"nav-toggle"
        ~control_class:"nav-hamburger" ~label:"Menu" ~glyph:"\xe2\x8b\xae" ();
      Ui.nav_links ~id:"nav-links"
        (List.map (page_link repo ~active) [ Summary; Commits; Files ]);
    ]

(** The same repository destinations as {!repo_nav}, condensed and pinned to the
    bottom of the viewport. CSS reveals it on narrow viewports, where the top
    link list is hidden.

    Named for its form rather than for a device: the viewport width decides when
    it appears, and this module has no notion of what hardware is in use. *)
let compact_repo_nav ~active repo =
  Ui.navigation ~id:"bottom-nav" ~label:"Compact navigation"
    [
      Ui.nav_links ~id:"bottom-nav-links" ~item_class:"bottom-nav-item"
        (List.map (page_link repo ~active) [ Summary; Commits; Files ]);
    ]

(** {1 Toolbar} *)

let toolbar children =
  Ui.toolbar ~id:"toolbar" ~label:"Repository toolbar" children

(** {1 Trees} *)

(** A directory row that both expands in place and links to its own page. *)
let directory ?modifier ~route ~name children =
  Ui.tree_branch ?modifier ~href:(url route) (name ^ "/") children

let file_entry ?modifier ~route name =
  Ui.tree_leaf ?modifier ~href:(url route) name

(** The row closing a truncated listing, linking to the full contents. *)
let overflow_row ~route count =
  Ui.tree_overflow ~href:(url route) (Printf.sprintf "%d more items..." count)

(** {1 Sections} *)

(** A collapsible group of repositories on the root page. *)
let group ?expanded ~title children =
  Ui.disclosure ?expanded ~summary_class:"section-toggle"
    ~summary:[ Ui.chevron (); Ui.heading [ Ui.text title ] ]
    children

(** {1 Inline pieces} *)

(** A conventional-commit type, coloured per type and linking to the filtered
    commit list. *)
let commit_type_badge ?href commit_type =
  Ui.badge ~base_class:"commit-pill" ~variant:commit_type ?href commit_type

(** A README displayed as semantic documentation.

    Markdown and Org mode receive dedicated rendering; other README filenames
    use the Markdown-compatible fallback until additional formats are added. *)
let inline_readme ?(filename = "README.md") content =
  Prose.Render.render ~filename content