(** Read package data from day10's html directory *)

let list_package_names ~html_dir =
  let p_dir = Filename.concat html_dir "p" in
  if Sys.file_exists p_dir && Sys.is_directory p_dir then
    Sys.readdir p_dir
    |> Array.to_list
    |> List.filter (fun name ->
        let path = Filename.concat p_dir name in
        Sys.is_directory path)
    |> List.sort String.compare
  else
    []

let compare_versions v1 v2 =
  (* Simple version comparison - compare segments numerically where possible *)
  let parse v =
    String.split_on_char '.' v
    |> List.map (fun s -> try `Int (int_of_string s) with _ -> `Str s)
  in
  let rec cmp l1 l2 = match l1, l2 with
    | [], [] -> 0
    | [], _ -> -1
    | _, [] -> 1
    | `Int a :: t1, `Int b :: t2 ->
        let c = Int.compare a b in if c <> 0 then c else cmp t1 t2
    | `Str a :: t1, `Str b :: t2 ->
        let c = String.compare a b in if c <> 0 then c else cmp t1 t2
    | `Int _ :: _, `Str _ :: _ -> -1
    | `Str _ :: _, `Int _ :: _ -> 1
  in
  cmp (parse v2) (parse v1)  (* Descending order *)

let list_package_versions ~html_dir ~name =
  let pkg_dir = Filename.concat (Filename.concat html_dir "p") name in
  if Sys.file_exists pkg_dir && Sys.is_directory pkg_dir then
    Sys.readdir pkg_dir
    |> Array.to_list
    |> List.filter (fun version ->
        let path = Filename.concat pkg_dir version in
        Sys.is_directory path)
    |> List.sort compare_versions
  else
    []

let list_packages ~html_dir =
  list_package_names ~html_dir
  |> List.concat_map (fun name ->
      list_package_versions ~html_dir ~name
      |> List.map (fun version -> (name, version)))

let package_has_docs ~html_dir ~name ~version =
  let path = Filename.concat html_dir
    (Filename.concat "p" (Filename.concat name version)) in
  Sys.file_exists path && Sys.is_directory path

let docs_path ~name ~version =
  Printf.sprintf "/docs/p/%s/%s/" name version