type t = { modname: Modname.t; filepath: string }
(* TODO(dinosaure): we probably should validate [filename] too as regular
   file path. *)

let invalid_arg fmt = Format.kasprintf invalid_arg fmt
let is_upper = function 'A' .. 'Z' -> true | _ -> false
let is_lower = function 'a' .. 'z' -> true | _ -> false

let modulize filepath =
  let filename = Filename.basename filepath in
  let name = Filename.remove_extension filename in
  if String.length name < 1 then
    invalid_arg "Impossible to modulize an empty string";
  if not (is_upper name.[0] || is_lower name.[0]) then
    invalid_arg "Impossible to modulize %S (from %S)" name filename;
  let modname = String.capitalize_ascii name in
  let modname = Modname.v modname in
  { modname; filepath }

let pp ppf { modname; filepath } =
  Fmt.pf ppf "%a(%s)" Modname.pp modname filepath

let pp_as_modname ppf { modname; _ } = Modname.pp ppf modname
let pp_as_filepath ppf { filepath; _ } = Format.pp_print_string ppf filepath
let reflect ppf t = Fmt.pf ppf "(Unitname.modulize %S)" t.filepath
let modname { modname; _ } = modname
let filename { filepath; _ } = Filename.basename filepath
let filepath { filepath; _ } = filepath
let compare_as_modnames a b = Modname.compare a.modname b.modname

let change_file_extension f t =
  match Filename.extension t.filepath with
  | "" -> t
  | ext ->
      let filepath = Filename.remove_extension t.filepath ^ "." ^ f ext in
      { t with filepath }

module Map = Map.Make (struct
  type nonrec t = t

  let compare a b = Modname.compare a.modname b.modname
end)

module Set = Set.Make (struct
  type nonrec t = t

  let compare a b = Modname.compare a.modname b.modname
end)