(**************************************************************************)
(*                                                                        *)
(*                                 OCaml                                  *)
(*                                                                        *)
(*             Florian Angeletti, projet Cambium, Inria Paris             *)
(*                                                                        *)
(*   Copyright 2023 Institut National de Recherche en Informatique et     *)
(*     en Automatique.                                                    *)
(*                                                                        *)
(*   All rights reserved.  This file is distributed under the terms of    *)
(*   the GNU Lesser General Public License version 2.1, with the          *)
(*   special exception on linking described in the file LICENSE.          *)
(*                                                                        *)
(**************************************************************************)

type intf_or_impl = Intf | Impl
type modname = string
type filename = string
type file_prefix = string

type error = Invalid_encoding of string
exception Error of error

type t = {
  source_file: filename;
  prefix: file_prefix;
  modname: modname;
  kind: intf_or_impl;
}

let source_file (x: t) = x.source_file
let modname (x: t) = x.modname
let kind (x: t) = x.kind
let prefix (x: t) = x.prefix

let basename_chop_extensions basename  =
  match String.index basename '.' with
  | dot_pos -> String.sub basename 0 dot_pos
  | exception Not_found -> basename

let strict_modulize s =
  match Misc.Utf8_lexeme.capitalize s with
  | Ok x -> x
  | Error _ -> raise (Error (Invalid_encoding s))

let modulize s = match Misc.Utf8_lexeme.capitalize s with Ok x | Error x -> x

(* We re-export the [Misc] definition, and ignore encoding errors under the
   assumption that we should focus our effort on not *producing* badly encoded
   module names *)
let normalize x = match Misc.normalized_unit_filename x with
  | Ok x | Error x -> x

let stem source_file =
  source_file |> Filename.basename |> basename_chop_extensions

let strict_modname_from_source source_file =
  source_file |> stem |> strict_modulize

let lax_modname_from_source source_file =
  source_file |> stem |> modulize

(* Check validity of module name *)
let is_unit_name name = Misc.Utf8_lexeme.is_valid_identifier name

let check_unit_name file =
  if not (is_unit_name (modname file)) then
    Location.prerr_warning (Location.in_file (source_file file))
      (Warnings.Bad_module_name (modname file))

let make ?(check_modname=true) ~source_file kind prefix =
  let modname = strict_modname_from_source prefix in
  let p = { modname; prefix; source_file; kind } in
  if check_modname then check_unit_name p;
  p

module Artifact = struct
  type t =
   {
     source_file: filename option;
     filename: filename;
     modname: modname;
   }
  let source_file x = x.source_file
  let filename x = x.filename
  let modname x = x.modname
  let prefix x = Filename.remove_extension (filename x)

  let from_filename filename =
    let modname = lax_modname_from_source filename in
    { modname; filename; source_file = None }

end

let mk_artifact ext u =
  {
    Artifact.filename = u.prefix ^ ext;
    modname = u.modname;
    source_file = Some u.source_file;
  }

let companion_artifact ext x =
  { x with Artifact.filename = Artifact.prefix x ^ ext }

let cmi f = mk_artifact ".cmi" f
let cmo f = mk_artifact ".cmo" f
let cmx f = mk_artifact ".cmx" f
let obj f = mk_artifact Config.ext_obj f
let cmt f = mk_artifact ".cmt" f
let cmti f = mk_artifact ".cmti" f
let annot f = mk_artifact ".annot" f

let companion_obj f = companion_artifact Config.ext_obj f
let companion_cmt f = companion_artifact ".cmt" f

let companion_cmi f =
  let prefix = Misc.chop_extensions f.Artifact.filename in
  { f with Artifact.filename = prefix ^ ".cmi"}

let mli_from_artifact f = Artifact.prefix f ^ !Config.interface_suffix
let mli_from_source u =
   let prefix = Filename.remove_extension (source_file u) in
   prefix  ^ !Config.interface_suffix

let is_cmi f = Filename.check_suffix (Artifact.filename f) ".cmi"

let find_normalized_cmi f =
  let filename = modname f ^ ".cmi" in
  let filename = Load_path.find_normalized filename in
  { Artifact.filename; modname = modname f; source_file = Some f.source_file  }

let report_error = function
  | Invalid_encoding name ->
      Location.errorf "Invalid encoding of output name: %s." name

let () =
  Location.register_error_of_exn
    (function
      | Error err -> Some (report_error err)
      | _ -> None
    )