module C = Colitur_naming.Config

let ok = function Ok x -> x | Error e -> Alcotest.failf "parse: %s" e

let sample =
  "[defaults]\n\
   lang = pl\n\
   overlay = ~/a.ini\n\
   overlay = ~/b.ini\n\
   template = ~/my-ordo.tex\n\
   format = json\n"

let test_reads_defaults () =
  let c = ok (C.of_string sample) in
  Alcotest.(check (option string)) "lang" (Some "pl") (C.lang c);
  Alcotest.(check (option string)) "template" (Some "~/my-ordo.tex") (C.template c);
  Alcotest.(check (option string)) "format" (Some "json") (C.format c)

(* Repeated keys accumulate for overlay -- a user has more than one. The INI
   reader keeps every line, so this asserts we do not silently take the last. *)
let test_overlays_accumulate () =
  let c = ok (C.of_string sample) in
  Alcotest.(check (list string)) "both overlays" [ "~/a.ini"; "~/b.ini" ] (C.overlays c)

let test_empty_config_is_all_none () =
  Alcotest.(check (option string)) "lang" None (C.lang C.empty);
  Alcotest.(check (list string)) "overlays" [] (C.overlays C.empty)

(* THE precedence rule: flag > config > default, and the SOURCE is reported,
   because a setting that silently comes from a file the user forgot about is
   worse than no setting at all. *)
let test_precedence_and_provenance () =
  let check ~flag ~config ~default (ev, es) =
    let v, s = C.resolve ~flag ~config ~default in
    Alcotest.(check string) "value" ev v;
    Alcotest.(check string) "source" es s
  in
  check ~flag:(Some "en") ~config:(Some "pl") ~default:"la" ("en", "flag");
  check ~flag:None ~config:(Some "pl") ~default:"la" ("pl", "config");
  check ~flag:None ~config:None ~default:"la" ("la", "default")

let test_malformed_is_error_not_crash () =
  match C.of_string "[defaults\nbroken" with
  | Error _ -> ()
  | Ok _ -> Alcotest.fail "a malformed config must be an Error, never accepted"

(* An unknown key is a WARNING case, not a hard error: a config written for a
   newer colitur must still work on an older one. But it must be reportable, so
   it is not silently dropped either -- assert it is actually COLLECTED, not
   only that parsing survives it: a no-op accumulator would also pass a test
   that checked survival alone. *)
let test_unknown_key_is_reported_not_fatal () =
  match C.of_string "[defaults]\nlang = la\nnonsense = 1\n" with
  | Error _ -> Alcotest.fail "an unknown key must not be fatal"
  | Ok c ->
      Alcotest.(check (option string)) "known key still read" (Some "la") (C.lang c);
      Alcotest.(check (list string)) "unknown key reported" [ "nonsense" ] (C.unknown_keys c)

(* The highest-value case: a misspelled SECTION name (not merely a misspelled
   key inside a recognised one). Before this fix the whole section, lang
   included, vanished with nothing reported -- exactly the typo this feature
   exists to surface, in its worst form: a user whose config silently does
   nothing has no way to discover why. *)
let test_misspelled_section_is_reported_not_silently_dropped () =
  let c = ok (C.of_string "[deafults]\nlang = pl\n") in
  Alcotest.(check (option string)) "lang not read from the wrong section" None (C.lang c);
  Alcotest.(check (list string)) "section reported" [ "deafults" ] (C.unknown_sections c)

let suite =
  ( "Config",
    [ Alcotest.test_case "reads defaults" `Quick test_reads_defaults;
      Alcotest.test_case "overlays accumulate" `Quick test_overlays_accumulate;
      Alcotest.test_case "empty is all none" `Quick test_empty_config_is_all_none;
      Alcotest.test_case "precedence and provenance" `Quick test_precedence_and_provenance;
      Alcotest.test_case "malformed is error" `Quick test_malformed_is_error_not_crash;
      Alcotest.test_case "unknown key not fatal" `Quick test_unknown_key_is_reported_not_fatal;
      Alcotest.test_case "misspelled section reported"
        `Quick test_misspelled_section_is_reported_not_silently_dropped ] )