(* SPDX-License-Identifier: AGPL-3.0-or-later *)

(* Every citation the engine can emit must parse. This is the check that
   would have caught the seven duplicate book spellings -- nothing validated
   them before.

   Same shape as test_lang_coverage.ml, which this file deliberately mirrors:
   a miss there is a slug with no name, a miss here is a citation the parser
   cannot read.

   The walk below also drives the round-trip check (Sigla facade, Task 5):
   ONE pass over 1970-2070 collects into TWO tables, [bad_parse] and
   [bad_round_trip], rather than walking the whole range twice for two
   independent Alcotest cases -- measured, a second walk would cost ~1.5s of
   a 5.65s fast suite for zero extra coverage. *)

module P = Colitur_citation.Parse

let bad_parse : (string, string) Hashtbl.t = Hashtbl.create 64
let bad_round_trip : (string, string) Hashtbl.t = Hashtbl.create 16
let walked = ref false

(* Parse -> render -> parse must reach the same structure.

   NOTE the [names] function: [Book.default_spelling], NOT [Book.to_string].
   [to_string] returns the internal id ("corinthians_1"), which is not a
   registered token, so rendering with it produces something Parse cannot
   read back -- 0 of 738 round-trip. Measured during Task 4; do not
   "simplify" this back to to_string. A renderer that emits an unparseable
   string, or a style whose own output it cannot read, fails here. Compares
   STRUCTURE, not text: the rendered form legitimately differs from the
   input (a normalised book spelling, a dropped trailing period), and
   asserting text equality would just pin those differences. *)
let sg =
  Colitur_citation.Sigla.make ~style:Colitur_citation.Render.default_style
    ~tradition:Colitur_citation.Book.vulgate
    ~names:(fun id _form -> Colitur_citation.Book.default_spelling id)

let walk () =
  if not !walked then begin
    walked := true;
    let layer =
      match Test_support.load_ef_layer () with
      | Ok l -> l
      | Error e -> Alcotest.failf "%s" e
    in
    let ctx = Test_support.ef_context () in
    for y = 1970 to 2070 do
      Array.iter
        (fun (d : (Rite_ef.Vocab_ef.season, Rite_ef.Vocab_ef.rank) Colitur_kernel.Liturgical_day.t) ->
          List.iter
            (fun (c : Colitur_kernel.Citation.t) ->
              let r = c.Colitur_kernel.Citation.reference in
              match P.parse r with
              | Error e -> if not (Hashtbl.mem bad_parse r) then Hashtbl.add bad_parse r e
              | Ok first ->
                  let rendered = Colitur_citation.Sigla.format sg r in
                  (match P.parse rendered with
                   | Error e ->
                       Hashtbl.replace bad_round_trip r ("re-parse failed: " ^ e)
                   | Ok again ->
                       if again <> first then
                         Hashtbl.replace bad_round_trip r ("structure changed: " ^ rendered)))
            d.Colitur_kernel.Liturgical_day.citations)
        (Colitur_kernel.Calendar.year ctx layer y)
    done
  end

let test_every_citation_parses () =
  walk ();
  if Hashtbl.length bad_parse > 0 then begin
    Hashtbl.iter (fun r e -> Printf.eprintf "UNPARSED %S: %s\n" r e) bad_parse;
    Alcotest.failf "%d citation(s) did not parse" (Hashtbl.length bad_parse)
  end

let test_round_trip () =
  walk ();
  if Hashtbl.length bad_round_trip > 0 then begin
    Hashtbl.iter (fun r e -> Printf.eprintf "ROUND-TRIP %S: %s\n" r e) bad_round_trip;
    Alcotest.failf "%d citation(s) failed round-trip" (Hashtbl.length bad_round_trip)
  end

(* This project has ONE test executable. Every test_<module>.ml exposes a
   [suite] value and test_colitur.ml aggregates them -- do NOT call
   Alcotest.run here. Marked `Slow like test_lang_coverage's own year walk. *)
let suite =
  ( "citation-coverage",
    [ Alcotest.test_case "every citation parses" `Slow test_every_citation_parses;
      Alcotest.test_case "sigla round-trip" `Slow test_round_trip ] )