module D = Colitur_kernel.Date
module C = Colitur_kernel.Computus

let fmt d = Printf.sprintf "%04d-%02d-%02d" (D.year d) (D.month d) (D.day d)

let easter_report y =
  [ ("easter", C.gregorian_easter y);
    ("ash-wednesday", C.ash_wednesday y);
    ("palm-sunday", C.palm_sunday y);
    ("ascension", C.ascension y);
    ("pentecost", C.pentecost y);
    ("corpus-christi", C.corpus_christi y) ]
  |> List.iter (fun (name, d) -> Printf.printf "%s %s\n" name (fmt d))

let temporal_report y =
  let jan1 = match D.make ~year:y ~month:1 ~day:1 with
    | Ok t -> t
    | Error e -> failwith e
  in
  let dec31 = match D.make ~year:y ~month:12 ~day:31 with
    | Ok t -> t
    | Error e -> failwith e
  in
  (* [week] is "" for roughly 30 days a year (outside any numbered week);
     printed as-is, that collapses two of the seven space-separated fields
     into a double space, so naive field-position parsing (e.g. awk '{print
     $4}') silently reads the wrong column on those days. Emit "-" instead,
     so every line always has exactly seven single-space-separated fields. *)
  let field s = if s = "" then "-" else s in
  let d = ref jan1 in
  while D.compare !d dec31 <= 0 do
    let t = Rite_ef.Temporal_ef.temporal !d in
    let r =
      Colitur_kernel.Record.of_temporal ~rite:Rite_ef.Temporal_ef.id
        Rite_ef.Vocab_ef.vocab !d t
    in
    Printf.printf "%s %s %s %s %s %s %s\n" r.Colitur_kernel.Record.date
      r.Colitur_kernel.Record.weekday r.Colitur_kernel.Record.season
      (field r.Colitur_kernel.Record.week) r.Colitur_kernel.Record.slug
      r.Colitur_kernel.Record.rank r.Colitur_kernel.Record.colour;
    d := D.add_days !d 1
  done

let usage () =
  prerr_endline "colitur: usage: colitur easter <year> | colitur temporal <year>";
  exit 2

let with_year ys f =
  match int_of_string_opt ys with
  | Some y when y >= 1583 && y <= 9999 -> f y
  | Some y ->
      Printf.eprintf "colitur: year %d out of range 1583..9999\n" y;
      exit 2
  | None -> usage ()

let () =
  match Sys.argv with
  | [| _; "easter"; ys |] -> with_year ys easter_report
  | [| _; "temporal"; ys |] -> with_year ys temporal_report
  | _ -> usage ()