module V = Colitur_render.View
module T = Colitur_render.Template

(* Build one civil year of resolved days exactly as the CLI does. *)
let days_of_year y =
  let layer =
    match Test_support.load_ef_layer () with Ok l -> l | Error e -> Alcotest.failf "layer: %s" e
  in
  let context = Test_support.ef_context () in
  let module Cal = Colitur_kernel.Calendar in
  let module D = Colitur_kernel.Date in
  let tbl = Hashtbl.create 400 in
  let index days =
    Array.iter (fun d -> Hashtbl.replace tbl (D.to_rata d.Colitur_kernel.Liturgical_day.date) d) days
  in
  index (Cal.year context layer (y - 1));
  index (Cal.year context layer y);
  let jan1 = Result.get_ok (D.make ~year:y ~month:1 ~day:1) in
  let dec31 = Result.get_ok (D.make ~year:y ~month:12 ~day:31) in
  let out = ref [] and d = ref jan1 in
  while D.compare !d dec31 <= 0 do
    (match Hashtbl.find_opt tbl (D.to_rata !d) with Some x -> out := x :: !out | None -> ());
    d := D.add_days !d 1
  done;
  List.rev !out

let view_of y =
  V.of_days ~vocab:Rite_ef.Vocab_ef.vocab ~rite:"ef" ~year:y (days_of_year y)

let get path v =
  let rec go v = function
    | [] -> v
    | k :: tl -> (
        match v with
        | T.Obj kvs -> (
            match List.assoc_opt k kvs with Some v' -> go v' tl | None -> Alcotest.failf "no key %s" k)
        | _ -> Alcotest.failf "not an object at %s" k)
  in
  go v path

let as_list = function T.List l -> l | _ -> Alcotest.fail "expected a list"
let as_str = function T.Str s -> s | _ -> Alcotest.fail "expected a string"
let as_bool = function T.Bool b -> b | _ -> Alcotest.fail "expected a bool"

let test_year_shape () =
  let v = view_of 2027 in
  Alcotest.(check string) "rite" "ef" (as_str (get [ "rite" ] v));
  Alcotest.(check string) "year" "2027" (as_str (get [ "year" ] v));
  Alcotest.(check int) "twelve months" 12 (List.length (as_list (get [ "months" ] v)));
  Alcotest.(check int) "365 days" 365 (List.length (as_list (get [ "days" ] v)))

(* THE property the grid depends on: weeks flatten to the month's days plus
   padding, and every real day appears exactly once (spec section 9.3). *)
let test_weeks_flatten_to_days () =
  let v = view_of 2027 in
  List.iter
    (fun m ->
      let weeks = as_list (get [ "weeks" ] m) in
      let cells = List.concat_map (fun w -> as_list (get [ "days" ] w)) weeks in
      List.iter
        (fun w -> Alcotest.(check int) "seven cells per week" 7 (List.length (as_list (get [ "days" ] w))))
        weeks;
      let real = List.filter (fun c -> as_bool (get [ "in_month" ] c)) cells in
      let own = as_list (get [ "days" ] m) in
      Alcotest.(check int) "real cells = month days" (List.length own) (List.length real);
      List.iter2
        (fun a b -> Alcotest.(check string) "same day, same order" (as_str (get [ "iso" ] a)) (as_str (get [ "iso" ] b)))
        own real)
    (as_list (get [ "months" ] v))

let test_padding_cells_are_flagged () =
  let v = view_of 2027 in
  let jan = List.hd (as_list (get [ "months" ] v)) in
  let first_week = List.hd (as_list (get [ "weeks" ] jan)) in
  let cells = as_list (get [ "days" ] first_week) in
  (* 1 January 2027 is a Friday, so the first week has five padding cells. *)
  Alcotest.(check int) "five padding cells" 5
    (List.length (List.filter (fun c -> not (as_bool (get [ "in_month" ] c))) cells));
  List.iter
    (fun c ->
      if not (as_bool (get [ "in_month" ] c)) then
        Alcotest.(check string) "padding has empty iso" "" (as_str (get [ "iso" ] c)))
    cells

let test_day_fields () =
  let v = view_of 2027 in
  let d =
    List.find (fun d -> as_str (get [ "iso" ] d) = "2027-01-13") (as_list (get [ "days" ] v))
  in
  Alcotest.(check string) "slug" "commemoration-of-the-baptism-of-the-lord" (as_str (get [ "slug" ] d));
  Alcotest.(check string) "colour" "white" (as_str (get [ "colour" ] d));
  Alcotest.(check bool) "is_white" true (as_bool (get [ "is_white" ] d));
  Alcotest.(check bool) "is_violet" false (as_bool (get [ "is_violet" ] d));
  Alcotest.(check int) "dow friday" 3 (int_of_string (as_str (get [ "dow" ] d)));
  Alcotest.(check bool) "first citation present" true (as_str (get [ "first" ] d) <> "");
  Alcotest.(check bool) "gospel citation present" true (as_str (get [ "gospel" ] d) <> "")

(* Exactly one of the six colour booleans is true on every day of a whole year:
   a template that keys a cell colour off them can never get no colour or two. *)
let test_exactly_one_colour_flag () =
  let v = view_of 2027 in
  List.iter
    (fun d ->
      let n =
        List.length
          (List.filter
             (fun k -> as_bool (get [ k ] d))
             [ "is_white"; "is_red"; "is_green"; "is_violet"; "is_rose"; "is_black" ])
      in
      if n <> 1 then Alcotest.failf "%s has %d colour flags set" (as_str (get [ "iso" ] d)) n)
    (as_list (get [ "days" ] v))

let suite =
  ( "View",
    [ Alcotest.test_case "year shape" `Quick test_year_shape;
      Alcotest.test_case "weeks flatten to days" `Quick test_weeks_flatten_to_days;
      Alcotest.test_case "padding cells flagged" `Quick test_padding_cells_are_flagged;
      Alcotest.test_case "day fields" `Quick test_day_fields;
      Alcotest.test_case "exactly one colour flag" `Quick test_exactly_one_colour_flag ] )