From a80e61963756a28a3963a0442a8ccc1572518373 Mon Sep 17 00:00:00 2001
From: Lukasz Kasprzak <lukas@labunix.xyz>
Date: Tue, 28 Jul 2026 14:35:24 +0200
Subject: fix(calendar): OF precedence/transfer + readings resolution; EF
 Pentecost octave

Fixes found by validating the offline engine per-day vs the LiturgicalCalendar
API (OF) and missalemeum (EF) across 2005-2050. OF calendar is now 0 real
errors in the forward window (season/cycle already perfect).

OF precedence/transfer (calendar):
- Ash Wednesday and Holy Week Mon-Wed are band-2 privileged, so a coinciding
  feast (Chair of St Peter on Ash Wednesday) is suppressed, not observed.
- Solemnities transfer out of Holy Week / the Easter octave: the Annunciation
  defers to the Monday after the 2nd Sunday of Easter; St Joseph is anticipated
  to the Saturday before Palm Sunday; the Nativity of St John the Baptist moves
  to Jun 23 when a Lord's solemnity (Sacred Heart / Corpus Christi) falls Jun 24.
- Within a precedence band, a solemnity of the Lord/BVM outranks a saint's
  (dignity tiebreak) rather than losing an alphabetical slug tie.
- Perpetua & Felicity corrected optional -> obligatory memorial.

OF readings resolution (bible.OFRef + lectionary data):
- Verse-accurate Hebrew->Vulgate psalm mapping incl. the split psalms
  (9/10, 114/115, 116, 147); "+" verse joins and abbreviated ranges ("127-28")
  normalized; single-chapter books (2/3 John, Jude) get chapter 1.
- Cleaned harvest artifacts from of-lectionary.ini (descriptive-suffix gospels,
  "or Year A" alternates, "*"/"[Vulg.]"/bracket markers, slash abbreviations);
  Joel/Malachi/Zechariah/Esther book-versification citations fixed to Vulgate.
- Split a merged Ps 15:10/11 row in vul.tsv. Result: 0 unresolvable OF readings
  over 2557 rendered days (cycles A/B/C, varied Easters).

EF: the Octave of Pentecost (Whit Monday-Saturday) is red, not white.
---
 internal/calendar/temporal.go | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

(limited to 'internal/calendar/temporal.go')

diff --git a/internal/calendar/temporal.go b/internal/calendar/temporal.go
index b0dc653..1c8d74f 100644
--- a/internal/calendar/temporal.go
+++ b/internal/calendar/temporal.go
@@ -117,6 +117,15 @@ func ferialDay(season Season, slug string, col Colour, week int, privFeria bool)
 		Cel: Celebration{Slug: slug, Rank: RankFerial, Colour: col, Layer: "temporal"}}
 }
 
+// privFerialDay builds a band-2 privileged weekday (Ash Wednesday, Holy Week
+// Monday-Wednesday): a ferial no sanctoral feast or memorial can displace (only
+// a solemnity may, and solemnities transfer off it -- Table of Liturgical Days
+// #2). Distinct from ferialDay's PrivFeria (band 9) Lenten/Advent weekdays.
+func privFerialDay(season Season, slug string, col Colour, week int) temporalDay {
+	return temporalDay{Season: season, Colour: col, Week: week, Rank: RankFerial, Privileged: true,
+		Cel: Celebration{Slug: slug, Rank: RankFerial, Colour: col, Layer: "temporal"}}
+}
+
 // temporal computes the temporal identity of date under the given Selection.
 func temporal(date time.Time, sel Selection) temporalDay {
 	date = date.UTC().Truncate(24 * time.Hour)
@@ -180,11 +189,16 @@ func temporal(date time.Time, sel Selection) temporalDay {
 		if sun {
 			return sundayDay(Lent, "palm-sunday", Red, 6)
 		}
-		return ferialDay(Lent, "holy-week-"+weekdayAbbr(wd), Violet, 6, true)
+		// Holy Week Mon-Wed are band-2 privileged: no feast/memorial is kept.
+		return privFerialDay(Lent, "holy-week-"+weekdayAbbr(wd), Violet, 6)
 
 	case !date.Before(ashWed) && date.Before(palmSunday): // Lent
-		if !date.Before(ashWed) && date.Before(ashWed.AddDate(0, 0, 4)) {
-			// Ash Wednesday through the Saturday after (before Lent I).
+		if sameDay(date, ashWed) {
+			// Ash Wednesday is band-2 privileged (suppresses any coinciding feast).
+			return privFerialDay(Lent, "lent-after-ashes-wed", Violet, 0)
+		}
+		if date.Before(ashWed.AddDate(0, 0, 4)) {
+			// Thursday-Saturday after Ash Wednesday (before Lent I): band-9 privileged.
 			return ferialDay(Lent, "lent-after-ashes-"+weekdayAbbr(wd), Violet, 0, true)
 		}
 		lent1 := nextWeekday(ashWed, time.Sunday)
-- 
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