package calendar_test

// Reproduction tests for three named EF precedence defects (colitur's
// differential/oracle audit against lectio's ~66-line EF precedence
// approximation, internal/calendar/precedence_ef.go). Each test fails before
// its fix and passes after -- see the report for the exact pre-fix failure
// message. These exercise the REAL tridentine sanctoral data
// (caldata.Tridentine()) through the public Compute entry point, since the
// bugs are about how real fixed-date feasts interact with the temporal
// calendar, not about precedenceEF's arithmetic in isolation (that is
// covered separately, package-internal, in precedence_ef_test.go).

import (
	"testing"
	"time"

	"github.com/lukaszkasprzak/lectio/internal/caldata"
	"github.com/lukaszkasprzak/lectio/internal/calendar"
)

func efCompute(date string) calendar.LiturgicalDay {
	sel := calendar.DefaultSelection()
	sel.Form = "old"
	d, _ := time.Parse("2006-01-02", date)
	return calendar.Compute(d.UTC(), sel, []calendar.Layer{caldata.Tridentine()})
}

// TestJosephYieldsToSundayOfLent: RG 91 entry 6 (Sundays of Lent, I class)
// vs entry 11 (I-class feasts of the universal Church not above) -- the
// Sunday holds; St Joseph (19 March) transfers to the next free day (RG 95,
// RG 96), landing on the 20th. Before the fix (defect 4: Sunday ranks), Lent
// Sundays were wrongly II class, so Joseph (I class) won outright every time
// this collision occurred.
func TestJosephYieldsToSundayOfLent(t *testing.T) {
	for _, year := range []string{"2006", "2017", "2023", "2028", "2034", "2045"} {
		sunday := efCompute(year + "-03-19")
		if sunday.Observed.Slug == "joseph-spouse-of-the-bl-virgin-mary" {
			t.Errorf("%s-03-19 observed = %q want the Lent Sunday (RG 91 entry 6 beats entry 11)", year, sunday.Observed.Slug)
		}
		next := efCompute(year + "-03-20")
		if next.Observed.Slug != "joseph-spouse-of-the-bl-virgin-mary" {
			t.Errorf("%s-03-20 observed = %q want joseph-spouse-of-the-bl-virgin-mary (transferred one day, RG 96)", year, next.Observed.Slug)
		}
	}
}

// TestTransferSkipsBothIAndIIClass: RG 96 -- an impeded I-class feast
// transfers to the next day that is NOT ITSELF I OR II CLASS (not merely "not
// I class"). 2011: the Sacred Heart (Friday after the Corpus Christi octave)
// falls on 1 July and impedes the Precious Blood (also 1 July, fixed). 2
// July is the Visitation (II class, fixed); 3 July is an ordinary II-class
// Sunday. Both must be skipped; the Precious Blood lands on 4 July, and the
// Visitation is observed, undisplaced, on its own day.
func TestTransferSkipsBothIAndIIClass(t *testing.T) {
	if got := efCompute("2011-07-01").Observed.Slug; got != "ef-sacred-heart" {
		t.Fatalf("2011-07-01 observed = %q want ef-sacred-heart", got)
	}
	if got := efCompute("2011-07-02").Observed.Slug; got != "visitation-of-the-blessed-virgin-mary" {
		t.Errorf("2011-07-02 observed = %q want visitation-of-the-blessed-virgin-mary (RG 96: the Precious Blood must skip past it, not displace it)", got)
	}
	if got := efCompute("2011-07-03").Observed.Slug; got != "ef-time-after-pentecost-sunday-3" {
		t.Errorf("2011-07-03 observed = %q want ef-time-after-pentecost-sunday-3 (an ordinary II-class Sunday also blocks a I-class transfer)", got)
	}
	if got := efCompute("2011-07-04").Observed.Slug; got != "precious-blood-of-our-lord-jesus-christ" {
		t.Errorf("2011-07-04 observed = %q want precious-blood-of-our-lord-jesus-christ (RG 96: first day that is neither I nor II class)", got)
	}
}

// TestMatthewBeatsSeptemberEmberWednesday: RG 91 -- St Matthew (21 September,
// II class) and the September Ember Wednesday are both II class; the table
// decides the tie. Entry 16 (II-class feasts of the universal Church) sits
// ABOVE entry 18 (II-class ferias, including the Ember days) -- the feast
// wins, the Ember feria is only commemorated.
func TestMatthewBeatsSeptemberEmberWednesday(t *testing.T) {
	// 21 September falls on the September Ember Wednesday whenever the third
	// Sunday of September is the 18th -- 2016 and 2022 both qualify.
	for _, date := range []string{"2016-09-21", "2022-09-21"} {
		day := efCompute(date)
		if day.Observed.Slug != "matthew" {
			t.Errorf("%s observed = %q want matthew (RG 91 entry 16 beats entry 18)", date, day.Observed.Slug)
		}
	}
}