package declaration

import (
	"testing"
	"time"
)

// A scheduled step is due when its cron says so, and the host both refuses a malformed cron on
// arrival and computes the next due minute the scheduler fires on (novox/hq ADR 0053). These test
// the parsing and the evaluation; the firing is tested against the scheduler.

func TestParseCronRefusesMalformed(t *testing.T) {
	for _, expr := range []string{
		"",             // nothing
		"* * * *",      // four fields
		"* * * * * *",  // six fields
		"60 * * * *",   // minute out of range
		"* 24 * * *",   // hour out of range
		"* * 0 * *",    // day-of-month below 1
		"* * 32 * *",   // day-of-month above 31
		"* * * 13 *",   // month out of range
		"* * * * 8",    // day-of-week above 7
		"a * * * *",    // not a number
		"*/0 * * * *",  // zero step
		"5-1 * * * *",  // inverted range
		"1,,2 * * * *", // empty element
	} {
		if _, err := ParseCron(expr); err == nil {
			t.Errorf("a malformed cron %q was accepted", expr)
		}
	}
}

func TestParseCronAcceptsTheOrdinaryForms(t *testing.T) {
	for _, expr := range []string{
		"* * * * *",      // every minute
		"0 3 * * *",      // 03:00 daily
		"*/15 * * * *",   // every 15 minutes
		"0 0 1 1 *",      // new year
		"0 9-17 * * 1-5", // business hours, weekdays
		"0 0 * * 7",      // Sunday as 7
		"0,30 * * * *",   // twice an hour
	} {
		if _, err := ParseCron(expr); err != nil {
			t.Errorf("a valid cron %q was refused: %v", expr, err)
		}
	}
}

func TestCronNextIsTheNextMatchingMinute(t *testing.T) {
	// A Monday at 12:00:30, so "next" must round up to a whole minute and land on the first match
	// strictly after now — never re-firing the minute we are already in.
	now := time.Date(2026, 9, 7, 12, 0, 30, 0, time.UTC) // 2026-09-07 is a Monday

	cases := []struct {
		expr string
		want time.Time
	}{
		{"* * * * *", time.Date(2026, 9, 7, 12, 1, 0, 0, time.UTC)},
		{"0 3 * * *", time.Date(2026, 9, 8, 3, 0, 0, 0, time.UTC)},
		{"*/15 * * * *", time.Date(2026, 9, 7, 12, 15, 0, 0, time.UTC)},
		{"0 0 1 1 *", time.Date(2027, 1, 1, 0, 0, 0, 0, time.UTC)},
	}
	for _, c := range cases {
		cron, err := ParseCron(c.expr)
		if err != nil {
			t.Fatalf("%q: %v", c.expr, err)
		}
		got, ok := cron.Next(now)
		if !ok {
			t.Errorf("%q: no next time found", c.expr)
			continue
		}
		if !got.Equal(c.want) {
			t.Errorf("%q: next is %s, want %s", c.expr, got, c.want)
		}
	}
}

func TestCronDayFieldsAreOredWhenBothRestricted(t *testing.T) {
	// The standard cron surprise: when day-of-month and day-of-week are both set, a day matches if
	// EITHER does. "1 * 13 * 5" is due on the 13th OR on any Friday. 2026-09-07 is a Monday the 7th
	// — neither — and 2026-09-11 is a Friday, and 2026-11-13 is the 13th.
	cron, err := ParseCron("0 0 13 * 5")
	if err != nil {
		t.Fatal(err)
	}
	friday := time.Date(2026, 9, 11, 0, 0, 0, 0, time.UTC)
	if !cron.Matches(friday) {
		t.Error("a Friday did not match a cron restricted to the 13th OR Friday")
	}
	thirteenth := time.Date(2026, 11, 13, 0, 0, 0, 0, time.UTC) // a non-Friday 13th
	if !cron.Matches(thirteenth) {
		t.Error("the 13th did not match a cron restricted to the 13th OR Friday")
	}
	neither := time.Date(2026, 9, 7, 0, 0, 0, 0, time.UTC)
	if cron.Matches(neither) {
		t.Error("a Monday the 7th matched a cron restricted to the 13th OR Friday")
	}
}