scheduler: Rewrite complex Next and TickerDuration

scheduler/complex.go

@@ -70,26 +70,12 @@ func (s multiSched) Next(t time.Time) (next time.Time) {
 }
 
 func (s multiSched) TickerDuration() time.Duration {
-	var downgrade bool
-	var res time.Duration
-	for _, i := range s {
-		d := gcd(res, i.TickerDuration())
-		if !downgrade && res == d {
-			downgrade = true
-		}
-		res = d
+	if l := len(s); l == 0 {
+		return 0
+	} else if l == 1 {
+		return s[0].TickerDuration()
 	}
-	if downgrade {
-		switch res {
-		case 24 * time.Hour:
-			return time.Hour
-		case time.Hour:
-			return time.Minute
-		case time.Minute:
-			return time.Second
-		}
-	}
-	return res
+	return time.Second
 }
 
 func (s multiSched) String() string {
@@ -137,12 +123,30 @@ func (s condSched) IsMatched(t time.Time) bool {
 	return true
 }
 
-func (s condSched) Next(t time.Time) time.Time {
-	if len(s) == 1 {
+func (s condSched) Next(t time.Time) (next time.Time) {
+	if l := len(s); l == 0 {
+		return time.Time{}
+	} else if l == 1 {
 		return s[0].Next(t)
 	}
-	d := s.TickerDuration()
-	return t.Add(d).Truncate(d)
+	var start time.Time
+	var duration time.Duration
+	for _, s := range s {
+		if d := s.TickerDuration(); d > duration {
+			duration = d
+			start = s.Next(t)
+		} else if d == duration {
+			if next := s.Next(t); next.Before(start) {
+				start = next
+			}
+		}
+	}
+	for next = start; !s.IsMatched(next); next = next.Add(duration) {
+		if next.Sub(t) >= time.Hour*24*366 {
+			return time.Time{}
+		}
+	}
+	return
 }
 
 func (s condSched) TickerDuration() time.Duration {

scheduler/complex_test.go

@@ -7,9 +7,6 @@ import (
 
 func TestMultiSchedule(t *testing.T) {
 	s := MultiSchedule(AtHour(3), AtMinute(4), AtSecond(5))
-	if d := s.TickerDuration(); d != time.Minute {
-		t.Fatalf("expected 1m: got %s", d)
-	}
 	if res := s.Next(time.Time{}).Format("15:04:05"); res != "00:00:05" {
 		t.Fatalf("expected 00:00:05: got %q", res)
 	}
@@ -28,27 +25,12 @@ func TestMultiSchedule(t *testing.T) {
 	}
 }
 
-func TestMultiScheduleTickerDuration(t *testing.T) {
-	for _, testcase := range []struct {
-		schedule Schedule
-		expected time.Duration
-	}{
-		{MultiSchedule(AtHour(3), AtMinute(4), AtSecond(5)), time.Minute},
-		{HourSchedule(9, 17, 23), time.Hour},
-		{MinuteSchedule(0, 59), time.Minute},
-	} {
-		if res := testcase.schedule.TickerDuration(); res != testcase.expected {
-			t.Errorf("expected %v; got %v", testcase.expected, res)
-		}
-	}
-}
-
 func TestConditionSchedule(t *testing.T) {
 	s := ConditionSchedule(Weekdays, MultiSchedule(AtClock(9, 30, 0), AtHour(15)))
 	if d := s.TickerDuration(); d != time.Second {
 		t.Fatalf("expected 1s: got %s", d)
 	}
-	if res := s.Next(time.Time{}).Format("15:04:05"); res != "00:00:01" {
+	if res := s.Next(time.Time{}).Format("15:04:05"); res != "09:30:00" {
 		t.Fatalf("expected 00:00:01: got %q", res)
 	}
 	for _, testcase := range []struct {

scheduler/scheduler_test.go

@@ -8,7 +8,7 @@ import (
 
 func TestScheduler(t *testing.T) {
 	now := time.Now()
-	s := NewScheduler().At(TimeSchedule(now.Add(time.Second)))
+	s := NewScheduler().At(TimeSchedule(now.Add(2 * time.Second)))
 	defer s.Stop()
 	var n atomic.Int32
 	if err := s.Run(func(_ time.Time) { n.Add(1) }).Start(); err != nil {
@@ -17,7 +17,7 @@ func TestScheduler(t *testing.T) {
 	if n := n.Load(); n != 0 {
 		t.Errorf("expected 0; got %d", n)
 	}
-	time.Sleep(1500 * time.Millisecond)
+	time.Sleep(3 * time.Second)
 	if n := n.Load(); n != 1 {
 		t.Errorf("expected 1; got %d", n)
 	}