string_spinner.go RawHistoryFolder

1package tui
2
3import "time"
4
5// StringSpinner selects one text frame for each configured interval. It owns
6// no ticker or goroutine; callers render it from their existing UI clock.
7type StringSpinner struct {
8	frames   []string
9	interval time.Duration
10}
11
12// NewStringSpinner creates a reusable text animation. Empty frames render an
13// empty string, and a non-positive interval keeps the first frame stable.
14func NewStringSpinner(frames []string, interval time.Duration) StringSpinner {
15	return StringSpinner{
16		frames:   append([]string(nil), frames...),
17		interval: interval,
18	}
19}
20
21// FrameAt returns the frame for now relative to startedAt. Times before the
22// start clamp to the first frame.
23func (s StringSpinner) FrameAt(startedAt, now time.Time) string {
24	if len(s.frames) == 0 {
25		return ""
26	}
27	if s.interval <= 0 || startedAt.IsZero() || now.IsZero() || now.Before(startedAt) {
28		return s.frames[0]
29	}
30	index := int(now.Sub(startedAt)/s.interval) % len(s.frames)
31	return s.frames[index]
32}