package display

import "sync/atomic"

// VideoPresence is the shared decoded-video signal between a display target
// session and the templates it drives. Sessions update it from
// display-server events about the video output itself: a presented video
// window is presence, its unmap or destroy is video end. Nothing here
// inspects WFB or launcher processes, so a running-but-silent receiver never
// hides the fallback and the video pipeline is never touched.
type VideoPresence struct {
	active atomic.Bool
}

// NewVideoPresence starts with video absent, so the fallback is visible
// before the first presented video output.
func NewVideoPresence() *VideoPresence {
	return &VideoPresence{}
}

// Active reports whether decoded video output is being presented.
func (p *VideoPresence) Active() bool {
	return p.active.Load()
}

// SetActive records video presence and reports whether the state changed, so
// callers can trigger exactly one redraw per lifecycle transition.
func (p *VideoPresence) SetActive(active bool) bool {
	return p.active.Swap(active) != active
}