package main

// Whether notifications are paused, said as this module's event `paused` {paused, machine} (the review of
// 2026-10-09, C4): at start, on every change, and again every PausedEvery. The desk shows a link's code only on
// a machine it heard is not paused lately, and says it cannot send one while none is: a code held back by a
// paused notifier would appear later, to whoever is then at the screen. The pause is read from dunst itself
// (`dunstctl is-paused`), so one set by a key or by hand is said like one set by dunst_pause.

import (
	"fmt"
	"os"
	"strings"
	"time"
)

const (
	// PausedEvent is the event's name; PausedEvery how often it is said when nothing changed; PausedLook how
	// often dunst is asked.
	PausedEvent = "paused"
	PausedEvery = 2 * time.Minute
	PausedLook  = 5 * time.Second
)

// pauseWatch says the pause; its two reaches are seams a test replaces.
type pauseWatch struct {
	isPaused func() (bool, error)
	say      func(paused bool) error
	saidAt   time.Time
	said     bool
	known    bool
}

// step looks once, and says it when it changed or was said PausedEvery ago. Nothing is said while dunst
// cannot be asked: the desk then hears nothing, and takes the machine as not known.
func (w *pauseWatch) step(now time.Time) {
	paused, err := w.isPaused()
	if err != nil {
		return
	}
	if w.known && paused == w.said && now.Sub(w.saidAt) < PausedEvery {
		return
	}
	if w.say(paused) == nil {
		w.known, w.said, w.saidAt = true, paused, now
	}
}

func isPaused() (bool, error) {
	out, err := dunstctl("is-paused")
	if err != nil {
		return false, err
	}
	switch strings.TrimSpace(out) {
	case "true":
		return true, nil
	case "false":
		return false, nil
	}
	return false, fmt.Errorf("dunstctl is-paused answered %q", out)
}

// watchPaused runs the watch for as long as the bundle runs.
func watchPaused() {
	w := &pauseWatch{isPaused: isPaused, say: func(p bool) error {
		return emit(PausedEvent, map[string]any{"paused": p, "machine": os.Getenv("MESH_NODE")})
	}}
	for {
		w.step(time.Now())
		time.Sleep(PausedLook)
	}
}