kde-lockscreen-suspend-display/main.go

package main

import(
	"after-lock/evdev"
	"after-lock/lockscreen"
	"after-lock/display"
	"after-lock/atomicflag"
	"time"
	"sync"
)

const (
	initialDelay = 3
	loopDelay = 6
	keyboardDeviceNode = "/dev/input/by-id/usb-Dell_Dell_USB_Entry_Keyboard-event-kbd"
)


func main() {
	al := newAfterLock()
	al.start()
}

type afterLock struct {
	wg sync.WaitGroup
	stopFlag *atomicflag.AtomicFlag
	keypressFlag *atomicflag.AtomicFlag
}

func newAfterLock() *afterLock {
	return &afterLock{
		stopFlag: atomicflag.New(false),
		keypressFlag: atomicflag.New(false),
	}
}

func (af *afterLock) start() {
	af.wg.Add(1)

	go af.detectKeypresses()
	time.Sleep(initialDelay * time.Second)
	af.hybernateDisplayLoop()
}

func (af *afterLock) detectKeypresses() {
	for {
		err := evdev.BlockUntilKeypress(keyboardDeviceNode)
		if err != nil {
			panic(err)
		}
		if af.stopFlag.Get() {
			af.wg.Done()
			return
		}
		af.keypressFlag.Set(true)
	}
}

func (af *afterLock) hybernateDisplayLoop() {
	for {
		screenLocked, err := lockscreen.IsActive()
		if err != nil {
			panic(err)
		}
		if !screenLocked {
			af.stopFlag.Set(true)
			af.wg.Wait()
			return
		}

		displayOn, err := display.IsOn()
		if err != nil {
			panic(err)
		}
		if displayOn {
			err := display.Suspend()
			if err != nil {
				panic(err)
			}
			for {
				time.Sleep(loopDelay * time.Second)
				if af.keypressFlag.Get() {
					af.keypressFlag.Set(false)
					continue
				} else {
					break
				}
			}
		}
	}
}