package ui import ( "context" "io" "log" "os/exec" "syscall" "time" "github.com/eiannone/keyboard" ) const ( CMD_FIM = "/usr/local/bin/pf-fim.sh" SLIDESHOW_INTERVAL = 300 * time.Second ) func Slideshow() { // fim placeholder so we can operate on it when a exit slideshow is received var fim *exec.Cmd = nil // Run slideshow fim = exec.Command(CMD_FIM) // Put fim into a process group so ALL processes that may be executed are exited when main process exits fim.SysProcAttr = &syscall.SysProcAttr{Setpgid: true} // Setup stdin for fim to control slideshow stdin, err := fim.StdinPipe() if err != nil { log.Fatalf("Error getting fim stdin : %s", err) } // Advance slideshow every interval as defined in const() ticker := time.NewTicker(SLIDESHOW_INTERVAL) stop_ticker := make(chan struct{}) go func() { for { select { case <-ticker.C: _, err = io.WriteString(stdin, "n") if err != nil { log.Fatalf("Error advancing slides : %s", err) } case <-stop_ticker: ticker.Stop() stdin.Close() return } } }() // Start watching for key strokes and echo them back to stdout keysEvents, err := keyboard.GetKeys(10) if err != nil { log.Fatalf("Error setting up keyboard listener : %s", err) } // NOT deferring keyboard.close as we do that by hand further down when fim exits ahead of showing the config UI // Goroutine for tracking which keys are pressed and controlling fim if appropriate keyboardCtx, keyboardCancel := context.WithCancel(context.Background()) go func(keyboardCtx context.Context) { for { select { case <-keyboardCtx.Done(): return case event := <-keysEvents: if event.Err != nil { log.Fatalf("Error listening to key events : %s", err) } log.Printf("You pressed: key %X\n", event.Key) // Keys for fim event management (previous/next in particular) fimKey := "" if event.Key == keyboard.KeyArrowLeft || event.Key == keyboard.KeyArrowDown { fimKey = "p" } if event.Key == keyboard.KeyArrowRight || event.Key == keyboard.KeyArrowUp { fimKey = "n" } // Exit fim and move to the config UI if event.Key == keyboard.KeyEsc || event.Key == keyboard.KeyEnter || event.Key == keyboard.KeySpace { if fim != nil { // Just in case someone lays on exit key or similar during startup pgid, err := syscall.Getpgid(fim.Process.Pid) if err == nil { if err := syscall.Kill(-pgid, 9); err != nil { log.Fatalf("failed to kill fim : %s", err) } } } break } // Control fim if we received a valid key for next/previous slide if fimKey != "" { log.Printf("Sending key to fim : %s", fimKey) _, err = io.WriteString(stdin, fimKey) if err != nil { log.Fatalf("Error controlling fim : %s", err) } ticker.Reset(SLIDESHOW_INTERVAL) } } } }(keyboardCtx) // Run fim if err := fim.Run(); err != nil { // Unwrap the error a bit so we can find out if a signal killed fim or something else // An exit code of -1 means the program didn't exit in time or was terminated by a signal (per the docs) if exitError, ok := err.(*exec.ExitError); ok && exitError.ExitCode() != -1 { log.Fatalf("Error running fim : %s", err) } } // Stop fim slideshow advancing go routine close(stop_ticker) // Stop listening to keyboard events keyboard.Close() keyboardCancel() }