waybar: update 2021-02-11T12:46:11Z

1 files changed, 94 insertions, 0 deletions

diff --git a/.config/waybar/modules/gammastep.go b/.config/waybar/modules/gammastep.go
new file mode 100644
index 0000000..c855e1b
--- /dev/null
+++ b/.config/waybar/modules/gammastep.go
@@ -0,0 +1,94 @@
+// usage:
+// go build -o waybar-gammastep gammastep.go
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"os"
+	"os/exec"
+	"os/signal"
+	"strings"
+
+	. "syscall"
+)
+
+func main() {
+	var (
+		update = make(chan os.Signal, 1)
+		cancel = make(chan os.Signal, 1)
+	)
+	signal.Notify(update, SIGUSR1, SIGUSR2, SIGHUP)
+	signal.Notify(cancel, SIGTERM, SIGINT)
+
+	// could use golang.org/x/sys/unix.Prctl here
+	// but I want to avoid the dependency
+	if _, _, e := Syscall6(SYS_PRCTL,
+		uintptr(PR_SET_PDEATHSIG),
+		uintptr(SIGTERM),
+		0, 0, 0, 0); e != 0 {
+		log.Printf("error: %v", e)
+		os.Exit(1)
+	}
+	// if err := Prctl(PR_SET_PDEATHSIG,
+	// 		SIGTERM,
+	// 		0, 0, 0); err != nil {
+	// 	fmt.Fprintln(os.Stderr, err)
+	// 	os.Exit(1)
+	// }
+
+	lookup()
+	for {
+		select {
+		case sig := <-update:
+			switch sig {
+			case SIGUSR1:
+				// redshift off
+				printJson("day", "day")
+			case SIGUSR2:
+				// redshift on
+				printJson("night", "night")
+			case SIGHUP:
+				lookup()
+			}
+		case <-cancel:
+			log.Printf("%v exiting\n", os.Args[0])
+			os.Exit(0)
+		}
+	}
+}
+
+func printJson(state, tooltip string) {
+	_ = json.NewEncoder(os.Stdout).Encode(map[string]interface{}{
+		"class":   state,
+		"alt":     state,
+		"tooltip": "gammastep: " + tooltip,
+		"text":    state,
+	})
+}
+
+func lookup() {
+	b, err := exec.Command("gammastep", "-p").CombinedOutput()
+	if err != nil {
+		log.Printf("error: %v", err)
+		return
+	}
+	var period string
+	var fds = strings.Fields(string(b))
+	for idx, f := range fds {
+		if f == "Period:" {
+			period = fds[idx+1]
+			break
+		}
+	}
+	switch period {
+	case "Night":
+		printJson("night", "night")
+	case "Transition":
+		printJson("night", "transition")
+	case "Daytime":
+		printJson("day", "day")
+	default:
+		printJson("unknown", "unknown")
+	}
+}