package main

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

func main() {
        for {
                t, err := ActiveWindowTitle()
                if err != nil {
                        panic(err)
                }
                fmt.Println(t)
                time.Sleep(1 * time.Second)
        }
}

func ActiveWindowTitle() (string, error) {
        // Grab the ID of the current active window
        out, err := exec.Command("xprop", "-root", "_NET_ACTIVE_WINDOW").Output()
        if err != nil {
                return "", err
        }
        parts := strings.Split(string(out), " ")
        if len(parts) != 5 {
                return "", fmt.Errorf("unexpected output from xprop -root _NET_ACTIVE_WINDOW: %s", string(out))
        }
        id := parts[4]

        // Grab the title of the current active window, using ID
        out, err = exec.Command("xprop", "-id", id, "WM_NAME").Output()
        if err != nil {
                return "", err
        }
        parts = strings.Split(string(out), "=")
        if len(parts) != 2 {
                return "", fmt.Errorf("unexpected output from xprop -id ID WM_NAME: %s", string(out))
        }
        return strings.Trim(strings.TrimSpace(parts[1]), `"`), nil
}