Auto dim external screen when there's no activity

dimextscreen.sh

#!/bin/bash

# This script will auto-dim an external screen if the mouse is outside the external screen, or if there's no window sitting 
# in the external screen. Meant to be polling in the background (every 2 seconds)
# Supports scaling.
# Requires: xdotool, wmctrl, xrandr, ddcutil
# Find your external screen $MONITOR_ID using: `ddcutil detect -t`
DEBUG=0
MONITOR_ID="1"

function get_bright_last()
{
    echo "$(ddcutil getvcp 10 -t --display $MONITOR_ID | tail -1 | awk '{print $4}')"
}

# $1=scaled size $2=physical size
function get_mouse_location_x()
{
    eval $(xdotool getmouselocation --shell)
    # Scale factors (from 1920x1080 → 2954x1662)
    scale_x=$1/$2
    expr="$X/($1/$2)"
    number=$(echo "$expr" | bc -l)
    printf "%.0f" "$number" 2>/dev/null
}

function echodebug()
{
    if [ "$DEBUG" == "1" ]; then
        echo "$1"
    fi
}

function has_windows_on_external() {
    awk_expr='$3 >= '
    awk_expr+=" $laptop_width_full "
    awk_expr+=' {print $0}'
    window_count=$(wmctrl -lG | awk "$awk_expr" | wc -l)
    if [ "$window_count" -gt 1 ]; then
        echo 1
    else
        echo 0
    fi
}

BRIGHT_LAST="$(get_bright_last)"
echodebug "BRIGHT_LAST: $BRIGHT_LAST"
BRIGHT_MIN="0"
LAST_STATE="none"
LAPTOP_RES="$(xrandr --current | grep '*' | awk '{print $1}' | head -1)"
LAPTOP_RES_FULL="$(xrandr --current | grep 'connected' | awk '{print $4}' | head -1)"
echodebug "LAPTOP_RES: $LAPTOP_RES"
echodebug "LAPTOP_RES_FULL: $LAPTOP_RES_FULL"
IFS='x' read laptop_width laptop_height <<< "$LAPTOP_RES"
IFS='x' read laptop_width_full laptop_height_full <<< "$LAPTOP_RES_FULL"
echodebug "LAPTOP WIDTH: $laptop_width"
echodebug "LAPTOP WIDTH FULL: $laptop_width_full"
mouse_real_x="$(get_mouse_location_x $laptop_width_full $laptop_width)"
trap 'ddcutil setvcp 10 $BRIGHT_LAST --display $MONITOR_ID' EXIT

while true; do
    mouse_real_x="$(get_mouse_location_x $laptop_width_full $laptop_width)"
    echodebug "mouse_real_x: $mouse_real_x"
    echodebug "has_windows_on_external: $(has_windows_on_external $laptop_width_full)"
    if [ $mouse_real_x -ge $laptop_width -o $(has_windows_on_external $laptop_width_full) -gt 0 ]; then
        current_state="active"
    else
        current_state="idle"
    fi
    if [ "$current_state" != "$LAST_STATE" ]; then
        if [ "$current_state" == "idle" ]; then
            BRIGHT_LAST="$(get_bright_last)"
            echodebug "BRIGHT_LAST: $BRIGHT_LAST"
            ddcutil setvcp 10 0 --display $MONITOR_ID
        else
            ddcutil setvcp 10 $BRIGHT_LAST --display $MONITOR_ID
        fi
        LAST_STATE=$current_state
    fi
    sleep 2
done