#!/bin/bash
# Adjust brightness of the focused output: internal panel via light,
# external monitors via DDC/CI.
# Usage: brightness.sh up|down

case "$1" in
    up)   light_factor=1.4;    ddc_op=+ ;;
    down) light_factor=0.7142; ddc_op=- ;;
    *)    echo "Usage: $0 up|down" >&2; exit 1 ;;
esac

IFS=$'\t' read -r name serial < <(swaymsg -t get_outputs |
    jq -r '.[] | select(.focused) | [.name, .serial] | @tsv')

if [[ -z "$name" || "$name" == eDP-* ]]; then
    exec light -T "$light_factor"
fi

exec ddcutil setvcp --sn "$serial" 10 "$ddc_op" 5 --noverify