brightness

#!/usr/bin/env sh
#
# Saumon i3blocks scripts
# brightness (brightness control for laptops and external monitors)
# Dependencies: `brightnessctl` (setuid) for laptops
#               `ddcutil` for desktop external monitors
# We could use brightnessctl with the ddcci kernel module, but it does not work on <6.3 as of 2023-05, so here we are
#   with ddcutil calls. It might be faster anyway though.
#

# Chassis types: https://www.dmtf.org/standards/SMBIOS
# 3 is Desktop
if [ "$(cat /sys/class/dmi/id/chassis_type)" = "3" ]; then

  if ! command -v ddcutil >/dev/null; then
    echo " !dep "
    exit 33
  fi

  # Initialise cache
  [ -e "$XDG_CACHE_HOME/ddcutil_detect" ] || ddcutil --brief detect | grep -v "should not exist" > "$XDG_CACHE_HOME/ddcutil_detect"

  # Match monitor name to I2C bus number
  monitor_name=${desktop_monitor:-"Monitor"}
  bus_number=$(grep -C2 "$monitor_name" "$XDG_CACHE_HOME/ddcutil_detect" | grep i2c | head -n1 | cut -d'-' -f2)

  command="ddcutil --bus $bus_number"

  case $BLOCK_BUTTON in
    2) # middle click: toggle night/day brightness
      current=$($command getvcp 10 --brief | tail -n1 | awk '{print $4}')
      if [ "$current" -le 20 ]; then
        if [ "$BLOCK_INSTANCE" -eq 6 ]; then
          new=100
        else
          new=60
        fi
      else
        if [ "$BLOCK_INSTANCE" -eq 6 ]; then
          new=20
        else
          new=0
        fi
      fi
      ;;
    3) # right click: set min/full brightness depending on context
      current=$($command getvcp 10 --brief | tail -n1 | awk '{print $4}')
      if [ "$current" -ge 50 ]; then
        new=100
      else
        new=1
      fi
      ;;
    4) # scroll up: increase brightness by 20%
      current=$($command getvcp 10 --brief | tail -n1 | awk '{print $4}')
      if [ "$current" -ge 80 ]; then
        new=100
      else
        new=$(expr $current + 20)
      fi
      ;;
    5) # scroll down: decrease brightness by 20%
      current=$($command getvcp 10 --brief | tail -n1 | awk '{print $4}')
      if [ "$current" -le 20 ]; then
        new=0
      else
        new=$(expr $current - 20)
      fi
      ;;
  esac

  if [ -n "$new" ]; then
    printf " <span fallback='true'>  </span>%s<span font_size='small'>%%</span> \n" "$new"
    $command setvcp 10 "$new" --noverify > /dev/null &
    exit 0
  fi

  current=$($command getvcp 10 --brief | tail -n1 | awk '{print $4}')
  # When ddcutil fails, it returns "DDC communication failed for monitor on bus /dev/i2c-X"
  # In that case, retry
  if [ "$current" = "for" ]; then
    current=$($command getvcp 10 --brief | tail -n1 | awk '{print $4}')
  fi
  # If we still don't have anything, give up, but at least hide the "for"
  if [ "$current" = "for" ]; then
    current=""
  fi

else

  if ! command -v brightnessctl >/dev/null; then
    echo " !dep "
    exit 33
  fi

  command="brightnessctl -m"

  case $BLOCK_BUTTON in
    3) # right click: toggle min/full brightness
      rounded=$($command | cut -d ',' -f4 |  tr -d '%')
      if [ "$rounded" -ge 50 ]; then
        command="brightnessctl -m set 100%"
      else
        command="brightnessctl -m set 1"
      fi
      ;;
    4) # scroll up: increase brightness by 2%
      command="brightnessctl -m set -m +2%"
      ;;
    5) # scroll down: decrease brightness by 2%
      command="brightnessctl -m set -m 2%-"
      ;;
  esac

  current=$($command | cut -d ',' -f4 |  tr -d '%')

fi


if [ -z "$current" ]; then
  printf " <span fallback='true'>  </span>?? \n"
  exit 0
fi

printf " <span fallback='true'>  </span>$current<span font_size='small'>%%</span> \n"