#!/bin/sh

# This is a script to enable automatic switching to and from HDMI audio output
# To run this script whenever and HDMI cable is connected, copy this file to /usr/local/bin/ and run 'chmod +x /usr/local/bin/hdmi_sound_toggle.sh'
# Then create the file /etc/udev/rules.d/99-hdmi_sound.rules with the following content :
# KERNEL=="card0", SUBSYSTEM=="drm", ACTION=="change", RUN+="/usr/local/bin/hdmi_sound_toggle.sh"
# Then run 'udevadm control --reload-rules' and reboot

export PATH=/usr/bin

USER_NAME=$(who | awk -v vt=tty$(fgconsole) '$0 ~ vt {print $1}')
USER_ID=$(id -u "$USER_NAME")
CARD_PATH="/sys/class/drm/card0/"
AUDIO_OUTPUT="analog-stereo"
PULSE_SERVER="unix:/run/user/"$USER_ID"/pulse/native"

for OUTPUT in $(cd "$CARD_PATH" && echo card*); do
  OUT_STATUS=$(<"$CARD_PATH"/"$OUTPUT"/status)
  if [[ $OUT_STATUS == connected ]]
  then
    echo $OUTPUT connected
    case "$OUTPUT" in
      "card0-HDMI-A-1")
        AUDIO_OUTPUT="hdmi-stereo" # Digital Stereo (HDMI 1)
     ;;
      "card0-HDMI-A-2")
        AUDIO_OUTPUT="hdmi-stereo-extra1" # Digital Stereo (HDMI 2)
     ;;
    esac
  fi
done
echo selecting output $AUDIO_OUTPUT
sudo -u "$USER_NAME" pactl --server "$PULSE_SERVER" set-card-profile 0 output:$AUDIO_OUTPUT+input:analog-stereo