#!/bin/sh

_usage() {
	cat<<EOF
Usage: ${0##*/}

This script will toggle HDMI Audio (and set video properly). To do this
automatically when the cable is plugged, add the following udev rule:

  $ cat /etc/udev/rules.d/hdmi.rules
  SUBSYSTEM=="drm", ACTION=="change", RUN+="/bin/sh $0"

To get audio working on radeon, you may need to boot with the following kernel
paremeter:

  radeon.audio=1

You must be root. This script is Linux only.
EOF
}

if [ "$(uname)" != "Linux" ]; then
	_usage
	exit 1
fi

if [ $(id -u) -ne 0 ]; then
	_usage
	exit 1
fi

ALSACONF="/etc/asound.conf"
HDMI_STATUS="$(cat /sys/class/drm/card0-HDMI-A-1/status)"
[ -z "$HDMI_STATUS" ] && exit

APLAY_BUF="$(aplay -l | grep HDMI)"
_getprop() {
	echo "$APLAY_BUF" | awk -v prop="$1" '{for(i=1; i<NF; i++) if ($i == prop) { print substr($(i+1), 1,1); exit}}'
}

CARD="$(_getprop card)"
DEVICE="$(_getprop device)"

udevadm settle --timeout=2

XRANDR_BUF="$(xrandr)"

PRIMARY="$(echo "$XRANDR_BUF" | awk '/^[[:alnum:]-]+ connected/ {print $1; exit}')"
HDMI="$(echo "$XRANDR_BUF" | awk '/^HDMI-[[:digit:]]+ connected/ {print $1; exit}')"

echo "PRIMARY=[$PRIMARY], HDMI=[$HDMI]"

## Video
if [ -n "$HDMI" ]; then
	# xrandr --output "$PRIMARY" --auto --primary --output "$HDMI" --auto --noprimary --right-of "$PRIMARY"
	xrandr --output "$HDMI" --auto --noprimary --right-of "$PRIMARY"
# else
# 	xrandr --output "$HDMI" --off
fi

## Sound
if [ "$HDMI_STATUS" = "connected" ]; then
	cat<<EOF > "$ALSACONF"
pcm.!default {
	type hw
	card $CARD
	device $DEVICE
}
EOF
	chmod 644 "${ALSACONF}"
	echo "HDMI sound enabled"
else
	rm -f "$ALSACONF"
	echo "HDMI sound disabled"
fi