#!/bin/sh
#
# 40autorandr: Change autorandr profile on thaw/resume
exec > /var/log/autorandr.log 2>&1

AUTORANDR="autorandr -c --default default"

# Work around #44: Long user names in w
export PROCPS_USERLEN=32

find_user() {
	# Determine user owning the display session from $1
	D="$1"

	# Prefer loginctl over all others, see bug #49
	if [ -x "`which loginctl`" ]; then
		# Based on http://unix.stackexchange.com/questions/203844/how-to-find-out-the-current-active-xserver-display-number/204498
		# by SO user intelfx
		user="$(
		loginctl list-sessions --no-legend | while read id uid user seat; do
			 loginctl show-session -p Display -p Active "$id" | while IFS='=' read property value; do
				case "$property" in
					Active)
						if [ "$value" != "yes" ]; then
							continue
						fi
						;;
					Display)
						if [ -n "$value" -a "$value" = "$D" ]; then
							echo $user
						fi
						;;
				esac
			done
		done
		)"
		if [ -n "$user" ]; then
			echo $user
			return 0
		fi
	fi

	# Prefer w to who, see bug #39
	if [ -x "`which w`" ]; then
		user="`w -h | awk -vD="$D" '$2 ~ ":"D"(.[0-9])?$" || $3 ~ ":"D"(.[0-9])?$" {print $1}' | head -n1`"

		if [ -z "$user" ];	then
			# This fallback checks if there is exactly one user (except
			# root) logged in an interactive session and assumes the
			# session belongs to him. See bug #39.
			user="`w -hu | awk '/^\w+/ && $1 !~ "root" { users[$1]=$1; } ENDFILE { if(asort(users) == 1) for(u in users) print users[u]; }'`"
		fi
	else
		user="`who --all | awk -vD="$D" '$3 ~ ":"D"(.[0-9])?$" {print $1}' | head -1`"

		if [ -z "$user" ];	then
			# Same fallback as above; see bug #39.
			user="`who -u | awk '/^\w+/ && $1 !~ "root" { users[$1]=$1; } ENDFILE { if(asort(users) == 1) for(u in users) print users[u]; }'`"
		fi
	fi

	if [ -n "$user" ]; then
		echo $user
		return 0
	fi

	# If none of the above worked, check if there is only one user owning
	# processes in $DISPLAY except root
	#
	# This code should be optimized somehow, but keep in mind that not all
	# systems symlink sh -> bash!
	OUTPUT="$(
		for p in /proc/*; do
			[ -d $p ] || continue
			d="$(awk -v RS='\0' -F= '$1=="DISPLAY" {print $2}' $p/environ 2>/dev/null)"
			if [ "$d" = "$D" ]; then
				stat -c %U $p
			fi
		done | sort | uniq | grep -v root | nl | head -n1
	)"
	count=$(echo $OUTPUT | awk '{print $1}')
	user=$(echo $OUTPUT | awk '{print $2}')

	if [ "$count" -eq 1 ]; then
		echo $user
		return 0
	fi

	return 1
}

detect_display()
{
	for X in /tmp/.X11-unix/X*; do
		D="${X##/tmp/.X11-unix/X}"

		user="$(find_user "$D")"

		if [ x"$user" != x"" ]; then
			logger "autorandr: Changing display configuration for display :$D, user '$user'"
			export DISPLAY=":$D"
			/bin/su -c "${AUTORANDR}" "$user"
		fi
	done
}

if grep -q systemd /proc/1/comm && [ "$2" = "udev" ]; then
    exec /bin/systemctl start autorandr-resume.service
fi

case "$1" in
	thaw|resume)
		detect_display
		;;
esac