#!/bin/sh
#
# Automatically select a display configuration based on connected devives
#
# Stefan Tomanek <stefan.tomanek@wertarbyte.de>
#
# How to use:
#
# Save your current display configuration and setup with
# autorandr --save mobile
#
# Connect an additional display, configure your setup and save it
# autorand --save docked
#
# Now autorandr can detect which hardware setup is active:
# # autorandr
# mobile
# docked (detected)
#
# To automatically reload your setup, just append --change to the command line
#
# To manually load a profile, you can use the --load <profile> option.
#
# To prevent a profile from being loaded, place a script call "block" in its
# directory. The script is evaluated before the screen setup is inspected, and
# in case of it returning a value of 0 the profile is skipped. This can be used
# to query the status of a docking station you are about to leave.
#
# If no suitable profile can be identified, the current configuration is kept.
# To change this behaviour and switch to a fallback configuration, specify
# --default <profile>
#
# Another script called "postswitch "can be placed in the directory
# ~/.auto-disper as well as in all profile directories: The scripts are
# executed after a mode switch has taken place and can notify window managers
# or other applications about it.

XRANDR=/usr/bin/xrandr
PROFILES=~/.autorandr/

CHANGE_PROFILE=0
DEFAULT_PROFILE=""
SAVE_PROFILE=""

setup_fp_xrandr_edid() {
	$XRANDR -q --verbose | awk '
	/^[^ ]+ (dis)?connected / { DEV=$1; }
	$1 ~ /^[a-f0-9]+$/ { ID[DEV] = ID[DEV] $1 }
	END { for (X in ID) { print X " " ID[X]; } }'
}

setup_fp_sysfs_edid() {
	# hash the EDIDs of all _connected_ devices
	for P in /sys/class/drm/card*-*/; do
		if grep -q "^connected$" < "${P}status"; then
			echo -n "$(basename "$P") "
			md5sum ${P}edid | awk '{print $1}'
		fi
	done
}

setup_fp() {
	local METHODS="setup_fp_xrandr_edid setup_fp_sysfs_edid"
	local FP="";
	for M in $METHODS; do
		FP="$($M)"
		[ -n "$FP" ] && break;
	done
	if [ -z "$FP" ]; then
		echo "Unable to fingerprint display configuration" >&2
		return
	fi
	echo "$FP"
}


current_cfg() {
	$XRANDR -q | awk '
	/^[^ ]+ disconnected / {
        print "output "$1;
	        print "off";
	}
	/^[^ ]+ connected / {
		split($3, A, "+");
		print "output "$1;
		print "mode "A[1];
		print "pos "A[2]"x"A[3];
	}'
}

blocked() {
	local PROFILE="$1"
	[ ! -x "$PROFILES/$PROFILE/block" ] && return 1

	"$PROFILES/$PROFILE/block" "$PROFILE"
}

load() {
	local PROFILE="$1"
	if [ "$CHANGE_PROFILE" -eq 1 ] && [ -e "$PROFILES/$PROFILE/config" ] ; then
		echo " -> loading profile $PROFILE"
		sed 's!^!--!' "$PROFILES/$PROFILE/config" | xargs xrandr

		[ -x "$PROFILES/$PROFILE/postswitch" ] && \
			"$PROFILES/$PROFILE/postswitch" "$PROFILE"
		[ -x "$PROFILES/postswitch" ] && \
			"$PROFILES/postswitch" "$PROFILE"
	fi
}

# process parameters
OPTS=$(getopt -n autorandr -o s:l:d:cf --long change,default:,save:,load:,fingerprint -- "$@")
if [ $? != 0 ] ; then echo "Terminating..." >&2 ; exit 1 ; fi
eval set -- "$OPTS"

while true; do
	case "$1" in
		-c|--change) CHANGE_PROFILE=1; shift ;;
		-d|--default) DEFAULT_PROFILE="$2"; shift 2 ;;
		-s|--save) SAVE_PROFILE="$2"; shift 2 ;;
		-l|--load) LOAD_PROFILE="$2"; shift 2 ;;
		--fingerprint) setup_fp; exit 0;;
		--) shift; break ;;
		*) echo "Error: $1"; exit 1;;
	esac
done

CURRENT_SETUP="$(setup_fp)"

if [ -n "$SAVE_PROFILE" ]; then
	echo "Saving current configuration as profile '${SAVE_PROFILE}'"
	mkdir -p "$PROFILES/$SAVE_PROFILE"
	echo "$CURRENT_SETUP" > "$PROFILES/$SAVE_PROFILE/setup"
	current_cfg > "$PROFILES/$SAVE_PROFILE/config"
	exit 0
fi

if [ -n "$LOAD_PROFILE" ]; then
	CHANGE_PROFILE=1 load "$LOAD_PROFILE"
	exit $?
fi

for SETUP_FILE in $PROFILES/*/setup; do
	if ! [ -e $SETUP_FILE ]; then
		break
	fi
	PROFILE="$(basename $(dirname "$SETUP_FILE"))"
	echo -n "$PROFILE"

	if blocked "$PROFILE"; then
		echo " (blocked)"
		continue
	fi

	FILE_SETUP="$(cat "$PROFILES/$PROFILE/setup")"
	if [ "$CURRENT_SETUP" = "$FILE_SETUP" ]; then
		echo " (detected)"
		load "$PROFILE"
		# found the profile, exit with success
		exit 0
	else
		echo ""
	fi
done

# we did not find the profile, load default
if [ -n "$DEFAULT_PROFILE" ]; then
	echo "No suitable profile detected, falling back to $DEFAULT_PROFILE"
	load "$DEFAULT_PROFILE"
fi
exit 1