#!/bin/bash
# This script is supposed to change the output display among the various possibilities.  Basically: just the laptop, same on both with safe resolution (aka presentation mode) and maximum throughput (dual-screen).
# This was made for i965.
# At the time of this writing, xorg.conf still requires  "Virtual 2560 2048"

# name of the screen
S1="LVDS1"
S2="VGA1"

# TODO: depending if the output is a screen or a beamer, the order of the outputs should be different
# this could be detected by the on the display's name provided by the edid, or by the resolution provided
# (prefered mode of beamer  never has a 5/4 ratio for instance)
# or it could just remember the last mode of each display according to their name

# xrandr is quite slow and used several times, so cache its result
xrand_output="$(mktemp)"
xrandr > "$xrand_output"
#xrand_output="xrandr.out2sc"


# Watch out: the order will influence the order of selection but also how the mode are detected
# When no state is match, the _second_ is applied
# Declares the list of possible states for one screen
one_screen_states="rotated preferred" # 1024 is not useful
# Declares the list of possible states for two screens
two_screen_states=" maxrotated presentation maximum 1024"

# First output is minimized version of a huge display, second output follows the mouse at a normal resolution
#xrandr --fb 3200x2000 --output $S1 --panning 0x0 --scale 2.5x2.5 --pos 0x0 --rotate normal --output VGA --pos 0x0 --panning 3200x2000+0+0/3200x2000+0+0/64/64/64/64


# one screen
probe_preferred(){
	# VGA disconnected but still displaying
	if grep -q "$S2 disconnected .*x.*+.*+.* (" $xrand_output; then
		# can't be this mode
		return 1
	fi
	if grep -q "*+" $xrand_output; then
		# select = preferred
		if grep -q "$S1 connected .*x.*+0+0 (" $xrand_output; then
			# no rotation
			return 0
		fi
	fi
	return 1
}

apply_preferred(){
	xrandr --auto --output $S1 --preferred --rotate normal
}

probe_rotated(){
	# VGA disconnected but still displaying
	if grep -q "$S2 disconnected .*x.*+.*+.* (" $xrand_output; then
		# can't be this mode
		return 1
	fi
	if grep -q "$S1 connected .*x.*+0+0 left (" $xrand_output; then
		# rotated to the left
		return 0
	fi
	return 1
}

apply_rotated(){
	xrandr --output $S1 --auto --rotate left
}

probe_1024(){
	# VGA disconnected but still displaying
	if grep -q "$S2 disconnected .*x.*+.*+.* (" $xrand_output; then
		# can't be this mode
		return 1
	fi
	grep -q "1024x768.*\*" $xrand_output # selected = 1024x768 
}

apply_1024(){
	xrandr --auto --output $S1 --mode 1024x768 --rotate normal
}

# two screens
probe_maximum(){
	if [ "$(grep -c "\*+" $xrand_output)" == 2 ]; then
		# select = preferred * 2
		if grep -q "$S2 connected .*x.*+...*+0 (" $xrand_output; then
			# no rotation and shifted horizontally
			return 0
		fi
	else
		# Maybe it failed just because the VGA has no preferred mode
		if [ "$(grep -c -E "^[[:blank:]]*[[:digit:]]+x[[:digit:]]+[[:blank:]]+[[:digit:]]+\.[[:digit:]]+.?\+" $xrand_output)" == 1 ]; then
			if [ "$(grep -c "\*+" $xrand_output)" == 1 ]; then
				if grep -q "$S2 connected .*x.*+...*+0 (" $xrand_output; then
					# no rotation
					return 0
				fi
			fi
		fi

	fi
	return 1
}

apply_maximum(){
	xrandr --output $S1 --auto --rotate normal --pos 0x0 --output $S2 --auto --rotate normal --right-of $S1 
}

probe_maxrotated(){
	if [ "$(grep -c "\*+" $xrand_output)" == 2 ]; then
		# select = preferred * 2
		if grep -q "$S2 connected .*x.*+.*+0 left (" $xrand_output; then
			# rotated to the left
			return 0
		fi
	else
		# Maybe it failed just because the VGA has no preferred mode
		if [ "$(grep -c -E "^[[:blank:]]*[[:digit:]]+x[[:digit:]]+[[:blank:]]+[[:digit:]]+\.[[:digit:]]+.?\+" $xrand_output)" == 1 ]; then
			if [ "$(grep -c "\*+" $xrand_output)" == 1 ]; then
				if grep -q "$S2 connected .*x.*+...*+0 left (" $xrand_output; then
					# no rotation
					return 0
				fi
			fi
		fi

	fi
	return 1
}

# we should put the LVDS at the bottom: dim1 of prefered VGA - dim 2 of prefered LVDS 
apply_maxrotated(){
	xrandr --output $S1 --auto --rotate normal --pos 0x0 --output $S2 --auto --rotate left --right-of $S1 
}

probe_1024(){
	if [ "$(grep -c "1024x768.*\*" $xrand_output)" == 2 ]; then
		# selected = 1024x768
		return 0
	fi
	return 1
}

# TODO disable the screensaver? How to re-initialise it? D-BUS command?
apply_1024(){
# note that PANEL_FITTING property is to force the black bars, better than deformation
	# TODO should be a "if the mode doesn't exist"
	xrandr --newmode "1024x768" 63.50  1024 1072 1176 1328  768 771 775 798 -hsync +vsync
	xrandr --addmode $S1 "1024x768"

	xrandr --output $S1 --mode 1024x768 --rotate normal --pos 0x0 --set PANEL_FITTING center --output $S2 --mode 1024x768  --rotate normal --same-as $S1
	xbacklight -set 100 # in addition we make sure it's very visible'
}

# TODO: instead of using 1024x768 we sould use the prefered size of the VGA, which fits inside the prefered size of LVDS
probe_presentation(){
	if [ "$(grep -c "1024x768.*\*" $xrand_output)" == 2 ]; then
		# selected = 1024x768
		return 0
	fi
	return 1
}

# TODO disable the screensaver? How to re-initialise it? D-BUS command?
apply_presentation(){
# note that PANEL_FITTING property is to force the black bars, better than deformation
	xrandr --output $S1 --mode 1024x768 --rotate normal --pos 0x0 --set PANEL_FITTING center --output $S2 --mode 1024x768  --rotate normal --same-as $S1
	xbacklight -set 100 # in addition we make sure it's very visible'
}

# XXX with panning
apply_presentationpanning(){
# note that PANEL_FITTING property is to force the black bars, better than deformation
	xrandr --output $S1 --scale 0.8x0.8 --rotate normal --pos 0x0 --panning 1024x768 --output $S2 --mode 1024x768 --rotate normal --pos 0x0
	xbacklight -set 100 # in addition we make sure it's very visible'
}


# returns as a string the state we are currently in
# if no state matchs, returns the first possible state compatible
# no arg
get_current_state(){
	for state in $(list_possible_states); do
		if probe_$state; then
			# found the current state!
			echo $state
			return
		fi
	done
	
	# no state found => return the first possible one
	list_possible_states | cut -d " " -f 1
}

# set the new state
# 1 arg: the name of the state as a string
set_state(){
	apply_$1
}

# List all the possible (interesting) states according to the screens connected
# no arg
# returns a string space separated
list_possible_states(){
# Two possibilities: with VGA screen connected or not
if grep -q "$S2 disconnected" $xrand_output; then
	# one screen
	echo -n $one_screen_states
else
	# two screens
	echo -n $two_screen_states
fi
}

# Return the next state in the list, wrapin around
# first arg is the current state
# following args are the possible states
# return the next state as a string name
get_next_state(){
	cur=$1
	shift
	prev=$1
	first=$prev
	shift
	for state in $*; do
		if [ $prev == $cur ]; then
			echo $state
			return
		fi
		prev=$state
	done
	echo $first
}

# Main

currrent=$(get_current_state)
list="$(list_possible_states)"
#echo $currrent $list
new=$(get_next_state $currrent $list) # no space protection
set_state $new	# Voila!