autorandr-update-display

#!/bin/bash

DATE=$(date +%Y%m%d-%H%M%S)
set -e

AUTORANDR="/usr/local/bin/autorandr"
XRANDR="/usr/bin/xrandr"
XBACKLIGHT="/usr/bin/xbacklight"

find_user() {
    local D="$1"
    #local user=$(who | grep 'tty' | awk -vD="$D" '$0 ~ "\\(:"D"\\)$" {print $1}')  ## Works better for GNOME
    #local user=$(who | awk -vD="$D m" '$2 ~ ":"D || $0 ~ "\\(:"D"\\)$" {print $1}' |head -n 1)  ## Works better for KDE
    local user=$(who | awk -vD="$D" '$2 ~ ":"D || $0 ~ "\\(:"D"\\)$" {print $1}' |head -n 1)  ## Works better for KDE and Ubuntu
    if [[ ! $user ]]; then
        echo "No user found!" >&2
	who >&2
	exit 10
    fi
    echo $user
}

run_as_x_user() {
    local user="$1"; shift
    local cmd="$@"

    case "$user" in
	"")
	    ;;
	# Run as root:
	"(unknown)")
	    eval ${cmd}
	    ;;
	*)
	    /bin/su -c "$cmd" "$user"
	    ;;
    esac
}

switch_external_off() {
    local user="$1"
    run_as_x_user $user $XRANDR --output DP1 --off --output DP2 --off --output DP3 --off
}

update_backlight() {
    local user="$1"

    case $(detect_autorandr $user) in
	docked*)
	    run_as_x_user $user $XBACKLIGHT -set 100%
	    ;;
	mobile*)
	    run_as_x_user $user $XBACKLIGHT -set 40%
	    ;;
	*)
            echo "Unrecognised autorandr session" >&2
            ;;
    esac
}

detect_autorandr() {
    local user="$1"
    run_as_x_user $user $AUTORANDR |awk '/detected/ {print $1}'
}

############################

update_backlight=""

while [[ "$1" ]]; do
    case "$1" in
        -backlight)
            update_backlight=1
            shift
            ;;
        *)
            echo "'$1' arg not recognised" >&2
            exit 1
            ;;
    esac
done

############################

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

    user=$(find_user $D)
    export DISPLAY=":$D"

    #switch_external_off $user
    run_as_x_user $user $AUTORANDR -c
    [[ $update_backlight ]] && update_backlight $user
done