brightness

#!/usr/bin/env bash

# MIT License
# 
# Copyright (c) 2020 Tom Meyers
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

# Maintained by Tom Meyers <tom@odex.be>
# USAGE: -s <percentage> sets the backlight to x percent
# USAGE: -a <percentage> adds x to the current percentage
# USAGE: -d <percentage> decreases x from the current percentage
# USAGE: -g get the current screen brightness is percentage
# USAGE: -D add debug logging (this should be the last option)
# USAGE: -F Force brightness by adjusting the maximum pixel value instead of the actual backlight (this should be the last option)
# USAGE: -h Print help message

debug="0" # enable debugging logs

function help {
    printf "This script detects the ideal way of monitoring your brightness. It even supports OLED\n"
    printf "USAGE:\n"
    printf "%s -h \t\t\t Print this help message\n" "$(basename $0)"
    printf "%s -s <x> \t\t Sets the brightness to x percent\n" "$(basename $0)"
    printf "%s -a <x> \t\t Increases the brightness by x percent\n" "$(basename $0)"
    printf "%s -d <x> \t\t Decreases the brightness by x percent\n" "$(basename $0)"
    printf "%s -g \t\t\t Get the current light value\n" "$(basename $0)"
    printf "%s -D \t\t\t Enable debugging messages (supply this as the last option)\n" "$(basename $0)"
    printf "%s -F \t\t\t Force hardcore setting (If all else fails try this) PS: supply this as the last option\n" "$(basename $0)"
}

# directly modify the files in the filesystem responsible for the backlight
function modifypath {
        bright="/sys/class/backlight/intel_backlight/brightness"
        max="/sys/class/backlight/intel_backlight/max_brightness"
        if [[ ! "$debug" == "0" ]]; then
            printf "Modifying $bright\n"
        fi
        max_brightness="$(cat $max)"

        if [[ "$1" == "-s" || "$1" == "--set" ]]; then
                awk -v "percent=$2" -v "total=$max_brightness" '{print (total/100)*percent}' "$bright" > "$bright"
        elif [[ "$1" == "-a" || "$1" == "--add" ]]; then
                awk -v "percent=$2" -v "total=$max_brightness" '{print ((total/100)*percent)+$1}' "$bright" > "$bright"
        elif [[ "$1" == "-d" || "$1" == "--decrease" ]]; then
                awk -v "percent=$2" -v "total=$max_brightness" '{print $1-((total/100)*percent)}' "$bright" > "$bright"
        elif [[ "$1" == "-g" || "$1" == "--get" ]]; then
                awk -v "total=$max_brightness" '{print ($1/total)*100}' "$bright"
        else
                printf "Couldn't understand command $2\n"
                help
        fi
}

# handle the light command
function handleLight {
        if [[ ! "$debug" == "0" ]]; then
            printf "Parsing commands to $(command -v light)\n"
        fi

        if [[ "$1" == "-s" || "$1" == "--set" ]]; then
                light -S "$2"
        elif [[ "$1" == "-a" || "$1" == "--add" ]]; then
                light -A "$2"
        elif [[ "$1" == "-d" || "$1" == "--decrease" ]]; then
                light -U "$2"
        elif [[ "$1" == "-g" || "$1" == "--get" ]]; then
                light -G
        else
                printf "Couldn't understand command $2\n"
                help
        fi
}

# handle the xbacklight command
function handleX {
        if [[ ! "$debug" == "0" ]]; then
            printf "Parsing commands to $(command -v xbacklight)\n"
        fi

        if [[ "$1" == "-s" || "$1" == "--set" ]]; then
                xbacklight -set "$2"
        elif [[ "$1" == "-a" || "$1" == "--add" ]]; then
                xbacklight -inc "$2"
        elif [[ "$1" == "-d" || "$1" == "--decrease" ]]; then
                xbacklight -dec "$2"
        elif [[ "$1" == "-g" || "$1" == "--get" ]]; then
                xbacklight -get
        else
                printf "Couldn't understand command $2\n"
                help
        fi
}

# handle xrandr
function handleScreen {
        if [[ ! "$debug" == "0" ]]; then
            printf "Parsing commands to $(command -v xrandr)\n"
        fi
        file=~/.cache/xrandr-brightness
        if [[ ! -f "$file" ]]; then
            printf "1" > "$file"
        fi
        for screen in $(xrandr | grep " connected" | cut -d " " -f1); do
            if [[ "$1" == "-s" || "$1" == "--set" ]]; then
                val=$(printf "%s" "$2" | awk '{printf $1/100}') 
                printf "%s" "$val" > "$file"
                xrandr --output "$screen" --brightness "$val"
            elif [[ "$1" == "-a" || "$1" == "--add" ]]; then
                orig="$(awk '{printf $1}' $file)"
                val=$(printf "%s" "$2" | awk -v "orig=$orig" '{printf ($1/100)+orig}') 
                printf "%s" "$val" > "$file"
                xrandr --output "$screen" --brightness "$val"
            elif [[ "$1" == "-d" || "$1" == "--decrease" ]]; then
                orig="$(awk '{printf $1}' $file)"
                val=$(printf "%s" "$2" | awk -v "orig=$orig" '{printf orig-($1/100)}') 
                printf "%s" "$val" > "$file"
                xrandr --output "$screen" --brightness "$val"
            elif [[ "$1" == "-g" || "$1" == "--get" ]]; then
                awk '{print $1*100}' "$file"
            else
                printf "Couldn't understand command $2\n"
                help
            fi
    done
}


# detect the most supported option there is
function detect {
        #Exit with 1 if $DISPLAY env isn't set. Helps when using the start up script below
        [ -z "$DISPLAY" ] && printf "No graphical environment found. Aborting now" &&exit 1;
        if [[ ! "$(command -v light)" == "" ]]; then 
            handleLight "$1" "$2"
        elif [[ ! "$(command -v xbacklight)" == "" ]]; then
            handleX "$1" "$2"
        elif [[ ! "$(command -v xrandr)" == "" ]]; then
            handleScreen "$1" "$2"
        else
            modifypath "$1" "$2"
        fi 
}

if [[ "$@" == *"-D"* || "$@" == *"--debug"* ]]; then
        debug="1"
fi

if [[ "$@" == *"-F"* || "$@" == *"--force"* ]]; then
        handleScreen "$1" "$2" # control the rgb brightness directly
        exit 0
fi

case "$1" in
    "-h"|"--help")
        help
        exit 0
    ;;
esac

detect "$1" "$2"