#!/bin/bash

max=$(cat /sys/class/backlight/intel_backlight/max_brightness)

sensitivity=$((max/90))

treshold=$((max/4))

panOut=$((sensitivity/4))

min=$((max/10))

delay=2

minSensor=404334


while [ 1 ]
do
        updated=1
        while [ $updated -gt 0 ]
        do
                updated=0
                backlight=$(cat /sys/class/backlight/intel_backlight/brightness)
                sensor=$(cat /sys/bus/iio/devices/iio:device0/in_illuminance_raw)
		# Scale the sensor a bit
		sensor=$((sensor/10))
		sensor=$((5*sensor))
		target=$backlight

		echo Current backlight: $backlight
		echo Max backlight: $max
		echo Sensitivity is: $sensitivity
		echo Threshold is: $treshold
		echo panOut is: $panOut
		echo min is: $min
		echo Current sensor reading: $sensor
		echo Target is: $backlight
		
                if [ $sensor -lt $treshold ]
                then
		    echo Sensor was less than backlight
                    sensor=$(((sensor+panOut)+min))
		    echo New sensor: $sensor
                fi



                if [ $sensor -gt $((backlight+sensitivity)) ]
                then
		    echo Sensor was greater than backlight+sensitivity
                    updated=1
                    target=$((target+(sensitivity/2)))
		    echo New target: $target
                fi


                if [ $sensor -lt $((backlight-sensitivity)) ]
                then
		    echo Sensor was less than backlight-sensitivity
                    updated=1
                    target=$((target-(sensitivity/2)))
		    echo New target: $target
                fi


                if [ $target -gt $max ]
                then
		    echo Target was greater than max brightness
                    target=$max
		    echo New target: $target		    
                fi

                if [ $target -lt 1 ]
                then
		    echo Target was less than 1
                    target=$min
		    echo New target: $target
                fi

                if [ $updated -gt 0 ]
                then
                        echo $target > /sys/class/backlight/intel_backlight/brightness
                fi

        done
	echo Sleeping
        sleep $delay
done