#!/bin/bash

# blink

set -e

# $1 = how many times to blink, $2 = pause between each blink
blink () {
    # find primary connected or else 1st connected monitor
    monitor="$(xrandr -q | grep -w "connected" | grep "primary" | cut -f1 -d ' ')"
    if [ -z "$monitor" ]; then # no primary AND connected found, lets try 1st connected
        monitor="$(xrandr -q | grep -w "connected" | cut -f1 -d ' ')"
    fi 
    [ -z "$monitor" ] && { >&2 echo "No monitors found error" ; exit 1; }
    
    # find current brightness of that monitor
    now="$(xrandr --verbose | grep -A 15 "$monitor" | grep -i brightness | cut -f2 -d ' ')"
    [ -z "$now" ] && { >&2 echo "Could not get current brightness error" ;  exit 1; }
    
    
    [ -z "$1" ] && loops="1" || loops="$1"
    for ((c=1; c<=loops; c++))
    do
        # blink up
        for i in $(seq "$now" 0.2 3.0); do     
            xrandr --output "$monitor" --brightness "$i"
            sleep 0.01
        done
        
        # blink down
        for i in $(seq 3.0 -0.2 "$now"); do     
            xrandr --output "$monitor" --brightness "$i"
            sleep 0.01
        done
    sleep "$2"
    xrandr --output "$monitor" --brightness "$now"
    done
}
[ -z "$1" ] && times="1" || times="$1"
[ -z "$2" ] && waitsome="0.3" || waitsome="$2"
blink "$times" "$waitsome"