round() { awk -v n=$1 -v d=$2 'BEGIN{print int((n+d/2)/d) * d}'; }

# e.g. 69.420%
percentage_raw=$(upower -i /org/freedesktop/UPower/devices/DisplayDevice | awk '/percentage:/ {print $2}')
# e.g. 7h
est_time=$(upower -i /org/freedesktop/UPower/devices/DisplayDevice | awk '/time to empty:/ {print $4substr($5, 1, 1)}')
# rounded to tens: 10 20 30 etc.
percentage_10s=$(round "${percentage_raw%%%}" 10); 

# when battery is low, highlight it
if [ $percentage_10s -le "10" ]; then 
	printf "#[bg=red,fg=brightwhite]";
elif [ $percentage_10s -le "20" ]; then
	printf "#[bg=brightyellow]";
fi
printf " ";
# icon
if [ $percentage_10s -le "10" ]; then printf "󰁺"; fi
if [ $percentage_10s -eq "20" ]; then printf "󰁻"; fi
if [ $percentage_10s -eq "30" ]; then printf "󰁼"; fi
if [ $percentage_10s -eq "40" ]; then printf "󰁽"; fi
if [ $percentage_10s -eq "50" ]; then printf "󰁾"; fi
if [ $percentage_10s -eq "60" ]; then printf "󰁿"; fi
if [ $percentage_10s -eq "70" ]; then printf "󰂀"; fi
if [ $percentage_10s -eq "80" ]; then printf "󰂁"; fi
if [ $percentage_10s -eq "90" ]; then printf "󰂂"; fi
if [ $percentage_10s -eq "100" ]; then printf "󰁹"; fi
printf " ";
# percentage level rounded to a whole number (69%)
printf "%.0f%%" "${percentage_raw%%%}";
printf " ";
# estimated time on battery
printf " $est_time"
printf " ";
# reset style
printf "#[default]";