#!/usr/bin/env bash
set -euo pipefail
IFS=$'\n\t'

acpi_output=""
battery_number=0
battery_percentage=0
battery_remaining=""

if [ -x /usr/bin/acpi ]; then
  acpi_output=$(/usr/bin/acpi -b)
  battery_number=$(echo $acpi_output|cut -d':' -f1|cut -d' ' -f2)
  battery_state=$(echo $acpi_output|cut -d' ' -f3)
  battery_state=${battery_state%","}
  battery_percentage=$(echo $acpi_output|cut -d' ' -f4)
  battery_percentage=${battery_percentage%","}
  battery_percentage=${battery_percentage%"%"}
  if [ $battery_number -ge 0 ]; then
    if [ $battery_state = "Discharging" ]; then
      battery_remaining=$(echo $acpi_output|cut -d' ' -f5)
      echo "$battery_percentage% ($battery_remaining)"
    else
      echo "$battery_percentage%"
    fi
  fi
else
  exit 1
fi