#!/bin/bash

BATT=$(ioreg -c AppleDeviceManagementHIDEventService -r -l | grep -i mouse -A 20 | grep BatteryPercent | cut -d= -f2 | cut -d' ' -f2)

# defaults to warn at 20%; accepts other number as 1st argument (useful for testing)
COMPARE=${1:-20}

if [ -z "$BATT" ]; then
  echo 'No mouse found.'
  exit 0
fi

if (( BATT < COMPARE )); then
  osascript -e "display notification \"Mouse battery is at ${BATT}%.\" with title \"Mouse Battery Low\""
fi

printf '🖱 %d%%\n' $BATT