#!/bin/sh

# Usage:
# $0 START_LIMIT STOP_LIMIT

# Sources:
# https://github.com/teleshoes/tpacpi-bat/blob/master/battery_asl
# https://www.reddit.com/r/freebsd/comments/lsygde/acpi_controlling_battery_charging_thresholds_on/
# https://forums.freebsd.org/threads/how-to-set-battery-charging-thresholds-on-laptop.79807/page-2

# Requirements:
# 1. Packages:
#    - acpi_call
# 2. Kernel modules:
#    - acpi_call
#    - acpi_ibm

# ACPI Calls:
# - BCTG - Get battery capacity start charge (1-99 or 0 = default)
# - BCCS - Set battery capacity start charge (1-99 or 0 = default)
# - BCSG - Get battery capacity stop  charge (1-99 or 0 = default)
# - BCSS - Set battery capacity stop  charge (1-99 or 0 = default)

ACPI_PATH="$(sysctl -n dev.acpi_ibm.0.%location | cut -d'=' -f2)"

if [ $# -eq 2 ]; then
  echo "Setting battery capacity start charge to $1%"
  acpi_call -p "$ACPI_PATH.BCCS" -i $1 >> /dev/null
  sleep 1
  echo "Setting battery capacity stop  charge to $2%"
  acpi_call -p "$ACPI_PATH.BCSS" -i $2 >> /dev/null
fi

ACPI_BCTG="$(acpi_call -p "$ACPI_PATH.BCTG" -i 1)"
ACPI_BCSG="$(acpi_call -p "$ACPI_PATH.BCSG" -i 1)"

BAT_START_CHG=$(($ACPI_BCTG - 768))
BAT_STOP_CHG=$(($ACPI_BCSG - 768))
if [ $BAT_STOP_CHG -eq 0 ]; then BAT_STOP_CHG=100; fi

echo "Battery will start charge at: $BAT_START_CHG%"
echo "Battery will stop  charge at: $BAT_STOP_CHG%"