#!/bin/sh
# ABOUTME: Restores the saved battery charge end threshold on boot.
# ABOUTME: Skips silently when the kernel already reports the same value (avoids EINVAL on some Lenovo drivers).

set -eu

STATE_FILE="/var/lib/moonarch/batsaver-threshold"
SYS_FILE="/sys/class/power_supply/BAT0/charge_control_end_threshold"

[ -f "$STATE_FILE" ] || exit 0
[ -f "$SYS_FILE" ] || exit 0

V=$(cat "$STATE_FILE")
case "$V" in
    ""|*[!0-9]*) exit 0 ;;
esac
[ "$V" -ge 1 ] && [ "$V" -le 100 ] || exit 0

# Some Lenovo drivers reject writing the same value with EINVAL.
C=$(cat "$SYS_FILE")
[ "$C" = "$V" ] && exit 0

printf %s "$V" > "$SYS_FILE"