#!/usr/bin/env bash

# ------------------------------
# Battery Threshold Udev Setup
# ------------------------------
# This script sets up udev rules to allow a non-root user to write to
# /sys/class/power_supply/BAT0/charge_control_end_threshold.
# It creates a group 'battery_ctl' and adds the target user to this group.
#
# Usage:
#  $ ./setup_rules.sh [username] [--non-interactive|-y]
# ------------------------------
set -e

SCRIPT_PATH="$(readlink -f "$0" 2>/dev/null || echo "$0")"

TARGET_USER=""
SKIP_PROMPT=false

for arg in "$@"; do
  case "$arg" in
  -y | --non-interactive)
    SKIP_PROMPT=true
    ;;
  -*)
    ;;
  *)
    if [ -z "$TARGET_USER" ]; then
      TARGET_USER="$arg"
    fi
    ;;
  esac
done

TARGET_USER="${TARGET_USER:-${SUDO_USER:-$USER}}"

if [ "$SKIP_PROMPT" = false ]; then
  echo "===================================================="
  echo " Battery Threshold Udev Setup"
  echo "===================================================="
  echo "Script location: $SCRIPT_PATH"
  echo "Target user:     $TARGET_USER"
  echo ""
  echo "Please examine the script location and contents above before proceeding."
  echo ""

  read -rp "Do you want to proceed with setup? (y/N): " CONFIRM
  case "$CONFIRM" in
  [yY][eE][sS] | [yY])
    ;;
  *)
    echo "Setup cancelled by user."
    read -rp "Press Enter to exit..."
    exit 1
    ;;
  esac
fi

# Escalate privileges via sudo only after user confirmation
if [ "$EUID" -ne 0 ]; then
  echo ""
  echo "Escalating privileges via sudo..."
  exec sudo bash "$SCRIPT_PATH" "$TARGET_USER" --non-interactive
fi

if [ -z "$TARGET_USER" ]; then
  echo "Error: No target user specified." >&2
  read -rp "Press Enter to exit..."
  exit 1
fi

if ! getent group battery_ctl >/dev/null; then
  echo "Creating battery_ctl group..."
  groupadd battery_ctl
fi

echo "Adding $TARGET_USER to battery_ctl group..."
usermod -aG battery_ctl "$TARGET_USER"

echo "Writing udev rule to /etc/udev/rules.d/99-battery-threshold.rules..."

cat <<'EOF' >/etc/udev/rules.d/99-battery-threshold.rules
# Battery Threshold Control - udev rule
# Grants write access to charge_control_end_threshold for users in the
# 'battery_ctl' group.
SUBSYSTEM=="power_supply", KERNEL=="BAT*", \
    RUN+="/bin/chgrp battery_ctl /sys$devpath/charge_control_end_threshold", \
    RUN+="/bin/chmod g+w /sys$devpath/charge_control_end_threshold"
EOF

echo "Reloading rules..."

udevadm control --reload-rules && udevadm trigger

echo ""
echo "You may need a reboot for the plugin's write access to take effect."
echo "Done!"
echo ""
read -rp "Press Enter to exit..."