#!/usr/bin/env bash
set -euo pipefail

SERVICE_NAME="daily-reboot.service"
TIMER_NAME="daily-reboot.timer"
SERVICE_PATH="/etc/systemd/system/${SERVICE_NAME}"
TIMER_PATH="/etc/systemd/system/${TIMER_NAME}"
ON_CALENDAR="*-*-* 02:30:00 Asia/Shanghai"

require_root() {
  if [[ ${EUID:-$(id -u)} -ne 0 ]]; then
    echo "请使用 root 或 sudo 运行此脚本。" >&2
    exit 1
  fi
}

require_systemd() {
  if ! command -v systemctl >/dev/null 2>&1; then
    echo "未找到 systemctl，当前系统似乎不是 systemd 环境。" >&2
    exit 1
  fi
}

write_unit_files() {
  cat > "$SERVICE_PATH" <<SERVICE_EOF
[Unit]
Description=Daily reboot service

[Service]
Type=oneshot
ExecStart=/usr/sbin/shutdown -r now
SERVICE_EOF

  cat > "$TIMER_PATH" <<TIMER_EOF
[Unit]
Description=Reboot every day at 02:30 Beijing Time (Asia/Shanghai)

[Timer]
OnCalendar=${ON_CALENDAR}
AccuracySec=1min
Unit=${SERVICE_NAME}

[Install]
WantedBy=timers.target
TIMER_EOF
}

install_or_update() {
  require_root
  require_systemd

  write_unit_files
  systemctl daemon-reload
  systemctl enable "$TIMER_NAME" >/dev/null
  systemctl restart "$TIMER_NAME"

  echo "已安装/更新：${TIMER_NAME}"
  echo "执行时间：北京时间每天 02:30（Asia/Shanghai）"
  echo
  systemctl list-timers "$TIMER_NAME" --all --no-pager || true
}

uninstall_units() {
  require_root
  require_systemd

  systemctl disable --now "$TIMER_NAME" >/dev/null 2>&1 || true
  systemctl stop "$SERVICE_NAME" >/dev/null 2>&1 || true
  rm -f "$SERVICE_PATH" "$TIMER_PATH"
  systemctl daemon-reload
  systemctl reset-failed "$SERVICE_NAME" "$TIMER_NAME" >/dev/null 2>&1 || true

  echo "已卸载：${SERVICE_NAME} / ${TIMER_NAME}"
}

usage() {
  cat <<USAGE
用法：
  sudo bash $(basename "$0")            # 交互选择安装/更新或卸载
  sudo bash $(basename "$0") install    # 安装或更新
  sudo bash $(basename "$0") update     # 更新（等同 install）
  sudo bash $(basename "$0") uninstall  # 卸载
USAGE
}

interactive_menu() {
  echo "请选择操作："
  echo "  1) 安装/更新"
  echo "  2) 卸载"
  read -r -p "请输入 1 或 2: " choice

  case "$choice" in
    1) install_or_update ;;
    2) uninstall_units ;;
    *)
      echo "无效选择。" >&2
      exit 1
      ;;
  esac
}

main() {
  case "${1:-}" in
    install|update|-i|--install|--update)
      install_or_update
      ;;
    uninstall|-u|--uninstall)
      uninstall_units
      ;;
    "")
      interactive_menu
      ;;
    -h|--help|help)
      usage
      ;;
    *)
      echo "未知参数：$1" >&2
      usage
      exit 1
      ;;
  esac
}

main "$@"