#!/usr/bin/env bash

set -euo pipefail

MAINTENANCE_FILE="${GENARRATIVE_MAINTENANCE_FILE:-/var/lib/genarrative/maintenance/enabled}"
MAINTENANCE_PAGE_FILE="${GENARRATIVE_MAINTENANCE_PAGE_FILE:-/var/lib/genarrative/maintenance/page.html}"
PAGE_SOURCE=""
REASON_PARTS=()

while [[ $# -gt 0 ]]; do
  case "$1" in
    --page-file)
      PAGE_SOURCE="${2:?缺少 --page-file 的值}"
      shift 2
      ;;
    -h|--help)
      echo "用法: $0 [--page-file <临时公告 HTML>] [维护原因]"
      exit 0
      ;;
    --*)
      echo "[maintenance] 未知参数: $1" >&2
      exit 1
      ;;
    *)
      REASON_PARTS+=("$1")
      shift
      ;;
  esac
done

REASON="${REASON_PARTS[*]:-manual}"

if [[ -n "${PAGE_SOURCE}" && ( ! -f "${PAGE_SOURCE}" || ! -s "${PAGE_SOURCE}" ) ]]; then
  echo "[maintenance] 临时公告页不存在或为空: ${PAGE_SOURCE}" >&2
  exit 1
fi

mkdir -p "$(dirname "${MAINTENANCE_FILE}")" "$(dirname "${MAINTENANCE_PAGE_FILE}")"

if [[ -n "${PAGE_SOURCE}" ]]; then
  page_temp="$(mktemp "${MAINTENANCE_PAGE_FILE}.tmp.XXXXXX")"
  trap 'rm -f "${page_temp:-}" "${marker_temp:-}"' EXIT
  install -m 0644 -- "${PAGE_SOURCE}" "${page_temp}"
  mv -fT -- "${page_temp}" "${MAINTENANCE_PAGE_FILE}"
  page_temp=""
  echo "[maintenance] 已安装本次运行态公告页: ${MAINTENANCE_PAGE_FILE}"
elif [[ ! -f "${MAINTENANCE_FILE}" && ( -e "${MAINTENANCE_PAGE_FILE}" || -L "${MAINTENANCE_PAGE_FILE}" ) ]]; then
  rm -f -- "${MAINTENANCE_PAGE_FILE}"
fi

marker_temp="$(mktemp "${MAINTENANCE_FILE}.tmp.XXXXXX")"
{
  printf "enabled_at=%s\n" "$(date -u +%Y-%m-%dT%H:%M:%SZ)"
  printf "reason=%s\n" "${REASON}"
} >"${marker_temp}"

chmod 0644 "${marker_temp}"
mv -fT -- "${marker_temp}" "${MAINTENANCE_FILE}"
marker_temp=""
trap - EXIT
echo "[maintenance] 已进入维护模式: ${MAINTENANCE_FILE}"