#!/usr/bin/env bash

set -euo pipefail

SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"
REPO_ROOT="$(cd -- "${SCRIPT_DIR}/../.." >/dev/null 2>&1 && pwd)"

TEMPLATE_PATH="${GENARRATIVE_PINGORA_REALPATH_CANARY_TEMPLATE_PATH:-${REPO_ROOT}/deploy/nginx/snippets/genarrative-pingora-realpath-canary.conf}"
TARGET_PATH="${GENARRATIVE_PINGORA_REALPATH_CANARY_TARGET_PATH:-/etc/nginx/conf.d/zz-genarrative-pingora-realpath-canary.conf}"
PROBE_TOKEN="${GENARRATIVE_PINGORA_REALPATH_CANARY_PROBE_TOKEN:-${GENARRATIVE_PINGORA_GATEWAY_PROBE_TOKEN:-}}"
BASE_URL="${GENARRATIVE_PINGORA_REALPATH_CANARY_BASE_URL:-http://127.0.0.1:18083}"
HOST_HEADER="${GENARRATIVE_PINGORA_REALPATH_CANARY_HOST:-}"
NGINX_BINARY="${GENARRATIVE_NGINX_BINARY:-nginx}"
NGINX_SERVICE="${GENARRATIVE_NGINX_SERVICE:-nginx.service}"
SYSTEMCTL_BINARY="${GENARRATIVE_SYSTEMCTL_BINARY:-systemctl}"
LIVE_SCRIPT="${GENARRATIVE_PINGORA_REALPATH_CANARY_LIVE_SCRIPT:-${REPO_ROOT}/scripts/check-pingora-canary-live.mjs}"
APPLY="false"
RUN_LIVE="true"
STATUS_AFTER="true"

PLACEHOLDER="__GENARRATIVE_PINGORA_PROBE_TOKEN__"

usage() {
  cat <<'EOF'
用法:
  scripts/deploy/pingora-realpath-canary-enable.sh [--apply] [--probe-token <token>] [--host <host>] [--base-url <url>] [--template-path <path>] [--target-path <path>] [--nginx-binary <path|name>] [--nginx-service <unit>] [--systemctl-binary <path|name>] [--live-script <path>] [--skip-live] [--no-status]

说明:
  启用 Nginx -> Pingora 真实路径 canary。脚本会把随包
  deploy/nginx/snippets/genarrative-pingora-realpath-canary.conf 渲染到
  /etc/nginx/conf.d/zz-genarrative-pingora-realpath-canary.conf。

默认是 dry-run，只打印计划；必须显式传 --apply 才会写 Nginx 配置。
--apply 会替换 probe token、写入目标文件、执行 nginx -t、reload nginx，
然后运行 realpath canary live smoke。任一阶段失败都会恢复写入前的目标文件状态。
EOF
}

while [[ $# -gt 0 ]]; do
  case "$1" in
    -h|--help)
      usage
      exit 0
      ;;
    --apply)
      APPLY="true"
      shift
      ;;
    --probe-token)
      PROBE_TOKEN="${2:-}"
      if [[ -z "${PROBE_TOKEN}" ]]; then
        echo "[pingora-realpath-canary-enable] --probe-token 缺少参数" >&2
        exit 1
      fi
      shift 2
      ;;
    --host)
      HOST_HEADER="${2:-}"
      if [[ -z "${HOST_HEADER}" ]]; then
        echo "[pingora-realpath-canary-enable] --host 缺少参数" >&2
        exit 1
      fi
      shift 2
      ;;
    --base-url)
      BASE_URL="${2:-}"
      if [[ -z "${BASE_URL}" ]]; then
        echo "[pingora-realpath-canary-enable] --base-url 缺少参数" >&2
        exit 1
      fi
      shift 2
      ;;
    --template-path)
      TEMPLATE_PATH="${2:-}"
      if [[ -z "${TEMPLATE_PATH}" ]]; then
        echo "[pingora-realpath-canary-enable] --template-path 缺少参数" >&2
        exit 1
      fi
      shift 2
      ;;
    --target-path)
      TARGET_PATH="${2:-}"
      if [[ -z "${TARGET_PATH}" ]]; then
        echo "[pingora-realpath-canary-enable] --target-path 缺少参数" >&2
        exit 1
      fi
      shift 2
      ;;
    --nginx-binary)
      NGINX_BINARY="${2:-}"
      if [[ -z "${NGINX_BINARY}" ]]; then
        echo "[pingora-realpath-canary-enable] --nginx-binary 缺少参数" >&2
        exit 1
      fi
      shift 2
      ;;
    --nginx-service)
      NGINX_SERVICE="${2:-}"
      if [[ -z "${NGINX_SERVICE}" ]]; then
        echo "[pingora-realpath-canary-enable] --nginx-service 缺少参数" >&2
        exit 1
      fi
      shift 2
      ;;
    --systemctl-binary)
      SYSTEMCTL_BINARY="${2:-}"
      if [[ -z "${SYSTEMCTL_BINARY}" ]]; then
        echo "[pingora-realpath-canary-enable] --systemctl-binary 缺少参数" >&2
        exit 1
      fi
      shift 2
      ;;
    --live-script)
      LIVE_SCRIPT="${2:-}"
      if [[ -z "${LIVE_SCRIPT}" ]]; then
        echo "[pingora-realpath-canary-enable] --live-script 缺少参数" >&2
        exit 1
      fi
      shift 2
      ;;
    --skip-live)
      RUN_LIVE="false"
      shift
      ;;
    --no-status)
      STATUS_AFTER="false"
      shift
      ;;
    *)
      echo "[pingora-realpath-canary-enable] 未知参数: $1" >&2
      usage >&2
      exit 1
      ;;
  esac
done

reject_control_characters() {
  local label="$1"
  local value="$2"
  if [[ "${value}" == *$'\n'* || "${value}" == *$'\r'* ]]; then
    echo "[pingora-realpath-canary-enable] ${label} 不能包含换行或 NUL 字符。" >&2
    exit 1
  fi
}

is_filesystem_root_path() {
  local value="$1"
  local without_slashes="${value//\//}"
  [[ -n "${value}" && -z "${without_slashes}" ]]
}

require_absolute_path() {
  local label="$1"
  local value="$2"
  if [[ "${value}" != /* ]]; then
    echo "[pingora-realpath-canary-enable] ${label} 必须是绝对路径。" >&2
    exit 1
  fi
  if is_filesystem_root_path "${value}"; then
    echo "[pingora-realpath-canary-enable] ${label} 不能是文件系统根目录。" >&2
    exit 1
  fi
}

validate_command_or_absolute_path() {
  local label="$1"
  local value="$2"
  if [[ "${value}" == */* ]]; then
    require_absolute_path "${label}" "${value}"
  fi
}

validate_host() {
  local label="$1"
  local value="$2"
  if [[ -z "${value}" ]]; then
    echo "[pingora-realpath-canary-enable] ${label} 必须提供。" >&2
    exit 1
  fi
  if [[ "${value}" == http://* || "${value}" == https://* || "${value}" == */* || "${value}" == *\?* || "${value}" =~ [[:space:]] ]]; then
    echo "[pingora-realpath-canary-enable] ${label} 必须是 Host 或 host:port，不能是 URL、路径、查询或包含空白。" >&2
    exit 1
  fi
}

validate_base_url() {
  if [[ "${BASE_URL}" != http://* && "${BASE_URL}" != https://* ]]; then
    echo "[pingora-realpath-canary-enable] --base-url 必须以 http:// 或 https:// 开头。" >&2
    exit 1
  fi
}

validate_probe_token() {
  if [[ "${APPLY}" != "true" ]]; then
    return
  fi
  if [[ -z "${PROBE_TOKEN}" ]]; then
    echo "[pingora-realpath-canary-enable] --apply 必须提供 --probe-token 或 GENARRATIVE_PINGORA_REALPATH_CANARY_PROBE_TOKEN。" >&2
    exit 1
  fi
  if [[ "${PROBE_TOKEN}" == "${PLACEHOLDER}" || "${#PROBE_TOKEN}" -lt 8 ]]; then
    echo "[pingora-realpath-canary-enable] probe token 不能是占位值或过短。" >&2
    exit 1
  fi
}

escape_nginx_double_quoted() {
  local value="$1"
  value="${value//\\/\\\\}"
  value="${value//\"/\\\"}"
  printf '%s' "${value}"
}

render_template_to() {
  local output_path="$1"
  local content escaped_token
  content="$(<"${TEMPLATE_PATH}")"
  escaped_token="$(escape_nginx_double_quoted "${PROBE_TOKEN}")"
  printf '%s' "${content//${PLACEHOLDER}/${escaped_token}}" >"${output_path}"
}

print_command() {
  printf '+'
  for arg in "$@"; do
    printf ' %q' "${arg}"
  done
  printf '\n'
}

run_or_print() {
  if [[ "${APPLY}" == "true" ]]; then
    "$@"
  else
    print_command "$@"
  fi
}

restore_previous() {
  local backup_path="$1"
  local had_target="$2"
  if [[ "${had_target}" == "true" ]]; then
    cp -p -- "${backup_path}" "${TARGET_PATH}"
  else
    rm -f -- "${TARGET_PATH}"
  fi
}

rollback_after_failure() {
  local backup_path="$1"
  local had_target="$2"
  local reason="$3"
  echo "[pingora-realpath-canary-enable] ${reason}，恢复写入前配置。" >&2
  restore_previous "${backup_path}" "${had_target}"
  "${NGINX_BINARY}" -t >/dev/null 2>&1 || true
  "${SYSTEMCTL_BINARY}" reload "${NGINX_SERVICE}" >/dev/null 2>&1 || true
}

reject_control_characters "--template-path" "${TEMPLATE_PATH}"
reject_control_characters "--target-path" "${TARGET_PATH}"
reject_control_characters "--probe-token" "${PROBE_TOKEN}"
reject_control_characters "--base-url" "${BASE_URL}"
reject_control_characters "--host" "${HOST_HEADER}"
reject_control_characters "--nginx-binary" "${NGINX_BINARY}"
reject_control_characters "--nginx-service" "${NGINX_SERVICE}"
reject_control_characters "--systemctl-binary" "${SYSTEMCTL_BINARY}"
reject_control_characters "--live-script" "${LIVE_SCRIPT}"

require_absolute_path "--template-path" "${TEMPLATE_PATH}"
require_absolute_path "--target-path" "${TARGET_PATH}"
if [[ "${RUN_LIVE}" == "true" ]]; then
  require_absolute_path "--live-script" "${LIVE_SCRIPT}"
fi
validate_command_or_absolute_path "--nginx-binary" "${NGINX_BINARY}"
validate_command_or_absolute_path "--systemctl-binary" "${SYSTEMCTL_BINARY}"
validate_host "--host" "${HOST_HEADER}"
validate_base_url
validate_probe_token

if [[ ! -f "${TEMPLATE_PATH}" ]]; then
  echo "[pingora-realpath-canary-enable] 未找到 realpath canary 模板: ${TEMPLATE_PATH}" >&2
  exit 1
fi
if [[ "${RUN_LIVE}" == "true" && ! -f "${LIVE_SCRIPT}" ]]; then
  echo "[pingora-realpath-canary-enable] 未找到 realpath canary live smoke 脚本: ${LIVE_SCRIPT}" >&2
  exit 1
fi

TARGET_DIR="$(dirname -- "${TARGET_PATH}")"
if [[ "${APPLY}" == "true" ]]; then
  if [[ ! -d "${TARGET_DIR}" ]]; then
    echo "[pingora-realpath-canary-enable] 目标目录不存在: ${TARGET_DIR}" >&2
    exit 1
  fi
  if [[ -L "${TARGET_DIR}" || -L "${TARGET_PATH}" ]]; then
    echo "[pingora-realpath-canary-enable] 目标目录或目标文件不能是符号链接。" >&2
    exit 1
  fi
fi

if [[ "${APPLY}" != "true" ]]; then
  echo "[pingora-realpath-canary-enable] dry-run：将渲染 realpath canary 到 ${TARGET_PATH}，probe token 输出已隐藏。"
  print_command install -m 0644 "<rendered-realpath-canary>" "${TARGET_PATH}"
  run_or_print "${NGINX_BINARY}" -t
  run_or_print "${SYSTEMCTL_BINARY}" reload "${NGINX_SERVICE}"
  if [[ "${RUN_LIVE}" == "true" ]]; then
    run_or_print node -- "${LIVE_SCRIPT}" --realpath --base-url "${BASE_URL}" --host "${HOST_HEADER}"
  fi
  exit 0
fi

tmp_path="$(mktemp "${TARGET_DIR}/.genarrative-pingora-realpath-canary.XXXXXX")"
backup_path="$(mktemp "${TARGET_DIR}/.genarrative-pingora-realpath-canary.backup.XXXXXX")"
had_target="false"
cleanup_paths=("${tmp_path}" "${backup_path}")
trap 'rm -f -- "${cleanup_paths[@]}"' EXIT

render_template_to "${tmp_path}"
chmod 0644 "${tmp_path}"

if [[ -e "${TARGET_PATH}" ]]; then
  if [[ ! -f "${TARGET_PATH}" ]]; then
    echo "[pingora-realpath-canary-enable] 目标已存在但不是普通文件: ${TARGET_PATH}" >&2
    exit 1
  fi
  cp -p -- "${TARGET_PATH}" "${backup_path}"
  had_target="true"
fi

install -m 0644 "${tmp_path}" "${TARGET_PATH}"
if ! "${NGINX_BINARY}" -t; then
  rollback_after_failure "${backup_path}" "${had_target}" "nginx -t 失败"
  exit 1
fi
if ! "${SYSTEMCTL_BINARY}" reload "${NGINX_SERVICE}"; then
  rollback_after_failure "${backup_path}" "${had_target}" "reload ${NGINX_SERVICE} 失败"
  exit 1
fi

if [[ "${RUN_LIVE}" == "true" ]]; then
  if ! node -- "${LIVE_SCRIPT}" --realpath --base-url "${BASE_URL}" --host "${HOST_HEADER}"; then
    rollback_after_failure "${backup_path}" "${had_target}" "realpath canary live smoke 失败"
    exit 1
  fi
fi

if [[ "${STATUS_AFTER}" == "true" ]]; then
  "${SYSTEMCTL_BINARY}" is-active "${NGINX_SERVICE}"
fi

echo "[pingora-realpath-canary-enable] 已启用 realpath canary: ${TARGET_PATH}"