'use strict';

const crypto = require('crypto');
const axios = require('axios');
const {
  getYydNotificationCenterRuntimeConfig,
} = require('./yydNotificationCenterSettings');

const NOTIFICATION_PATH = '/v1/notifications';
const DEFAULT_TIMEOUT_MS = 15000;

function normalizeText(value, maxLength = 4800) {
  return String(value ?? '').trim().slice(0, maxLength);
}

async function getYydNotificationCenterConfig(options = {}) {
  const config = await getYydNotificationCenterRuntimeConfig(options);
  return {
    baseUrl: normalizeText(config.baseUrl, 1000).replace(/\/+$/, ''),
    projectCode: normalizeText(config.projectCode, 120),
    projectSecret: normalizeText(config.projectSecret, 1000),
    timeoutMs: Math.max(Number(config.timeoutMs) || DEFAULT_TIMEOUT_MS, 3000),
  };
}

function isYydNotificationCenterConfigured(config = {}) {
  return Boolean(config.baseUrl && config.projectCode && config.projectSecret);
}

function buildYydNotificationSignature({
  projectSecret,
  timestamp,
  nonce,
  method = 'POST',
  path = NOTIFICATION_PATH,
  rawBody = '',
}) {
  const bodyHash = crypto.createHash('sha256').update(rawBody, 'utf8').digest('hex');
  const canonical = `${timestamp}\n${nonce}\n${String(method).toUpperCase()}\n${path}\n${bodyHash}`;
  return crypto.createHmac('sha256', projectSecret).update(canonical, 'utf8').digest('hex');
}

function validateNotificationPayload(input = {}) {
  const payload = {
    idempotencyKey: normalizeText(input.idempotencyKey, 160),
    title: normalizeText(input.title, 100),
    content: normalizeText(input.content, 4800),
  };
  const recipientUserId = normalizeText(input.recipientUserId, 160);
  const recipientAlias = normalizeText(input.recipientAlias, 50);
  if (!payload.idempotencyKey || !payload.title || !payload.content) {
    throw new Error('通知缺少幂等键、标题或正文');
  }
  if (Boolean(recipientUserId) === Boolean(recipientAlias)) {
    throw new Error('通知收件人必须且只能提供 recipientUserId 或 recipientAlias');
  }
  if (recipientUserId) payload.recipientUserId = recipientUserId;
  if (recipientAlias) payload.recipientAlias = recipientAlias;
  const actionTitle = normalizeText(input.actionTitle, 20);
  const actionUrl = normalizeText(input.actionUrl, 2000);
  if (actionTitle) payload.actionTitle = actionTitle;
  if (actionUrl) payload.actionUrl = actionUrl;
  return payload;
}

async function sendYydNotification(input = {}, options = {}) {
  const config = options.config || await getYydNotificationCenterConfig();
  if (!isYydNotificationCenterConfigured(config)) {
    const error = new Error('统一通知中心尚未配置');
    error.code = 'YYD_NOTIFICATION_CENTER_NOT_CONFIGURED';
    throw error;
  }

  const payload = validateNotificationPayload(input);
  const rawBody = JSON.stringify(payload);
  const timestamp = String(options.timestamp || Math.trunc(Date.now() / 1000));
  const nonce = String(options.nonce || crypto.randomBytes(16).toString('hex'));
  const signature = buildYydNotificationSignature({
    projectSecret: config.projectSecret,
    timestamp,
    nonce,
    rawBody,
  });

  try {
    const response = await axios.post(`${config.baseUrl}${NOTIFICATION_PATH}`, rawBody, {
      timeout: config.timeoutMs,
      headers: {
        'Content-Type': 'application/json',
        'x-yyd-project-code': config.projectCode,
        'x-yyd-timestamp': timestamp,
        'x-yyd-nonce': nonce,
        'x-yyd-signature': signature,
      },
      transformRequest: [(body) => body],
    });
    return response.data;
  } catch (error) {
    const detail = error?.response?.data;
    const wrapped = new Error(
      detail?.message || detail?.error || error.message || '统一通知中心请求失败'
    );
    wrapped.code = detail?.code || error.code || 'YYD_NOTIFICATION_CENTER_REQUEST_FAILED';
    wrapped.status = Number(error?.response?.status || 0) || 502;
    throw wrapped;
  }
}

module.exports = {
  NOTIFICATION_PATH,
  buildYydNotificationSignature,
  getYydNotificationCenterConfig,
  isYydNotificationCenterConfigured,
  sendYydNotification,
  validateNotificationPayload,
};