const { BASE_URL } = require('./config.js');

const TOKEN_KEY = 'pets_token';
const REFRESH_KEY = 'pets_refresh_token';

function getToken() {
  return wx.getStorageSync(TOKEN_KEY) || '';
}
function setToken(t) {
  wx.setStorageSync(TOKEN_KEY, t);
}
function getRefreshToken() {
  return wx.getStorageSync(REFRESH_KEY) || '';
}
function setRefreshToken(t) {
  if (t) wx.setStorageSync(REFRESH_KEY, t);
}
function clearToken() {
  wx.removeStorageSync(TOKEN_KEY);
  wx.removeStorageSync(REFRESH_KEY);
}

// token 失效时的重新登录钩子，由 store 注册（放在这里避免 request ← api ← store 循环依赖）
let reAuth = null;
function setReAuthHandler(fn) {
  reAuth = fn;
}

const TIMEOUT = 15000;

// access token 只有 2 小时，过期后先拿 refresh token 换新的（用户无感），
// 换不到（刷新令牌也过期/被吊销）才退回 wx.login 重新登录。
// 单飞：并发请求同时 401 时只发一次刷新，否则刷新令牌会被并发轮换掉。
let refreshing = null;

function refreshAccessToken() {
  if (!refreshing) {
    const rt = getRefreshToken();
    refreshing = (rt
      ? request({ url: '/api/auth/refresh', method: 'POST', data: { refresh_token: rt }, noAuthRetry: true })
      : Promise.reject(new Error('没有刷新令牌'))
    ).then((data) => {
      setToken(data.token);
      setRefreshToken(data.refresh_token);
      return data.token;
    });
    const done = () => {
      refreshing = null;
    };
    refreshing.then(done, done);
  }
  return refreshing;
}

// 恢复登录态：先续期，续不了就整套重新登录
function recoverAuth() {
  return refreshAccessToken().catch(() => {
    clearToken();
    if (!reAuth) throw new Error('登录已过期');
    return reAuth();
  });
}

// 统一请求：注入 token，解析 {code,message,data}，成功返回 data，失败 reject(Error)。
// token 失效（40100）时自动续期/重新登录并重试一次，避免 JWT 过期后小程序静默白屏。
function request(options, _retried) {
  const { url, method = 'GET', data, header = {}, noAuthRetry } = options;
  return new Promise((resolve, reject) => {
    const token = getToken();
    wx.request({
      url: BASE_URL + url,
      method,
      data,
      timeout: TIMEOUT,
      header: Object.assign(
        { 'Content-Type': 'application/json' },
        token ? { Authorization: 'Bearer ' + token } : {},
        header,
      ),
      success(res) {
        const body = res.data;
        if (body && typeof body === 'object' && 'code' in body) {
          if (body.code === 0) return resolve(body.data);
          if (body.code === 40100) {
            // 只重试一次，防止刷新/登录接口本身出问题时无限循环
            if (_retried || noAuthRetry) {
              clearToken();
              return reject(new Error(body.message || '登录已过期，请重进小程序'));
            }
            return recoverAuth()
              .then(() => request(options, true).then(resolve, reject))
              .catch(() => {
                clearToken();
                reject(new Error(body.message || '登录已过期，请重进小程序'));
              });
          }
          return reject(new Error(body.message || '请求失败'));
        }
        resolve(body);
      },
      fail(err) {
        const msg = (err && err.errMsg) || '网络错误';
        reject(new Error(/timeout/i.test(msg) ? '网络超时，请稍后重试' : msg));
      },
    });
  });
}

// 文件上传（multipart）；token 过期同样先续期再重试一次
function uploadFile(filePath, _retried) {
  return new Promise((resolve, reject) => {
    const token = getToken();
    wx.uploadFile({
      url: BASE_URL + '/api/upload',
      filePath,
      name: 'file',
      timeout: 60000,
      header: token ? { Authorization: 'Bearer ' + token } : {},
      success(res) {
        try {
          const body = JSON.parse(res.data);
          if (body.code === 0) return resolve(body.data);
          if (body.code === 40100 && !_retried) {
            return recoverAuth()
              .then(() => uploadFile(filePath, true).then(resolve, reject))
              .catch(() => reject(new Error('登录已过期，请重进小程序')));
          }
          reject(new Error(body.message || '上传失败'));
        } catch (e) {
          reject(new Error('上传响应解析失败'));
        }
      },
      fail(err) {
        reject(new Error((err && err.errMsg) || '上传失败'));
      },
    });
  });
}

module.exports = {
  request,
  uploadFile,
  getToken,
  setToken,
  getRefreshToken,
  setRefreshToken,
  clearToken,
  setReAuthHandler,
};