const { getBaseUrl } = require('./constants');

function withAuthHeader(needAuth, header) {
  const app = getApp();
  if (!needAuth) return header;
  const token = app && app.globalData ? app.globalData.accessToken : '';
  if (typeof token === 'string' && token.length > 0) {
    header = header || {};
    header.Authorization = `Bearer ${token}`;
  }
  return header;
}

function normalizeError(payload) {
  if (!payload) return new Error('Empty response');
  // RESTfulResult usually has `errors` and/or `message`
  if (typeof payload === 'string') return new Error(payload);
  if (payload.errors) return new Error(payload.errors.toString());
  if (payload.message) return new Error(payload.message);
  return new Error(JSON.stringify(payload));
}

function request({
  path,
  method = 'GET',
  data = {},
  needAuth = false,
  contentType = 'application/json'
}) {
  const baseUrl = getBaseUrl();
  const url = `${baseUrl}${path}`;

  const header = withAuthHeader(needAuth, {
    'content-type': contentType
  });

  return new Promise((resolve, reject) => {
    wx.request({
      url,
      method: method.toUpperCase(),
      data: method.toUpperCase() === 'GET' ? data : data,
      header: header,
      success(res) {
        const payload = res && res.data !== undefined ? res.data : null;

        // Most backend uses RESTfulResult wrapper
        if (payload && typeof payload === 'object' && typeof payload.succeeded === 'boolean') {
          if (payload.succeeded) resolve(payload.data);
          else reject(normalizeError(payload));
          return;
        }

        // Fallback
        resolve(payload);
      },
      fail(err) {
        reject(err);
      }
    });
  });
}

module.exports = {
  request
};