'use strict';

var defaults = require('./defaults');
var utils = require('./utils');
var dispatchRequest = require('./core/dispatchRequest');
var InterceptorManager = require('./core/InterceptorManager');

// Polyfill ES6 Promise if needed
(function () {
  // webpack is being used to set es6-promise to the native Promise
  // for the standalone build. It's necessary to make sure polyfill exists.
  var P = require('es6-promise');
  if (P && typeof P.polyfill === 'function') {
    P.polyfill();
  }
})();

var axios = module.exports = function axios(config) {
  config = utils.merge({
    method: 'get',
    headers: {},
    transformRequest: defaults.transformRequest,
    transformResponse: defaults.transformResponse
  }, config);

  // Don't allow overriding defaults.withCredentials
  config.withCredentials = config.withCredentials || defaults.withCredentials;

  // Hook up interceptors middleware
  var chain = [dispatchRequest, undefined];
  var promise = Promise.resolve(config);

  axios.interceptors.request.forEach(function (interceptor) {
    chain.unshift(interceptor.fulfilled, interceptor.rejected);
  });

  axios.interceptors.response.forEach(function (interceptor) {
    chain.push(interceptor.fulfilled, interceptor.rejected);
  });

  while (chain.length) {
    promise = promise.then(chain.shift(), chain.shift());
  }

  return promise;
};

// Expose defaults
axios.defaults = defaults;

// Expose all/spread
axios.all = function (promises) {
  return Promise.all(promises);
};
axios.spread = require('./helpers/spread');

// Expose interceptors
axios.interceptors = {
  request: new InterceptorManager(),
  response: new InterceptorManager()
};

// Provide aliases for supported request methods
(function () {
  function createShortMethods() {
    utils.forEach(arguments, function (method) {
      axios[method] = function (url, config) {
        return axios(utils.merge(config || {}, {
          method: method,
          url: url
        }));
      };
    });
  }

  function createShortMethodsWithData() {
    utils.forEach(arguments, function (method) {
      axios[method] = function (url, data, config) {
        return axios(utils.merge(config || {}, {
          method: method,
          url: url,
          data: data
        }));
      };
    });
  }

  createShortMethods('delete', 'get', 'head');
  createShortMethodsWithData('post', 'put', 'patch');
})();