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

// Polyfill ES6 Promise if needed
require('es6-promise').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());
  }

  // Provide alias for success
  promise.success = function success(fn) {
    deprecatedMethod('success', 'then', 'https://github.com/mzabriskie/axios/blob/master/README.md#response-api');

    promise.then(function(response) {
      fn(response.data, response.status, response.headers, response.config);
    });
    return promise;
  };

  // Provide alias for error
  promise.error = function error(fn) {
    deprecatedMethod('error', 'catch', 'https://github.com/mzabriskie/axios/blob/master/README.md#response-api');

    promise.then(null, function(response) {
      fn(response.data, response.status, response.headers, response.config);
    });
    return promise;
  };

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

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
      }));
    };
  });
}