'use strict';

var global = require('global');
var Promise = global.Promise || require('es6-promise').Promise;

// This is the standalone browser build entry point
// Browser implementation of the Algolia Search JavaScript client,
// using XMLHttpRequest, XDomainRequest and JSONP as fallback
module.exports = function createAlgoliasearch(AlgoliaSearch, uaSuffix) {
  var inherits = require('inherits');
  var errors = require('../errors');
  var inlineHeaders = require('./inline-headers');
  var jsonpRequest = require('./jsonp-request');
  var places = require('../places.js');
  uaSuffix = uaSuffix || '';

  if (process.env.NODE_ENV === 'debug') {
    require('debug').enable('algoliasearch*');
  }

  function algoliasearch(applicationID, apiKey, opts) {
    var cloneDeep = require('../clone.js');

    opts = cloneDeep(opts || {});

    opts._ua = opts._ua || algoliasearch.ua;

    return new AlgoliaSearchBrowser(applicationID, apiKey, opts);
  }

  algoliasearch.version = require('../version.js');
  algoliasearch.ua = 'Algolia for vanilla JavaScript ' + uaSuffix + algoliasearch.version;
  algoliasearch.initPlaces = places(algoliasearch);

  // we expose into window no matter how we are used, this will allow
  // us to easily debug any website running algolia
  global.__algolia = {
    debug: require('debug'),
    algoliasearch: algoliasearch
  };

  var support = {
    hasXMLHttpRequest: 'XMLHttpRequest' in global,
    hasXDomainRequest: 'XDomainRequest' in global
  };

  if (support.hasXMLHttpRequest) {
    support.cors = 'withCredentials' in new XMLHttpRequest();
  }

  function AlgoliaSearchBrowser() {
    // call AlgoliaSearch constructor
    AlgoliaSearch.apply(this, arguments);
  }

  inherits(AlgoliaSearchBrowser, AlgoliaSearch);

  AlgoliaSearchBrowser.prototype._request = function request(url, opts) {
    return new Promise(function wrapRequest(resolve, reject) {
      // no cors or XDomainRequest, no request
      if (!support.cors && !support.hasXDomainRequest) {
        // very old browser, not supported
        reject(new errors.Network('CORS not supported'));
        return;
      }

      url = inlineHeaders(url, opts.headers);

      var body = opts.body;
      var req = support.cors ? new XMLHttpRequest() : new XDomainRequest();
      var reqTimeout;
      var timedOut;
      var connected = false;

      reqTimeout = setTimeout(onTimeout, opts.timeouts.connect);
      // we set an empty onprogress listener
      // so that XDomainRequest on IE9 is not aborted
      // refs:
      //  - https://github.com/algolia/algoliasearch-client-js/issues/76
      //  - https://social.msdn.microsoft.com/Forums/ie/en-US/30ef3add-767c-4436-b8a9-f1ca19b4812e/ie9-rtm-xdomainrequest-issued-requests-may-abort-if-all-event-handlers-not-specified?forum=iewebdevelopment
      req.onprogress = onProgress;
      if ('onreadystatechange' in req) req.onreadystatechange = onReadyStateChange;
      req.onload = onLoad;
      req.onerror = onError;

      // do not rely on default XHR async flag, as some analytics code like hotjar
      // breaks it and set it to false by default
      if (req instanceof XMLHttpRequest) {
        req.open(opts.method, url, true);

        // The Analytics API never accepts Auth headers as query string
        // this option exists specifically for them.
        if (opts.forceAuthHeaders) {
          req.setRequestHeader(
            'x-algolia-application-id',
            opts.headers['x-algolia-application-id']
          );
          req.setRequestHeader(
            'x-algolia-api-key',
            opts.headers['x-algolia-api-key']
          );
        }
      } else {
        req.open(opts.method, url);
      }

      // headers are meant to be sent after open
      if (support.cors) {
        if (body) {
          if (opts.method === 'POST') {
            // https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS#Simple_requests
            req.setRequestHeader('content-type', 'application/x-www-form-urlencoded');
          } else {
            req.setRequestHeader('content-type', 'application/json');
          }
        }
        req.setRequestHeader('accept', 'application/json');
      }

      if (body) {
        req.send(body);
      } else {
        req.send();
      }

      // event object not received in IE8, at least
      // but we do not use it, still important to note
      function onLoad(/* event */) {
        // When browser does not supports req.timeout, we can
        // have both a load and timeout event, since handled by a dumb setTimeout
        if (timedOut) {
          return;
        }

        clearTimeout(reqTimeout);

        var out;

        try {
          out = {
            body: JSON.parse(req.responseText),
            responseText: req.responseText,
            statusCode: req.status,
            // XDomainRequest does not have any response headers
            headers: req.getAllResponseHeaders && req.getAllResponseHeaders() || {}
          };
        } catch (e) {
          out = new errors.UnparsableJSON({
            more: req.responseText
          });
        }

        if (out instanceof errors.UnparsableJSON) {
          reject(out);
        } else {
          resolve(out);
        }
      }

      function onError(event) {
        if (timedOut) {
          return;
        }

        clearTimeout(reqTimeout);

        // error event is trigerred both with XDR/XHR on:
        //   - DNS error
        //   - unallowed cross domain request
        reject(
          new errors.Network({
            more: event
          })
        );
      }

      function onTimeout() {
        timedOut = true;
        req.abort();

        reject(new errors.RequestTimeout());
      }

      function onConnect() {
        connected = true;
        clearTimeout(reqTimeout);
        reqTimeout = setTimeout(onTimeout, opts.timeouts.complete);
      }

      function onProgress() {
        if (!connected) onConnect();
      }

      function onReadyStateChange() {
        if (!connected && req.readyState > 1) onConnect();
      }
    });
  };

  AlgoliaSearchBrowser.prototype._request.fallback = function requestFallback(url, opts) {
    url = inlineHeaders(url, opts.headers);

    return new Promise(function wrapJsonpRequest(resolve, reject) {
      jsonpRequest(url, opts, function jsonpRequestDone(err, content) {
        if (err) {
          reject(err);
          return;
        }

        resolve(content);
      });
    });
  };

  AlgoliaSearchBrowser.prototype._promise = {
    reject: function rejectPromise(val) {
      return Promise.reject(val);
    },
    resolve: function resolvePromise(val) {
      return Promise.resolve(val);
    },
    delay: function delayPromise(ms) {
      return new Promise(function resolveOnTimeout(resolve/* , reject*/) {
        setTimeout(resolve, ms);
      });
    },
    all: function all(promises) {
      return Promise.all(promises);
    }
  };

  return algoliasearch;
};