/* {http} v{version} | MIT | https:// */
(function(root, factory) {
    /* eslint-disable */
    if (typeof define === 'function' && define.amd) {
        // AMD
        define(['http'], factory);
    } else if(typeof module === 'object' && module.exports) {
        // CommonJS / NodeJS
        module.exports = factory();
    } else {
        // Global
        root.http = factory();
    }

}(this, function() {
    'use strict';

    return function http(params, callback) {
        // Any variable used more than once is var'd here because
        // minification will munge the variables whereas it can't munge
        // the object access.
        var headers = params.headers || {}
            , body = params.body
            , method = params.method || (body ? 'POST' : 'GET')
            , called = false;

        var req = getRequest(params.cors);

        var reqfields = [
            'responseType', 'withCredentials', 'timeout', 'onprogress'
        ];

        function getRequest(cors) {
            if (window.XMLHttpRequest) {
                return new XMLHttpRequest;
            }
        }

        function setDefault(obj, key, value) {
            obj[key] = obj[key] || value;
        }

        function cb(statusCode, responseText) {
            return function () {
                if (!called) {
                    callback(req.status === undefined ? statusCode : req.status,
                        req.status === 0 ? 'Error' : (req.response || req.responseText || responseText),
                        req);
                    called = true;
                }
            };
        }

        req.open(method, params.url, true);

        var success = req.onload = cb(200);
        req.onreadystatechange = function () {
            if (req.readyState === 4) success();
        };

        req.onerror = cb(null, 'Error');
        req.ontimeout = cb(null, 'Timeout');
        req.onabort = cb(null, 'Abort');

        if (body) {
            setDefault(headers, 'X-Requested-With', 'XMLHttpRequest');

            if (!window.FormData || !(body instanceof window.FormData)) {
                setDefault(headers, 'Content-Type', 'application/x-www-form-urlencoded');
            }
        }

        for (var i = 0, len = reqfields.length, field; i < len; i++) {
            field = reqfields[i];
            if (params[field] !== undefined) {
                req[field] = params[field];
            }
        }

        for (let field in headers) {
            req.setRequestHeader(field, headers[field]);
        }

        req.send(body);

        return req;
    }
}));