/* Copyright (c) 2017 Environmental Systems Research Institute, Inc.
 * Apache-2.0 */
import { loadCss } from './utils/css';
import utils from './utils/index';
import { getCdnUrl } from './utils/url';
var defaultOptions = {};
function createScript(url) {
    var script = document.createElement('script');
    script.type = 'text/javascript';
    script.src = url;
    script.setAttribute('data-esri-loader', 'loading');
    return script;
}
// add a one-time load handler to script
// and optionally add a one time error handler as well
function handleScriptLoad(script, callback, errback) {
    var onScriptError;
    if (errback) {
        // set up an error handler as well
        onScriptError = handleScriptError(script, errback);
    }
    var onScriptLoad = function () {
        // pass the script to the callback
        callback(script);
        // remove this event listener
        script.removeEventListener('load', onScriptLoad, false);
        if (onScriptError) {
            // remove the error listener as well
            script.removeEventListener('error', onScriptError, false);
        }
    };
    script.addEventListener('load', onScriptLoad, false);
}
// add a one-time error handler to the script
function handleScriptError(script, callback) {
    var onScriptError = function (e) {
        // reject the promise and remove this event listener
        callback(e.error || new Error("There was an error attempting to load " + script.src));
        // remove this event listener
        script.removeEventListener('error', onScriptError, false);
    };
    script.addEventListener('error', onScriptError, false);
    return onScriptError;
}
// allow the user to configure default script options rather than passing options to `loadModules` each time
export function setDefaultOptions(options) {
    if (options === void 0) { options = {}; }
    defaultOptions = options;
}
// get the script injected by this library
export function getScript() {
    return document.querySelector('script[data-esri-loader]');
}
// has ArcGIS API been loaded on the page yet?
export function isLoaded() {
    var globalRequire = window['require'];
    // .on() ensures that it's Dojo's AMD loader
    return globalRequire && globalRequire.on;
}
// load the ArcGIS API on the page
export function loadScript(options) {
    if (options === void 0) { options = {}; }
    // we would have liked to use spread like { ...defaultOptions, ...options }
    // but TS would inject a polyfill that would require use to configure rollup w content: 'window'
    // if we have another occasion to use spread, let'd do that and replace this for...in
    var opts = {};
    [defaultOptions, options].forEach(function (obj) {
        for (var prop in obj) {
            if (Object.prototype.hasOwnProperty.call(obj, prop)) {
                opts[prop] = obj[prop];
            }
        }
    });
    // URL to load
    var version = opts.version;
    var url = opts.url || getCdnUrl(version);
    return new utils.Promise(function (resolve, reject) {
        var script = getScript();
        if (script) {
            // the API is already loaded or in the process of loading...
            // NOTE: have to test against scr attribute value, not script.src
            // b/c the latter will return the full url for relative paths
            var src = script.getAttribute('src');
            if (src !== url) {
                // potentially trying to load a different version of the API
                reject(new Error("The ArcGIS API for JavaScript is already loaded (" + src + ")."));
            }
            else {
                if (isLoaded()) {
                    // the script has already successfully loaded
                    resolve(script);
                }
                else {
                    // wait for the script to load and then resolve
                    handleScriptLoad(script, resolve, reject);
                }
            }
        }
        else {
            if (isLoaded()) {
                // the API has been loaded by some other means
                // potentially trying to load a different version of the API
                reject(new Error("The ArcGIS API for JavaScript is already loaded."));
            }
            else {
                // this is the first time attempting to load the API
                var css = opts.css;
                if (css) {
                    var useVersion = css === true;
                    // load the css before loading the script
                    loadCss(useVersion ? version : css, opts.insertCssBefore);
                }
                if (opts.dojoConfig) {
                    // set dojo configuration parameters before loading the script
                    window['dojoConfig'] = opts.dojoConfig;
                }
                // create a script object whose source points to the API
                script = createScript(url);
                // _currentUrl = url;
                // once the script is loaded...
                handleScriptLoad(script, function () {
                    // update the status of the script
                    script.setAttribute('data-esri-loader', 'loaded');
                    // return the script
                    resolve(script);
                }, reject);
                // load the script
                document.body.appendChild(script);
            }
        }
    });
}