import { globalState } from '../../../app/global-state';
import PowerduckState from '../../../app/powerduck-state';

export default class GoogleMapsApiLoader {
	private static _loading: boolean;
	static load(): Promise<boolean> {
		return new Promise((resolve, reject) => {
			if (GoogleMapsApiLoader.apiLoaded()) {
				resolve(true);
				return;
			}

			if (GoogleMapsApiLoader._loading == null) {
				GoogleMapsApiLoader._loading = true;
			} else {
				const looper = function () {
					if (GoogleMapsApiLoader.apiLoaded()) {
						resolve(true);
					} else {
						setTimeout(() => {
							looper();
						}, 50);
					}
				};

				looper();
				return;
			}

			const script = document.createElement('script');
			script.async = true;
			script.defer = true;
			script.onload = function () {
				delete GoogleMapsApiLoader._loading;
				resolve(true);
			};
			script.onerror = function (e) {
				delete GoogleMapsApiLoader._loading;
				reject(e);
			};
			script.src = `https://maps.googleapis.com/maps/api/js?key=${PowerduckState.getGoogleMapsApiKey()}&libraries=places`;
			document.head.appendChild(script);
		});
	}

	private static apiLoaded(): boolean {
		return (globalState.google && globalState.google.maps && globalState.google.maps.places && globalState.google.maps.places.Autocomplete) != null;
	}
}