/**
 * Internal dependencies
 */
import { isStagingSimulated } from './is-staging-simulated';
import type { Settings } from '../../types';

export async function maybeLoadCheckerScript(): Promise< void > {
	const win = window as unknown;
	if ( ! hasSettings( win ) ) {
		return;
	}

	const { debugGui } = win.nabSettings;
	if ( ! debugGui ) {
		return;
	}

	if ( ! win.nabSettings.isStagingSite && ! isStagingSimulated() ) {
		return;
	}

	await new Promise< void >( ( resolve ) => {
		const script = document.createElement( 'script' );
		script.src = debugGui;
		script.async = true;

		const actualResolve = resolve;
		resolve = () => {
			setTimeout( actualResolve, 1000 );
		};

		script.onload = () => resolve();
		script.onerror = () => {
			// eslint-disable-next-line no-console
			console.error( `Failed to load ${ debugGui }` );
			resolve();
		};

		document.head.appendChild( script );
	} );
}

// ========
// INTERNAL
// ========

const hasSettings = (
	win: unknown
): win is { nabSettings: Partial< Settings > } =>
	!! win && 'object' === typeof win && 'nabSettings' in win;