// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
import {
	invalidOriginException,
	invalidPreferredRedirectUrlException,
	invalidRedirectException,
} from '../../../../errors/constants';

/** @internal */
export function getRedirectUrl(
	redirects: string[],
	preferredRedirectUrl?: string,
): string {
	if (preferredRedirectUrl) {
		const redirectUrl = redirects?.find(
			redirect => redirect === preferredRedirectUrl,
		);
		if (!redirectUrl) {
			throw invalidPreferredRedirectUrlException;
		}

		return redirectUrl;
	} else {
		const redirectUrlFromTheSameOrigin =
			redirects?.find(isSameOriginAndPathName) ??
			redirects?.find(isTheSameDomain);
		const redirectUrlFromDifferentOrigin =
			redirects?.find(isHttps) ?? redirects?.find(isHttp);

		if (redirectUrlFromTheSameOrigin) {
			return redirectUrlFromTheSameOrigin;
		} else if (redirectUrlFromDifferentOrigin) {
			throw invalidOriginException;
		}
		throw invalidRedirectException;
	}
}

// origin + pathname => https://example.com/app
const isSameOriginAndPathName = (redirect: string) =>
	redirect.startsWith(
		String(window.location.origin + (window.location.pathname || '/')),
	);
// domain => outlook.live.com, github.com
const isTheSameDomain = (redirect: string) =>
	redirect.includes(String(window.location.hostname));
const isHttp = (redirect: string) => redirect.startsWith('http://');
const isHttps = (redirect: string) => redirect.startsWith('https://');