<?php

function validUrl1(string $url) {
    $parsedUri = parse_url($url);

    return $parsedUri && isset($parsedUri['scheme']);
}

function validUrl2(string $url) {
    return preg_match('/^[a-zA-Z][a-zA-Z0-9+.-]*:(?:\/\/[^\/\s?#]+(?:\/[^\s?#]*)?|\/[^\s?#]*)?(?:\?[^\s#]*)?(?:#[^\s]*)?$/', $url) === 1;
}

echo 'Results with filter_var()'.PHP_EOL;
var_dump(filter_var('http://google.com', \FILTER_VALIDATE_URL));
var_dump(filter_var('http://google.com/test', \FILTER_VALIDATE_URL));
var_dump(filter_var('http://google.com/test?query=test', \FILTER_VALIDATE_URL));
var_dump(filter_var('invalid', \FILTER_VALIDATE_URL));
var_dump(filter_var('http://invalid url', \FILTER_VALIDATE_URL));
var_dump(filter_var('io.curity.client:/callback', \FILTER_VALIDATE_URL)); // false -> should return url
var_dump(filter_var('com.my.app:/', \FILTER_VALIDATE_URL)); // false -> should return url
var_dump(filter_var('myapp://callback#token=123', \FILTER_VALIDATE_URL));

echo PHP_EOL;

echo 'Results with parse_url()'.PHP_EOL;
var_dump(validUrl1('http://google.com'));
var_dump(validUrl1('http://google.com/test'));
var_dump(validUrl1('http://google.com/test?query=test'));
var_dump(validUrl1('invalid'));
var_dump(validUrl1('http://invalid url')); // true -> should be false because of whitespace
var_dump(validUrl1('io.curity.client:/callback'));
var_dump(validUrl1('com.my.app:/'));
var_dump(validUrl1('myapp://callback#token=123'));

echo PHP_EOL;

echo 'Results with preg_match()'.PHP_EOL;
var_dump(validUrl2('http://google.com'));
var_dump(validUrl2('http://google.com/test'));
var_dump(validUrl2('http://google.com/test?query=test'));
var_dump(validUrl2('invalid'));
var_dump(validUrl2('http://invalid url'));
var_dump(validUrl2('io.curity.client:/callback'));
var_dump(validUrl2('com.my.app:/'));
var_dump(validUrl2('myapp://callback#token=123'));