<?php declare(strict_types=1);

error_reporting(E_ALL);

require_once(__DIR__.'/../../includes/functions.php');

$config = require_once(__DIR__.'/../../config.php');

if ('GET' !== filter_input(INPUT_SERVER, 'REQUEST_METHOD')) {
    respondAndExit(405, 'Method Not Allowed');
}

$requestedUrl = filter_input(INPUT_GET, 'url', FILTER_VALIDATE_URL);

if (!$requestedUrl || strlen($requestedUrl) > $config['max_url_length']) {
    respondAndExit(400, 'Bad Request');
}

$urls = file($config['path_to_file'], FILE_IGNORE_NEW_LINES);

// Remove requested url from list if present.
$remaingUrls = array_diff($urls, [$requestedUrl]);

// Count will not have changed if requested url doesn't exist in the list.
if (count($remaingUrls) === count($urls)) {
    respondAndExit(404, 'Not Found');
}

if (!file_put_contents($config['path_to_file'], implode("\n", $remaingUrls))) {
    respondAndExit(500, 'Internal Server Error');
}

respondAndExit(308, 'Permanent Redirect', ["Location: $requestedUrl"]);