<?php

declare(strict_types=1);

namespace LinkCheckup\Features\Fixes;

use LinkCheckup\Shared\Database\QueryRunner;
use LinkCheckup\Shared\Database\Tables;
use LinkCheckup\Shared\Links\Outcome;
use LinkCheckup\Shared\Urls\AddressRules;

use function array_merge;
use function is_string;
use function md5;

final class RedirectServer {

	private const PERMANENT_REDIRECT   = 301;
	private const ALLOWED_HOSTS_FILTER = 'allowed_redirect_hosts';

	public function __construct(
		private QueryRunner $query_runner,
		private Tables $tables,
		private AddressRules $address_rules
	) {
	}

	public function serve(): void {
		if ( ! isset( $_SERVER['REQUEST_URI'] )
			|| ! is_string( $_SERVER['REQUEST_URI'] ) ) {
			return;
		}

		$requested = $this->address_rules->normalize(
			esc_url_raw( wp_unslash( $_SERVER['REQUEST_URI'] ) )
		);

		if ( null === $requested ) {
			return;
		}

		$redirect_to = $this->query_runner->value(
			$this->query_runner->prepare(
				'SELECT redirect_to FROM ' . $this->tables->links()
					. ' WHERE url_hash = %s AND outcome = %s'
					. ' AND redirect_to IS NOT NULL AND redirect_to <> url',
				md5( $requested ),
				Outcome::Resolved->value
			)
		);

		if ( null === $redirect_to ) {
			return;
		}

		$target_host = $this->address_rules->host_of( $redirect_to );

		add_filter(
			self::ALLOWED_HOSTS_FILTER,
			fn( array $allowed_hosts ): array => array_merge(
				$allowed_hosts,
				array( $target_host )
			)
		);
		wp_safe_redirect( $redirect_to, self::PERMANENT_REDIRECT );
		wp_die(
			'',
			'',
			array( 'response' => absint( self::PERMANENT_REDIRECT ) )
		);
	}
}