<?php
/**
 * User-initiated requests to the site's own URL.
 *
 * @package AIBlackout
 */

namespace AIBlackout\Audit;

defined( 'ABSPATH' ) || exit;

/**
 * Fetches the site's own front page or a path on it, as a chosen user
 * agent.
 *
 * @since 1.0.0
 */
class Loopback {

	/**
	 * Seconds to wait before giving up.
	 *
	 * @var int
	 */
	const TIMEOUT = 10;

	/**
	 * Performs a request to a path on this site.
	 *
	 * @param string $path       Path relative to the site root, e.g. '/robots.txt'.
	 * @param string $user_agent User-Agent header to send.
	 * @return array|\WP_Error Response array with 'code', 'headers' and 'body', or WP_Error.
	 */
	public function get( string $path = '/', string $user_agent = '' ) {
		$url = home_url( '/' === $path ? '/' : $path );

		/** This filter is documented in wp-includes/class-wp-http-streams.php */
		// phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- Core's filter, for a local request of exactly the kind it governs.
		$sslverify = apply_filters( 'https_local_ssl_verify', false, $url );

		$args = array(
			'timeout'     => self::TIMEOUT,
			'redirection' => 0,
			'sslverify'   => $sslverify,
			'headers'     => array(
				'Cache-Control' => 'no-cache',
			),

			'user-agent'  => '' !== $user_agent ? $user_agent : $this->get_default_user_agent(),
		);

		$response = wp_remote_get( $url, $args );

		if ( is_wp_error( $response ) ) {
			return $response;
		}

		return array(
			'url'     => $url,
			'code'    => (int) wp_remote_retrieve_response_code( $response ),
			'headers' => wp_remote_retrieve_headers( $response ),
			'body'    => (string) wp_remote_retrieve_body( $response ),
		);
	}

	/**
	 * Returns the user agent used when the caller does not specify one.
	 *
	 * @return string User agent.
	 */
	public function get_default_user_agent(): string {
		return 'AI Blackout Self-Test/' . AIBLACKOUT_VERSION . '; ' . home_url( '/' );
	}

	/**
	 * Whether loopback requests are likely to work at all.
	 *
	 * @return bool True when a basic request to the home page succeeds.
	 */
	public function is_available(): bool {
		$response = $this->get( '/' );

		return ! is_wp_error( $response );
	}
}