<?php
defined( 'ABSPATH' ) || exit;

/**
 * "Is the cache really serving, and if not, why?" Five rows (setup, page cache, web server, edge,
 * features), each ok / warn / bad / n/a with a reason code. Every code has an owner (the site owner,
 * the host, or us), one sentence, and steps that can be pasted as they are: a support ticket that is
 * solved in one round instead of "ask your host about mod_rewrite".
 */
class ZeroConfig_Doctor {

	const ROWS = array( 'setup', 'cache', 'server', 'edge', 'features' );

	/** Run the checks now (two requests to the home page) and store the result. */
	public static function run() {
		$o    = ZeroConfig_Options::all();
		$rows = array();
		if ( empty( $o['engine'] ) ) {
			return self::save( array( 'off' => true ) );
		}
		$home = home_url( '/' );

		// 1. Setup: files, constants, background tasks.
		$setup = array();
		if ( defined( 'ZEROCONFIG_DISABLE' ) && ZEROCONFIG_DISABLE ) {
			$setup[] = array( 'bad', 'disabled_constant' );
		}
		$dropin = WP_CONTENT_DIR . '/advanced-cache.php';
		if ( is_file( $dropin ) && false === strpos( (string) file_get_contents( WP_CONTENT_DIR . '/advanced-cache.php' ), ZeroConfig_Page_Cache::DROPIN_MARKER ) ) {
			$setup[] = array( 'warn', 'dropin_foreign' );
		} elseif ( ! is_file( $dropin ) ) {
			$setup[] = array( 'warn', is_writable( WP_CONTENT_DIR ) ? 'dropin_missing' : 'dropin_write' ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_is_writable -- a diagnostic, nothing is written
		} elseif ( ! defined( 'WP_CACHE' ) || ! WP_CACHE ) {
			$setup[] = array( 'warn', 'wpconfig_readonly' );
		}
		$next = wp_next_scheduled( ZeroConfig_Cron::HEARTBEAT );
		if ( $next && $next < time() - 2 * HOUR_IN_SECONDS ) {
			$setup[] = array( 'warn', 'cron_stalled' );
		}
		$rows['setup'] = self::worst( $setup );

		// 2. Page cache: ask twice as a visitor; the second answer must come from the cache.
		// The whole check fits in about 10 s: people press "Check again" when the site is slow, and a
		// check that runs into PHP's time limit gives them an error page instead of an answer.
		$t0     = microtime( true );
		$left   = function () use ( $t0 ) {
			return 10 - ( microtime( true ) - $t0 );
		};
		$first  = ZeroConfig_Probe::fetch( $home, 'd', false, 6 );
		$second = 'error' === $first['layer'] || $left() < 1.5 ? $first : ZeroConfig_Probe::fetch( $home, 'd', false, (int) min( 4, floor( $left() ) ) );
		// The page timed out while this check runs inside a PHP request (the admin button, cron). If a
		// static file from the same server comes back at once, the web server is fine and PHP was busy:
		// on a server with one PHP worker, busy with this very check. That is a host setting, not a slow
		// page. (From WP-CLI the check runs outside PHP's workers, so a timeout there means slow.)
		$single = false;
		if ( apply_filters( 'zeroconfig_doctor_in_request', PHP_SAPI !== 'cli' ) && ZeroConfig_Probe::timed_out( $first ) && 'loopback' === $first['via'] && $left() >= 1.5 ) {
			$static = ZeroConfig_Probe::fetch_static( includes_url( 'css/dashicons.min.css' ), (int) min( 2, floor( $left() ) ) );
			$single = 200 === $static['code'];
		}
		$stored = is_file( ZeroConfig_Probe::file_for( $home, 'd' ) );
		$cache  = array();
		$seen   = isset( $_SERVER['HTTP_HOST'] ) ? strtolower( sanitize_text_field( wp_unslash( $_SERVER['HTTP_HOST'] ) ) ) : '';
		if ( '' !== $seen && is_admin() && ! self::same_host( $seen ) ) {
			$cache[] = array( 'warn', 'host_mismatch', array( $seen, (string) wp_parse_url( $home, PHP_URL_HOST ) ) );
		}
		$layer  = $second['layer'];
		$public = 'public' === $second['via'];
		if ( $single ) {
			$cache[] = array( 'warn', 'single_worker', array( (string) round( $first['ms'] / 1000 ) ) );
		} elseif ( ZeroConfig_Probe::timed_out( $second ) ) {
			$cache[] = array( 'warn', 'slow_answer', array( (string) round( $second['ms'] / 1000 ) ) ); // no verdict, and that is the finding
		} elseif ( 'error' === $layer ) {
			$cache[] = array( 'warn', 'loopback_blocked', array( $second['error'] ) );
		} elseif ( 0 === strpos( $layer, 'http_3' ) ) {
			$cache[] = array( 'bad', 'redirected', array( (string) $second['code'] ) );
		} elseif ( 0 === strpos( $layer, 'http_' ) ) {
			$cache[] = array( 'bad', 'http_error', array( (string) $second['code'] ) );
		} elseif ( in_array( $layer, array( 'foreign', 'unknown' ), true ) && $public ) {
			// Reached over the public address and a CDN answered: the server itself was never asked.
			// Unknown, not broken.
			$cache[] = array( 'na', 'edge_answered', array( implode( ', ', $second['foreign'] ) ) );
		} elseif ( 'foreign' === $layer ) {
			$cache[] = array( 'warn', 'foreign_page_cache', array( implode( ', ', $second['foreign'] ) ) );
		} elseif ( 'unknown' === $layer ) {
			$cache[] = array( 'warn', 'not_ours' );
		} elseif ( 'miss' === $layer ) {
			$cache[] = array( 'bad', $stored ? 'not_served' : 'not_stored' );
		}
		// The warm-up never falls back to the public address; say so when it had to stop for that reason.
		$reached_itself = 'loopback' === $first['via'] && 'error' !== $first['layer'];
		if ( ! $reached_itself && 'loopback_blocked' === ( ZeroConfig_Probe::health()['warm']['stop'] ?? '' ) ) {
			$cache[] = array( 'warn', 'warm_skipped' );
		}
		$rows['cache'] = self::worst( $cache );

		// 3. Web server: on Apache/LiteSpeed the fastest path skips PHP entirely. Decided from two signals,
		// never from our header alone: the ping rule (do the .htaccess rules run at all) and who answered.
		$server = strtolower( self::server_software() );
		if ( '' === $server ) {
			$server = strtolower( (string) ( $second['server'] ?? '' ) ); // from the command line: what the server calls itself
		}
		$srv  = array();
		$ping = '';
		if ( '' !== trim( (string) wp_parse_url( $home, PHP_URL_PATH ), '/' ) ) {
			// Site at example.com/blog/: our rules are written for sites at the root, so they are not
			// installed. Our limit, not the host's: never send this owner to their host.
			$srv[] = array( 'na', 'subdir_site', array( (string) wp_parse_url( $home, PHP_URL_PATH ) ) );
		} elseif ( '' === $server ) {
			$srv[] = array( 'na', 'server_unknown' );
		} elseif ( false === strpos( $server, 'apache' ) && false === strpos( $server, 'litespeed' ) ) {
			$srv[] = array( 'na', 'nginx' );
		} elseif ( ! ZeroConfig_Htaccess::installed() ) {
			$srv[] = array( 'warn', 'htaccess_not_written' );
		} elseif ( 'error' === $first['layer'] || $single || $left() < 1.5 ) {
			$srv[] = array( 'na', 'server_unknown' ); // no time or no answer left to ping with
		} else {
			$ping    = ZeroConfig_Probe::ping( (int) min( 3, floor( $left() ) ) );
			$verdict = self::apache_verdict( $ping, $layer, (string) ( $second['browser'] ?? '' ) );
			if ( $verdict ) {
				$srv[] = $verdict;
			}
		}
		$perma = (string) get_option( 'permalink_structure' );
		if ( '' !== $perma && '/' !== substr( $perma, -1 ) ) {
			$srv[] = array( 'warn', 'permalink_no_slash' );
		}
		$rows['server'] = self::worst( $srv );

		// 4. Edge: images, CSS and JS from the edge.
		$edge = array();
		if ( ! ZeroConfig_Options::is_connected() ) {
			$edge[] = array( 'warn', 'not_connected' );
		} elseif ( ! empty( $o['cdn_paused'] ) ) {
			$edge[] = array( 'warn', 'quota_paused' );
		} elseif ( 'down' === get_transient( 'zeroconfig_edge' ) ) { // the last state; asking now could flip it and purge the cache
			$edge[] = array( 'bad', 'edge_unreachable', array( (string) wp_parse_url( ZEROCONFIG_API, PHP_URL_HOST ) ) );
		}
		$rows['edge'] = self::worst( $edge );

		// 5. Features the Safety Check switched off.
		$off = array_keys( array_filter( (array) $o['disabled'] ) );
		$rows['features'] = self::worst( $off ? array( array( 'warn', 'safemode_off', array( implode( ', ', $off ) ) ) ) : array() );

		return self::save(
			array(
				'rows'   => $rows,
				'probe'  => array( 'first' => $first, 'second' => $second, 'stored' => $stored, 'ping' => $ping ),
				'server' => $server,
			)
		);
	}

	/**
	 * The web server row on Apache/LiteSpeed with our rules installed, from three observations: the ping
	 * ('ok' | 'no' | 'unknown'), the layer that answered the second request, and whether that answer told
	 * the browser anything about caching ('told' | 'none'). Null when the shortcut works.
	 */
	public static function apache_verdict( $ping, $layer, $browser ) {
		if ( 'no' === $ping ) {
			return array( 'warn', 'htaccess_ignored' );
		}
		if ( 'unknown' === $ping ) {
			return array( 'na', 'server_unknown' );
		}
		if ( 'noted' === $layer ) {
			// Rules run, our copy came back, our header did not. Without mod_expires either, nothing tells
			// browsers to recheck the page: then it is more than cosmetic.
			return 'none' === $browser ? array( 'warn', 'headers_missing' ) : array( 'warn', 'headers_stripped' );
		}
		if ( in_array( $layer, array( 'dropin', 'wp' ), true ) ) {
			return array( 'warn', 'htaccess_skipped' );
		}
		if ( 'htaccess' !== $layer ) {
			return array( 'na', 'server_unknown' ); // the page cache row already says why
		}
		return null;
	}

	/** Is $host (as a browser sends it, port included) one of this site's addresses? Compared in one form. */
	public static function same_host( $host ) {
		$norm = function ( $h ) {
			return preg_replace( '/^www\./', '', preg_replace( '/[^a-z0-9.\-]/', '', strtolower( (string) $h ) ) );
		};
		return in_array( $norm( $host ), array_map( $norm, ZeroConfig_Page_Cache::hosts( true ) ), true );
	}

	private static function save( array $result ) {
		$result['at'] = time();
		ZeroConfig_Probe::save_health( array( 'doctor' => $result ) );
		return $result;
	}

	/** Status of a row: its worst finding, and every finding for the details. */
	private static function worst( array $findings ) {
		$rank   = array( 'ok' => 0, 'na' => 1, 'warn' => 2, 'bad' => 3 );
		$status = 'ok';
		foreach ( $findings as $f ) {
			if ( $rank[ $f[0] ] > $rank[ $status ] ) {
				$status = $f[0];
			}
		}
		$items = array();
		foreach ( $findings as $f ) {
			$items[] = array( 'code' => $f[1], 'args' => isset( $f[2] ) ? array_map( 'strval', $f[2] ) : array() );
		}
		return array( 'status' => $status, 'items' => $items );
	}

	/** Server software, remembered from web requests (cron from the command line does not know it). */
	public static function server_software() {
		$now = isset( $_SERVER['SERVER_SOFTWARE'] ) ? sanitize_text_field( wp_unslash( $_SERVER['SERVER_SOFTWARE'] ) ) : '';
		if ( '' !== $now ) {
			$h = ZeroConfig_Probe::health();
			if ( ( $h['server_software'] ?? '' ) !== $now ) {
				ZeroConfig_Probe::save_health( array( 'server_software' => $now ) );
			}
			return $now;
		}
		return (string) ( ZeroConfig_Probe::health()['server_software'] ?? '' );
	}

	/* ---------- words ---------- */

	public static function row_label( $row ) {
		$labels = array(
			'setup'    => __( 'Setup', 'zeroconfig' ),
			'cache'    => __( 'Page cache', 'zeroconfig' ),
			'server'   => __( 'Web server shortcut', 'zeroconfig' ),
			'edge'     => __( 'Edge (images, CSS, JS)', 'zeroconfig' ),
			'features' => __( 'Features', 'zeroconfig' ),
		);
		return isset( $labels[ $row ] ) ? $labels[ $row ] : $row;
	}

	public static function owner_label( $owner ) {
		$labels = array(
			'you'  => __( 'You can fix this', 'zeroconfig' ),
			'host' => __( 'Ask your host', 'zeroconfig' ),
			'us'   => __( 'On us', 'zeroconfig' ),
			'none' => __( 'Expected', 'zeroconfig' ),
		);
		return isset( $labels[ $owner ] ) ? $labels[ $owner ] : $owner;
	}

	/** Code → owner, one sentence, and steps that can be pasted as they are. Plain text: escape on output. */
	public static function reason( $code, array $args = array() ) {
		$a = array_pad( array_map( 'strval', $args ), 2, '' );
		switch ( $code ) {
			case 'disabled_constant':
				return array( 'you', __( 'ZEROCONFIG_DISABLE is set in wp-config.php, so nothing is served from cache.', 'zeroconfig' ), __( "Remove the line define( 'ZEROCONFIG_DISABLE', true ); from wp-config.php.", 'zeroconfig' ) );
			case 'dropin_foreign':
				return array( 'you', __( 'Another caching plugin owns wp-content/advanced-cache.php. Cached pages still work, through WordPress.', 'zeroconfig' ), __( 'Deactivate the other caching plugin, then turn ZeroConfig off and on again. Two page caches only fight each other.', 'zeroconfig' ) );
			case 'dropin_write':
				return array( 'host', __( 'wp-content is not writable, so the fast cache file could not be installed. Cached pages still work, through WordPress.', 'zeroconfig' ), __( 'Message for your host: "Please make the wp-content folder writable for the web server user; a caching plugin needs to create wp-content/advanced-cache.php."', 'zeroconfig' ) );
			case 'dropin_missing':
				return array( 'us', __( 'The fast cache file is missing. Cached pages still work, through WordPress.', 'zeroconfig' ), __( 'Turn ZeroConfig off and on again to reinstall it.', 'zeroconfig' ) );
			case 'wpconfig_readonly':
				return array( 'host', __( 'WP_CACHE could not be switched on in wp-config.php. Cached pages still work, through WordPress.', 'zeroconfig' ), __( "Add this line to wp-config.php, above the line /* That's all, stop editing! */ : define( 'WP_CACHE', true );", 'zeroconfig' ) );
			case 'cron_stalled':
				/* translators: %s: the site's wp-cron.php address */
				return array( 'host', __( 'Background tasks (WP-Cron) have not run for over two hours, so expired pages are not cleaned up on time.', 'zeroconfig' ), sprintf( __( 'If wp-config.php has DISABLE_WP_CRON, add a server cron job: */5 * * * * wget -q -O - %s >/dev/null 2>&1', 'zeroconfig' ), site_url( 'wp-cron.php' ) ) );
			case 'host_mismatch':
				/* translators: 1: address in the browser, 2: address WordPress uses */
				return array( 'you', sprintf( __( 'You are visiting %1$s, but WordPress thinks the site is %2$s. Pages are cached for %2$s only.', 'zeroconfig' ), $a[0], $a[1] ), sprintf( __( 'Settings → General: set both addresses to the one your visitors use, or redirect %1$s to %2$s.', 'zeroconfig' ), $a[0], $a[1] ) );
			case 'loopback_blocked':
				/* translators: %s: error message */
				return array( 'host', sprintf( __( 'This server cannot open its own pages (%s), so the cache could not be checked from here.', 'zeroconfig' ), $a[0] ), __( 'Message for your host: "Please allow this site to make HTTP requests to its own address (loopback requests)." WordPress Tools → Site Health reports the same problem.', 'zeroconfig' ) );
			case 'redirected':
				/* translators: %s: HTTP status code */
				return array( 'you', sprintf( __( 'The home page answers with a redirect (HTTP %s) instead of the page.', 'zeroconfig' ), $a[0] ), __( 'Settings → General: make the WordPress Address and Site Address exactly the address visitors use (https and www included).', 'zeroconfig' ) );
			case 'http_error':
				/* translators: %s: HTTP status code */
				return array( 'you', sprintf( __( 'The home page answers HTTP %s to a normal visitor.', 'zeroconfig' ), $a[0] ), __( 'Open the home page in a private window. Maintenance mode, a login wall or a security plugin may be blocking visitors.', 'zeroconfig' ) );
			case 'foreign_page_cache':
				/* translators: %s: cache headers */
				return array( 'you', sprintf( __( 'Another cache in front of WordPress answered (%s). Visitors get its copy before ZeroConfig sees the visit.', 'zeroconfig' ), $a[0] ), __( 'Turn off page (HTML) caching in that layer and keep it for images and files, or exclude HTML from it. Your host or CDN dashboard has the switch.', 'zeroconfig' ) );
			case 'not_ours':
				return array( 'host', __( 'Something other than this WordPress answered the home page.', 'zeroconfig' ), __( 'A proxy, firewall or host cache replaced the answer. Check the caching or security layer in your hosting panel.', 'zeroconfig' ) );
			case 'not_stored':
				return array( 'us', __( 'Pages are built but not stored in the cache.', 'zeroconfig' ), __( 'A theme or plugin may mark every page as not cacheable or set a cookie on every visit. Use "Something looks off?" below so we can look.', 'zeroconfig' ) );
			case 'not_served':
				return array( 'us', __( 'Pages are stored but not served from the cache.', 'zeroconfig' ), __( 'Turn ZeroConfig off and on again. If this stays, use "Something looks off?" below.', 'zeroconfig' ) );
			case 'warm_skipped':
				return array( 'host', __( 'Cached pages are not refilled after a purge: this server cannot open its own pages, so the first visitor after each purge waits for a fresh page.', 'zeroconfig' ), __( "If the site sits behind a proxy that ends HTTPS (Docker, a load balancer), add this line to wp-config.php with the web server's own address: define( 'ZEROCONFIG_LOOPBACK', 'http://127.0.0.1:80' ); Otherwise ask your host to allow loopback requests.", 'zeroconfig' ) );
			case 'single_worker':
				/* translators: %s: seconds */
				return array( 'host', sprintf( __( 'Your web server answered at once, but PHP did not answer within %s seconds while this check was running: the site runs one PHP request at a time, or all PHP workers were busy. While it builds a page for one visitor, the next one waits.', 'zeroconfig' ), $a[0] ), __( 'Message for your host: "Please allow more than one PHP worker for this site (for example PHP-FPM pm.max_children of 4 or more)."', 'zeroconfig' ) );
			case 'slow_answer':
				/* translators: %s: seconds */
				return array( 'you', sprintf( __( 'Your home page did not answer within %s seconds, so the check stopped there. A page this slow is the first thing to look at.', 'zeroconfig' ), $a[0] ), __( 'Open the home page yourself. If it is this slow, turn ZeroConfig off for a minute to see whether it is us; otherwise look at recently added plugins, or ask your host about the server load.', 'zeroconfig' ) );
			case 'subdir_site':
				/* translators: %s: folder, e.g. /blog/ */
				return array( 'us', sprintf( __( 'Your site lives in %s, so the web server shortcut is not used yet: PHP serves the cached pages (still fast).', 'zeroconfig' ), $a[0] ), __( 'Nothing to change on your side or your host\'s. This is a current limit of ZeroConfig.', 'zeroconfig' ) );
			case 'edge_answered':
				/* translators: %s: cache headers */
				return array( 'none', sprintf( __( 'A CDN in front answered with its own copy (%s), so this check could not see your server itself.', 'zeroconfig' ), $a[0] ), '' );
			case 'headers_stripped':
				return array( 'host', __( 'Apache serves cached pages straight from disk, but without ZeroConfig\'s headers: the mod_headers module is off. Pages are still fast and browsers are still told not to keep them.', 'zeroconfig' ), __( 'Message for your host: "Please enable the Apache module mod_headers for this site."', 'zeroconfig' ) );
			case 'headers_missing':
				return array( 'host', __( 'Apache serves cached pages straight from disk, but with no caching headers at all: mod_headers and mod_expires are both off. Browsers may keep a page longer than they should.', 'zeroconfig' ), __( 'Message for your host: "Please enable the Apache modules mod_headers and mod_expires for this site."', 'zeroconfig' ) );
			case 'htaccess_skipped':
				return array( 'us', __( 'The .htaccess rules run, but did not pick up the home page; PHP served it from cache instead (still fast).', 'zeroconfig' ), __( 'Use "Something looks off?" below so we can look.', 'zeroconfig' ) );
			case 'nginx':
				return array( 'none', __( 'Not Apache (Nginx or similar): cached pages are served through PHP by the drop-in. That is the expected fast path here.', 'zeroconfig' ), '' );
			case 'server_unknown':
				return array( 'none', __( 'Depends on the page cache check above.', 'zeroconfig' ), '' );
			case 'htaccess_not_written':
				return array( 'host', __( 'The .htaccess rules could not be written, so cached pages go through PHP (still fast).', 'zeroconfig' ), __( 'Make the .htaccess file in the site folder writable, then turn ZeroConfig off and on again.', 'zeroconfig' ) );
			case 'htaccess_ignored':
				return array( 'host', __( 'The .htaccess rules are in place, but the web server ignores them, so cached pages go through PHP (still fast).', 'zeroconfig' ), __( 'Message for your host: "Please enable mod_rewrite and AllowOverride All (at least FileInfo) for this site\'s document root."', 'zeroconfig' ) );
			case 'permalink_no_slash':
				return array( 'none', __( 'Your permalinks do not end with a slash, so the web server shortcut does not apply to posts. PHP still serves them from cache.', 'zeroconfig' ), __( 'Nothing to do. Permalinks ending in / get the very fastest path.', 'zeroconfig' ) );
			case 'not_connected':
				return array( 'us', __( 'Waiting for the edge to verify this site. The page cache already works.', 'zeroconfig' ), __( 'Usually a few minutes. If it stays like this, press Try again.', 'zeroconfig' ) );
			case 'quota_paused':
				return array( 'us', __( 'The CDN is paused for this site after unusually high use: images and files come from your server for now. Nothing is broken.', 'zeroconfig' ), __( 'We have e-mailed you about it; reply to that e-mail or write to hello@zeroconfigwp.com.', 'zeroconfig' ) );
			case 'edge_unreachable':
				/* translators: %s: edge host name */
				return array( 'host', sprintf( __( 'This server cannot reach the edge (%s), so images and files come from your server for now.', 'zeroconfig' ), $a[0] ), sprintf( __( 'Message for your host: "Please allow outgoing HTTPS (port 443) to %s."', 'zeroconfig' ), $a[0] ) );
			case 'safemode_off':
				/* translators: %s: feature names */
				return array( 'us', sprintf( __( 'The Safety Check switched off %s because it changed how your pages look.', 'zeroconfig' ), $a[0] ), __( 'That keeps your site looking right. After changing theme or plugins, press Re-check.', 'zeroconfig' ) );
		}
		return array( 'us', $code, '' );
	}

	/** One honest sentence for the top of the card. */
	public static function summary() {
		$h = ZeroConfig_Probe::health();
		$w = isset( $h['warm'] ) ? $h['warm'] : array();
		if ( ! empty( $w['stored'] ) ) {
			$addresses = count( array_unique( wp_list_pluck( array_filter( (array) ( $w['items'] ?? array() ), function ( $i ) { return ! empty( $i['stored'] ); } ), 'url' ) ) );
			/* translators: 1: addresses refilled, 2: addresses tried, 3: seconds */
			$line = sprintf( __( 'Refilled after the last purge: %1$d of %2$d addresses, desktop and mobile, in %3$s s.', 'zeroconfig' ), $addresses, (int) $w['urls'], number_format_i18n( (float) $w['seconds'], 1 ) );
			if ( ! empty( $w['warm_ms'] ) ) {
				/* translators: %d: milliseconds */
				$line .= ' ' . sprintf( __( 'A cached page then answered in %d ms.', 'zeroconfig' ), (int) $w['warm_ms'] );
			}
			$why  = array(
				'time'    => __( 'It stopped early: the time limit was reached.', 'zeroconfig' ),
				'slow'    => __( 'It stopped early: the server was answering slowly.', 'zeroconfig' ),
				'load'    => __( 'It stopped early: the server was busy.', 'zeroconfig' ),
				'purged'  => __( 'It stopped early: the cache was cleared again meanwhile.', 'zeroconfig' ),
				'loopback_blocked' => __( 'It stopped early: this server could not open its own pages.', 'zeroconfig' ),
			);
			return empty( $w['stop'] ) || ! isset( $why[ $w['stop'] ] ) ? $line : $line . ' ' . $why[ $w['stop'] ];
		}
		$d = isset( $h['doctor']['probe']['second'] ) ? $h['doctor']['probe']['second'] : array();
		if ( ! empty( $d['ms'] ) && in_array( $d['layer'] ?? '', array( 'htaccess', 'noted', 'dropin', 'wp' ), true ) ) {
			/* translators: %d: milliseconds */
			return sprintf( __( 'Your home page was served from cache in %d ms.', 'zeroconfig' ), (int) $d['ms'] );
		}
		return '';
	}
}