<?php
/**
 * Explicit read-only public markup and signed-in browser diagnostics; no permanent visitor probe.
 *
 * @package AffStackDevImageManager
 */

namespace AffStackDev\ImageManager;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}
/**
 * Delivery checks on request: what a public page's markup offers for a picture, and what the owner's own signed-in
 * browser loaded (no visitor is checked).
 */
final class Verification {
	/**
	 * A fingerprint of what a source delivers now (its revision, switches, generation and copies), so an older check is
	 * not shown as current.
	 *
	 * @param array $r The source row.
	 * @return string SHA-256.
	 */
	public static function signature( array $r ): string {
		$v = array();
		foreach ( Variants::flatten( $r['manifest'] ) as  $f ) {
			$v[] = array( $f['file'], $f['output_hash'] ?? '' );
		}
		return hash( 'sha256', wp_json_encode( array( (int) $r['revision'], $r['delivery'], $r['excluded'], Settings::get()['generation'], $v ) ) );
	}
	/**
	 * The first public page Image Manager may read where the source was found.
	 *
	 * @param array $r The source row.
	 * @return string The page's address.
	 * @throws \RuntimeException With delivery_no_page when the source has no such page.
	 */
	public static function page( array $r ): string {
		foreach ( $r['details']['pages'] ?? array() as  $url ) {
			$p = Urls::page( $url );
			if ( ! is_wp_error( $p ) ) {
				return $p;
			}
		}
		throw new \RuntimeException( 'delivery_no_page' );
	}
	/**
	 * The addresses of a source's copies.
	 *
	 * @param array $r       The source row.
	 * @param bool  $retired Whether to include copies kept only for cached pages.
	 * @return array The addresses.
	 */
	public static function urls( array $r, bool $retired = false ): array {
		return array_values(
			array_unique(
				array_map(
					array( Delivery::class, 'url' ),
					Variants::flatten(
						array_diff_key(
							$r['manifest'],
							array(
								'draft'   => true,
								'pending' => true,
							)
						),
						$retired
					)
				)
			)
		);
	}
	/**
	 * Check a public page's markup for a source: whether it offers the source's copies.
	 *
	 * @param array $r The source row.
	 * @return array The check.
	 * @throws \RuntimeException With a reason code as its message when the step cannot be done.
	 */
	public static function check_row( array $r ): array {
		$im_reviewed_owner_lock = Reviewed_Store::enter();
		try {
			if ( ! Sources::eligible( $r ) ) {
				throw new \RuntimeException( 'preview_public_required' );
			}
			$page     = self::page( $r );
			$cache    = 'afsd_im_htmlcheck_' . substr( hash( 'sha256', $page ), 0, 32 );
			$response = get_transient( $cache );
			if ( ! is_array( $response ) || ( $response['expires'] ?? 0 ) < time() ) {
				$response = Urls::fetch( $page );
				if ( ! is_wp_error( $response ) ) {
					$response['expires'] = time() + 60;
					Reviewed_Store::set_transient( $cache, $response, 60 );
				}
			}
			$check = array(
				'signature'      => self::signature( $r ),
				'time'           => time(),
				'page'           => $page,
				'kind'           => 'public_html',
				'status'         => 'unavailable',
				'matches'        => 0,
				'native_matches' => 0,
				'older_matches'  => 0,
				'coverage'       => Delivery::coverage( $r ),
			);
			if ( is_wp_error( $response ) ) {
				$check['reason'] = sanitize_key( $response->get_error_code() );
			} else {
				$seen                    = self::markup_urls( $response['html'], $response['url'] );
				$active                  = self::urls( $r );
				$history                 = array_diff( self::urls( $r, true ), $active );
				$current                 = array_values( array_intersect( $seen, $active ) );
				$old                     = array_intersect( $seen, $history );
				$native                  = array_intersect( $seen, (array) ( $r['details']['urls'] ?? array() ) );
				$check['status']         = $current ? 'offered' : ( $old ? 'older' : ( $native ? 'original' : ( ! $active ? 'no_files' : 'not_found' ) ) );
				$check['matches']        = count( $current );
				$check['native_matches'] = count( $native );
				$check['older_matches']  = count( $old );
			}
			$fresh = Repository::row( (int) $r['id'] );
			if ( $fresh && self::signature( $fresh ) === $check['signature'] ) {
				$d                   = $fresh['details'];
				$d['delivery_check'] = $check;
				Repository::update( (int) $r['id'], array( 'details' => $d ), (int) $r['revision'] );
			}
			return $check;

		} finally {
			Reviewed_Store::leave( $im_reviewed_owner_lock );
		}
	}
	/**
	 * The picture addresses a page's markup offers (img and source elements), within the page's own origin.
	 *
	 * @param string $html The page.
	 * @param string $page Its address.
	 * @return array The addresses, or an empty array for a page over 2 MB.
	 */
	public static function markup_urls( string $html, string $page ): array {
		if ( strlen( $html ) > 2097152 ) {
			return array();
		}$p      = new \WP_HTML_Tag_Processor( $html );
		$urls    = array();
		$n       = 0;
		$blocked = 0;
		while ( $n++ < 8000 && $p->next_tag( array( 'tag_closers' => 'visit' ) ) ) {
			$tag   = $p->get_tag();
			$close = $p->is_tag_closer();
			if ( 'BASE' === $tag ) {
				return array();
			}
			if ( in_array( $tag, array( 'NOSCRIPT', 'TEMPLATE', 'SVG', 'VIDEO', 'AUDIO' ), true ) ) {
				$blocked = $close ? max( 0, $blocked - 1 ) : $blocked + 1;
				continue;
			}
			if ( $blocked || $close || ! in_array( $tag, array( 'IMG', 'SOURCE' ), true ) ) {
				continue;
			}
			$src = $p->get_attribute( 'src' );
			if ( is_string( $src ) ) {
				$urls[] = Urls::absolute( $src, $page );
			}
			$set = $p->get_attribute( 'srcset' );if ( is_string( $set ) ) {
				$parsed = Urls::srcset( $set );
				if ( $parsed ) {
					foreach ( $parsed as  $c ) {
						$urls[] = Urls::absolute( $c['url'], $page );
					}
				} elseif ( ! str_contains( $set, ',' ) && preg_match( '/^\s*([^\s]+)\s*$/D', $set, $single ) ) {
					$urls[] = Urls::absolute( html_entity_decode( $single[1], ENT_QUOTES | ENT_HTML5, 'UTF-8' ), $page );
				}
			}
			if ( count( $urls ) > 2048 ) {
				break;
			}
		}return array_values( array_unique( $urls ) );
	}
	/**
	 * The words for a source's latest delivery check, when it still matches what the source delivers.
	 *
	 * @param array $r The source row.
	 * @return string The translated words.
	 */
	public static function label( array $r ): string {
		$b   = $r['details']['browser_check'] ?? array();
		$h   = $r['details']['delivery_check'] ?? array();
		$sig = self::signature( $r );
		if ( ( $b['signature'] ?? '' ) === $sig && time() - (int) $b['time'] < 86400 ) {
			return ( ! empty( $b['optimized'] ) ? __( 'This signed-in browser loaded optimized files', 'affstackdev-image-manager' ) : ( ! empty( $b['original'] ) ? __( 'This signed-in browser loaded the original', 'affstackdev-image-manager' ) : __( 'Image not observed as loaded in this signed-in check', 'affstackdev-image-manager' ) ) ) . ' · ' . gmdate( 'H:i', (int) $b['time'] ) . ' UTC';
		}
		if ( ( $h['signature'] ?? '' ) === $sig && time() - (int) $h['time'] < 86400 ) {
			$status  = $h['status'] ?? '';
			$current = (int) ( $h['matches'] ?? 0 );
			$native  = (int) ( $h['native_matches'] ?? 0 );
			if ( 'offered' === $status ) {
				$text = __( 'Public page offers current optimized files', 'affstackdev-image-manager' );
				if ( $current ) {
					/* translators: %d: number of current optimized file URLs the public page offers. */
					$text .= sprintf( _n( ' (%d current URL)', ' (%d current URLs)', $current, 'affstackdev-image-manager' ), $current );
				}if ( $native ) {
					$text .= __( '; original fallback/candidates are also present', 'affstackdev-image-manager' );
				}$text .= __( '; browser not checked', 'affstackdev-image-manager' );
			} elseif ( 'older' === $status ) {
				$text = __( 'Public page still references older managed copies. Refresh ordinary page/CDN caches before diagnosing current delivery.', 'affstackdev-image-manager' );
			} elseif ( 'original' === $status ) {
				$c        = $h['coverage'] ?? Delivery::coverage( $r );
				$complete = ! empty( $c['complete_managed_mime_families'] );
				$text     = $complete ? __( 'Public page offers the original even though stored optimized coverage is complete; cache or this output integration needs review.', 'affstackdev-image-manager' ) : __( 'Public page offers the original and stored optimized coverage is incomplete for this image family.', 'affstackdev-image-manager' );
			} else {
				$map  = array(
					'no_files'    => __( 'No optimized files available for this image', 'affstackdev-image-manager' ),
					'not_found'   => __( 'Image not found in checked public markup', 'affstackdev-image-manager' ),
					'unavailable' => __( 'Public-page check could not finish', 'affstackdev-image-manager' ),
				);
				$text = $map[ $status ] ?? __( 'Delivery not checked', 'affstackdev-image-manager' );
			}
			return $text . ' · ' . gmdate( 'H:i', (int) $h['time'] ) . ' UTC';
		}
		return __( 'Website delivery not checked for these files yet', 'affstackdev-image-manager' );
	}
	/**
	 * The address of the browser inspector for a source (with a nonce).
	 *
	 * @param int $id The source row.
	 * @return string The address.
	 */
	public static function inspector_url( int $id ): string {
		return add_query_arg(
			array(
				'action'   => 'afsd_im_inspect',
				'source'   => $id,
				'_wpnonce' => wp_create_nonce( 'afsd_im_inspect_' . $id ),
			),
			admin_url( 'admin-post.php' )
		);
	}
	/**
	 * Record what the owner's browser loaded for a source on its page.
	 *
	 * @param int    $id           The source row.
	 * @param string $signature    The signature the inspector was opened with.
	 * @param array  $observations The files the browser reported loading.
	 * @param int    $width        The browser's viewport width.
	 * @param float  $dpr          Its device pixel ratio.
	 * @return string The translated result.
	 * @throws \RuntimeException With delivery_check_stale when the source changed since the inspector opened.
	 */
	public static function browser_record( int $id, string $signature, array $observations, int $width, float $dpr ): string {
		$im_reviewed_owner_lock = Reviewed_Store::enter();
		try {
			$r = Preview::row( $id );
			if ( ! Sources::eligible( $r ) || ! hash_equals( self::signature( $r ), $signature ) ) {
				throw new \RuntimeException( 'delivery_check_stale' );
			}
			if ( $width < 240 || $width > 2560 || $dpr < 0.5 || $dpr > 8 || count( $observations ) > 256 ) {
				throw new \RuntimeException( 'delivery_invalid_result' );
			}
			$active    = self::urls( $r );
			$natives   = $r['details']['urls'] ?? array();
			$optimized = 0;
			$original  = 0;
			foreach ( $observations as  $o ) {
				if ( ! is_array( $o ) || ! is_string( $o['url'] ?? null ) || empty( $o['loaded'] ) || ! is_numeric( $o['width'] ?? null ) || (int) $o['width'] < 1 ) {
					continue;
				}
				if ( in_array( $o['url'], $active, true ) ) {
					++$optimized;
				} elseif ( in_array( $o['url'], $natives, true ) ) {
					++$original;
				}
			}
			$d                  = $r['details'];
			$d['browser_check'] = array(
				'signature' => $signature,
				'time'      => time(),
				'width'     => $width,
				'dpr'       => $dpr,
				'optimized' => $optimized,
				'original'  => $original,
				'kind'      => 'signed_in_browser',
			);
			Repository::update( $id, array( 'details' => $d ), (int) $r['revision'] );
			if ( $optimized ) {
				return __( 'This browser loaded optimized files. This signed-in diagnostic does not certify anonymous cached visitors.', 'affstackdev-image-manager' );
			}
			if ( $original ) {
				$c = Delivery::coverage( $r );
				return empty( $c['complete_managed_mime_families'] )
					? __( 'This browser loaded the original. Stored optimized coverage is incomplete for this image family; review size results before blaming cache.', 'affstackdev-image-manager' )
					: __( 'This browser loaded the original even though stored optimized coverage is complete. Check public markup, cache state, and whether this output surface uses the supported delivery path.', 'affstackdev-image-manager' );
			}
			return __( 'This image was not observed as loaded. It may be lazy-loaded, absent, or blocked from this inspection.', 'affstackdev-image-manager' );

		} finally {
			Reviewed_Store::leave( $im_reviewed_owner_lock );
		}
	}
	/**
	 * The browser inspector: a GET for a source with a valid nonce, answered as the inspector page or the recorded result.
	 *
	 * @throws \RuntimeException Only inside this function, where it is caught; callers get no exception.
	 */
	public static function inspector(): void {
		try {
			if ( ! current_user_can( 'manage_options' ) || ! current_user_can( 'upload_files' ) ) {
				throw new \RuntimeException( 'image_access_denied' );
			}
			$get    = Plugin::fields( array( 'source', '_wpnonce' ), true );
			$id     = is_scalar( $get['source'] ?? null ) ? absint( $get['source'] ) : 0;
			$method = isset( $_SERVER['REQUEST_METHOD'] ) && is_string( $_SERVER['REQUEST_METHOD'] ) ? sanitize_text_field( wp_unslash( $_SERVER['REQUEST_METHOD'] ) ) : '';
			if ( 'GET' !== $method ) {
				throw new \RuntimeException( 'image_access_denied' );
			}
			if ( ! isset( $get['_wpnonce'] ) || ! is_string( $get['_wpnonce'] ) || ! wp_verify_nonce( $get['_wpnonce'], 'afsd_im_inspect_' . $id ) ) {
				throw new \RuntimeException( 'image_access_denied' );
			}
			$r = Preview::row( $id );
			if ( ! Sources::eligible( $r ) ) {
				throw new \RuntimeException( 'preview_public_required' );
			}$page = self::page( $r );
			nocache_headers();
			header( 'Cache-Control: private, no-store, max-age=0' );
			header( 'Referrer-Policy: same-origin' );
			header( 'X-Content-Type-Options: nosniff' );
			header( 'Content-Type: text/html; charset=utf-8' );
			wp_enqueue_script( 'afsd-im-inspector', plugins_url( 'assets/inspector.js', FILE ), array(), VERSION, true );
			wp_localize_script(
				'afsd-im-inspector',
				'afsdImageManagerInspector',
				array(
					'widthChanged'    => __( 'Preview width changed. Allow responsive images to settle, then check again.', 'affstackdev-image-manager' ),
					'loaded'          => __( 'Preview loaded. Scroll inside it to the image, then click Check loaded images.', 'affstackdev-image-manager' ),
					'noImages'        => __( 'Preview unavailable, blocked from embedding, or contains no images.', 'affstackdev-image-manager' ),
					'foreignEndpoint' => __( 'The diagnostic endpoint is not on this website.', 'affstackdev-image-manager' ),
					'notSaved'        => __( 'The result could not be saved.', 'affstackdev-image-manager' ),
					'evidence'        => __( 'Observed selected image URLs (not transfer-size measurements):', 'affstackdev-image-manager' ),
					/* translators: %d: the image's intrinsic width in pixels. */
					'intrinsicWidth'  => __( 'intrinsic width %d', 'affstackdev-image-manager' ),
					'failed'          => __( 'This preview could not be inspected.', 'affstackdev-image-manager' ),
				)
			);
			echo '<!doctype html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1"><title>'
				. esc_html__( 'Image delivery check', 'affstackdev-image-manager' )
				. '</title>';
			// The page's own styles, through WordPress's style queue like its script.
			wp_register_style( 'afsd-im-inspector', false, array(), VERSION );
			wp_add_inline_style(
				'afsd-im-inspector',
				'body{font:16px/1.5 system-ui;margin:24px;background:#f5f7fb;color:#142136}main{max-width:1400px;margin:auto}'
				. 'button,select,a{font:inherit;padding:8px}section{background:white;padding:16px;border:1px solid #ccd4e3;border-radius:8px;margin:16px 0}'
				. '.frame{overflow:auto}iframe{height:560px;max-width:none;border:1px solid #ccd4e3}pre{white-space:pre-wrap;overflow-wrap:anywhere}'
			);
			wp_print_styles( array( 'afsd-im-inspector' ) );
			echo '</head><body><main id="im-inspector" data-source="'
				. esc_attr( (string) $id ) . '" data-signature="' . esc_attr( self::signature( $r ) ) . '" data-nonce="' . esc_attr( wp_create_nonce( 'afsd_im_action' ) )
				. '" data-endpoint="' . esc_url( admin_url( 'admin-ajax.php' ) ) . '"><h1>' . esc_html__( 'Check what this browser loads', 'affstackdev-image-manager' )
				. '</h1><p>'
				/* translators: %s: the words "signed-in diagnostic", shown in bold. */
				. sprintf( esc_html__( 'This is a %s of a known public page, not a test of anonymous cached visitors. Only this inspection tab runs the check. Scroll inside the preview to load an image below the fold, then check again.', 'affstackdev-image-manager' ), '<strong>' . esc_html__( 'signed-in diagnostic', 'affstackdev-image-manager' ) . '</strong>' )
				. '</p><a href="' . esc_url( Admin::url( 'images', array( 'im_image' => $id ) ) ) . '">' . esc_html__( 'Return to Image Manager', 'affstackdev-image-manager' )
				. '</a><section><label>' . esc_html__( 'Preview width', 'affstackdev-image-manager' ) . ' <select id="im-width"><option value="390">'
				. esc_html__( 'Phone — 390 px', 'affstackdev-image-manager' ) . '</option><option value="1280">'
				. esc_html__( 'Desktop — 1280 px', 'affstackdev-image-manager' ) . '</option></select></label> <button id="im-check" type="button">'
				. esc_html__( 'Check loaded images', 'affstackdev-image-manager' ) . '</button><p id="im-status" role="status">'
				. esc_html__( 'Waiting for the preview. Sites that block embedding cannot be inspected here.', 'affstackdev-image-manager' )
				. '</p></section><section class="frame"><iframe id="im-frame" width="390" title="' . esc_attr__( 'Signed-in public-page preview', 'affstackdev-image-manager' )
				. '" sandbox="allow-scripts allow-same-origin" src="' . esc_url( $page ) . '"></iframe></section><pre id="im-evidence"></pre></main>';
			wp_print_scripts( array( 'afsd-im-inspector' ) );
			echo '</body></html>';
			exit;
		} catch ( \Throwable $e ) {
			wp_die( esc_html__( 'This image inspection is unavailable or access expired. Return to Image Manager.', 'affstackdev-image-manager' ), '', array( 'response' => 403 ) );
		}
	}
}