<?php
/**
 * Library-wide "no use found" report. Reads saved content and site settings only; never deletes, moves or edits a file.
 * A file in the report is one that none of the places checked refers to, which does not prove it unused.
 *
 * @package AffStackDevImageManager
 */

namespace AffStackDev\ImageManager;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Files with no use found: a check of the saved content, settings and comments for every library file, done in steps;
 * the files found are listed and can be put in a collection for review. Nothing is deleted.
 */
final class Unused_Media {
	public const OPTION          = 'afsd_im_unused';
	private const CONTENT_BATCH  = 100;
	private const FILE_BATCH     = 200;
	private const CONTENT_BYTES  = 262144;
	private const META_BYTES     = 65536;
	private const COMMENT_BATCH  = 500;
	private const MAX_REFERENCES = 50000;
	private const MAX_LISTED     = 5000;

	/**
	 * The saved check.
	 *
	 * @return array The check, or an empty array.
	 */
	public static function state(): array {
		$s = Settings::fresh_option( self::OPTION, array() );
		return is_array( $s ) && 1 === ( $s['v'] ?? 0 ) ? $s : array();
	}
	/**
	 * The post types whose content the check reads.
	 *
	 * @return array Post type names.
	 */
	private static function types(): array {
		$types = array_merge( get_post_types( array( 'public' => true ) ), array( 'post', 'page', 'product', 'product_variation', 'wp_block', 'wp_template', 'wp_template_part', 'wp_navigation', 'wp_global_styles', 'custom_css' ) );
		return array_values( array_diff( array_unique( $types ), array( 'attachment', 'revision', 'nav_menu_item' ) ) );
	}
	/** The path part of the uploads address, such as /wp-content/uploads. Any host counts: a CDN or another address of the site. */
	private static function uploads_path(): string {
		$u    = wp_get_upload_dir();
		$path = wp_parse_url( (string) ( $u['baseurl'] ?? '' ), PHP_URL_PATH );
		return is_string( $path ) ? untrailingslashit( $path ) : '';
	}
	/**
	 * Count an attachment as used (up to the limit; beyond it the check notes it overflowed).
	 *
	 * @param array $s  The check, changed in place.
	 * @param mixed $id The attachment.
	 */
	private static function add_id( array &$s, $id ): void {
		$id = absint( $id );
		if ( $id && count( $s['ids'] ) < self::MAX_REFERENCES ) {
			$s['ids'][ $id ] = true;
		} elseif ( $id ) {
			$s['overflow'] = true;
		}
	}
	/**
	 * A folder an Image Manager folder gallery names; with its sub-folders when the gallery includes them.
	 *
	 * @param array $s          The check, changed in place.
	 * @param mixed $value      The folder's ID.
	 * @param bool  $subfolders Whether the gallery includes its sub-folders.
	 */
	private static function add_folder( array &$s, $value, bool $subfolders ): void {
		$id = absint( is_scalar( $value ) ? $value : 0 );
		if ( ! $id ) {
			return;
		}
		$s['folders'][ $id ] = ! empty( $s['folders'][ $id ] ) || $subfolders;
	}
	/**
	 * Count every attachment of a list (a comma or space separated text or an array) as used.
	 *
	 * @param array $s     The check, changed in place.
	 * @param mixed $value The IDs.
	 */
	private static function add_ids( array &$s, $value ): void {
		if ( is_string( $value ) ) {
			$value = preg_split( '/[\s,]+/', trim( $value ) );
		}
		if ( is_array( $value ) ) {
			foreach ( $value as  $v ) {
				if ( is_int( $v ) || ( is_string( $v ) && ctype_digit( $v ) ) ) {
					self::add_id( $s, $v );
				}
			}
		}
	}
	/**
	 * Every uploads address in a text, in any attribute, block setting, style or JSON.
	 *
	 * @param array  $s    The check, changed in place.
	 * @param string $text The text.
	 */
	private static function add_paths( array &$s, string $text ): void {
		$base = self::uploads_path();
		if ( '' === $base || ! str_contains( $text, $base ) && ! str_contains( $text, str_replace( '/', '\\/', $base ) ) ) {
			return;
		}
		$text = str_replace( '\\/', '/', $text );
		if ( ! preg_match_all( '~' . preg_quote( $base, '~' ) . '/([^\s"\'<>()\\\\?#,;]+)~i', $text, $m ) ) {
			return;
		}
		foreach ( $m[1] as  $path ) {
			$path = rawurldecode( html_entity_decode( $path, ENT_QUOTES | ENT_HTML5, 'UTF-8' ) );
			if ( str_contains( $path, '..' ) || strlen( $path ) > 512 ) {
				continue;
			}
			if ( count( $s['paths'] ) < self::MAX_REFERENCES ) {
				$s['paths'][ strtolower( $path ) ] = true;
			} else {
				$s['overflow'] = true;
			}
		}
	}
	/**
	 * Saved markup only: no shortcode, block, theme code or page is run. Same reading as Check usage, for every file at
	 * once.
	 *
	 * @param array  $s       The check, changed in place.
	 * @param string $content The saved markup.
	 * @param int    $owner   The post it belongs to, or 0.
	 */
	private static function content( array &$s, string $content, int $owner ): void {
		if ( '' === $content ) {
			return;
		}
		$tags = new \WP_HTML_Tag_Processor( $content );
		while ( $tags->next_tag( 'IMG' ) ) {
			$classes = $tags->get_attribute( 'class' );
			if ( is_string( $classes ) && preg_match_all( '/(?:^|\s)wp-image-([0-9]+)(?:\s|$)/', $classes, $m ) ) {
				foreach ( $m[1] as  $id ) {
					self::add_id( $s, $id );
				}
			}
		}
		preg_match_all( '/<!--\s+wp:(?:core\/)?(image|gallery|cover|media-text|file|audio|video)\s+(\{.*?\})\s*\/?-->/s', $content, $blocks, PREG_SET_ORDER );
		foreach ( $blocks as  $block ) {
			$attrs = json_decode( $block[2], true, 16 );
			if ( ! is_array( $attrs ) ) {
				continue;
			}
			$key   = 'media-text' === $block[1] ? 'mediaId' : ( 'gallery' === $block[1] ? 'ids' : 'id' );
			$value = $attrs[ $key ] ?? array();
			self::add_ids( $s, is_array( $value ) ? $value : array( (string) $value ) );
		}
		preg_match_all( '/' . get_shortcode_regex( array( 'gallery' ) ) . '/s', $content, $shortcodes, PREG_SET_ORDER );
		foreach ( $shortcodes as  $shortcode ) {
			if ( '[' === $shortcode[1] && ']' === $shortcode[6] ) {
				continue;
			}
			$attrs = shortcode_parse_atts( $shortcode[3] );
			$attrs = is_array( $attrs ) ? $attrs : array();
			$ids   = $attrs['ids'] ?? ( $attrs['include'] ?? '' );
			if ( $ids ) {
				self::add_ids( $s, $ids );
			} elseif ( $owner || isset( $attrs['id'] ) ) {
				$parent = isset( $attrs['id'] ) ? absint( $attrs['id'] ) : $owner;
				if ( $parent ) {
					$s['parents'][ $parent ] = true;
				}
			}
		}
		// Image Manager's own folder galleries show the pictures of the folder they name.
		preg_match_all( '/' . get_shortcode_regex( array( Folder_Gallery::SHORTCODE ) ) . '/s', $content, $folder_codes, PREG_SET_ORDER );
		foreach ( $folder_codes as  $code ) {
			if ( '[' === $code[1] && ']' === $code[6] ) {
				continue;
			}
			$attrs = shortcode_parse_atts( $code[3] );
			$attrs = is_array( $attrs ) ? $attrs : array();
			self::add_folder( $s, $attrs['folder'] ?? 0, in_array( strtolower( (string) ( $attrs['subfolders'] ?? '' ) ), array( '1', 'yes', 'true' ), true ) );
		}
		preg_match_all( '/<!--\s+wp:affstackdev-image-manager\/folder-gallery\s+(\{.*?\})\s*\/?-->/s', $content, $folder_blocks, PREG_SET_ORDER );
		foreach ( $folder_blocks as  $block ) {
			$attrs = json_decode( $block[1], true, 16 );
			if ( is_array( $attrs ) ) {
				self::add_folder( $s, $attrs['folder'] ?? 0, ! empty( $attrs['subfolders'] ) );
			}
		}
		self::add_paths( $s, $content );
	}
	/**
	 * Walk a saved setting (widgets and the like): attachment_id / ids keys and any text.
	 *
	 * @param array $s     The check, changed in place.
	 * @param mixed $value The setting's value.
	 * @param int   $depth How deep the walk is (it stops past 8).
	 */
	private static function walk( array &$s, $value, int $depth = 0 ): void {
		if ( $depth > 8 ) {
			return;
		}
		if ( is_string( $value ) ) {
			if ( strlen( $value ) <= self::CONTENT_BYTES ) {
				self::content( $s, $value, 0 );
			} else {
				++$s['skipped'];
			} return;
		}
		if ( ! is_array( $value ) ) {
			return;
		}
		foreach ( $value as  $k => $v ) {
			if ( in_array( $k, array( 'attachment_id', 'image_id', 'thumbnail_id' ), true ) ) {
				self::add_id( $s, is_scalar( $v ) ? $v : 0 );
			} elseif ( 'ids' === $k ) {
				self::add_ids( $s, $v );
			} else {
				self::walk( $s, $v, $depth + 1 );
			}
		}
	}
	/**
	 * Site-wide places: icon, logo, header and background, WooCommerce, product categories, widgets.
	 *
	 * @param array $s The check, changed in place.
	 */
	private static function site( array &$s ): void {
		global $wpdb;
		foreach ( array( 'site_icon', 'site_logo', 'woocommerce_placeholder_image' ) as  $option ) {
			self::add_id( $s, get_option( $option, 0 ) );
		}
		$email = get_option( 'woocommerce_email_header_image', '' );
		if ( is_string( $email ) ) {
			self::add_paths( $s, $email );
		}
		$mods = get_theme_mods();
		$mods = is_array( $mods ) ? $mods : array();
		self::add_id( $s, $mods['custom_logo'] ?? 0 );
		if ( is_object( $mods['header_image_data'] ?? null ) ) {
			self::add_id( $s, $mods['header_image_data']->attachment_id ?? 0 );
		} elseif ( is_array( $mods['header_image_data'] ?? null ) ) {
			self::add_id( $s, $mods['header_image_data']['attachment_id'] ?? 0 );
		}
		foreach ( array( 'header_image', 'background_image' ) as  $mod ) {
			if ( is_string( $mods[ $mod ] ?? null ) ) {
				self::add_paths( $s, $mods[ $mod ] );
			}
		}
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- One bounded read of category pictures (term meta thumbnail_id) for the report.
		$thumbs = $wpdb->get_col( $wpdb->prepare( 'SELECT meta_value FROM %i WHERE meta_key = %s LIMIT %d', $wpdb->termmeta, 'thumbnail_id', 20000 ) );
		foreach ( (array) $thumbs as  $id ) {
			self::add_id( $s, $id );
		}
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- One bounded read of the saved widget settings for the report.
		$widgets = $wpdb->get_results( $wpdb->prepare( 'SELECT option_name, LENGTH(option_value) AS bytes, option_value FROM %i WHERE option_name LIKE %s LIMIT 200', $wpdb->options, $wpdb->esc_like( 'widget_' ) . '%' ), ARRAY_A );
		foreach ( (array) $widgets as  $w ) {
			if ( (int) $w['bytes'] > 1048576 ) {
				++$s['skipped'];
				continue;
			}
			self::walk( $s, maybe_unserialize( $w['option_value'] ) );
		}
		// Every file in a folder a folder gallery names counts as used, whether the folder is switched on now or not.
		foreach ( (array) ( $s['folders'] ?? array() ) as  $folder => $subfolders ) {
			$terms = array( (int) $folder );
			if ( $subfolders ) {
				$children = get_term_children( (int) $folder, Library::FOLDER );
				if ( is_array( $children ) ) {
					$terms = array_merge( $terms, array_map( 'intval', $children ) );
				}
			}
			$objects = get_objects_in_term( $terms, Library::FOLDER );
			if ( is_array( $objects ) ) {
				foreach ( $objects as  $id ) {
					self::add_id( $s, $id );
				}
			}
		}
	}
	/**
	 * Start (or restart) a check, or continue it. Each request works for a few seconds and saves its position.
	 *
	 * @param bool $start True to start a new check.
	 * @return array The check.
	 * @throws \RuntimeException With a reason code as its message when the step cannot be done.
	 */
	public static function step( bool $start ): array {
		$im_reviewed_owner_lock = Reviewed_Store::enter();
		try {
			if ( ! current_user_can( 'manage_options' ) || ! current_user_can( 'upload_files' ) ) {
				throw new \RuntimeException( 'unused_access' );
			}
			$token = Repository::acquire( 'unused_media', 300 );
			if ( ! $token ) {
				throw new \RuntimeException( 'unused_busy' );
			}
			global $wpdb;
			try {
				$s = self::state();
				if ( $start ) {
					$types = self::types();
					// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Fixes the content range of this check at its start.
					$max = (int) $wpdb->get_var( $wpdb->prepare( 'SELECT MAX(ID) FROM %i WHERE post_type IN (' . implode( ',', array_fill( 0, count( $types ), '%s' ) ) . ')', array_merge( array( $wpdb->posts ), $types ) ) );
					// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Fixes the file range of this check at its start.
					$files = (int) $wpdb->get_var( $wpdb->prepare( 'SELECT MAX(ID) FROM %i WHERE post_type = %s', $wpdb->posts, 'attachment' ) );
					$s     = array(
						'v'             => 1,
						'actor'         => get_current_user_id(),
						'started'       => time(),
						'updated'       => time(),
						'phase'         => 'content',
						'cursor'        => 0,
						'max'           => $max,
						'files_max'     => $files,
						'types'         => $types,
						'checked'       => 0,
						'skipped'       => 0,
						'ids'           => array(),
						'paths'         => array(),
						'parents'       => array(),
						'folders'       => array(),
						'files_checked' => 0,
						'listed'        => array(),
						'more_listed'   => 0,
						'overflow'      => false,
						'status'        => 'more',
						'collection'    => 0,
						'collected'     => 0,
					);
				} elseif ( ! $s || 'more' !== $s['status'] ) {
					throw new \RuntimeException( 'unused_stale' );
				}
				$until = microtime( true ) + 8;
				while ( 'more' === $s['status'] && microtime( true ) < $until ) {
					if ( 'content' === $s['phase'] ) {
						self::content_batch( $s );
					} elseif ( 'comments' === $s['phase'] ) {
						self::comment_batch( $s );
					} elseif ( 'site' === $s['phase'] ) {
						self::site( $s );
						$s['phase']  = 'files';
						$s['cursor'] = 0;
					} else {
						self::file_batch( $s );
					}
					// Uses that could not all be remembered would make used files look unused: such a check lists nothing.
					if ( $s['overflow'] ) {
						$s['status']      = 'limit';
						$s['listed']      = array();
						$s['more_listed'] = 0;
					}
					if ( ! Repository::owns( $token, 'unused_media' ) ) {
						throw new \RuntimeException( 'unused_busy' );
					}
				}
				$s['updated'] = time();
				if ( ! Reviewed_Store::update_option( self::OPTION, $s, false ) && self::state() !== $s ) {
					throw new \RuntimeException( 'unused_storage' );
				}
				return $s;
			} finally {
				Repository::release( $token, 'unused_media' );
			}
		} finally {
			Reviewed_Store::leave( $im_reviewed_owner_lock );
		}
	}
	/**
	 * Read the next posts' saved content and excerpts for uses.
	 *
	 * @param array $s The check, changed in place.
	 * @throws \RuntimeException With unused_database when the content cannot be read.
	 */
	private static function content_batch( array &$s ): void {
		global $wpdb;
		$types = $s['types'];
        // phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Bounded keyset scan of saved content; SQL caps the bytes read per item and must see current edits.
		$rows = $wpdb->get_results(
			$wpdb->prepare(
				'SELECT ID, LENGTH(post_content)+LENGTH(post_excerpt) AS bytes, CASE WHEN LENGTH(post_content)+LENGTH(post_excerpt)<=%d THEN post_content ELSE \'\' END AS body, CASE WHEN LENGTH(post_content)+LENGTH(post_excerpt)<=%d THEN post_excerpt ELSE \'\' END AS excerpt FROM %i WHERE ID>%d AND ID<=%d AND post_type IN ('
				. implode( ',', array_fill( 0, count( $types ), '%s' ) ) . ') AND post_status NOT IN (\'trash\',\'auto-draft\') ORDER BY ID ASC LIMIT %d',
				array_merge( array( self::CONTENT_BYTES, self::CONTENT_BYTES, $wpdb->posts, (int) $s['cursor'], (int) $s['max'] ), $types, array( self::CONTENT_BATCH ) )
			),
			ARRAY_A
		);
		// phpcs:enable WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
		if ( $wpdb->last_error || ! is_array( $rows ) ) {
			throw new \RuntimeException( 'unused_database' );
		}
		if ( ! $rows ) {
			$s['phase']  = 'comments';
			$s['cursor'] = 0;
			return;
		}
		$ids = array_map( 'intval', array_column( $rows, 'ID' ) );
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Featured images and product galleries of this batch.
		$meta = $wpdb->get_results( $wpdb->prepare( 'SELECT meta_key, LEFT(meta_value,16385) AS value FROM %i WHERE post_id IN (' . implode( ',', array_fill( 0, count( $ids ), '%d' ) ) . ') AND meta_key IN (%s,%s) LIMIT 2000', array_merge( array( $wpdb->postmeta ), $ids, array( '_thumbnail_id', '_product_image_gallery' ) ) ), ARRAY_A );
		foreach ( (array) $meta as  $m ) {
			if ( '_thumbnail_id' === $m['meta_key'] ) {
				self::add_id( $s, $m['value'] );
			} else {
				self::add_ids( $s, $m['value'] );
			}
		}
		$base = self::uploads_path();
		if ( '' !== $base ) {
			// Custom fields and page-builder data: read for picture addresses (not for bare numbers, which could mean anything).
            // phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Bounded read of this batch's custom fields that hold an uploads address.
			$fields = $wpdb->get_results(
				$wpdb->prepare(
					'SELECT LENGTH(meta_value) AS bytes, LEFT(meta_value,%d) AS value FROM %i WHERE post_id IN (' . implode( ',', array_fill( 0, count( $ids ), '%d' ) ) . ') AND meta_key NOT IN (%s,%s) AND (meta_value LIKE %s OR meta_value LIKE %s) LIMIT 2000',
					array_merge( array( self::META_BYTES, $wpdb->postmeta ), $ids, array( '_wp_attachment_metadata', '_wp_attached_file' ), array( '%' . $wpdb->esc_like( $base ) . '%', '%' . $wpdb->esc_like( str_replace( '/', '\\/', $base ) ) . '%' ) )
				),
				ARRAY_A
			);
			// phpcs:enable WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
			foreach ( (array) $fields as  $f ) {
				if ( (int) $f['bytes'] > self::META_BYTES ) {
					++$s['skipped'];
				} self::add_paths( $s, (string) $f['value'] );
			}
		}
		foreach ( $rows as  $row ) {
			$s['cursor'] = (int) $row['ID'];
			if ( (int) $row['bytes'] > self::CONTENT_BYTES ) {
				++$s['skipped'];
				continue;
			}
			++$s['checked'];
			self::content( $s, $row['body'] . "\n" . $row['excerpt'], (int) $row['ID'] );
		}
	}
	/**
	 * Comments and reviews: their saved text, for pictures in it.
	 *
	 * @param array $s The check, changed in place.
	 * @throws \RuntimeException With unused_database when the comments cannot be read.
	 */
	private static function comment_batch( array &$s ): void {
		global $wpdb;
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Bounded keyset scan of saved comment text.
		$rows = $wpdb->get_results( $wpdb->prepare( 'SELECT comment_ID, LENGTH(comment_content) AS bytes, LEFT(comment_content,%d) AS body FROM %i WHERE comment_ID > %d AND comment_approved NOT IN (%s,%s) ORDER BY comment_ID ASC LIMIT %d', self::META_BYTES, $wpdb->comments, (int) $s['cursor'], 'trash', 'spam', self::COMMENT_BATCH ), ARRAY_A );
		if ( $wpdb->last_error || ! is_array( $rows ) ) {
			throw new \RuntimeException( 'unused_database' );
		}
		if ( ! $rows ) {
			$s['phase']  = 'site';
			$s['cursor'] = 0;
			return;
		}
		foreach ( $rows as  $row ) {
			$s['cursor'] = (int) $row['comment_ID'];
			if ( (int) $row['bytes'] > self::META_BYTES ) {
				++$s['skipped'];
				continue;
			}
			if ( '' !== (string) $row['body'] ) {
				self::content( $s, (string) $row['body'], 0 );
			}
		}
	}
	/**
	 * All names one attachment has under uploads: its file, every size and the kept original.
	 *
	 * @param int $id The attachment.
	 * @return array Its names under uploads, in lower case.
	 */
	private static function names( int $id ): array {
		$file = (string) get_post_meta( $id, '_wp_attached_file', true );
		if ( '' === $file ) {
			return array();
		}
		$dir  = str_contains( $file, '/' ) ? substr( $file, 0, strrpos( $file, '/' ) + 1 ) : '';
		$out  = array( strtolower( $file ) );
		$meta = wp_get_attachment_metadata( $id );
		$meta = is_array( $meta ) ? $meta : array();
		foreach ( array_slice( (array) ( $meta['sizes'] ?? array() ), 0, 100 ) as  $size ) {
			if ( is_array( $size ) && is_string( $size['file'] ?? null ) && '' !== $size['file'] ) {
				$out[] = strtolower( $dir . wp_basename( $size['file'] ) );
			}
		}
		if ( is_string( $meta['original_image'] ?? null ) && '' !== $meta['original_image'] ) {
			$out[] = strtolower( $dir . wp_basename( $meta['original_image'] ) );
		}
		return array_values( array_unique( $out ) );
	}
	/**
	 * Check the next library files against the uses found, and list those with none.
	 *
	 * @param array $s The check, changed in place.
	 * @throws \RuntimeException With unused_database when the library cannot be read.
	 */
	private static function file_batch( array &$s ): void {
		global $wpdb;
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Bounded keyset scan of the Media Library.
		$rows = $wpdb->get_results( $wpdb->prepare( 'SELECT ID, post_parent, post_mime_type FROM %i WHERE post_type = %s AND post_status <> %s AND ID > %d AND ID <= %d ORDER BY ID ASC LIMIT %d', $wpdb->posts, 'attachment', 'trash', (int) $s['cursor'], (int) $s['files_max'], self::FILE_BATCH ), ARRAY_A );
		if ( $wpdb->last_error || ! is_array( $rows ) ) {
			throw new \RuntimeException( 'unused_database' );
		}
		if ( ! $rows ) {
			$s['status'] = 'done';
			$s['phase']  = 'done';
			return;
		}
		foreach ( $rows as  $row ) {
			$id          = (int) $row['ID'];
			$s['cursor'] = $id;
			++$s['files_checked'];
			if ( isset( $s['ids'][ $id ] ) || ( str_starts_with( (string) $row['post_mime_type'], 'image/' ) && isset( $s['parents'][ (int) $row['post_parent'] ] ) ) ) {
				continue;
			}
			$used = false;
			foreach ( self::names( $id ) as  $name ) {
				if ( isset( $s['paths'][ $name ] ) ) {
					$used = true;
					break;
				}
			}
			if ( $used ) {
				continue;
			}
			if ( count( $s['listed'] ) < self::MAX_LISTED ) {
				$s['listed'][] = $id;
			} else {
				++$s['more_listed'];
			}
		}
	}
	/**
	 * Put the listed files into a new collection, in steps, so they can be reviewed in the library. Nothing is deleted.
	 *
	 * @return array The check, with the collection's progress.
	 * @throws \RuntimeException With a reason code as its message when the step cannot be done.
	 */
	public static function collect(): array {
		$im_reviewed_owner_lock = Reviewed_Store::enter();
		try {
			if ( ! current_user_can( 'manage_options' ) || ! current_user_can( 'upload_files' ) ) {
				throw new \RuntimeException( 'unused_access' );
			}
			$s = self::state();
			if ( ! $s || 'done' !== $s['status'] || ! $s['listed'] ) {
				throw new \RuntimeException( 'unused_stale' );
			}
			if ( ! $s['collection'] || ! get_term( (int) $s['collection'], Library::COLLECTION ) ) {
				/* translators: %s: date and time of the check, in UTC. */
				$made = Library::create_term( Library::COLLECTION, sprintf( __( 'No use found %s', 'affstackdev-image-manager' ), gmdate( 'Y-m-d H:i', (int) $s['started'] ) ) );
				// A collection of the same name (a check started in the same minute) is reused.
				$same = is_wp_error( $made ) && 'term_exists' === $made->get_error_code() ? (int) $made->get_error_data( 'term_exists' ) : 0;
				if ( is_wp_error( $made ) && ! $same ) {
					throw new \RuntimeException( 'unused_collection' );
				}
				$s['collection'] = $same ?: (int) $made['term_id'];
				$s['collected']  = 0;
			}
			$until = microtime( true ) + 8;
			while ( $s['collected'] < count( $s['listed'] ) && microtime( true ) < $until ) {
				$chunk = array_slice( $s['listed'], (int) $s['collected'], 100 );
				Library::assign( $chunk, Library::COLLECTION, array( (int) $s['collection'] ) );
				$s['collected'] += count( $chunk );
			}
			Reviewed_Store::update_option( self::OPTION, $s, false );
			return $s;
		} finally {
			Reviewed_Store::leave( $im_reviewed_owner_lock );
		}
	}
	/**
	 * The words for the check's reason code.
	 *
	 * @param string $code The reason code.
	 * @return string The translated words.
	 */
	public static function human_error( string $code ): string {
		$m = array(
			'unused_access'     => __( 'You cannot check site media.', 'affstackdev-image-manager' ),
			'unused_busy'       => __( 'A check is still working. Reload the library in a moment.', 'affstackdev-image-manager' ),
			'unused_stale'      => __( 'This check finished or changed in another window. Reload the library.', 'affstackdev-image-manager' ),
			'unused_database'   => __( 'The check could not read the site’s content. Reload the library and continue.', 'affstackdev-image-manager' ),
			'unused_storage'    => __( 'The check could not save its progress. Reload the library and continue.', 'affstackdev-image-manager' ),
			'unused_collection' => __( 'The collection could not be made. Reload the library and try again.', 'affstackdev-image-manager' ),
		);
		return $m[ $code ] ?? __( 'The check could not finish. Reload the library and continue.', 'affstackdev-image-manager' );
	}
}