<?php
/**
 * Accesswell_Alt
 *
 * Alternative text tools:
 *  - images in the Media Library without alternative text, editable in bulk;
 *  - images inserted into content with an empty or missing alt attribute
 *    while the Media Library has alternative text for that image.
 *    WordPress copies the text only when an image is inserted, so text
 *    added to the library later never reaches existing posts. The fix
 *    copies it in, and saves each post as a revision.
 *
 * @package Accesswell
 */

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

class Accesswell_Alt {

	/** Posts checked for content images. */
	const MAX_POSTS = 1000;

	/**
	 * Media Library images without alternative text.
	 *
	 * @return array List of { id, title, file }.
	 */
	public static function missing_in_library() {
		global $wpdb;

		$rows = $wpdb->get_results( // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- One query instead of one per image.
			"SELECT p.ID, p.post_title, f.meta_value AS file
			FROM {$wpdb->posts} p
			LEFT JOIN {$wpdb->postmeta} a ON a.post_id = p.ID AND a.meta_key = '_wp_attachment_image_alt'
			LEFT JOIN {$wpdb->postmeta} f ON f.post_id = p.ID AND f.meta_key = '_wp_attached_file'
			WHERE p.post_type = 'attachment' AND p.post_mime_type LIKE 'image/%' AND ( a.meta_value IS NULL OR TRIM( a.meta_value ) = '' )
			ORDER BY p.ID DESC",
			ARRAY_A
		);

		$out = array();
		foreach ( $rows as $row ) {
			$out[] = array(
				'id'    => (int) $row['ID'],
				'title' => (string) $row['post_title'],
				'file'  => (string) $row['file'],
			);
		}
		return $out;
	}

	/**
	 * Save alternative text for several images.
	 *
	 * @param array $alts Attachment ID => text.
	 * @return array { saved: int, skipped: int }
	 */
	public static function save_library( array $alts ) {
		$saved   = 0;
		$skipped = 0;
		foreach ( $alts as $id => $alt ) {
			$id  = (int) $id;
			$alt = trim( sanitize_text_field( (string) $alt ) );
			if ( '' === $alt ) {
				continue;
			}
			if ( 'attachment' !== get_post_type( $id ) || ! current_user_can( 'edit_post', $id ) ) {
				++$skipped;
				continue;
			}
			update_post_meta( $id, '_wp_attachment_image_alt', $alt );
			++$saved;
		}
		return array(
			'saved'   => $saved,
			'skipped' => $skipped,
		);
	}

	/**
	 * Posts with content images that have no alternative text.
	 *
	 * @return array List of { id, title, type, status, fixable, missing }:
	 *               fixable images have text in the Media Library; missing
	 *               ones need text added there first.
	 */
	public static function content_gaps() {
		global $wpdb;

		$types   = Accesswell_Settings::post_types();
		$holders = implode( ',', array_fill( 0, count( $types ), '%s' ) );
		$posts   = $wpdb->get_results( // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Content search across post types.
			$wpdb->prepare( // phpcs:ignore WordPress.DB.PreparedSQLPlaceholders.ReplacementsWrongNumber -- One %s per type plus the limit, passed as an array.
				"SELECT ID, post_title, post_type, post_status, post_content FROM {$wpdb->posts} WHERE post_type IN ($holders) AND post_status IN ( 'publish', 'future', 'draft', 'pending', 'private' ) AND post_content LIKE %s ORDER BY post_modified DESC LIMIT %d", // phpcs:ignore WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare,WordPress.DB.PreparedSQL.InterpolatedNotPrepared
				array_merge( $types, array( '%' . $wpdb->esc_like( '<img' ) . '%', self::MAX_POSTS ) )
			),
			ARRAY_A
		);

		$out = array();
		foreach ( $posts as $post ) {
			$fixable = 0;
			$missing = 0;
			foreach ( self::images_without_alt( $post['post_content'] ) as $image ) {
				if ( '' !== $image['library_alt'] ) {
					++$fixable;
				} else {
					++$missing;
				}
			}
			if ( $fixable || $missing ) {
				$out[] = array(
					'id'      => (int) $post['ID'],
					'title'   => '' !== $post['post_title'] ? $post['post_title'] : __( '(no title)', 'accesswell' ),
					'type'    => $post['post_type'],
					'status'  => $post['post_status'],
					'fixable' => $fixable,
					'missing' => $missing,
				);
			}
		}
		return $out;
	}

	/**
	 * Images in content with no alternative text.
	 *
	 * Images marked decorative on purpose (role="presentation" or
	 * aria-hidden) are skipped. An empty alt="" usually means the text was
	 * never filled in, since the block editor writes alt="" by default.
	 *
	 * @param string $content Content.
	 * @return array List of { tag, id, library_alt }.
	 */
	public static function images_without_alt( $content ) {
		if ( ! preg_match_all( '/<img\b[^>]*>/i', (string) $content, $tags ) ) {
			return array();
		}
		$out = array();
		foreach ( $tags[0] as $tag ) {
			if ( preg_match( '/\brole\s*=\s*["\']?(presentation|none)/i', $tag ) || preg_match( '/\baria-hidden\s*=\s*["\']?true/i', $tag ) ) {
				continue;
			}
			if ( preg_match( '/\balt\s*=\s*(["\'])(.*?)\1/is', $tag, $alt ) && '' !== trim( $alt[2] ) ) {
				continue;
			}
			$id    = preg_match( '/\bwp-image-(\d+)\b/', $tag, $m ) ? (int) $m[1] : 0;
			$out[] = array(
				'tag'         => $tag,
				'id'          => $id,
				'library_alt' => $id ? trim( (string) get_post_meta( $id, '_wp_attachment_image_alt', true ) ) : '',
			);
		}
		return $out;
	}

	/**
	 * Copy Media Library alternative text into a post's images that have
	 * none. Saved as a revision.
	 *
	 * @param int $post_id Post ID.
	 * @return int|WP_Error Number of images changed.
	 */
	public static function fix_post( $post_id ) {
		$post = get_post( $post_id );
		if ( ! $post ) {
			return new WP_Error( 'accesswell_missing', __( 'That content no longer exists.', 'accesswell' ) );
		}
		if ( ! current_user_can( 'edit_post', $post_id ) ) {
			return new WP_Error( 'accesswell_cap', __( 'You are not allowed to edit that content.', 'accesswell' ) );
		}

		$changed = 0;
		$content = preg_replace_callback(
			'/<img\b[^>]*>/i',
			function ( $m ) use ( &$changed ) {
				$tag = $m[0];
				foreach ( self::images_without_alt( $tag ) as $image ) {
					if ( '' === $image['library_alt'] ) {
						return $tag;
					}
					$value = 'alt="' . esc_attr( $image['library_alt'] ) . '"';
					if ( preg_match( '/\balt\s*=\s*(["\'])(.*?)\1/is', $tag ) ) {
						$tag = preg_replace( '/\balt\s*=\s*(["\'])(.*?)\1/is', $value, $tag, 1 );
					} elseif ( preg_match( '/\balt(?=[\s\/>])/i', $tag ) ) {
						$tag = preg_replace( '/\balt(?=[\s\/>])/i', $value, $tag, 1 ); // A bare "alt" attribute.
					} else {
						$tag = preg_replace( '/^<img\b/i', '<img ' . $value, $tag );
					}
					++$changed;
				}
				return $tag;
			},
			$post->post_content
		);

		if ( ! $changed || null === $content ) {
			return 0;
		}

		$result = wp_update_post(
			array(
				'ID'           => $post_id,
				'post_content' => wp_slash( $content ),
			),
			true
		);
		return is_wp_error( $result ) ? $result : $changed;
	}
}