<?php
/**
 * Alt text and titles from file names (1.9.0, D-500 gap 3). With Settings > "Fill empty alt text and titles from file
 * names" on, a new image whose alt text is empty gets one made from its file name ("red-summer_dress-2.jpg" becomes
 * "Red summer dress 2"), and its title too when WordPress copied the bare file name into it. Text a person wrote is
 * never replaced; names that say nothing (camera names such as IMG_1234, screenshots, numbers, hashes) give no text.
 * Tools > "Fill empty alt text now" does the same for images already in the library (alt text only).
 *
 * @package AffStackDevImageManager
 */

namespace AffStackDev\ImageManager;

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

/** Text for images from their file names. */
final class Auto_Text {
	const BATCH  = 300;
	const RETRY  = Hooks::AUTO_TEXT_RETRY;
	const CURSOR = 'afsd_im_auto_text_cursor';

	/**
	 * Words from a file name, or '' when the name says nothing.
	 *
	 * @param string $file A file name or path, or a title WordPress copied from one.
	 * @return string
	 */
	public static function from_file( string $file ): string {
		$name = wp_basename( $file );
		$name = (string) preg_replace( '/\.[a-z0-9]{2,5}$/i', '', $name );
		// WordPress's own additions to a file name: the scaled and rotated copies, edits and size suffixes.
		$name = (string) preg_replace( '/-(?:scaled|rotated|e\d{10,13}|\d+x\d+)$/i', '', $name );
		$name = trim( (string) preg_replace( '/[\s._-]+/u', ' ', $name ) );
		if ( '' === $name
			|| preg_match( '/^(?:img|image|dsc|dscn|dscf|pxl|mvimg|photo|pic|picture|vid|whatsapp image|signal)\b[\s\d]*$/i', $name )
			|| preg_match( '/^(?:screenshot|screen shot)\b/i', $name )
			|| preg_match( '/^[\d\s]+$/', $name )
			|| preg_match( '/^[a-f0-9]{16,}$/i', str_replace( ' ', '', $name ) ) ) {
			return '';
		}
		return mb_strtoupper( mb_substr( $name, 0, 1 ) ) . mb_substr( $name, 1 );
	}

	/**
	 * Whether a title is the bare file name WordPress copied at upload (also when WordPress added "-1" to the file
	 * name because one with that name was already there).
	 *
	 * @param int    $id    Attachment.
	 * @param string $title Its title.
	 * @return bool
	 */
	public static function copied_title( int $id, string $title ): bool {
		if ( '' === $title || str_contains( $title, ' ' ) ) {
			return false;
		}
		$base = (string) preg_replace( '/\.[a-z0-9]{2,5}$/i', '', wp_basename( (string) get_attached_file( $id ) ) );
		$base = sanitize_title( (string) preg_replace( '/-(?:scaled|rotated)$/i', '', $base ) );
		$name = sanitize_title( $title );
		return $name === $base || 1 === preg_match( '/^' . preg_quote( $name, '/' ) . '-\d+$/', $base );
	}

	/**
	 * A new upload (or its retry): fill its empty alt text and its copied title. Copies Image Manager makes itself
	 * (edited copies, PDF pages, restored backups) keep the text they were given: they are added while this request
	 * holds the owner lock, as is an upload through Image Manager's own Upload media to a folder form, which is told
	 * apart by the upload receipt that form gives the file. Inside an approved change nothing is filled. While another
	 * Image Manager change is being written, the upload is not held up: the fill is tried again in a minute, then two
	 * and four.
	 *
	 * @param int $id Attachment.
	 * @return void
	 */
	public static function on_upload( $id ): void {
		$id = (int) $id;
		if ( empty( Settings::get()['auto_text'] ) || '' !== Reviewed_Store::execution_marker() ) {
			return;
		}
		if ( Reviewed_Store::holding() && '' === (string) get_post_meta( $id, '_afsd_im_upload_receipt', true ) ) {
			return;
		}
		try {
			$lock = Reviewed_Store::enter();
		} catch ( \RuntimeException $e ) {
			$attempt = (int) get_post_meta( $id, '_afsd_im_auto_text_retry', true );
			if ( Reviewed_Store::busy( $e ) && $attempt < 3 && ! wp_next_scheduled( self::RETRY, array( $id ) ) ) {
				update_post_meta( $id, '_afsd_im_auto_text_retry', $attempt + 1 );
				wp_schedule_single_event( time() + 60 * ( 2 ** $attempt ), self::RETRY, array( $id ) );
			}
			return;
		}
		try {
			self::fill( $id, true );
			Reviewed_Store::delete_post_meta( $id, '_afsd_im_auto_text_retry' );
		} finally {
			Reviewed_Store::leave( $lock );
		}
	}

	/**
	 * Fill one image's empty alt text (and, on upload, a copied title) from its file name. The caller holds the lock.
	 *
	 * @param int  $id     Attachment.
	 * @param bool $titles Also the title, when WordPress copied the bare file name into it.
	 * @return array|null The fields filled (alt, title), or null when the file name gives no text.
	 */
	private static function fill( int $id, bool $titles ): ?array {
		$post = get_post( $id );
		if ( ! $post || 'attachment' !== $post->post_type || ! str_starts_with( (string) $post->post_mime_type, 'image/' ) ) {
			return array();
		}
		$copied = self::copied_title( $id, (string) $post->post_title );
		$text   = sanitize_text_field( self::from_file( $copied ? $post->post_title : (string) get_attached_file( $id ) ) );
		if ( '' === $text ) {
			return null;
		}
		$filled = array();
		if ( '' === trim( (string) get_post_meta( $id, '_wp_attachment_image_alt', true ) ) ) {
			Reviewed_Store::update_post_meta( $id, '_wp_attachment_image_alt', $text );
			$filled[] = 'alt';
		}
		if ( $titles && $copied ) {
			$done = Reviewed_Store::wp_update_post(
				wp_slash(
					array(
						'ID'         => $id,
						'post_title' => $text,
					)
				),
				true
			);
			if ( ! is_wp_error( $done ) ) {
				$filled[] = 'title';
			}
		}
		return $filled;
	}

	/**
	 * Images in the library without alt text, oldest first, after a given ID.
	 *
	 * @param int $limit At most this many.
	 * @param int $after Only IDs above this one (the cursor of the previous batch).
	 * @return array Attachment IDs.
	 */
	public static function missing( int $limit, int $after = 0 ): array {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- one bounded batch the administrator starts on Tools; it must read the current rows.
		$ids = $wpdb->get_col(
			$wpdb->prepare(
				"SELECT p.ID FROM {$wpdb->posts} p LEFT JOIN {$wpdb->postmeta} m ON m.post_id = p.ID AND m.meta_key = '_wp_attachment_image_alt' WHERE p.post_type = 'attachment' AND p.post_status = 'inherit' AND p.post_mime_type LIKE %s AND p.ID > %d AND ( m.meta_id IS NULL OR TRIM( m.meta_value ) = '' ) ORDER BY p.ID ASC LIMIT %d",
				'image/%',
				$after,
				$limit
			)
		);
		return array_map( 'intval', (array) $ids );
	}

	/**
	 * Tools > Fill empty alt text now: the next bounded batch of the library (alt text only; titles are left as they
	 * are). A cursor remembers where the batch ended, so the next click goes on from there.
	 *
	 * @return array Counts: checked, filled, no_usable_name, skipped (images this user may not edit), more (true while
	 *               the library has more to check), busy (another Image Manager change is being written; nothing checked).
	 * @throws \RuntimeException When the owner lock fails for a reason other than another writer.
	 */
	public static function fill_missing(): array {
		$out = array(
			'checked'        => 0,
			'filled'         => 0,
			'no_usable_name' => 0,
			'skipped'        => 0,
			'more'           => false,
			'busy'           => false,
		);
		try {
			$lock = Reviewed_Store::enter( 8 );
		} catch ( \RuntimeException $e ) {
			if ( ! Reviewed_Store::busy( $e ) ) {
				throw $e;
			}
			$out['busy'] = true;
			return $out;
		}
		try {
			$ids = self::missing( self::BATCH, (int) get_option( self::CURSOR, 0 ) );
			foreach ( $ids as $id ) {
				if ( ! current_user_can( 'edit_post', $id ) ) {
					++$out['skipped'];
					continue;
				}
				$filled = self::fill( $id, false );
				if ( null === $filled ) {
					++$out['no_usable_name'];
				} elseif ( in_array( 'alt', $filled, true ) ) {
					++$out['filled'];
				}
			}
			$out['checked'] = count( $ids );
			$out['more']    = count( $ids ) === self::BATCH;
			Reviewed_Store::update_option( self::CURSOR, $out['more'] ? (int) end( $ids ) : 0, false );
		} finally {
			Reviewed_Store::leave( $lock );
		}
		return $out;
	}
}