<?php
/**
 * Media library alt text: find images without it, save it, mark decorative.
 *
 * Alt text saved here goes into WordPress's own field (_wp_attachment_image_alt),
 * so it stays when Fixlight is removed.
 *
 * @package Fixlight
 */

namespace Fixlight;

defined( 'ABSPATH' ) || exit;

/**
 * Alt text audit.
 */
class Images {

	const DECORATIVE_META = '_fixlight_decorative';
	const LEDGER          = 'fixlight_ledger';

	/**
	 * Counts for the Images screen.
	 *
	 * @return array{total:int,missing:int,decorative:int,described:int}
	 */
	public static function counts() {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
		$total   = (int) $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM {$wpdb->posts} WHERE post_type = 'attachment' AND post_mime_type LIKE %s AND post_mime_type NOT IN ('image/svg+xml','image/x-icon','image/vnd.microsoft.icon')", $wpdb->esc_like( 'image/' ) . '%' ) );
		$missing = self::query_missing( 0, 0, true );
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
		$decorative = (int) $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM {$wpdb->postmeta} WHERE meta_key = %s AND meta_value = '1'", self::DECORATIVE_META ) );
		return array(
			'total'      => $total,
			'missing'    => $missing,
			'decorative' => $decorative,
			'described'  => max( 0, $total - $missing - $decorative ),
		);
	}

	/**
	 * Images with no alt text that are not marked decorative.
	 *
	 * @param int  $offset Offset.
	 * @param int  $limit  Page size.
	 * @param bool $count  Return the count instead of rows.
	 * @return int|int[] Count or attachment ids.
	 */
	public static function query_missing( $offset = 0, $limit = 20, $count = false ) {
		global $wpdb;
		if ( $count ) {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
			return (int) $wpdb->get_var(
				$wpdb->prepare(
					"SELECT COUNT(*) FROM {$wpdb->posts} p
					LEFT JOIN {$wpdb->postmeta} alt ON alt.post_id = p.ID AND alt.meta_key = '_wp_attachment_image_alt'
					LEFT JOIN {$wpdb->postmeta} deco ON deco.post_id = p.ID AND deco.meta_key = %s
					WHERE p.post_type = 'attachment'
					AND p.post_mime_type LIKE %s
					AND p.post_mime_type NOT IN ('image/svg+xml','image/x-icon','image/vnd.microsoft.icon')
					AND ( alt.meta_value IS NULL OR TRIM(alt.meta_value) = '' )
					AND ( deco.meta_value IS NULL OR deco.meta_value <> '1' )",
					self::DECORATIVE_META,
					$wpdb->esc_like( 'image/' ) . '%'
				)
			);
		}
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
		$ids = $wpdb->get_col(
			$wpdb->prepare(
				"SELECT p.ID FROM {$wpdb->posts} p
				LEFT JOIN {$wpdb->postmeta} alt ON alt.post_id = p.ID AND alt.meta_key = '_wp_attachment_image_alt'
				LEFT JOIN {$wpdb->postmeta} deco ON deco.post_id = p.ID AND deco.meta_key = %s
				WHERE p.post_type = 'attachment'
				AND p.post_mime_type LIKE %s
				AND p.post_mime_type NOT IN ('image/svg+xml','image/x-icon','image/vnd.microsoft.icon')
				AND ( alt.meta_value IS NULL OR TRIM(alt.meta_value) = '' )
				AND ( deco.meta_value IS NULL OR deco.meta_value <> '1' )
				ORDER BY p.post_date DESC LIMIT %d OFFSET %d",
				self::DECORATIVE_META,
				$wpdb->esc_like( 'image/' ) . '%',
				$limit,
				$offset
			)
		);
		return array_map( 'intval', $ids );
	}

	/**
	 * Data the Images screen shows for one attachment.
	 *
	 * @param int $id Attachment id.
	 * @return array
	 */
	public static function describe( $id ) {
		$parent = (int) wp_get_post_parent_id( $id );
		$file   = get_attached_file( $id );
		return array(
			'id'           => $id,
			'thumb'        => wp_get_attachment_image_url( $id, 'thumbnail' ),
			'medium'       => wp_get_attachment_image_url( $id, 'medium_large' ),
			'title'        => get_the_title( $id ),
			'file'         => $file ? wp_basename( $file ) : '',
			'alt'          => (string) get_post_meta( $id, '_wp_attachment_image_alt', true ),
			'decorative'   => (bool) get_post_meta( $id, self::DECORATIVE_META, true ),
			'parent_title' => $parent ? get_the_title( $parent ) : '',
			'parent_link'  => $parent ? get_edit_post_link( $parent, 'raw' ) : '',
			'edit_link'    => get_edit_post_link( $id, 'raw' ),
		);
	}

	/**
	 * Saves alt text or marks an image decorative.
	 *
	 * @param int    $id         Attachment id.
	 * @param string $alt        Alt text.
	 * @param bool   $decorative Whether the image is decorative.
	 * @return array|\WP_Error Updated image data.
	 */
	public static function save( $id, $alt, $decorative ) {
		$post = get_post( $id );
		if ( ! $post || 'attachment' !== $post->post_type || ! wp_attachment_is_image( $id ) ) {
			return new \WP_Error( 'fixlight_not_image', __( 'That is not an image in the media library.', 'fixlight' ), array( 'status' => 404 ) );
		}
		if ( ! current_user_can( 'edit_post', $id ) ) {
			return new \WP_Error( 'fixlight_forbidden', __( 'You cannot edit this image.', 'fixlight' ), array( 'status' => 403 ) );
		}
		$alt = trim( sanitize_text_field( $alt ) );
		// The ledger counts images, so saving the same image again does not add to it.
		$had_alt        = '' !== trim( (string) get_post_meta( $id, '_wp_attachment_image_alt', true ) );
		$was_decorative = (bool) get_post_meta( $id, self::DECORATIVE_META, true );
		if ( $decorative ) {
			update_post_meta( $id, self::DECORATIVE_META, '1' );
			delete_post_meta( $id, '_wp_attachment_image_alt' );
			if ( ! $was_decorative ) {
				self::count( 'decorative' );
			}
		} else {
			delete_post_meta( $id, self::DECORATIVE_META );
			if ( '' === $alt ) {
				delete_post_meta( $id, '_wp_attachment_image_alt' );
			} else {
				update_post_meta( $id, '_wp_attachment_image_alt', $alt );
				if ( ! $had_alt ) {
					self::count( 'alt_written' );
				}
			}
		}
		Cache::purge_soon();
		return self::describe( $id );
	}

	/**
	 * Adds to the fix ledger.
	 *
	 * @param string $key Counter.
	 */
	private static function count( $key ) {
		$ledger         = get_option( self::LEDGER, array() );
		$ledger         = is_array( $ledger ) ? $ledger : array();
		$ledger[ $key ] = isset( $ledger[ $key ] ) ? (int) $ledger[ $key ] + 1 : 1;
		update_option( self::LEDGER, $ledger, false );
	}

	/**
	 * Ledger counters.
	 *
	 * @return array{alt_written:int,decorative:int}
	 */
	public static function ledger() {
		$ledger = get_option( self::LEDGER, array() );
		$ledger = is_array( $ledger ) ? $ledger : array();
		return array(
			'alt_written' => isset( $ledger['alt_written'] ) ? (int) $ledger['alt_written'] : 0,
			'decorative'  => isset( $ledger['decorative'] ) ? (int) $ledger['decorative'] : 0,
		);
	}
}