<?php
/**
 * Which images belong to a product.
 *
 * @package CortexCommerce
 */

namespace CortexCommerce\Sync;

defined( 'ABSPATH' ) || exit;

/**
 * The one rule for "a product image", used by the approved-product sync and by PUT cortex/v1/media/{id}/alt: an
 * attachment that is a product's main image, one of its gallery pictures, a variation's image, or an upload made from
 * the product's or a variation's editor (post_parent). The product counts unless it is trashed or an auto-draft, as
 * for the SEO route and the sync's own writes. Any other attachment in the media library is refused.
 */
final class ProductImages {

	/**
	 * Statuses whose products' images are never touched.
	 */
	private const DEAD_STATUSES = array( 'trash', 'auto-draft' );

	/**
	 * The product's own images and the ids an upload's post_parent may name (the product and its variations), read
	 * fresh: the product's images may change while a sync runs. Build it once per write and check each image with
	 * contains().
	 *
	 * @return array{images: array<int, int>, family: array<int, int>}
	 */
	public static function of_product( int $product_id ): array {
		clean_post_cache( $product_id );
		$product = wc_get_product( $product_id );
		if ( ! $product instanceof \WC_Product ) {
			return array(
				'images' => array(),
				'family' => array(),
			);
		}
		$family   = array( $product_id );
		$images   = array_map( 'intval', $product->get_gallery_image_ids( 'edit' ) );
		$images[] = (int) $product->get_image_id( 'edit' );
		foreach ( $product->get_children() as $child ) {
			$family[]  = (int) $child;
			$variation = wc_get_product( (int) $child );
			if ( $variation instanceof \WC_Product ) {
				$images[] = (int) $variation->get_image_id( 'edit' );
			}
		}
		return array(
			'images' => array_values( array_filter( array_unique( $images ) ) ),
			'family' => $family,
		);
	}

	/**
	 * Whether $attachment_id is one of the images in $set (from of_product()).
	 *
	 * @param array{images: array<int, int>, family: array<int, int>} $set The product's images.
	 */
	public static function contains( array $set, int $attachment_id ): bool {
		if ( $attachment_id <= 0 || 'attachment' !== get_post_type( $attachment_id ) ) {
			return false;
		}
		return in_array( $attachment_id, $set['images'], true ) || in_array( (int) get_post_field( 'post_parent', $attachment_id ), $set['family'], true );
	}

	/**
	 * Whether $attachment_id is an image of any product that counts, cheapest check first: its post_parent (a primary
	 * key read), then products naming it as their main image, then galleries (each narrowed by the meta_key index).
	 * Nothing is cached: the answer guards a single write and the relations change under the editor's feet.
	 */
	public static function of_any_product( int $attachment_id ): bool {
		if ( $attachment_id <= 0 || 'attachment' !== get_post_type( $attachment_id ) ) {
			return false;
		}
		$parent = (int) get_post_field( 'post_parent', $attachment_id );
		if ( $parent > 0 && self::counts( $parent ) ) {
			return true;
		}
		global $wpdb;
		$id = (string) $attachment_id;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- Existence check on one meta key, uncached on purpose; see the docblock.
		$thumbnail_of = $wpdb->get_col( $wpdb->prepare( "SELECT post_id FROM {$wpdb->postmeta} WHERE meta_key = '_thumbnail_id' AND meta_value = %s", $id ) );
		// A whole list entry only: FIND_IN_SET never matches an id whose digits sit inside another id, unlike LIKE alone.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- As above.
		$gallery_of = $wpdb->get_col( $wpdb->prepare( "SELECT post_id FROM {$wpdb->postmeta} WHERE meta_key = '_product_image_gallery' AND meta_value LIKE %s AND FIND_IN_SET( %s, meta_value )", '%' . $wpdb->esc_like( $id ) . '%', $id ) );
		foreach ( array_merge( (array) $thumbnail_of, (array) $gallery_of ) as $owner ) {
			if ( self::counts( (int) $owner ) ) {
				return true;
			}
		}
		return false;
	}

	/**
	 * Whether $post_id is a product or variation that is neither trashed nor an auto-draft.
	 */
	private static function counts( int $post_id ): bool {
		$post = get_post( $post_id );
		return $post instanceof \WP_Post
			&& in_array( $post->post_type, array( 'product', 'product_variation' ), true )
			&& ! in_array( $post->post_status, self::DEAD_STATUSES, true );
	}
}