<?php
namespace TDL_GMC_Lite;

use WC_Product;
use WC_Product_Attribute;
use WC_Product_Variation;

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


/** UTF-8-safe length helper with a byte-string fallback when mbstring is unavailable. */
function text_length( string $value ): int {
    return function_exists( 'mb_strlen' ) ? mb_strlen( $value, 'UTF-8' ) : strlen( $value );
}

/** UTF-8-safe substring helper with a byte-string fallback when mbstring is unavailable. */
function limit_text( string $value, int $length ): string {
    if ( $length <= 0 ) {
        return '';
    }
    return function_exists( 'mb_substr' ) ? mb_substr( $value, 0, $length, 'UTF-8' ) : substr( $value, 0, $length );
}

/** Allow developers to provide Google Product Category per product. */
function map_google_category( WC_Product $product ): string {
    return trim( (string) apply_filters( 'tdl_gmc_google_category', '', $product ) );
}

/** Global fallback brand configured in plugin settings. */
function resolve_brand(): string {
    $brand = trim( (string) get_option( 'tdl_gmc_brand_name', '' ) );
    $use_site_name = (bool) get_option( 'tdl_gmc_brand_use_site_name', false );
    $use_site_name = (bool) apply_filters( 'tdl_gmc_brand_fallback_to_site_name', $use_site_name );

    if ( $brand === '' && $use_site_name ) {
        $brand = trim( (string) get_bloginfo( 'name' ) );
        $brand = trim( (string) preg_replace( '/\s*\.cz$/i', '', $brand ) );
    }

    return trim( (string) apply_filters( 'tdl_gmc_brand', $brand ) );
}

/** Resolve a product-specific brand before falling back to the global setting. */
function resolve_product_brand( WC_Product $product, ?WC_Product_Variation $variation = null ): string {
    $subjects = [];
    if ( $variation instanceof WC_Product_Variation ) {
        $subjects[] = $variation;
    }
    $subjects[] = $product;

    $meta_keys = [ '_brand', 'brand', '_manufacturer', 'manufacturer' ];
    foreach ( $subjects as $subject ) {
        foreach ( $meta_keys as $key ) {
            $raw = $subject->get_meta( $key, true );
            if ( is_scalar( $raw ) ) {
                $value = trim( wp_strip_all_tags( (string) $raw ) );
                if ( $value !== '' ) {
                    return trim( (string) apply_filters( 'tdl_gmc_product_brand', $value, $product, $variation ) );
                }
            }
        }
    }

    // WooCommerce Brands uses the product_brand taxonomy in current WooCommerce versions.
    if ( taxonomy_exists( 'product_brand' ) ) {
        $terms = get_the_terms( $product->get_id(), 'product_brand' );
        if ( is_array( $terms ) && ! empty( $terms ) ) {
            foreach ( $terms as $term ) {
                if ( isset( $term->name ) ) {
                    $value = trim( wp_strip_all_tags( (string) $term->name ) );
                    if ( $value !== '' ) {
                        return trim( (string) apply_filters( 'tdl_gmc_product_brand', $value, $product, $variation ) );
                    }
                }
            }
        }
    }

    $attribute_keys = [
        'pa_brand', 'brand', 'pa_manufacturer', 'manufacturer',
        'pa_znacka', 'znacka', 'pa_vyrobce', 'vyrobce',
    ];
    foreach ( $subjects as $subject ) {
        foreach ( $attribute_keys as $key ) {
            $value = trim( wp_strip_all_tags( (string) $subject->get_attribute( $key ) ) );
            if ( $value !== '' ) {
                $value = trim( (string) explode( ',', $value )[0] );
                return trim( (string) apply_filters( 'tdl_gmc_product_brand', $value, $product, $variation ) );
            }
        }
    }

    return trim( (string) apply_filters( 'tdl_gmc_product_brand', resolve_brand(), $product, $variation ) );
}

function get_option_gtin_keys(): array {
    return _tdl_gmc_parse_list_option( (string) get_option( 'tdl_gmc_gtin_keys', '' ) );
}

function get_option_mpn_keys(): array {
    return _tdl_gmc_parse_list_option( (string) get_option( 'tdl_gmc_mpn_keys', '' ) );
}

/** Validate a GTIN-8/12/13/14 including the GS1 check digit and Google-restricted prefixes. */
function _tdl_gmc_is_valid_gtin( string $value ): bool {
    $length = strlen( $value );
    if ( ! in_array( $length, [ 8, 12, 13, 14 ], true ) || ! ctype_digit( $value ) ) {
        return false;
    }

    // Google Merchant Center does not accept restricted/internal-use or coupon GTIN ranges.
    if ( strpos( $value, '02' ) === 0 || strpos( $value, '04' ) === 0 || strpos( $value, '2' ) === 0 || strpos( $value, '98' ) === 0 || strpos( $value, '99' ) === 0 ) {
        return false;
    }

    $sum = 0;
    $weight = 3;
    for ( $i = $length - 2; $i >= 0; $i-- ) {
        $sum += (int) $value[ $i ] * $weight;
        $weight = ( $weight === 3 ) ? 1 : 3;
    }

    $check_digit = ( 10 - ( $sum % 10 ) ) % 10;
    return $check_digit === (int) $value[ $length - 1 ];
}

/** Normalize a possible GTIN and return it only when it is valid for Google Merchant Center. */
function _tdl_gmc_norm_gtin( $value ): string {
    if ( is_array( $value ) ) {
        if ( isset( $value['gtin'] ) && is_scalar( $value['gtin'] ) ) {
            $value = $value['gtin'];
        } elseif ( isset( $value['identifier_gtin'] ) && is_scalar( $value['identifier_gtin'] ) ) {
            $value = $value['identifier_gtin'];
        } else {
            $value = '';
        }
    }

    $value = is_scalar( $value ) ? trim( (string) $value ) : '';
    if ( $value === '' ) {
        return '';
    }

    if ( $value[0] === '{' || $value[0] === '[' ) {
        $decoded = json_decode( $value, true );
        if ( is_array( $decoded ) ) {
            if ( isset( $decoded['gtin'] ) ) {
                $value = (string) $decoded['gtin'];
            } elseif ( isset( $decoded['identifier_gtin'] ) ) {
                $value = (string) $decoded['identifier_gtin'];
            }
        }
    }

    $value = (string) preg_replace( '/[^0-9]/', '', $value );
    return _tdl_gmc_is_valid_gtin( $value ) ? $value : '';
}

/** Variation-first GTIN lookup, then parent product. */
function find_gtin( WC_Product $product, ?WC_Product_Variation $variation = null ): string {
    $subjects = [];
    if ( $variation instanceof WC_Product_Variation ) {
        $subjects[] = $variation;
    } elseif ( $product instanceof WC_Product_Variation ) {
        $subjects[] = $product;
        $parent = wc_get_product( $product->get_parent_id() );
        if ( $parent instanceof WC_Product ) {
            $subjects[] = $parent;
        }
    }
    if ( ! in_array( $product, $subjects, true ) ) {
        $subjects[] = $product;
    }

    foreach ( $subjects as $subject ) {
        if ( method_exists( $subject, 'get_global_unique_id' ) ) {
            $value = _tdl_gmc_norm_gtin( $subject->get_global_unique_id() );
            if ( $value !== '' ) {
                return (string) apply_filters( 'tdl_gmc_gtin_value', $value, $subject );
            }
        }
    }

    $default_keys = [
        '_wc_gpf_gtin', '_woocommerce_gpf_gtin', '_woocommerce_gpf_data',
        '_wpm_gtin_code', '_alg_ean', '_alg_wc_ean', '_gtin', 'gtin',
        '_ean', 'ean', 'product_ean', '_product_ean', 'woodmart_barcode',
        'woodmart_ean', '_woodmart_barcode', '_barcode', 'barcode',
        'hwp_product_gtin', '_yith_wcgpf_gtin', '_yoast_wpseo_product_gtin',
        'global_unique_id', 'variable_global_unique_id',
    ];
    $keys = array_values( array_unique( array_merge( $default_keys, get_option_gtin_keys() ) ) );
    $keys = (array) apply_filters( 'tdl_gmc_gtin_keys', $keys, $product, $variation );

    foreach ( $subjects as $subject ) {
        foreach ( $keys as $key ) {
            $key = trim( (string) $key );
            if ( $key === '' ) {
                continue;
            }
            $raw = $subject->get_meta( $key, true );
            $value = _tdl_gmc_norm_gtin( $raw );
            if ( $value !== '' ) {
                return (string) apply_filters( 'tdl_gmc_gtin_value', $value, $subject );
            }

            if ( $key === '_woocommerce_gpf_data' ) {
                $maybe = is_string( $raw ) ? maybe_unserialize( $raw ) : $raw;
                if ( is_array( $maybe ) && isset( $maybe['gtin'] ) ) {
                    $value = _tdl_gmc_norm_gtin( $maybe['gtin'] );
                    if ( $value !== '' ) {
                        return (string) apply_filters( 'tdl_gmc_gtin_value', $value, $subject );
                    }
                }
            }
        }

        $attrs = $subject->get_attributes();
        if ( is_array( $attrs ) ) {
            foreach ( $attrs as $attr ) {
                if ( ! $attr instanceof WC_Product_Attribute ) {
                    continue;
                }
                $name = $attr->get_name();
                $name_norm = strtolower( sanitize_title( $name ) );
                if ( strpos( $name_norm, 'ean' ) === false && strpos( $name_norm, 'gtin' ) === false ) {
                    continue;
                }
                $value = _tdl_gmc_norm_gtin( $subject->get_attribute( $name ) );
                if ( $value !== '' ) {
                    return (string) apply_filters( 'tdl_gmc_gtin_value', $value, $subject );
                }
            }
        }
    }

    return (string) apply_filters( 'tdl_gmc_gtin_value', '', $product );
}

/** Variation-first MPN lookup. SKU is used only when explicitly enabled. */
function find_mpn( WC_Product $product, ?WC_Product_Variation $variation = null ): string {
    $subjects = [];
    if ( $variation instanceof WC_Product_Variation ) {
        $subjects[] = $variation;
    } elseif ( $product instanceof WC_Product_Variation ) {
        $subjects[] = $product;
        $parent = wc_get_product( $product->get_parent_id() );
        if ( $parent instanceof WC_Product ) {
            $subjects[] = $parent;
        }
    }
    if ( ! in_array( $product, $subjects, true ) ) {
        $subjects[] = $product;
    }

    $default_keys = [
        '_mpn', 'mpn', '_manufacturer_part_number', 'manufacturer_part_number',
        '_wc_gpf_mpn', '_woocommerce_gpf_mpn', '_wpm_mpn', '_yith_wcgpf_mpn',
    ];
    $keys = array_values( array_unique( array_merge( $default_keys, get_option_mpn_keys() ) ) );
    $keys = (array) apply_filters( 'tdl_gmc_mpn_keys', $keys, $product, $variation );

    foreach ( $subjects as $subject ) {
        foreach ( $keys as $key ) {
            $raw = $subject->get_meta( (string) $key, true );
            if ( is_scalar( $raw ) ) {
                $value = trim( wp_strip_all_tags( (string) $raw ) );
                if ( $value !== '' ) {
                    return limit_text( (string) apply_filters( 'tdl_gmc_mpn_value', $value, $subject ), 70 );
                }
            }
        }

        $attrs = $subject->get_attributes();
        if ( is_array( $attrs ) ) {
            foreach ( $attrs as $attr ) {
                if ( ! $attr instanceof WC_Product_Attribute ) {
                    continue;
                }
                $name = strtolower( sanitize_title( $attr->get_name() ) );
                if ( strpos( $name, 'mpn' ) === false && strpos( $name, 'manufacturer-part-number' ) === false ) {
                    continue;
                }
                $value = trim( wp_strip_all_tags( (string) $subject->get_attribute( $attr->get_name() ) ) );
                if ( $value !== '' ) {
                    return limit_text( (string) apply_filters( 'tdl_gmc_mpn_value', $value, $subject ), 70 );
                }
            }
        }
    }

    $use_sku = (bool) get_option( 'tdl_gmc_use_sku_as_mpn', false );
    $use_sku = (bool) apply_filters( 'tdl_gmc_use_sku_as_mpn', $use_sku, $product, $variation );
    if ( $use_sku ) {
        foreach ( $subjects as $subject ) {
            $sku = trim( (string) $subject->get_sku() );
            if ( $sku !== '' ) {
                return limit_text( (string) apply_filters( 'tdl_gmc_mpn_value', $sku, $subject ), 70 );
            }
        }
    }

    return (string) apply_filters( 'tdl_gmc_mpn_value', '', $variation ?: $product );
}

/** Return [identifier_exists, gtin, mpn, brand]. */
function identifier_block( WC_Product $product, ?WC_Product_Variation $variation = null ): array {
    $gtin  = find_gtin( $product, $variation );
    $mpn   = find_mpn( $product, $variation );
    $brand = resolve_product_brand( $product, $variation );
    $identifier_exists = ( $gtin !== '' || ( $mpn !== '' && $brand !== '' ) ) ? 'yes' : 'no';

    return [ $identifier_exists, $gtin, $mpn, $brand ];
}

function _tdl_gmc_format_number( float $number ): string {
    $formatted = number_format( $number, 6, '.', '' );
    $formatted = rtrim( rtrim( $formatted, '0' ), '.' );
    return $formatted === '' ? '0' : $formatted;
}

function _tdl_gmc_normalize_measure_unit( string $unit ): string {
    $unit = strtolower( trim( $unit ) );
    $map = [
        'gram' => 'g', 'grams' => 'g', 'kg' => 'kg', 'kilogram' => 'kg', 'kilograms' => 'kg',
        'mg' => 'mg', 'milligram' => 'mg', 'milligrams' => 'mg',
        'oz' => 'oz', 'ounce' => 'oz', 'ounces' => 'oz',
        'lb' => 'lb', 'lbs' => 'lb', 'pound' => 'lb', 'pounds' => 'lb',
        'ml' => 'ml', 'milliliter' => 'ml', 'millilitre' => 'ml', 'milliliters' => 'ml', 'millilitres' => 'ml',
        'cl' => 'cl', 'centiliter' => 'cl', 'centilitre' => 'cl',
        'l' => 'l', 'lt' => 'l', 'liter' => 'l', 'litre' => 'l', 'liters' => 'l', 'litres' => 'l',
    ];
    return $map[ $unit ] ?? $unit;
}

function _tdl_gmc_measure_base_for_unit( string $unit ): string {
    $bases = [
        'mg' => '100mg', 'g' => '100g', 'kg' => '1kg', 'oz' => '1oz', 'lb' => '1lb',
        'ml' => '100ml', 'cl' => '1cl', 'l' => '1l',
    ];
    return $bases[ $unit ] ?? '';
}

function derive_unit_measures( WC_Product $product, ?WC_Product_Variation $variation = null ): array {
    $value = '';
    $attr_keys = [
        'pa_weight', 'weight', 'pa_hmotnost', 'hmotnost', 'pa_vyberte-hmotnost', 'vyberte-hmotnost',
        'pa_volume', 'volume', 'pa_objem', 'objem',
    ];

    foreach ( $attr_keys as $key ) {
        if ( $variation instanceof WC_Product_Variation ) {
            $value = trim( (string) $variation->get_attribute( $key ) );
        }
        if ( $value === '' ) {
            $value = trim( (string) $product->get_attribute( $key ) );
        }
        if ( $value !== '' ) {
            break;
        }
    }

    // Do not fall back to WooCommerce's generic product weight. That field is often
    // used for shipping/logistics, while Google's unit_pricing_measure must describe
    // the quantity of product being sold (for example 100 g of tea or 750 ml of oil).
    // Unit pricing is therefore emitted only from an explicit weight/volume attribute.

    if ( ! preg_match( '/([0-9]+(?:[\.,][0-9]+)?)\s*([a-zA-Z]+)/u', $value, $matches ) ) {
        return [ '', '' ];
    }

    $number = (float) str_replace( ',', '.', $matches[1] );
    $unit = _tdl_gmc_normalize_measure_unit( $matches[2] );
    $base = _tdl_gmc_measure_base_for_unit( $unit );
    if ( $number <= 0 || $base === '' ) {
        return [ '', '' ];
    }

    return [ _tdl_gmc_format_number( $number ) . $unit, $base ];
}

function product_variant_url( WC_Product $product, ?WC_Product_Variation $variation = null ): string {
    $link = $product->get_permalink();

    if ( $variation instanceof WC_Product_Variation ) {
        $attrs = $variation->get_attributes();
        if ( is_array( $attrs ) && $attrs ) {
            $query = [];
            foreach ( $attrs as $taxonomy => $value ) {
                if ( $value === '' ) {
                    continue;
                }
                $key = strpos( $taxonomy, 'attribute_' ) === 0
                    ? $taxonomy
                    : 'attribute_' . ( strpos( $taxonomy, 'pa_' ) === 0 ? $taxonomy : sanitize_title( $taxonomy ) );
                $query[ $key ] = (string) $value;
            }

            $parts = wp_parse_url( $link );
            if ( is_array( $parts ) ) {
                $existing = [];
                if ( ! empty( $parts['query'] ) ) {
                    parse_str( (string) $parts['query'], $existing );
                }
                $parts['query'] = http_build_query( array_merge( $existing, $query ), '', '&', PHP_QUERY_RFC3986 );
                $link = _tdl_gmc_build_url_from_parts( $parts );
            } else {
                $link = add_query_arg( $query, $link );
            }
        }
    }

    return (string) apply_filters( 'tdl_gmc_product_url', esc_url_raw( $link ), $product, $variation );
}

function _tdl_gmc_build_url_from_parts( array $parts ): string {
    $url = '';
    if ( isset( $parts['scheme'] ) ) $url .= $parts['scheme'] . '://';
    if ( isset( $parts['user'] ) ) {
        $url .= $parts['user'];
        if ( isset( $parts['pass'] ) ) $url .= ':' . $parts['pass'];
        $url .= '@';
    }
    if ( isset( $parts['host'] ) ) $url .= $parts['host'];
    if ( isset( $parts['port'] ) ) $url .= ':' . $parts['port'];
    if ( isset( $parts['path'] ) ) {
        $segments = explode( '/', (string) $parts['path'] );
        $segments = array_map( static function ( string $segment ): string {
            return rawurlencode( rawurldecode( $segment ) );
        }, $segments );
        $url .= implode( '/', $segments );
    }
    if ( ! empty( $parts['query'] ) ) $url .= '?' . $parts['query'];
    if ( ! empty( $parts['fragment'] ) ) $url .= '#' . rawurlencode( rawurldecode( (string) $parts['fragment'] ) );
    return $url;
}

function _tdl_gmc_parse_list_option( string $option ): array {
    $parts = preg_split( '/[\s,\n\r;]+/', $option );
    if ( ! is_array( $parts ) ) return [];
    $out = [];
    foreach ( $parts as $part ) {
        $part = trim( (string) $part );
        if ( $part !== '' ) $out[] = $part;
    }
    return array_values( array_unique( $out ) );
}

function _tdl_gmc_parse_measure_to_base( string $raw ): array {
    $raw = trim( $raw );
    if ( $raw === '' || ! preg_match( '/([0-9]+(?:[\.,][0-9]+)?)\s*([a-zA-Z]+)/u', $raw, $matches ) ) {
        return [ '', 0.0 ];
    }

    $number = (float) str_replace( ',', '.', $matches[1] );
    $unit = _tdl_gmc_normalize_measure_unit( $matches[2] );
    switch ( $unit ) {
        case 'mg': return [ 'mg', $number ];
        case 'g': return [ 'mg', $number * 1000.0 ];
        case 'kg': return [ 'mg', $number * 1000000.0 ];
        case 'oz': return [ 'oz', $number ];
        case 'lb': return [ 'oz', $number * 16.0 ];
        case 'ml': return [ 'ml', $number ];
        case 'cl': return [ 'ml', $number * 10.0 ];
        case 'l': return [ 'ml', $number * 1000.0 ];
        default: return [ '', 0.0 ];
    }
}

function _tdl_gmc_subject_measure_base( WC_Product $product, ?WC_Product_Variation $variation = null ): array {
    [ $measure ] = derive_unit_measures( $product, $variation );
    return $measure === '' ? [ '', 0.0 ] : _tdl_gmc_parse_measure_to_base( $measure );
}

function tdl_gmc_filter_result( WC_Product $product, ?WC_Product_Variation $variation = null ): array {
    $subject = $variation ?: $product;

    if ( (bool) get_option( 'tdl_gmc_exclude_out_of_stock', false ) && ! $subject->is_in_stock() ) {
        return [ 'pass' => false, 'reason' => 'out_of_stock' ];
    }

    $price_raw = wc_get_price_including_tax( $subject );
    $price = is_numeric( $price_raw ) ? (float) $price_raw : (float) $subject->get_price();
    if ( (bool) get_option( 'tdl_gmc_exclude_zero_price', true ) && $price <= 0 ) {
        return [ 'pass' => false, 'reason' => 'zero_price' ];
    }

    $sku_list = _tdl_gmc_parse_list_option( (string) get_option( 'tdl_gmc_filter_skus', '' ) );
    if ( $sku_list ) {
        $sku = strtolower( trim( (string) $subject->get_sku() ) );
        $allowed = array_map( static function ( $value ): string {
            return strtolower( trim( (string) $value ) );
        }, $sku_list );
        if ( $sku === '' || ! in_array( $sku, $allowed, true ) ) {
            return [ 'pass' => false, 'reason' => 'sku_filter' ];
        }
    }

    $include = _tdl_gmc_parse_list_option( (string) get_option( 'tdl_gmc_filter_cat_include', '' ) );
    $exclude = _tdl_gmc_parse_list_option( (string) get_option( 'tdl_gmc_filter_cat_exclude', '' ) );
    if ( $include || $exclude ) {
        $terms = get_the_terms( $product->get_id(), 'product_cat' );
        $term_ids = [];
        $term_slugs = [];
        if ( is_array( $terms ) ) {
            foreach ( $terms as $term ) {
                $term_ids[] = (int) $term->term_id;
                if ( isset( $term->slug ) ) $term_slugs[] = sanitize_title( (string) $term->slug );
                $ancestors = get_ancestors( (int) $term->term_id, 'product_cat' );
                if ( is_array( $ancestors ) ) {
                    foreach ( $ancestors as $ancestor_id ) {
                        $term_ids[] = (int) $ancestor_id;
                        $ancestor = get_term( (int) $ancestor_id, 'product_cat' );
                        if ( $ancestor && ! is_wp_error( $ancestor ) && isset( $ancestor->slug ) ) {
                            $term_slugs[] = sanitize_title( (string) $ancestor->slug );
                        }
                    }
                }
            }
        }
        $term_ids = array_values( array_unique( $term_ids ) );
        $term_slugs = array_values( array_unique( $term_slugs ) );
        $matches_any = static function ( array $needles ) use ( $term_ids, $term_slugs ): bool {
            foreach ( $needles as $needle ) {
                $needle = trim( (string) $needle );
                if ( $needle === '' ) continue;
                if ( ctype_digit( $needle ) && in_array( (int) $needle, $term_ids, true ) ) return true;
                if ( in_array( sanitize_title( $needle ), $term_slugs, true ) ) return true;
            }
            return false;
        };
        if ( $include && ! $matches_any( $include ) ) {
            return [ 'pass' => false, 'reason' => 'category_filter' ];
        }
        if ( $exclude && $matches_any( $exclude ) ) {
            return [ 'pass' => false, 'reason' => 'category_filter' ];
        }
    }

    $min_raw = trim( (string) get_option( 'tdl_gmc_filter_price_min', '' ) );
    $max_raw = trim( (string) get_option( 'tdl_gmc_filter_price_max', '' ) );
    $min = $min_raw === '' ? null : (float) str_replace( ',', '.', $min_raw );
    $max = $max_raw === '' ? null : (float) str_replace( ',', '.', $max_raw );
    if ( $min !== null && $price < $min ) return [ 'pass' => false, 'reason' => 'price_filter' ];
    if ( $max !== null && $price > $max ) return [ 'pass' => false, 'reason' => 'price_filter' ];

    $weights = _tdl_gmc_parse_list_option( (string) get_option( 'tdl_gmc_filter_weights', '' ) );
    if ( $weights ) {
        [ $unit, $value ] = _tdl_gmc_subject_measure_base( $product, $variation );
        if ( $unit === '' ) return [ 'pass' => false, 'reason' => 'measure_filter' ];
        $allowed = false;
        foreach ( $weights as $weight ) {
            [ $required_unit, $required_value ] = _tdl_gmc_parse_measure_to_base( (string) $weight );
            if ( $required_unit === $unit && abs( $required_value - $value ) < 0.0001 ) {
                $allowed = true;
                break;
            }
        }
        if ( ! $allowed ) return [ 'pass' => false, 'reason' => 'measure_filter' ];
    }

    $pass = (bool) apply_filters( 'tdl_gmc_passes_filters', true, $product, $variation );
    return [ 'pass' => $pass, 'reason' => $pass ? '' : 'custom_filter' ];
}

function tdl_gmc_passes_filters( WC_Product $product, ?WC_Product_Variation $variation = null ): bool {
    $result = tdl_gmc_filter_result( $product, $variation );
    return ! empty( $result['pass'] );
}