[site-reviews-filters] Multiple category and custom field filters

/**
 * Example usage:
 *
 * new CustomReviewFilters([
 *     // Add a custom filter for some child categories
 *     'filter_by_food' => [                    // filter name (must start with "filter_by_")
 *         'parent_term' => 'foods',            // parent category ID or slug (must be a Site Reviews category!)
 *         'placeholder' => 'All Foods',        // dropdown placeholder
 *         'type' => 'term',                    // type of filter (term or custom)
 *     ],
 *     // Add a custom filter for a custom field named "surcharge"
 *     'filter_by_surcharge' => [               // filter name (must start with "filter_by_")
 *         'cast' => 'string',                  // What to cast the value as (string or int)
 *         'type' => 'custom',                  // type of filter (term or custom)
 *         'placeholder' => 'Any Surcharge',    // dropdown placeholder
 *         'options' => [                       // dropdown options
 *             'Yes' => 'Surcharge: Yes',
 *             'No' => 'Surcharge: No',
 *         ],
 *     ],
 * ]);
 *
 */

class CustomReviewFilters
{
    public $filters = [];

    public function __construct(array $filters = [])
    {
        add_action('init', function () use ($filters) {
            if (!function_exists('glsr')
                || !function_exists('glsr_get')
                || !glsr()->addon('site-reviews-filters')
                || !class_exists('\GeminiLabs\SiteReviews\Addon\Filters\Defaults\FilteredDefaults')) {
                return;
            }
            $this->filters = $this->normalize($filters);
            foreach ($this->filters as $filter => $values) {
                if ('custom' === $values['type']) {
                    add_action('site-reviews-filters/sql-and/build/'.$filter, [$this, 'filterSqlAndForCustom'], 10, 3);
                    add_action('site-reviews-filters/sql-join/build/'.$filter, [$this, 'filterSqlJoinForCustom'], 10, 3);
                }
            }
            add_filter('site-reviews-filters/defaults/filtered/defaults', [$this, 'filterDefaults']);
            add_filter('site-reviews-filters/defaults/filtered/casts', [$this, 'filterCasts']);
            add_filter('site-reviews-filters/config/forms/filters-form', [$this, 'filterConfig']);
            add_filter('site-reviews-filters/status/filtered-by', [$this, 'filterFilteredBy'], 10, 2);
            add_filter('site-reviews/shortcode/atts', [$this, 'filterShortcodeAttributes'], 10, 3);
        });
    }

    public function filterDefaults(array $defaults)
    {
        foreach ($this->filters as $filter => $values) {
            $defaults[$filter] = '';
        }
        return $defaults;
    }

    public function filterCasts(array $casts)
    {
        foreach ($this->filters as $filter => $values) {
            $casts[$filter] = glsr_get($values, 'cast', 'string');
        }
        return $casts;
    }

    public function filterConfig(array $config)
    {
        foreach ($this->filters as $filter => $values) {
            $config[$filter] = [
                'options' => ['' => $values['placeholder']] + $values['options'],
                'type' => 'select',
                'value' => filter_input(INPUT_GET, $filter, FILTER_SANITIZE_FULL_SPECIAL_CHARS),
            ];
        }
        return $config;
    }

    public function filterFilteredBy(array $filteredBy, array $filters)
    {
        foreach ($filters as $filter => $value) {
            if (array_key_exists($filter, $this->filters)) {
                $filteredBy[] = $this->filters[$filter]['name'] ?? $this->filters[$filter]['options'][$value] ?? $value;
            }
        }
        return $filteredBy;
    }

    public function filterShortcodeAttributes(array $attributes, $type, $shortcode)
    {
        if ('site_reviews' !== $shortcode) {
            return $attributes;
        }
        $parameters = glsr('Addon\Filters\Defaults\FilteredDefaults')->merge();
        $terms = [$attributes['assigned_terms'] ?? ''];
        foreach ($this->filters as $filter => $values) {
            if ('term' === $values['type'] && !empty($parameters[$filter])) {
                $terms[] = $parameters[$filter];
            }
        }
        $attributes['assigned_terms'] = implode(',', $terms);
        return $attributes;
    }

    public function filterSqlAndForCustom($value, $key, $modifier)
    {
        $tablekey = str_replace('filters/', '', $key);
        $metakey = str_replace('filters/filter_by_', '_custom_', $key);
        $modifier->values[$key] = sprintf("AND (%s.meta_key = '%s' AND %s.meta_value = '%s')", $tablekey, $metakey, $tablekey, $value);
    }

    public function filterSqlJoinForCustom($value, $key, $modifier)
    {
        global $wpdb;
        $tablekey = str_replace('filters/', '', $key);
        $modifier->values[$key] = "INNER JOIN {$wpdb->posts} AS p ON r.review_id = p.ID";
        $modifier->values[$key] = sprintf("INNER JOIN {$wpdb->postmeta} AS %s ON r.review_id = %s.post_id", $tablekey, $tablekey);
    }

    public function normalize(array $filters)
    {
        $normalized = [];
        foreach ($filters as $filter => $values) {
            $filter = sanitize_key($filter);
            if (!str_starts_with($filter, 'filter_by_')) {
                continue;
            }
            $values = wp_parse_args($values, [
                'cast' => '',
                'name' => null,
                'options' => [],
                'parent_term' => '',
                'placeholder' => '',
                'type' => '',
            ]);
            if ('custom' === $values['type']) {
                $normalized[$filter] = $this->normalizeCustomFilter($values);
            } elseif ('term' === $values['type']) {
                $term = term_exists($values['parent_term'], glsr()->taxonomy);
                if (!empty($term)) {
                    $normalized[$filter] = $this->normalizeTermFilter($values, $term['term_id']);
                }
            }
        }
        return $normalized;
    }

    protected function normalizeCustomFilter(array $values)
    {
        $values['options'] = is_array($values['options']) ? $values['options'] : [];
        return $values;
    }

    protected function normalizeTermFilter(array $values, int $termId)
    {
        $values['cast'] = 'int';
        $values['options'] = get_terms([
            'count' => false,
            'fields' => 'id=>name',
            'hide_empty' => true,
            'parent' => $termId,
            'taxonomy' => glsr()->taxonomy,
        ]);
        $values['parent_term'] = $termId;
        return $values;
    }
}