AJAX Filter Implementation

<?php
// Filter form
?>
<form id="product-filter" class="filter-form">
    <div class="filter-group">
        <label><?php _e( 'Category:', 'mytheme' ); ?></label>
        <?php
        wp_dropdown_categories( array(
            'taxonomy'        => 'product_category',
            'name'            => 'product_cat',
            'show_option_all' => __( 'All Categories', 'mytheme' ),
            'hierarchical'    => true,
            'show_count'      => true,
            'orderby'         => 'name',
        ) );
        ?>
    </div>
    
    <div class="filter-group">
        <label><?php _e( 'Sort by:', 'mytheme' ); ?></label>
        <select name="orderby" id="orderby">
            <option value="date"><?php _e( 'Latest', 'mytheme' ); ?></option>
            <option value="title"><?php _e( 'Name', 'mytheme' ); ?></option>
            <option value="price_asc"><?php _e( 'Price: Low to High', 'mytheme' ); ?></option>
            <option value="price_desc"><?php _e( 'Price: High to Low', 'mytheme' ); ?></option>
            <option value="popularity"><?php _e( 'Popularity', 'mytheme' ); ?></option>
        </select>
    </div>
    
    <div class="filter-group">
        <label><?php _e( 'Price Range:', 'mytheme' ); ?></label>
        <input type="number" name="min_price" placeholder="Min" min="0">
        <input type="number" name="max_price" placeholder="Max" min="0">
    </div>
    
    <button type="submit"><?php _e( 'Filter Products', 'mytheme' ); ?></button>
    <button type="reset" id="reset-filter"><?php _e( 'Reset', 'mytheme' ); ?></button>
</form>

<div id="products-container">
    <!-- Products will be loaded here -->
</div>

<?php
// AJAX handler for filtering
add_action( 'wp_ajax_filter_products', 'mytheme_filter_products' );
add_action( 'wp_ajax_nopriv_filter_products', 'mytheme_filter_products' );

function mytheme_filter_products() {
    $args = array(
        'post_type' => 'product',
        'posts_per_page' => 12,
        'paged' => isset( $_POST['page'] ) ? $_POST['page'] : 1,
    );
    
    // Category filter
    if ( ! empty( $_POST['product_cat'] ) && $_POST['product_cat'] != '0' ) {
        $args['tax_query'] = array(
            array(
                'taxonomy' => 'product_category',
                'field' => 'term_id',
                'terms' => intval( $_POST['product_cat'] ),
            ),
        );
    }
    
    // Price filter
    if ( ! empty( $_POST['min_price'] ) || ! empty( $_POST['max_price'] ) ) {
        $meta_query = array( 'relation' => 'AND' );
        
        if ( ! empty( $_POST['min_price'] ) ) {
            $meta_query[] = array(
                'key' => '_product_price',
                'value' => intval( $_POST['min_price'] ),
                'compare' => '>=',
                'type' => 'NUMERIC',
            );
        }
        
        if ( ! empty( $_POST['max_price'] ) ) {
            $meta_query[] = array(
                'key' => '_product_price',
                'value' => intval( $_POST['max_price'] ),
                'compare' => '<=',
                'type' => 'NUMERIC',
            );
        }
        
        $args['meta_query'] = $meta_query;
    }
    
    // Sorting
    if ( ! empty( $_POST['orderby'] ) ) {
        switch ( $_POST['orderby'] ) {
            case 'title':
                $args['orderby'] = 'title';
                $args['order'] = 'ASC';
                break;
            case 'price_asc':
                $args['orderby'] = 'meta_value_num';
                $args['meta_key'] = '_product_price';
                $args['order'] = 'ASC';
                break;
            case 'price_desc':
                $args['orderby'] = 'meta_value_num';
                $args['meta_key'] = '_product_price';
                $args['order'] = 'DESC';
                break;
            case 'popularity':
                $args['orderby'] = 'meta_value_num';
                $args['meta_key'] = '_product_views';
                $args['order'] = 'DESC';
                break;
            default:
                $args['orderby'] = 'date';
                $args['order'] = 'DESC';
        }
    }
    
    $query = new WP_Query( $args );
    
    if ( $query->have_posts() ) :
        while ( $query->have_posts() ) :
            $query->the_post();
            get_template_part( 'template-parts/content', 'product' );
        endwhile;
        
        // Pagination
        echo paginate_links( array(
            'total' => $query->max_num_pages,
            'current' => $args['paged'],
        ) );
    else :
        echo '<p>' . __( 'No products found.', 'mytheme' ) . '</p>';
    endif;
    
    wp_reset_postdata();
    wp_die();
}