Simple Wine filter for WordPress

<?php
/**
 * Plugin Name: Wine Filter
 * Description: Een plugin waarmee klanten verschillende wijnen kunnen filteren.
 */

// Voorkom directe toegang tot het bestand
if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

// Voeg een shortcode toe voor het tonen van de wijnfilter
function wine_filter_shortcode() {
    ob_start(); ?>

    <form id="wine-filter-form">
        <label for="wine-type">Type wijn:</label>
        <select id="wine-type" name="wine-type">
            <option value="all">Alle</option>
            <option value="red">Rood</option>
            <option value="white">Wit</option>
            <option value="rose">Rosé</option>
        </select>

        <label for="wine-country">Land:</label>
        <select id="wine-country" name="wine-country">
            <option value="all">Alle</option>
            <option value="france">Frankrijk</option>
            <option value="italy">Italië</option>
            <option value="spain">Spanje</option>
            <option value="spain">Kroatië</option>
        </select>

        <button type="submit">Filter</button>
    </form>

    <div id="wine-results"></div>

    <script>
    document.getElementById('wine-filter-form').addEventListener('submit', function(event) {
        event.preventDefault();

        var wineType = document.getElementById('wine-type').value;
        var wineCountry = document.getElementById('wine-country').value;

        var data = {
            action: 'filter_wines',
            wine_type: wineType,
            wine_country: wineCountry
        };

        jQuery.post(ajaxurl, data, function(response) {
            document.getElementById('wine-results').innerHTML = response;
        });
    });
    </script>

    <?php return ob_get_clean();
}
add_shortcode('wine_filter', 'wine_filter_shortcode');

// Verwerk de AJAX-aanvraag voor het filteren van wijnen
function filter_wines() {
    $wine_type = sanitize_text_field( $_POST['wine_type'] );
    $wine_country = sanitize_text_field( $_POST['wine_country'] );

    // Dit is een voorbeeldarray met wijnen. In een echte plugin haal je dit waarschijnlijk uit de database.
    $wines = [
        ['name' => 'Merlot', 'type' => 'red', 'country' => 'france'],
        ['name' => 'Chardonnay', 'type' => 'white', 'country' => 'france'],
        ['name' => 'Chianti', 'type' => 'red', 'country' => 'italy'],
        ['name' => 'Prosecco', 'type' => 'white', 'country' => 'italy'],
        ['name' => 'Rioja', 'type' => 'red', 'country' => 'spain'],
        ['name' => 'Cava', 'type' => 'rose', 'country' => 'spain'],
    ];

    $filtered_wines = array_filter($wines, function($wine) use ($wine_type, $wine_country) {
        $type_match = $wine_type === 'all' || $wine['type'] === $wine_type;
        $country_match = $wine_country === 'all' || $wine['country'] === $wine_country;
        return $type_match && $country_match;
    });

    if (!empty($filtered_wines)) {
        foreach ($filtered_wines as $wine) {
            echo '<p>' . esc_html($wine['name']) . ' (' . esc_html($wine['type']) . ' - ' . esc_html($wine['country']) . ')</p>';
        }
    } else {
        echo '<p>Geen wijnen gevonden.</p>';
    }

    wp_die();
}
add_action('wp_ajax_filter_wines', 'filter_wines');
add_action('wp_ajax_nopriv_filter_wines', 'filter_wines');