function woo_media_deduplicator_main() {
    if (!current_user_can('manage_options') || !isset($_GET['preview_duplicates'])) {
        return;
    }

    if (!class_exists('WooCommerce')) {
        echo '<div class="notice notice-error"><p>WooCommerce non è attivo.</p></div>';
        return;
    }

    $filter_id = isset($_GET['product_filter']) ? intval($_GET['product_filter']) : null;
    $delete_mode = isset($_GET['delete_duplicates']) && $filter_id;

    $products = wc_get_products(['limit' => -1, 'status' => 'publish']);
    $hash_map = [];
    $to_delete = [];

    foreach ($products as $product) {
        $product_id = $product->get_id();
        if ($filter_id && $product_id !== $filter_id) continue;

        $thumbnail_id = get_post_thumbnail_id($product_id);
        $gallery_ids = $product->get_gallery_image_ids();

        foreach ($gallery_ids as $attachment_id) {
            $file_path = get_attached_file($attachment_id);
            if (!$file_path || !file_exists($file_path)) continue;

            $hash = md5_file($file_path);

            if (!isset($hash_map[$hash])) {
                $hash_map[$hash] = [
                    'attachment_id' => $attachment_id,
                    'product_id' => $product_id,
                    'file' => $file_path,
                ];
            } else {
                if (
                    $attachment_id == $thumbnail_id ||
                    $attachment_id == $hash_map[$hash]['attachment_id']
                ) {
                    continue;
                }

                $to_delete[] = [
                    'product_id' => $product_id,
                    'duplicate_id' => $attachment_id,
                    'original_id' => $hash_map[$hash]['attachment_id'],
                    'file' => $file_path,
                ];
            }
        }
    }

    // Esegui cancellazione duplicati + pulizia gallery
    if ($delete_mode) {
        $deleted = 0;
        foreach ($to_delete as $dup) {
            wp_delete_attachment($dup['duplicate_id'], true);
            $deleted++;
        }

        // Pulizia della gallery del prodotto (ID validi, no img in evidenza)
        $product = wc_get_product($filter_id);
        $thumbnail_id = get_post_thumbnail_id($filter_id);
        $gallery_ids = $product->get_gallery_image_ids();
        $valid_ids = [];

        foreach ($gallery_ids as $aid) {
            if ($aid != $thumbnail_id && get_post($aid)) {
                $valid_ids[] = $aid;
            }
        }

        update_post_meta($filter_id, '_product_image_gallery', implode(',', $valid_ids));

        echo '<div class="notice notice-success"><p>✅ Eliminati ' . $deleted . ' media duplicati per il prodotto ID ' . $filter_id . '. Gallery aggiornata e immagine in evidenza rimossa dalla gallery.</p></div>';
        return;
    }

    // Preview
    echo '<div class="notice notice-warning"><p><strong>Rilevate ' . count($to_delete) . ' immagini duplicate' . ($filter_id ? ' per il prodotto ID ' . $filter_id : '') . ' (nessuna cancellata):</strong></p>';

    if ($filter_id) {
        $back_link = admin_url('admin.php?preview_duplicates=1');
        $delete_link = admin_url('admin.php?preview_duplicates=1&product_filter=' . $filter_id . '&delete_duplicates=1');
        echo '<p><a href="' . esc_url($back_link) . '">&larr; Torna a tutti i risultati</a></p>';
        if (count($to_delete)) {
            echo '<p><a href="' . esc_url($delete_link) . '" class="button button-danger" style="color:red">🗑 Elimina le immagini duplicate per questo prodotto</a></p>';
        }
    }

    echo '<ul>';
    foreach ($to_delete as $dup) {
        $product_link = admin_url('post.php?post=' . $dup['product_id'] . '&action=edit');
        $filter_link = admin_url('admin.php?preview_duplicates=1&product_filter=' . $dup['product_id']);
        echo '<li>';
        echo 'Prodotto ID: <a href="' . esc_url($filter_link) . '" title="Filtra solo questo prodotto"><strong>' . $dup['product_id'] . '</strong></a> ';
        echo '(<a href="' . esc_url($product_link) . '" target="_blank">modifica</a>) — ';
        echo 'Duplicato ID: <code>' . $dup['duplicate_id'] . '</code> — ';
        echo 'Originale ID: <code>' . $dup['original_id'] . '</code> — ';
        echo 'File: <code>' . esc_html(basename($dup['file'])) . '</code>';
        echo '</li>';
    }
    echo '</ul></div>';
}