plugin development. fields save and update

I’m trying to build a simple woocommerce plugin.

I want to add new badge for products. There is a simple text form and a checkbox for settings.

Text form for products published in the last x days.

Checkbox for active / deactive

Checkbox working fine, but I don’t use text form value. I saw it and saving default value. But I can’t upload and use it. When I want to use the field getting undefined variable error.

<?php

/**
 * Custom Woocommerce Options
 *
 * @since  1.0.0
 * @return void
 */

if ( ! defined( 'ABSPATH' ) ) {
exit; // Exit if accessed directly.
}

/**
 * Show Woocommerce Customizer Page
 */
function add_customwoo_admin_menu() {
add_submenu_page(
    'woocommerce',
    __( 'Custom Woocommerce Options', 'hazirwoo' ),
    __( 'Custom Options', 'hazirwoo' ),
    'manage_woocommerce',
    'hw-woo-custom-options',
    'hw_woocommerce_custom_options_page'
);
}

add_action( 'admin_menu', 'add_customwoo_admin_menu' );

/**
 * Customizer Page Content
 */
function hw_woocommerce_custom_options_page() {
?>
<div class="wrap">
    <h2><?php echo esc_html( get_admin_page_title() ); ?></h2>
    <?php settings_errors(); ?>

    <form method="post" action="options.php">
        <?php

            $options = get_option( 'hw_woocommerce_custom_options' );

            $hw_new_badge = $options['hw_new_badge'];
            $hw_new_day = $options['hw_new_day'];

            settings_fields( 'hw_woocommerce_custom_options_group' );
            do_settings_sections( 'hw_woocommerce_custom_options_group' );

        ?>

        <h3><?php _e( 'Custom Functions', 'hazirwoo' ); ?></h3>

        <table class="form-table">
            <tbody>
                <tr>
                    <th scope="row">Ürün Ayarları</th>
                    <td>
                        <fieldset>
                            <label for="woocommerce_custom_options_new_badge">
                            <input id="woocommerce_custom_options_new_badge" name="hw_woocommerce_custom_options[hw_new_badge]" type="checkbox" value="1" <?php checked( $hw_new_badge, 1 ); ?> />
                            Yeni Ürünleri Belirt</label>
                            <br>
                            <div id="newbadge">
                                <label for="hw_custom_options_new">Yeni Etiketini</label>
                                <input id="hw_custom_options_new" name="hw_custom_options[hw_new_day]" type="text" value="<?php if(!empty($hw_new_day)) esc_attr_e($hw_new_day, 'hw_woocommerce_custom_options');?>"> <span class="description">güncen önce eklenmiş ürünlerde göster</span>
                            </div>
                        </fieldset>
                    </td>
                </tr>
            </tbody>
        </table>            

        <?php submit_button(); ?>
    </form>
</div>
<?php
}

/**
 * Customizer Settings
 */
function hw_register_functions() {
register_setting( 'hw_woocommerce_custom_options_group', 'hw_woocommerce_custom_options', 'hw_validate_functions' );
}

add_action( 'admin_init', 'hw_register_functions' );

/**
 * Validate Settings
 */
function hw_validate_functions( $input ) {

$valid = array();

$valid['hw_new_badge'] = (isset($input['hw_new_badge']) && !empty($input['hw_new_badge'])) ? 1 : 0 ;
$valid['hw_new_day'] = (isset($input['hw_new_day']) && !empty($input['hw_new_day'])) ? sanitize_text_field($input['hw_new_day']) : 30;

return $valid;
}

/**
 * Run
 */
function hw_custom_woocommerce_options() {

$hw_woo_options = get_option('hw_woocommerce_custom_options');

//var_dump($hw_woo_options);

$day = $hw_woo_options['hw_new_day'];

if($hw_woo_options['hw_new_badge']) {

    function hw_show_new_badge() {
        $postdate       = get_the_time( 'Y-m-d' );
        $postdatestamp  = strtotime( $postdate );

        if ( ( time() - ( 60 * 60 * 24 * $day ) ) < $postdatestamp ) { // If the product was published within the newness time frame display the new badge
            echo '<span class="wc-new-badge">' . __( 'YENİ', 'hazirwoo' ) . '</span>';
        }
    }
    add_action( 'woocommerce_before_shop_loop_item_title', 'hw_show_new_badge', 30 ); 

}
}

wp-options table hw_woocommerce_custom_options values;

a:12:{ s:12:”hw_new_badge”;i:1; s:10:”hw_new_day”;i:30; }

https://wordpress.org/plugins/woocommerce/