User Profile Discount Field and Application

<?php

/**
 * Adds a custom field (dropdown) for discounts in user profiles.
 */
function cwpai_add_user_discount_field($user) {
    // Check if $user is an object before trying to access its properties
    $user_id = is_object($user) ? $user->ID : get_current_user_id();

    // Get the current selected value
    $selected = get_user_meta($user_id, 'cwpai_user_discount', true);

    echo '<h3>' . __('Discount Settings', 'codewp') . '</h3>';
    echo '<table class="form-table"><tr>';
    echo '<th><label for="cwpai_user_discount">' . __('Discount Rate', 'codewp') . '</label></th>';
    echo '<td>';
    echo '<select id="cwpai_user_discount" name="cwpai_user_discount" class="regular-text">';

    // Define discount options
    $discounts = array('40%', '30%', '20%', '10%');
    foreach ($discounts as $discount) {
        echo '<option value="' . esc_attr($discount) . '"' . selected($selected, $discount, false) . '>' . esc_html($discount) . '</option>';
    }

    echo '</select>';
    echo '</td></tr></table>';
}
add_action('show_user_profile', 'cwpai_add_user_discount_field');
add_action('edit_user_profile', 'cwpai_add_user_discount_field');
add_action('woocommerce_edit_account_form', 'cwpai_add_user_discount_field');

/**
 * Saves the selected discount rate when the profile is updated.
 */
function cwpai_save_user_discount_field($user_id) {
    if (!current_user_can('edit_user', $user_id)) {
        return false;
    }
    update_user_meta($user_id, 'cwpai_user_discount', $_POST['cwpai_user_discount']);
    return true;
}
add_action('personal_options_update', 'cwpai_save_user_discount_field');
add_action('edit_user_profile_update', 'cwpai_save_user_discount_field');
add_action('woocommerce_save_account_details', 'cwpai_save_user_discount_field');

/**
 * Applies the selected discount for the user viewing WooCommerce products.
 */
function cwpai_apply_user_discount_to_products($price, $product) {
    $user_id = get_current_user_id();
    $user_discount = get_user_meta($user_id, 'cwpai_user_discount', true);

    if (!empty($user_discount)) {
        $discount_decimal = rtrim($user_discount, '%') / 100;
        $price -= ($price * $discount_decimal);
    }

    return $price;
}
add_filter('woocommerce_product_get_price', 'cwpai_apply_user_discount_to_products', 10, 2);
add_filter('woocommerce_product_variation_get_price', 'cwpai_apply_user_discount_to_products', 10, 2);