Modify PayPal Payments order number during order creation and order patching with custom get_my_invoice_number() function

functions.php

<?php

function customize_paypal_invoice_number( $data ) {
    // Access the global WooCommerce object
    global $woocommerce;

    // Get the current order
    $order = $woocommerce->session->get('order_awaiting_payment') ?
        wc_get_order($woocommerce->session->get('order_awaiting_payment')) : null;

    // Check if the order object exists
    if ( $order ) {
        // Get the custom invoice number using the provided function
        $custom_invoice_number = get_my_invoice_number( $order );

        // Check if the purchase_units are available in the data array
        if ( isset( $data['purchase_units'][0] ) ) {
            // Set the custom invoice number
            $data['purchase_units'][0]['invoice_id'] = $custom_invoice_number;
        }
    }

    return $data;
}
add_filter( 'ppcp_create_order_request_body_data', 'customize_paypal_invoice_number', 10, 1 );

function customize_paypal_patch_invoice_number( $patches_array ) {
    // Access the global WooCommerce object
    global $woocommerce;

    // Get the current order
    $order = $woocommerce->session->get('order_awaiting_payment') ?
        wc_get_order($woocommerce->session->get('order_awaiting_payment')) : null;

    // Check if the order object exists
    if ( $order ) {
        // Get the custom invoice number using the provided function
        $custom_invoice_number = get_my_invoice_number( $order );

        // Add a new patch operation to set the custom invoice number
        $patches_array[] = array(
            'op' => 'add',
            'path' => '/purchase_units/@reference_id==\'default\'/invoice_id',
            'value' => $custom_invoice_number,
        );
    }

    return $patches_array;
}
add_filter( 'ppcp_patch_order_request_body_data', 'customize_paypal_patch_invoice_number', 10, 1 );