Payment method on InvoiceXpress document observations

invoicexpress_woocommerce_data_obs_payment_method.php

<?php

// This code snippet is to be used with the "Invoicing with InvoiceXpress for WooCommerce" plugin - https://invoicexpress-woocommerce.com/

$types = array(
	'invoice',
	'simplified_invoice',
	'invoice_receipt',
	'credit_note',
	'quote',
	'proforma',
	'transport_guide',
	'devolution_guide',
);
foreach ( $types as $type ) {
	add_filter( "invoicexpress_woocommerce_{$type}_data", 'my_woocommerce_ixpro_payment_method_obs_filter', 10, 2 );
}

function my_woocommerce_ixpro_payment_method_obs_filter( $document_data, $order_object ) {
	if ( $method = $order_object->get_payment_method_title() ) {
		$observations                  = explode( PHP_EOL, trim( $document_data['observations'] ) );
		$observations[]                = 'Payment method: '.trim( $method );
		$document_data['observations'] = implode( PHP_EOL, array_filter( $observations, function( $value ) { return trim( $value ) !== ''; } ) );
	}
	return $document_data;
}