Wallee Commerce: Payment and Invoicing

What is the Wallee service

https://wallee.com is a 3rd party service which provides a single interface for integration with a large number of different payment gateways.
It also provides payment related functionalities, such as invoicing, recurrent payments, payment reminders e.t.c.
Wallee provides a REST API through which, all of its functionalities can be integrated into a php application such as Drupal.

Drupal 9 beta work is in progress and it will be available soon.

Initial Motivation

The initial motivation for this module was the full integration of PostFinance to a Drupal 8 commerce app.
By full integration, we mean the following functionalities:

• Integrate Commerce payments by Wallee through PostFinance

• Use online payments via various credit cards (ie. Visa & Mastercard)

• Use offline payments (invoice with ISR slip).

  Invoice is to be printed and sent to the customer who made the purchase. It should therefore contain an Inpayment slip, so that the payment can be tracked in PostFinance. https://www.postfinance.ch/en/business/products/accounts-receivable-solutions/inpayment-slip-isr.html

• Use of PostFinance's File Delivery Services (FDS)

  for automatic payment status update.

In addition to the PostFinance related features, we also needed to implement the following:

• Easy creation of invoices

• Use multiple invoice templates

Challenges

By the time this module's implementation started, no PostFinance Drupal 8 module was available
https://www.drupal.org/project/commerce_postfinance

Even if that module existed, creating a PostFinance invoice with a compatible Inpayment Slip (ISR), was a big undertaking.
Furthermore, offline payment status update, either by uploading a PostFinance's payment files (e.g. camt.054) or using FDS was another pain point.

Wallee to the rescue

Wallee service, provides all the above and a lot more, via an intuitive user interface. Therefore its easy to configure all interfaces to payment gateways (e.g PostFinance).
It also allows to easily create multiple invoice templates, via TWIG.
PostFinance ISR is preconfigured and can be used with no extra hustle.
PostFinance FDS service or uploading of payment files (e.g camt.054) is also easily configurable.

Most importantly, Wallee allows for its full integration to other systems.
It provides a PHP SDK (https://github.com/wallee-payment/php-sdk)
It also allows for custom webhook creation, so that it make requests to your app, in several different occasions e.g. invoice has been created, payment has been made, e.t.c.

The Drupal Wallee Module

This module has been created in order to make the Drupal-Wallee integration easy and automate many of the required tasks.
Prior to Wallee module installation, one should have already taken care of the below prerequisites

Prerequisites:
1. Drupal Commerce v2
Drupal commerce should have already be installed and configured.

2. Wallee service account
A Wallee account should be created and the desired online/offline payment methods also. It's not necessary that they are related to PostFinance.

Configuration
This module currently provides the following
1. Connection to specific Wallee account
2. Configuration of automatic Invoice creation upon order state change
3. Manual Invoice creation for any order
4. Automatic fetching of invoice PDFs from Wallee into Drupal's filesystem
5. Creation of a new order tab, by the name 'Invoices', where one can find the order's invoice, or create a new one by clicking on the respective button.
6. Automatic invoice and order state change, when an offline payment has been made (via PostFinance FDS and Wallee webhooks).

Current status
A first dev version of this module will be released shortly.