We are looking at writing a module for Ezidebit. Ezidebit allow the setup of Direct Debit payments online. However, the initial request to Ezidebit includes the payment frequency and Ezidebit initiates these future payments on the frequency provided.
So once setup Civi does not need to request any further payments from Ezidebit. Instead it just needs to import the payment receipts - which are available from Ezidebit via an API.
I'm wondering what the best way to go about building a module for this will be? It's not really a payment gateway as there are no real-time payments available via this aspect of Ezidebits service. It is probably more like a bank account with payments being received by Ezidebit that need to be entered in to Civi.
In Civi it is most likely going to be used for Regular Donors and if so we would need to be able to track the commitment the donor has made and also the actual payments received. This doesn't seem to quite fit Pledges (as it is ongoing) or recurring payments (as Civi does not initiate the payment).
Any suggestions on the best approach for this?