I would like to know how to show all the pending orders that have a given payment method for a given user on the checkout page when they are logged in. Is it also possible for the total of the previous orders to be added to the current order and checkout at once.
This seems very specific and I doubt there’s an already implemented solution for it.
One option would obviously be to create your own plugin, hook to the call of the checkout page and get a list of those orders from the database per request.
I would strongly recomment NOT to add the sum of those unfinished orders as it’d be really complicated to track which has been payed for and which wasn’t if your backend is full of orders that contain pending payments from previous encounters.
If you got customers who don’t pay their bills, wouldn’t it be a better option to prevent them from even checking out when they haven’t payed up at least all their bills from a certain time frame ago?
There’s also a list of user-related orders on the user profile, maybe you can use the tpl that’s used for that and work with that as base…?