Pickup Location could scale well if it is per Shipment instead of Order

[bhtabor]

The idea of having pickup location per order doesn't scale well. For instance, for multi vendor orders. Vendors might have their own pickup location. But spree_pickup allows only one location per order. I think spree_pickup would scale well if pickup location is per shipment.

Even the code highlights this discrepancy. The pickup location is checked on order but the delivery is in fact per shipment. https://github.com/vinsol-spree-contrib/spree_pickup/blob/master/app/overrides/add_ship_condition.rb#L13

[bhtabor]

Here is a much simplified, per shipment, pickup option. https://github.com/bhtabor/spree_pickup_shipment/tree/spree-3-7

No need to override the checkout Address step. It works seamlessly with the checkout process since the pickup location is added on the shipping method. It also avoids use of Geocoder since Google Map is not needed. But, that means each pickup location will need to have its own shipping method.

Do you see any issue with this approach? If interested, I could send a pull request to spree_pickup.