Overview
========

Receiving happens when an order is delivered to the retailer after
being shipped from the vendor.  In most cases an invoice will
accompany the order.  Depending on the retailer, in some cases the
purchase order will already exist, e.g. in Rattail or the POS system.

Rattail considers the primary concerns for this phase to be:

* update inventory counts
* (optional) record costs from invoice
* (optional) request credits from vendor
* (optional) detect/highlight other anomalies

Note that recording costs is "optional" mostly because that can be
handled in a separate third phase; see
:doc:`/features/purchasing/accounting/index`.  Vendor credits are not
always applicable but often will be.  Anomalies refers to anything you
want it to, e.g. if a product cost has increased too much.

Receiving is done via batch.  The user creates a batch via one of the
supported workflows:

* From Scratch - aka. just start scanning items
* From Invoice - upload invoice file, then scan "against" it
* From Purchase Order - choose existing PO, then scan against it
* From Purchase Order, with Invoice - choose PO *and* upload invoice
  file, scan against it

We say "scan" above, as it is possible to do these tasks with a mobile
phone and bluetooth scanner.  But paper-based receiving is also a
supported method; in this case after paper check-in has been
completed, user would "auto-update" all line items to be "received"
and then *undo* that for any exceptions (credits).

The user then will review the batch, add/modify line items as
appropriate.  Once satisfied that all data is correct, batch is
executed, which typically will update the master purchase record etc.