:mod:`rattail.ext.purchasing` Module
------------------------------------

This extension adds a more or less generic purchasing system to Rattail.

Core Mappings
=============

In addition to providing extra classes (listed below), the ``purchasing`` extension also
adds the following attribute to the core :class:`rattail.Product` class:

.. attribute:: sources

   A list of :class:`rattail.ProductSource` instances for the product.

Classes
=======

.. autoclass:: rattail.ProductSource

   .. attribute:: product

      A reference to the :class:`rattail.Product` provided by this source.

   .. attribute:: vendor

      A reference to the :class:`rattail.Vendor` from which this source is available.

   .. attribute:: sku

      A vendor-specific SKU to be used when ordering product via this source.

   .. attribute:: quantity

      Quantity of the product which is represented by this source.

   .. attribute:: suggested_retail

      The suggested retail price for the product, specific to this source.

   .. attribute:: unit_cost

      The per-unit cost of the product when purchased via this source.

   .. attribute:: cost_recorded

      Date and time when this source's cost was last recorded.  (For use in catalog
      data import tracking.)

   .. attribute:: cost_expires

      Date and time when this source's cost will expire, if known.

.. autoclass:: rattail.PurchaseOrder

   .. attribute:: id

      An integer field which may contain a human-friendly ID for the purchase order.

   .. attribute:: vendor

      A reference to the :class:`rattail.Vendor` to whom this purchase order is submitted.

   .. attribute:: buyer

      A reference to the :class:`rattail.Employee` who is assembling the purchase order.

   .. attribute:: confirmer

      A reference to the :class:`rattail.Employee` who is confirming the purchase order.

   .. attribute:: ordered

      Date and time when the order was submitted to the vendor.

   .. attribute:: expected

      Date and time when the order is expected to arrive, if known.

   .. attribute:: received

      Date and time when the order is received.

   .. attribute:: receiver

      A reference to the :class:`rattail.Employee` who receives the purchase order.

   .. attribute:: details

      A list of :class:`rattail.PurchaseOrderProduct` instances belonging to the purchase order.

.. autoclass:: rattail.PurchaseOrderProduct

   .. attribute:: product

      A reference to the :class:`rattail.Product` being ordered.

   .. attribute:: product_source

      A reference to the specific :class:`rattail.ProductSource` being ordered.

   .. attribute:: quantity_ordered

      Quantity of the product being ordered.  This value should be interpreted relative to
      :attr:`PurchaseOrderProduct.product_source`.

   .. attribute:: quantity_received

      Quantity of the product which is received, for comparison to :attr:`PurchaseOrderProduct.quantity_ordered`.

.. autoclass:: rattail.Vendor

   .. attribute:: name

      The name of the vendor.