Improve tax support for POS batches

also add ref to tender, in batch rows

rattail/batch/pos.py

@@ -24,6 +24,8 @@
 POS Batch Handler
 """
 
+import decimal
+
 from sqlalchemy import orm
 
 from rattail.batch import BatchHandler
@@ -149,55 +151,94 @@ class POSBatchHandler(BatchHandler):
         # entry?  maybe only if config says so, e.g. might be nice to
         # only record badscan if entry truly came from scanner device,
         # in which case only the caller would know that
+        if not product:
+            return
 
-        if product:
+        # product located, so add item row
+        row = self.make_row()
+        row.user = user
+        row.item_entry = kwargs.get('item_entry', entry)
+        row.upc = product.upc
+        row.item_id = product.item_id
+        row.product = product
+        row.brand_name = product.brand.name if product.brand else None
+        row.description = product.description
+        row.size = product.size
+        row.full_description = product.full_description
+        dept = product.department
+        if dept:
+            row.department_number = dept.number
+            row.department_name = dept.name
+        subdept = product.subdepartment
+        if subdept:
+            row.subdepartment_number = subdept.number
+            row.subdepartment_name = subdept.name
+        row.foodstamp_eligible = product.food_stampable
+        row.sold_by_weight = product.weighed # TODO?
+        row.quantity = quantity
 
-            # product located, so add item row
+        regprice = product.regular_price
-            row = self.make_row()
+        if regprice:
-            row.user = user
+            row.reg_price = regprice.price
-            row.item_entry = kwargs.get('item_entry', entry)
-            row.upc = product.upc
-            row.item_id = product.item_id
-            row.product = product
-            row.brand_name = product.brand.name if product.brand else None
-            row.description = product.description
-            row.size = product.size
-            row.full_description = product.full_description
-            dept = product.department
-            if dept:
-                row.department_number = dept.number
-                row.department_name = dept.name
-            subdept = product.subdepartment
-            if subdept:
-                row.subdepartment_number = subdept.number
-                row.subdepartment_name = subdept.name
-            row.foodstamp_eligible = product.food_stampable
-            row.sold_by_weight = product.weighed # TODO?
-            row.quantity = quantity
 
-            regprice = product.regular_price
+        txnprice = product.current_price or product.regular_price
-            if regprice:
+        if txnprice:
-                row.reg_price = regprice.price
+            row.txn_price = txnprice.price
 
-            txnprice = product.current_price or product.regular_price
+        if row.txn_price:
-            if txnprice:
+            row.sales_total = row.txn_price * row.quantity
-                row.txn_price = txnprice.price
+            batch.sales_total = (batch.sales_total or 0) + row.sales_total
 
-            if row.txn_price:
+        tax = product.tax
-                row.sales_total = row.txn_price * row.quantity
+        if tax:
-                batch.sales_total = (batch.sales_total or 0) + row.sales_total
+            row.tax_code = tax.code
+            row.tax_rate = tax.rate
 
-            row.tax1 = product.tax1
+        if row.txn_price:
-            row.tax2 = product.tax2
+            row.row_type = self.enum.POS_ROW_TYPE_SELL
+            if tax:
+                self.update_tax(batch, row, tax)
+        else:
+            row.row_type = self.enum.POS_ROW_TYPE_BADPRICE
 
-            if row.txn_price:
+        self.add_row(batch, row)
-                row.row_type = self.enum.POS_ROW_TYPE_SELL
+        session.flush()
-            else:
+        return row
-                row.row_type = self.enum.POS_ROW_TYPE_BADPRICE
 
-            self.add_row(batch, row)
+    def update_tax(self, batch, row, tax=None, tax_code=None, **kwargs):
+        """
+        Update the tax totals for the batch, basd on given row.
+        """
+        if not tax and not tax_code:
+            raise ValueError("must specify either tax or tax_code")
+
+        session = self.app.get_session(batch)
+        if not tax:
+            tax = self.get_tax(session, tax_code)
+
+        btax = batch.taxes.get(tax.code)
+        if not btax:
+            btax = self.model.POSBatchTax()
+            btax.tax = tax
+            btax.tax_code = tax.code
+            btax.tax_rate = tax.rate
+            session.add(btax)
+            btax.batch = batch
             session.flush()
-            return row
+
+        # calculate relevant sales
+        rows = [r for r in batch.active_rows()
+                if r.tax_code == tax.code
+                and not r.void]
+        sales = sum([r.sales_total for r in rows])
+        # nb. must add row separately if not yet in batch
+        if not row.batch and not row.batch_uuid:
+            sales += row.sales_total
+
+        # total for this tax
+        before = btax.tax_total or 0
+        btax.tax_total = (sales * (tax.rate / 100)).quantize(decimal.Decimal('0.02'))
+        batch.tax_total = (batch.tax_total or 0) - before + btax.tax_total
 
     def record_badscan(self, batch, entry, quantity=1, user=None, **kwargs):
         """
@@ -212,6 +253,19 @@ class POSBatchHandler(BatchHandler):
         self.add_row(batch, row)
         return row
 
+    def get_tax(self, session, code, **kwargs):
+        """
+        Return the tax record corresponding to the given code.
+
+        :param session: Current DB session.
+
+        :param code: Tax code to fetch.
+        """
+        model = self.model
+        return session.query(model.Tax)\
+                      .filter(model.Tax.code == code)\
+                      .one()
+
     def get_tender(self, session, key, **kwargs):
         """
         Return the tender record corresponding to the given key.
@@ -276,6 +330,8 @@ class POSBatchHandler(BatchHandler):
 
         # adjust totals
         batch.sales_total = (batch.sales_total or 0) - orig_sales_total + orig_row.sales_total
+        if orig_row.tax_code:
+            self.update_tax(batch, orig_row, tax_code=orig_row.tax_code)
 
         # add another row indicating who/when
         row = self.make_row()
@@ -301,6 +357,8 @@ class POSBatchHandler(BatchHandler):
         # adjust batch totals
         if orig_row.sales_total:
             batch.sales_total = (batch.sales_total or 0) - orig_row.sales_total
+        if orig_row.tax_code:
+            self.update_tax(batch, orig_row, tax_code=orig_row.tax_code)
 
         # add another row indicating who/when
         row = self.make_row()
@@ -406,7 +464,7 @@ class POSBatchHandler(BatchHandler):
             row.user = user
             row.row_type = self.enum.POS_ROW_TYPE_CHANGE_BACK
             row.item_entry = item_entry
-            row.description = "CHANGE BACK"
+            row.description = "CHANGE DUE"
             row.tender_total = -balance
             row.tender = cash
             batch.tender_total = (batch.tender_total or 0) + row.tender_total

rattail/db/alembic/versions/d69dd44f495c_add_tender_kick_drawer.py

@@ -27,7 +27,27 @@ def upgrade():
     op.add_column('tender_version', sa.Column('kick_drawer', sa.Boolean(), autoincrement=False, nullable=True))
     op.add_column('tender_version', sa.Column('disabled', sa.Boolean(), autoincrement=False, nullable=True))
 
+    # batch_pos
+    op.alter_column('batch_pos', 'tax1_total', new_column_name='tax_total')
+    op.drop_column('batch_pos', 'tax2_total')
+
+    # batch_pos_tax
+    op.create_table('batch_pos_tax',
+                    sa.Column('uuid', sa.String(length=32), nullable=False),
+                    sa.Column('batch_uuid', sa.String(length=32), nullable=False),
+                    sa.Column('tax_uuid', sa.String(length=32), nullable=True),
+                    sa.Column('tax_code', sa.String(length=30), nullable=False),
+                    sa.Column('tax_rate', sa.Numeric(precision=7, scale=5), nullable=False),
+                    sa.Column('tax_total', sa.Numeric(precision=9, scale=2), nullable=True),
+                    sa.ForeignKeyConstraint(['batch_uuid'], ['batch_pos.uuid'], name='batch_pos_tax_fk_batch'),
+                    sa.ForeignKeyConstraint(['tax_uuid'], ['tax.uuid'], name='batch_pos_tax_fk_tax'),
+                    sa.PrimaryKeyConstraint('uuid')
+                    )
+
     # batch_pow_row
+    op.drop_column('batch_pos_row', 'tax2')
+    op.drop_column('batch_pos_row', 'tax1')
+    op.add_column('batch_pos_row', sa.Column('tax_code', sa.String(length=30), nullable=True))
     op.add_column('batch_pos_row', sa.Column('tender_uuid', sa.String(length=32), nullable=True))
     op.create_foreign_key('batch_pos_row_fk_tender', 'batch_pos_row', 'tender', ['tender_uuid'], ['uuid'])
 
@@ -37,6 +57,16 @@ def downgrade():
     # batch_pos_row
     op.drop_constraint('batch_pos_row_fk_tender', 'batch_pos_row', type_='foreignkey')
     op.drop_column('batch_pos_row', 'tender_uuid')
+    op.drop_column('batch_pos_row', 'tax_code')
+    op.add_column('batch_pos_row', sa.Column('tax1', sa.BOOLEAN(), autoincrement=False, nullable=True))
+    op.add_column('batch_pos_row', sa.Column('tax2', sa.BOOLEAN(), autoincrement=False, nullable=True))
+
+    # batch_pos_tax
+    op.drop_table('batch_pos_tax')
+
+    # batch_pos
+    op.add_column('batch_pos', sa.Column('tax2_total', sa.NUMERIC(precision=9, scale=2), autoincrement=False, nullable=True))
+    op.alter_column('batch_pos', 'tax_total', new_column_name='tax1_total')
 
     # tender
     op.drop_column('tender_version', 'disabled')

rattail/db/model/__init__.py

@@ -89,7 +89,7 @@ from .batch.inventory import InventoryBatch, InventoryBatchRow
 from .batch.labels import LabelBatch, LabelBatchRow
 from .batch.newproduct import NewProductBatch, NewProductBatchRow
 from .batch.delproduct import DeleteProductBatch, DeleteProductBatchRow
-from .batch.pos import POSBatch, POSBatchRow
+from .batch.pos import POSBatch, POSBatchTax, POSBatchRow
 from .batch.pricing import PricingBatch, PricingBatchRow
 from .batch.product import ProductBatch, ProductBatchRow
 from .batch.purchase import PurchaseBatch, PurchaseBatchRow, PurchaseBatchRowClaim, PurchaseBatchCredit

rattail/db/model/batch/pos.py

@@ -27,8 +27,9 @@ Models for POS transaction batch
 import sqlalchemy as sa
 from sqlalchemy import orm
 from sqlalchemy.ext.declarative import declared_attr
+from sqlalchemy.orm.collections import attribute_mapped_collection
 
-from rattail.db.model import Base, BatchMixin, BatchRowMixin
+from rattail.db.model import Base, BatchMixin, BatchRowMixin, uuid_column
 from rattail.db.types import GPCType
 
 
@@ -143,12 +144,8 @@ class POSBatch(BatchMixin, Base):
     Sales total for the transaction.
     """)
 
-    tax1_total = sa.Column(sa.Numeric(precision=9, scale=2), nullable=True, doc="""
+    tax_total = sa.Column(sa.Numeric(precision=9, scale=2), nullable=True, doc="""
-    Tax 1 total for the transaction.
+    Tax total for the transaction.
-    """)
-
-    tax2_total = sa.Column(sa.Numeric(precision=9, scale=2), nullable=True, doc="""
-    Tax 2 total for the transaction.
     """)
 
     tender_total = sa.Column(sa.Numeric(precision=9, scale=2), nullable=True, doc="""
@@ -166,11 +163,53 @@ class POSBatch(BatchMixin, Base):
 
     def get_balance(self):
         return ((self.sales_total or 0)
-                + (self.tax1_total or 0)
+                + (self.tax_total or 0)
-                + (self.tax2_total or 0)
                 + (self.tender_total or 0))
 
 
+class POSBatchTax(Base):
+    """
+    A tax total for a POS batch.
+
+    Each row in the batch may be associated with a tax (or not).
+    Those which are must be aggregated, to determine overall tax total
+    for the batch.  Arbitrary number of taxes may be involved, hence
+    we store them in this table.
+    """
+    __tablename__ = 'batch_pos_tax'
+    __table_args__ = (
+        sa.ForeignKeyConstraint(['batch_uuid'], ['batch_pos.uuid'],
+                                name='batch_pos_tax_fk_batch'),
+        sa.ForeignKeyConstraint(['tax_uuid'], ['tax.uuid'],
+                                name='batch_pos_tax_fk_tax'),
+    )
+
+    uuid = uuid_column()
+
+    batch_uuid = sa.Column(sa.String(length=32), nullable=False)
+    batch = orm.relationship(
+        POSBatch,
+        backref=orm.backref(
+            'taxes',
+            collection_class=attribute_mapped_collection('tax_code'),
+        ))
+
+    tax_uuid = sa.Column(sa.String(length=32), nullable=True)
+    tax = orm.relationship('Tax')
+
+    tax_code = sa.Column(sa.String(length=30), nullable=False, doc="""
+    Unique "code" for the tax rate.
+    """)
+
+    tax_rate = sa.Column(sa.Numeric(precision=7, scale=5), nullable=False, doc="""
+    Percentage rate for the tax, e.g. 8.25.
+    """)
+
+    tax_total = sa.Column(sa.Numeric(precision=9, scale=2), nullable=True, doc="""
+    Total for the tax.
+    """)
+
+
 class POSBatchRow(BatchRowMixin, Base):
     """
     Row of data within a POS batch.
@@ -297,12 +336,8 @@ class POSBatchRow(BatchRowMixin, Base):
     Sales total for the item.
     """)
 
-    tax1 = sa.Column(sa.Boolean(), nullable=True, doc="""
+    tax_code = sa.Column(sa.String(length=30), nullable=True, doc="""
-    Flag indicating Tax 1 should be added for the item.
+    Unique "code" for the item tax rate, if applicable.
-    """)
-
-    tax2 = sa.Column(sa.Boolean(), nullable=True, doc="""
-    Flag indicating Tax 2 should be added for the item.
     """)
 
     tender_total = sa.Column(sa.Numeric(precision=9, scale=2), nullable=True, doc="""

rattail/db/model/products.py

@@ -129,9 +129,9 @@ class Tax(Base):
     """)
 
     def __str__(self):
-        if self.description:
+        if self.rate is not None:
-            return self.description
+            return f"{self.description} {self.rate:0.3f} %"
-        return "{} ({}%)".format(self.code, pretty_quantity(self.rate))
+        return self.description or ''
 
 
 class Product(Base):