handle tax childs

mixin.py

@@ -5,6 +5,7 @@
 
 
 from decimal import Decimal
+import datetime
 import html
 from trytond.exceptions import UserError
 from trytond.i18n import gettext
@@ -100,21 +101,30 @@ class EdocumentMixin(object):
         """ get tax of invoice-line,
             fire exception if no/multiple taxes exists
         """
-        if len(line.invoice_taxes) != 1:
+        if len(line.taxes) != 1:
             raise UserError(gettext(
                 'edocument_xrechnung.msg_linetax_invalid_number',
                 linename=line.rec_name,
-                numtax=len(line.invoice_taxes)))
+                numtax=len(line.taxes)))
+
+        tax = line.taxes[0]
+        date = line.invoice.accounting_date or line.invoice.invoice_date
+        for child in tax.childs:
+            start_date = tax.start_date or datetime.date.min
+            end_date = tax.end_date or datetime.date.max
+            if start_date <= date <= end_date:
+                tax = child
+                break
 
         allowed_cat = ['AE', 'L', 'M', 'E', 'S', 'Z', 'G', 'O', 'K', 'B']
-        unece_category_code = self.get_category_code(line.invoice_taxes[0].tax)
+        unece_category_code = self.get_category_code(tax)
         if unece_category_code not in allowed_cat:
             raise UserError(gettext(
                 'edocument_xrechnung.msg_linetax_invalid_catcode',
-                taxname=line.invoice_taxes[0].tax.rec_name,
+                taxname=tax.rec_name,
                 allowed=', '.join(allowed_cat)))
 
-        return line.invoice_taxes[0].tax
+        return tax
 
     def taxident_data(self, tax_identifier):
         """ get tax-scheme-id and codes

template/Factur-X-1.07.2-extended/invoice.xml

@@ -83,9 +83,7 @@ this repository contains the full copyright notices and license terms. -->
                 <ram:BilledQuantity py:attrs="{'unitCode': line.unit.unece_code} if line.unit and line.unit.unece_code else {}">${line.quantity * this.type_sign}</ram:BilledQuantity>
             </ram:SpecifiedLineTradeDelivery>
             <ram:SpecifiedLineTradeSettlement>
-                <py:for each="tax in line.invoice_taxes">
-                    ${TradeTax(tax.tax)}
-                </py:for>
+                    ${TradeTax(this.invoice_line_tax(line))}
                 <ram:SpecifiedTradeSettlementLineMonetarySummation>
                     <ram:LineTotalAmount py:attrs="{'currencyID': this.invoice.currency.code}">${line.amount}</ram:LineTotalAmount>
                 </ram:SpecifiedTradeSettlementLineMonetarySummation>