xrechnung weiter, line fehlt noch

edocument.py

@@ -4,14 +4,43 @@
 # full copyright notices and license terms.
 
 import genshi.template
-import os
+import os, html
+from trytond.exceptions import UserError
+from trytond.i18n import gettext
 from trytond.modules.edocument_uncefact.edocument import Invoice
+from decimal import Decimal
 
 
 class Invoice(Invoice):
     'EDocument XRechnung'
     __name__ = 'edocument.xrechnung.invoice'
 
+    def prepaid_amount(self, invoice):
+        """ compute already paid amount
+        """
+        return invoice.total_amount - invoice.amount_to_pay
+
+    def tax_rate(self, tax):
+        """ get tax-rate in procent
+        """
+        return (tax.tax.rate * Decimal('100.0')).quantize(Decimal('0.01'))
+
+    def tax_category_code(self, tax):
+        """ read tax-category, fire exception if missing
+        """
+        if len(tax.tax.unece_category_code or '') == 0:
+            raise UserError(gettext(
+                'edocument_xrechnung.mds_tax_category_missing',
+                taxname = tax.rec_name,
+                ))
+        return tax.tax.unece_category_code
+
+    def quote_text(self, text):
+        """ replace critical chars
+        """
+        if text is not None:
+            return html.quote(text)
+
     def _get_template(self, version):
         """ load our own template if 'version' is ours
         """