Check if duplicated invoices on SII report

aeat.py

@@ -405,6 +405,7 @@ class SIIReport(Workflow, ModelSQL, ModelView):
     def confirm(cls, reports):
         for report in reports:
             report.check_invoice_state()
+            report.check_duplicate_invoices()
 
     @classmethod
     @ModelView.button
@@ -1129,6 +1130,17 @@ class SIIReport(Workflow, ModelSQL, ModelView):
                 cls.confirm(received_reports)
                 cls.send(received_reports)
 
+    def check_duplicate_invoices(self):
+        if self.operation_type in ('A0', 'D0'):
+            invoices = set()
+            for line in self.lines:
+                if line.invoice in invoices:
+                    raise UserError(gettext(
+                        'aeat_sii.msg_report_duplicated_invoice',
+                        invoice=line.invoice.rec_name,
+                        report=self.rec_name))
+                invoices.add(line.invoice)
+
 
 class SIIReportLine(ModelSQL, ModelView):
     '''

locale/es.po

@@ -1789,4 +1789,8 @@ msgstr "Forzar borrador factura enviada a SII"
 
 msgctxt "model:ir.message,text:msg_report_wrong_invoice_state"
 msgid "Invoice \"%(invoice)s\" must be posted or paid."
-msgstr "La factura \"%(invoice)s\" debe estar contabilizada o pagada."
+msgstr "La factura \"%(invoice)s\" debe estar contabilizada o pagada."
+
+msgctxt "model:ir.message,text:msg_report_duplicated_invoice"
+msgid "Invoice \"%(invoice)s\" is duplicated on SII Report \"%(report)s\"."
+msgstr "La factura \"%(invoice)s\" se ha incluído varias veces en el Libro SII \"%(report)s\"."

message.xml

@@ -48,6 +48,8 @@ If you edit them take care if you need to update again to SII</field>
             <field name="text">Cannot modify "%(fields)s" on invoice "%(invoice)s" because its SII state is "%(sii_state)s". Please first include the invoice in a Delete Invoice SII Book and send to AEAT.</field>
         <record model="ir.message" id="msg_report_wrong_invoice_state">
             <field name="text">Invoice "%(invoice)s" must be posted or paid.</field>
+        <record model="ir.message" id="msg_report_duplicated_invoice">
+            <field name="text">Invoice "%(invoice)s" is duplicated on SII Report "%(report)s".</field>
         </record>
     </data>
 </tryton>