[FIX] l10n_es_edi_tbai: fix unit price, discount in multicurrency export

Currently there are the following bugs when XML-exporting invoices
that are not in company currency and use discounts:
  * The discount is computed and exported in document currency.
    But it should be exported in company currency.
  * The unit price value (excl. discount) is computed wrongly
    since it uses the wrong discount value.

This commit corrects the discount and unit price computation / export.

closes odoo/odoo#148566

X-original-commit: 1cc846e8a53fd7c4298b7324d9c4f272592f0497
Signed-off-by: William André (wan) <wan@odoo.com>
Signed-off-by: Sven Führ (svfu) <svfu@odoo.com>

addons/l10n_es_edi_tbai/models/account_edi_format.py

@@ -330,10 +330,11 @@ class AccountEdiFormat(models.Model):
         invoice_lines = []
         for line in invoice.invoice_line_ids.filtered(lambda line: line.display_type not in ('line_section', 'line_note')):
             if line.discount == 100.0:
-                gross_price_subtotal = line.price_unit * line.quantity
+                inverse_currency_rate = abs(line.move_id.amount_total_signed / line.move_id.amount_total) if line.move_id.amount_total else 1
+                balance_before_discount = - line.price_unit * line.quantity * inverse_currency_rate
             else:
-                gross_price_subtotal = line.price_subtotal / (1 - line.discount / 100.0)
-            discount = (gross_price_subtotal - line.price_subtotal) * refund_sign
+                balance_before_discount = line.balance / (1 - line.discount / 100)
+            discount = (balance_before_discount - line.balance)
 
             if not any([t.l10n_es_type == 'sujeto_isp' for t in line.tax_ids]):
                 total = line.price_total * abs(line.balance / line.amount_currency if line.amount_currency != 0 else 1) * -refund_sign

addons/l10n_es_edi_tbai/tests/test_edi_xml.py

@@ -43,6 +43,81 @@ class TestEdiTbaiXmls(TestEsEdiTbaiCommon):
             xml_expected = etree.fromstring(super().L10N_ES_TBAI_SAMPLE_XML_POST)
             self.assertXmlTreeEqual(xml_doc, xml_expected)
 
+    def test_xml_tree_post_multicurrency(self):
+        """Test of Customer Invoice XML. The invoice is not in company currency and has a line with a 100% discount"""
+
+        currency_usd = self.env.ref('base.USD')
+        currency_usd.active = True
+        date = str(self.out_invoice.invoice_date)
+        self.env['res.currency.rate'].create({
+            'name': date,
+            'company_id': self.company_data['company'].id,
+            'currency_id': currency_usd.id,
+            'rate': 0.5})
+        invoice = self.env['account.move'].create({
+            'name': 'INV/01',
+            'move_type': 'out_invoice',
+            'invoice_date': date,
+            'partner_id': self.partner_a.id,
+            'currency_id': currency_usd.id,
+            'invoice_line_ids': [
+                (0, 0, {
+                    'product_id': self.product_a.id,
+                    'price_unit': 123.00,
+                    'quantity': 5,
+                    'discount': 20.0,
+                    'tax_ids': [(6, 0, self._get_tax_by_xml_id('s_iva21b').ids)],
+                }),
+                (0, 0, {
+                    'product_id': self.product_a.id,
+                    'price_unit': 123.00,
+                    'quantity': 5,
+                    'discount': 100.0,
+                    'tax_ids': [(6, 0, self._get_tax_by_xml_id('s_iva21b').ids)],
+                }),
+            ],
+        })
+
+        with freeze_time(self.frozen_today):
+            xml_doc = self.edi_format._get_l10n_es_tbai_invoice_xml(invoice, cancel=False)[invoice]['xml_file']
+            xml_doc.remove(xml_doc.find("Signature", namespaces=NS_MAP))
+            xml_expected_base = etree.fromstring(super().L10N_ES_TBAI_SAMPLE_XML_POST)
+            xpath = """
+                <xpath expr="//DetallesFactura" position="replace">
+                    <DetallesFactura>
+                      <IDDetalleFactura>
+                          <DescripcionDetalle>producta</DescripcionDetalle>
+                          <Cantidad>5.00</Cantidad>
+                          <ImporteUnitario>246.00</ImporteUnitario>
+                          <Descuento>246.00</Descuento>
+                          <ImporteTotal>1190.64</ImporteTotal>
+                      </IDDetalleFactura>
+                      <IDDetalleFactura>
+                          <DescripcionDetalle>producta</DescripcionDetalle>
+                          <Cantidad>5.00</Cantidad>
+                          <ImporteUnitario>246.00</ImporteUnitario>
+                          <Descuento>1230.00</Descuento>
+                          <ImporteTotal>0.00</ImporteTotal>
+                      </IDDetalleFactura>
+                    </DetallesFactura>
+                </xpath>
+                <xpath expr="//ImporteTotalFactura" position="replace">
+                    <ImporteTotalFactura>1190.64</ImporteTotalFactura>
+                </xpath>
+                <xpath expr="//DesgloseIVA" position="replace">
+                    <DesgloseIVA>
+                      <DetalleIVA>
+                        <BaseImponible>984.00</BaseImponible>
+                        <TipoImpositivo>21.00</TipoImpositivo>
+                        <CuotaImpuesto>206.64</CuotaImpuesto>
+                        <OperacionEnRecargoDeEquivalenciaORegimenSimplificado>N</OperacionEnRecargoDeEquivalenciaORegimenSimplificado>
+                      </DetalleIVA>
+                    </DesgloseIVA>
+                </xpath>
+            """
+            xml_expected = self.with_applied_xpath(xml_expected_base, xpath)
+            self.assertXmlTreeEqual(xml_doc, xml_expected)
+
     def test_xml_tree_in_post(self):
         """Test XML of vendor bill for LROE Batuz"""
         with freeze_time(self.frozen_today):