feat: add BT-120 VAT exemption reason

eu_einvoice/european_e_invoice/custom/sales_invoice.py

@@ -127,6 +127,7 @@ def __init__(
 		self.doc = None
 		self.item_tax_rates = set()
 		self.delivery_dates = []
+		self.vat_exemption_reason_text = ""
 
 	def get_einvoice(self) -> Document | None:
 		"""Return the einvoice document as a Python object."""
@@ -135,6 +136,9 @@ def get_einvoice(self) -> Document | None:
 	def create_einvoice(self):
 		"""Create the einvoice document as a Python object."""
 		self.doc = Document()
+		self.vat_exemption_reason_text = str(
+			frappe.db.get_single_value("E Invoice Settings", "vat_exemption_reason_text") or ""
+		).strip()
 
 		self._set_context()
 		self._set_header()
@@ -273,7 +277,10 @@ def _set_seller(self):
 		self._set_seller_address()
 
 	def _set_seller_id(self):
-		for row in self.customer.supplier_numbers:
+		supplier_numbers = getattr(self.customer, "supplier_numbers", None)
+		if not supplier_numbers:
+			return
+		for row in supplier_numbers:
 			if row.company == self.invoice.company and row.supplier_number:
 				self.doc.trade.agreement.seller.id = row.supplier_number
 				break
@@ -486,6 +493,7 @@ def _add_line_item(self, item: SalesInvoiceItem):
 					("Sales Taxes and Charges Template", self.invoice.taxes_and_charges),
 				]
 			).upper()
+			self._set_optional_vat_exemption_reason_text(li.settlement.trade_tax)
 
 		li.settlement.monetary_summation.total_amount = flt(item.net_amount, item.precision("net_amount"))
 		self.doc.trade.items.add(li)
@@ -614,8 +622,13 @@ def _add_empty_tax(self):
 				("Sales Taxes and Charges Template", self.invoice.taxes_and_charges),
 			]
 		).upper()
+		self._set_optional_vat_exemption_reason_text(trade_tax)
 		self.doc.trade.settlement.trade_tax.add(trade_tax)
 
+	def _set_optional_vat_exemption_reason_text(self, trade_tax: ApplicableTradeTax) -> None:
+		if self.vat_exemption_reason_text:
+			trade_tax.exemption_reason = self.vat_exemption_reason_text
+
 	def _add_delivery_date(self):
 		if self.delivery_dates:
 			delivery_date = sorted(self.delivery_dates)[-1]

eu_einvoice/european_e_invoice/doctype/e_invoice_import/e_invoice_import.py

@@ -1,6 +1,7 @@
 # Copyright (c) 2024, ALYF GmbH and contributors
 # For license information, please see license.txt
 
+from __future__ import annotations
 
 from pathlib import Path
 from typing import TYPE_CHECKING
@@ -279,6 +280,8 @@ def parse_tax(self, tax: ApplicableTradeTax):
 		t.basis_amount = flt_or_none(tax.basis_amount._value)
 		t.rate_applicable_percent = flt_or_none(tax.rate_applicable_percent._value)
 		t.calculated_amount = flt_or_none(tax.calculated_amount._value)
+		reason_text = tax.exemption_reason._text
+		t.vat_exemption_reason_text = str(reason_text).strip() if reason_text else None
 
 	def parse_payment_term(self, term: PaymentTerms):
 		if not term.partial_amount.children:

eu_einvoice/european_e_invoice/doctype/e_invoice_settings/e_invoice_settings.json

@@ -12,6 +12,8 @@
   "error_action_on_save",
   "error_action_on_submit",
   "sales_invoice_number_field",
+  "section_break_bt120",
+  "vat_exemption_reason_text",
   "section_break_yldr",
   "auto_attach_xml",
   "attach_field_for_xml_file"
@@ -74,13 +76,24 @@
    "fieldname": "sales_invoice_number_field",
    "fieldtype": "Autocomplete",
    "label": "Sales Invoice Number Field"
+  },
+  {
+   "fieldname": "section_break_bt120",
+   "fieldtype": "Section Break",
+   "label": "VAT exemption (e-invoice)"
+  },
+  {
+   "description": "If set, written to BT-120 (<code>ram:ExemptionReason</code>) on VAT breakdowns where an exemption reason code is emitted. Left unset in the XML when empty.",
+   "fieldname": "vat_exemption_reason_text",
+   "fieldtype": "Small Text",
+   "label": "Default VAT exemption reason"
   }
  ],
  "grid_page_length": 50,
  "index_web_pages_for_search": 1,
  "issingle": 1,
  "links": [],
- "modified": "2026-02-06 17:52:09.990716",
+ "modified": "2026-04-21 12:00:00.000000",
  "modified_by": "Administrator",
  "module": "European e-Invoice",
  "name": "E Invoice Settings",

eu_einvoice/european_e_invoice/doctype/e_invoice_settings/e_invoice_settings.py

@@ -23,6 +23,7 @@ class EInvoiceSettings(Document):
 		sales_invoice_number_field: DF.Autocomplete | None
 		validate_sales_invoice_on_save: DF.Check
 		validate_sales_invoice_on_submit: DF.Check
+		vat_exemption_reason_text: DF.SmallText | None
 	# end: auto-generated types
 
 	def before_validate(self):

eu_einvoice/european_e_invoice/doctype/e_invoice_trade_tax/e_invoice_trade_tax.json

@@ -9,6 +9,7 @@
   "basis_amount",
   "rate_applicable_percent",
   "calculated_amount",
+  "vat_exemption_reason_text",
   "tax_account"
  ],
  "fields": [
@@ -35,6 +36,12 @@
    "options": "currency",
    "read_only": 1
   },
+  {
+   "fieldname": "vat_exemption_reason_text",
+   "fieldtype": "Small Text",
+   "label": "VAT exemption reason",
+   "read_only": 1
+  },
   {
    "fieldname": "tax_account",
    "fieldtype": "Link",
@@ -45,7 +52,7 @@
  "index_web_pages_for_search": 1,
  "istable": 1,
  "links": [],
- "modified": "2024-09-26 21:18:13.837830",
+ "modified": "2026-04-21 14:00:00.000000",
  "modified_by": "Administrator",
  "module": "European e-Invoice",
  "name": "E Invoice Trade Tax",

eu_einvoice/european_e_invoice/doctype/e_invoice_trade_tax/e_invoice_trade_tax.py

@@ -21,6 +21,7 @@ class EInvoiceTradeTax(Document):
 		parenttype: DF.Data
 		rate_applicable_percent: DF.Percent
 		tax_account: DF.Link | None
+		vat_exemption_reason_text: DF.SmallText | None
 	# end: auto-generated types
 
 	pass