fix: split_invoices_based_on_payment_terms (backport #37859) (#38488)

* refactor: `split_invoices_based_on_payment_terms`

- Invoices were in the wrong order due to the logic. The invoices with payment terms were added first and the rest after.
- Overly long function with unnecessary loops (reduced to one main loop) and complexity
- The split row as per payment terms was not ordered. So the second installment was allocated first

(cherry picked from commit 6bd56d2d5f)

* test: `get_outstanding_reference_documents` (triggered via UI)

(cherry picked from commit 162c0497d1)

# Conflicts:
#	erpnext/accounts/doctype/payment_entry/test_payment_entry.py

* fix: Alert message and make sure invoice due dates are different for effective test

- Make invoice due dates are different so that the invoice with the earliest due date is allocated first in the test
- Translate voucher type, simplify alert message. The invoice could be "split" into 1 row, no. of rows in the message seems unnecessary.

(cherry picked from commit 56ac3424d2)

* style: Remove spaces introduced via merge conflict

(cherry picked from commit 4b4b176fcf)

# Conflicts:
#	erpnext/accounts/doctype/payment_entry/test_payment_entry.py

* fix: Re-add no.of rows split in alert message

(cherry picked from commit 1fc5844025)

* fix: Merge conflicts in tests

---------

Co-authored-by: marination <maricadsouza221197@gmail.com>

erpnext/accounts/doctype/payment_entry/payment_entry.py

@@ -1689,13 +1689,42 @@ def get_outstanding_reference_documents(args, validate=False):
 	return data
 
 
-def split_invoices_based_on_payment_terms(outstanding_invoices, company):
+def split_invoices_based_on_payment_terms(outstanding_invoices, company) -> list:
-	invoice_ref_based_on_payment_terms = {}
+	"""Split a list of invoices based on their payment terms."""
+	exc_rates = get_currency_data(outstanding_invoices, company)
 
+	outstanding_invoices_after_split = []
+	for entry in outstanding_invoices:
+		if entry.voucher_type in ["Sales Invoice", "Purchase Invoice"]:
+			if payment_term_template := frappe.db.get_value(
+				entry.voucher_type, entry.voucher_no, "payment_terms_template"
+			):
+				split_rows = get_split_invoice_rows(entry, payment_term_template, exc_rates)
+				if not split_rows:
+					continue
+
+				frappe.msgprint(
+					_("Splitting {0} {1} into {2} rows as per Payment Terms").format(
+						_(entry.voucher_type), frappe.bold(entry.voucher_no), len(split_rows)
+					),
+					alert=True,
+				)
+				outstanding_invoices_after_split += split_rows
+				continue
+
+		# If not an invoice or no payment terms template, add as it is
+		outstanding_invoices_after_split.append(entry)
+
+	return outstanding_invoices_after_split
+
+
+def get_currency_data(outstanding_invoices: list, company: str = None) -> dict:
+	"""Get currency and conversion data for a list of invoices."""
+	exc_rates = frappe._dict()
 	company_currency = (
 		frappe.db.get_value("Company", company, "default_currency") if company else None
 	)
-	exc_rates = frappe._dict()
+
 	for doctype in ["Sales Invoice", "Purchase Invoice"]:
 		invoices = [x.voucher_no for x in outstanding_invoices if x.voucher_type == doctype]
 		for x in frappe.db.get_all(
@@ -1710,72 +1739,54 @@ def split_invoices_based_on_payment_terms(outstanding_invoices, company):
 				company_currency=company_currency,
 			)
 
-	for idx, d in enumerate(outstanding_invoices):
+	return exc_rates
-		if d.voucher_type in ["Sales Invoice", "Purchase Invoice"]:
+
-			payment_term_template = frappe.db.get_value(
+
-				d.voucher_type, d.voucher_no, "payment_terms_template"
+def get_split_invoice_rows(invoice: dict, payment_term_template: str, exc_rates: dict) -> list:
+	"""Split invoice based on its payment schedule table."""
+	split_rows = []
+	allocate_payment_based_on_payment_terms = frappe.db.get_value(
+		"Payment Terms Template", payment_term_template, "allocate_payment_based_on_payment_terms"
+	)
+
+	if not allocate_payment_based_on_payment_terms:
+		return [invoice]
+
+	payment_schedule = frappe.get_all(
+		"Payment Schedule", filters={"parent": invoice.voucher_no}, fields=["*"], order_by="due_date"
+	)
+	for payment_term in payment_schedule:
+		if not payment_term.outstanding > 0.1:
+			continue
+
+		doc_details = exc_rates.get(payment_term.parent, None)
+		is_multi_currency_acc = (doc_details.currency != doc_details.company_currency) and (
+			doc_details.party_account_currency != doc_details.company_currency
+		)
+		payment_term_outstanding = flt(payment_term.outstanding)
+		if not is_multi_currency_acc:
+			payment_term_outstanding = doc_details.conversion_rate * flt(payment_term.outstanding)
+
+		split_rows.append(
+			frappe._dict(
+				{
+					"due_date": invoice.due_date,
+					"currency": invoice.currency,
+					"voucher_no": invoice.voucher_no,
+					"voucher_type": invoice.voucher_type,
+					"posting_date": invoice.posting_date,
+					"invoice_amount": flt(invoice.invoice_amount),
+					"outstanding_amount": payment_term_outstanding
+					if payment_term_outstanding
+					else invoice.outstanding_amount,
+					"payment_term_outstanding": payment_term_outstanding,
+					"payment_amount": payment_term.payment_amount,
+					"payment_term": payment_term.payment_term,
+				}
 			)
-			if payment_term_template:
+		)
-				allocate_payment_based_on_payment_terms = frappe.get_cached_value(
-					"Payment Terms Template", payment_term_template, "allocate_payment_based_on_payment_terms"
-				)
-				if allocate_payment_based_on_payment_terms:
-					payment_schedule = frappe.get_all(
-						"Payment Schedule", filters={"parent": d.voucher_no}, fields=["*"]
-					)
 
-					for payment_term in payment_schedule:
+	return split_rows
-						if payment_term.outstanding > 0.1:
-							doc_details = exc_rates.get(payment_term.parent, None)
-							is_multi_currency_acc = (doc_details.currency != doc_details.company_currency) and (
-								doc_details.party_account_currency != doc_details.company_currency
-							)
-							payment_term_outstanding = flt(payment_term.outstanding)
-							if not is_multi_currency_acc:
-								payment_term_outstanding = doc_details.conversion_rate * flt(payment_term.outstanding)
-
-							invoice_ref_based_on_payment_terms.setdefault(idx, [])
-							invoice_ref_based_on_payment_terms[idx].append(
-								frappe._dict(
-									{
-										"due_date": d.due_date,
-										"currency": d.currency,
-										"voucher_no": d.voucher_no,
-										"voucher_type": d.voucher_type,
-										"posting_date": d.posting_date,
-										"invoice_amount": flt(d.invoice_amount),
-										"outstanding_amount": payment_term_outstanding
-										if payment_term_outstanding
-										else d.outstanding_amount,
-										"payment_term_outstanding": payment_term_outstanding,
-										"payment_amount": payment_term.payment_amount,
-										"payment_term": payment_term.payment_term,
-										"account": d.account,
-									}
-								)
-							)
-
-	outstanding_invoices_after_split = []
-	if invoice_ref_based_on_payment_terms:
-		for idx, ref in invoice_ref_based_on_payment_terms.items():
-			voucher_no = ref[0]["voucher_no"]
-			voucher_type = ref[0]["voucher_type"]
-
-			frappe.msgprint(
-				_("Spliting {} {} into {} row(s) as per Payment Terms").format(
-					voucher_type, voucher_no, len(ref)
-				),
-				alert=True,
-			)
-
-			outstanding_invoices_after_split += invoice_ref_based_on_payment_terms[idx]
-
-			existing_row = list(filter(lambda x: x.get("voucher_no") == voucher_no, outstanding_invoices))
-			index = outstanding_invoices.index(existing_row[0])
-			outstanding_invoices.pop(index)
-
-	outstanding_invoices_after_split += outstanding_invoices
-	return outstanding_invoices_after_split
 
 
 def get_orders_to_be_billed(

erpnext/accounts/doctype/payment_entry/test_payment_entry.py

@@ -6,11 +6,12 @@ import unittest
 import frappe
 from frappe import qb
 from frappe.tests.utils import FrappeTestCase, change_settings
-from frappe.utils import flt, nowdate
+from frappe.utils import add_days, flt, nowdate
 
 from erpnext.accounts.doctype.account.test_account import create_account
 from erpnext.accounts.doctype.payment_entry.payment_entry import (
 	InvalidPaymentEntry,
+	get_outstanding_reference_documents,
 	get_payment_entry,
 	get_reference_details,
 )
@@ -1471,6 +1472,45 @@ class TestPaymentEntry(FrappeTestCase):
 			for field in ["account", "debit", "credit"]:
 				self.assertEqual(self.expected_gle[row][field], gl_entries[row][field])
 
+	def test_outstanding_invoices_api(self):
+		"""
+		Test if `get_outstanding_reference_documents` fetches invoices in the right order.
+		"""
+		customer = create_customer("Max Mustermann", "INR")
+		create_payment_terms_template()
+
+		# SI has an earlier due date and SI2 has a later due date
+		si = create_sales_invoice(
+			qty=1, rate=100, customer=customer, posting_date=add_days(nowdate(), -4)
+		)
+		si2 = create_sales_invoice(do_not_save=1, qty=1, rate=100, customer=customer)
+		si2.payment_terms_template = "Test Receivable Template"
+		si2.submit()
+
+		args = {
+			"posting_date": nowdate(),
+			"company": "_Test Company",
+			"party_type": "Customer",
+			"payment_type": "Pay",
+			"party": customer,
+			"party_account": "Debtors - _TC",
+		}
+		args.update(
+			{
+				"get_outstanding_invoices": True,
+				"from_posting_date": add_days(nowdate(), -4),
+				"to_posting_date": add_days(nowdate(), 2),
+			}
+		)
+		references = get_outstanding_reference_documents(args)
+
+		self.assertEqual(len(references), 3)
+		self.assertEqual(references[0].voucher_no, si.name)
+		self.assertEqual(references[1].voucher_no, si2.name)
+		self.assertEqual(references[2].voucher_no, si2.name)
+		self.assertEqual(references[1].payment_term, "Basic Amount Receivable")
+		self.assertEqual(references[2].payment_term, "Tax Receivable")
+
 
 def create_payment_entry(**args):
 	payment_entry = frappe.new_doc("Payment Entry")
@@ -1531,6 +1571,9 @@ def create_payment_terms_template():
 def create_payment_terms_template_with_discount(
 	name=None, discount_type=None, discount=None, template_name=None
 ):
+	"""
+	Create a Payment Terms Template with %  or amount discount.
+	"""
 	create_payment_term(name or "30 Credit Days with 10% Discount")
 	template_name = template_name or "Test Discount Template"