feat: Fetch Payment Terms from linked Purchase Order

erpnext/accounts/doctype/purchase_invoice/purchase_invoice.js

@@ -508,6 +508,8 @@ frappe.ui.form.on("Purchase Invoice", {
 				}
 			}
 		}
+
+		frm.events.set_payment_terms(frm);
 	},
 
 	refresh: function(frm) {
@@ -570,4 +572,21 @@ frappe.ui.form.on("Purchase Invoice", {
 	company: function(frm) {
 		erpnext.accounts.dimensions.update_dimension(frm, frm.doctype);
 	},
-})
+
+	set_payment_terms: function (frm) {
+		frappe.call({
+			'method': 'erpnext.accounts.doctype.purchase_invoice.purchase_invoice.set_payment_terms_from_po',
+			'args': {
+				doc: frm.doc
+			},
+			'callback': (r) => {
+				if (r.message) {
+					var doc = frappe.model.sync(r.message)[0];
+					console.log("doc: ", doc)
+					frappe.set_route("Form", doc.doctype, doc.name);
+				}
+			}
+			
+		});
+	},
+})

erpnext/accounts/doctype/purchase_invoice/purchase_invoice.py

@@ -7,6 +7,8 @@ import frappe, erpnext
 from frappe.utils import cint, cstr, formatdate, flt, getdate, nowdate, get_link_to_form
 from frappe import _, throw
 import frappe.defaults
+import json
+import six
 
 from erpnext.assets.doctype.asset_category.asset_category import get_asset_category_account
 from erpnext.controllers.buying_controller import BuyingController
@@ -1171,6 +1173,43 @@ class PurchaseInvoice(BuyingController):
 		if update:
 			self.db_set('status', self.status, update_modified = update_modified)
 
+@frappe.whitelist()
+def set_payment_terms_from_po(doc):
+	if isinstance(doc, six.string_types):
+		doc = json.loads(doc)
+
+	purchase_order = doc.get('items')[0].get('purchase_order')
+	
+	if linked_po_has_payment_terms(doc, purchase_order) and all_items_have_same_po(doc, purchase_order):
+		purchase_order = frappe.get_cached_doc('Purchase Order', purchase_order)
+		doc['payment_terms_template'] = purchase_order.payment_terms_template
+		doc['terms'] = purchase_order.payment_terms_template
+
+		for schedule in purchase_order.payment_schedule:
+			payment_schedule = {
+				'payment_term': schedule.payment_term,
+				'due_date': schedule.due_date,
+				'invoice_portion': schedule.invoice_portion,
+				'discount_type': schedule.discount_type,
+				'discount': schedule.discount,
+				'base_payment_amount': schedule.base_payment_amount,
+				'payment_amount': schedule.payment_amount,
+				'outstanding': schedule.outstanding
+			}
+			doc['payment_schedule'].append(payment_schedule)
+
+		return doc
+
+def linked_po_has_payment_terms(doc, purchase_order):
+	return not doc.get('payment_schedule') and purchase_order
+
+def all_items_have_same_po(doc, purchase_order):
+	for item in doc.get('items'):
+		if item.get('purchase_order') != purchase_order:
+			return False
+	
+	return True
+
 # to get details of purchase invoice/receipt from which this doc was created for exchange rate difference handling
 def get_purchase_document_details(doc):
 	if doc.doctype == 'Purchase Invoice':