feat(selling): add amount-based proforma option

Let a proforma be created by editing item amount instead of quantity, for
value/advance-style proformas.

- "Based On" (Quantity | Amount) on the proforma and the create dialog
- Amount basis keeps the ordered qty and derives a rate so the line totals
  the entered amount; the PDF renders the same in-memory Sales Order copy
- Proforma Invoice Item now stores rate and amount

erpnext/public/js/sales_order_proforma.js

@@ -82,6 +82,14 @@ Object.assign(erpnext.proforma, {
 					options: "Letter Head",
 				},
 				{ fieldname: "items_section", fieldtype: "Section Break", label: __("Items") },
+				{
+					fieldname: "based_on",
+					fieldtype: "Select",
+					label: __("Based On"),
+					options: ["Quantity", "Amount"],
+					default: "Quantity",
+					onchange: () => this.toggle_basis(dialog),
+				},
 				{
 					fieldname: "items",
 					fieldtype: "Table",
@@ -100,8 +108,22 @@ Object.assign(erpnext.proforma, {
 							fieldtype: "Float",
 							label: __("Qty"),
 							in_list_view: 1,
+							onchange: function () {
+								// Keep the read-only Amount in sync while editing qty (Quantity basis).
+								if (!this.doc) return;
+								this.doc.amount = flt(this.doc.qty) * flt(this.doc.rate);
+								this.grid_row?.refresh_field("amount");
+							},
+						},
+						{
+							fieldname: "amount",
+							fieldtype: "Currency",
+							label: __("Amount"),
+							in_list_view: 1,
+							read_only: 1,
 						},
 						{ fieldname: "item_name", fieldtype: "Data", hidden: 1 },
+						{ fieldname: "rate", fieldtype: "Currency", hidden: 1 },
 						{ fieldname: "so_detail", fieldtype: "Data", hidden: 1 },
 					],
 				},
@@ -113,13 +135,23 @@ Object.assign(erpnext.proforma, {
 		dialog.show();
 	},
 
+	// Both Qty and Amount columns stay visible; only the one matching the chosen basis is editable.
+	toggle_basis(dialog) {
+		const by_amount = dialog.get_value("based_on") === "Amount";
+		const grid = dialog.get_field("items").grid;
+		grid.toggle_enable("qty", !by_amount);
+		grid.toggle_enable("amount", by_amount);
+	},
+
 	create(frm, dialog, values) {
+		const by_amount = values.based_on === "Amount";
+		const field = by_amount ? "amount" : "qty";
 		const items = (values.items || [])
-			.filter((row) => flt(row.qty) > 0)
-			.map((row) => ({ so_detail: row.so_detail, qty: row.qty }));
+			.filter((row) => flt(row[field]) > 0)
+			.map((row) => ({ so_detail: row.so_detail, [field]: row[field] }));
 
 		if (!items.length) {
-			frappe.msgprint(__("Please enter a quantity for at least one item."));
+			frappe.msgprint(__("Please enter a quantity or amount for at least one item."));
 			return;
 		}
 
@@ -128,6 +160,7 @@ Object.assign(erpnext.proforma, {
 			args: {
 				sales_order: frm.doc.name,
 				items: JSON.stringify(items),
+				based_on: values.based_on,
 				naming_series: values.naming_series,
 				print_format: values.print_format,
 				letter_head: values.letter_head,

erpnext/selling/doctype/proforma_invoice/proforma_invoice.json

@@ -13,6 +13,7 @@
   "proforma_date",
   "company",
   "currency",
+  "based_on",
   "items_section",
   "items",
   "total_qty",
@@ -96,6 +97,14 @@
    "print_hide": 1,
    "read_only": 1
   },
+  {
+   "default": "Quantity",
+   "fieldname": "based_on",
+   "fieldtype": "Select",
+   "label": "Based On",
+   "options": "Quantity\nAmount",
+   "read_only": 1
+  },
   {
    "fieldname": "items_section",
    "fieldtype": "Section Break",

erpnext/selling/doctype/proforma_invoice/proforma_invoice.py

@@ -22,6 +22,7 @@ class ProformaInvoice(Document):
 		)
 
 		amended_from: DF.Link | None
+		based_on: DF.Literal["Quantity", "Amount"]
 		company: DF.Link
 		currency: DF.Link | None
 		customer: DF.Link | None
@@ -64,16 +65,21 @@ class ProformaInvoice(Document):
 		self.db_set("proforma_pdf", file.file_url)
 
 	def render_pdf(self) -> dict:
-		"""Render the proforma PDF from an in-memory, qty-adjusted copy of the Sales Order.
+		"""Render the proforma PDF from an in-memory, adjusted copy of the Sales Order.
 
 		The Sales Order copy is never saved; it exists only to reuse the standard tax/total
-		calculation and print format so the proforma shows accurate gross for the partial qty.
+		calculation and print format so the proforma shows the accurate gross. Each line's qty
+		and rate are set from the proforma (amount-based lines carry a derived rate), so the
+		recomputed amount matches whichever basis the proforma was created on.
 		"""
 		sales_order = frappe.get_doc("Sales Order", self.sales_order)
-		qty_by_detail = {item.so_detail: item.qty for item in self.items}
-		sales_order.items = [item for item in sales_order.items if item.name in qty_by_detail]
+		lines = {item.so_detail: item for item in self.items}
+		sales_order.items = [item for item in sales_order.items if item.name in lines]
 		for item in sales_order.items:
-			item.qty = qty_by_detail[item.name]
+			item.qty = lines[item.name].qty
+			item.rate = lines[item.name].rate
+			item.discount_amount = 0
+			item.discount_percentage = 0
 		sales_order.run_method("calculate_taxes_and_totals")
 		sales_order.proforma_no = self.name
 		sales_order.proforma_date = self.proforma_date
@@ -99,6 +105,8 @@ def get_sales_order_items(sales_order: str) -> list[dict]:
 			"uom": item.uom,
 			"so_detail": item.name,
 			"qty": flt(item.qty),
+			"rate": flt(item.rate),
+			"amount": flt(item.amount),
 		}
 		for item in sales_order_doc.items
 	]
@@ -108,11 +116,16 @@ def get_sales_order_items(sales_order: str) -> list[dict]:
 def make_proforma_invoice(
 	sales_order: str,
 	items: str,
+	based_on: str = "Quantity",
 	naming_series: str | None = None,
 	print_format: str | None = None,
 	letter_head: str | None = None,
 ) -> str:
-	"""The sole creation path for a Proforma Invoice (the doctype is `in_create`)."""
+	"""The sole creation path for a Proforma Invoice (the doctype is `in_create`).
+
+	`based_on` decides what the user edited per line: "Quantity" (rate fixed, amount = qty x rate)
+	or "Amount" (qty fixed at ordered, rate derived so the line totals the entered amount).
+	"""
 	validate_feature_enabled()
 	selected = frappe.parse_json(items)
 	sales_order_doc = frappe.get_doc("Sales Order", sales_order)
@@ -120,6 +133,7 @@ def make_proforma_invoice(
 
 	proforma = frappe.new_doc("Proforma Invoice")
 	proforma.sales_order = sales_order
+	proforma.based_on = based_on
 	if naming_series:
 		proforma.naming_series = naming_series
 	proforma.print_format = print_format or frappe.db.get_single_value(
@@ -128,29 +142,46 @@ def make_proforma_invoice(
 	proforma.letter_head = letter_head
 
 	for row in selected:
-		qty = flt(row.get("qty"))
 		so_item = so_items.get(row.get("so_detail"))
-		if qty <= 0 or not so_item:
+		if not so_item:
 			continue
-		proforma.append(
-			"items",
-			{
-				"item_code": so_item.item_code,
-				"item_name": so_item.item_name,
-				"uom": so_item.uom,
-				"qty": qty,
-				"so_detail": so_item.name,
-			},
-		)
+		line = _proforma_line(so_item, based_on, row)
+		if line:
+			proforma.append("items", line)
 
 	if not proforma.items:
-		frappe.throw(_("Please enter a quantity for at least one item."))
+		frappe.throw(_("Please enter a quantity or amount for at least one item."))
 
 	proforma.insert()
 	proforma.submit()
 	return proforma.name
 
 
+def _proforma_line(so_item, based_on: str, row: dict) -> dict | None:
+	if based_on == "Amount":
+		qty = flt(so_item.qty)
+		amount = flt(row.get("amount"))
+		if amount <= 0 or qty <= 0:
+			return None
+		rate = amount / qty
+	else:
+		qty = flt(row.get("qty"))
+		if qty <= 0:
+			return None
+		rate = flt(so_item.rate)
+		amount = qty * rate
+
+	return {
+		"item_code": so_item.item_code,
+		"item_name": so_item.item_name,
+		"uom": so_item.uom,
+		"qty": qty,
+		"rate": rate,
+		"amount": amount,
+		"so_detail": so_item.name,
+	}
+
+
 @frappe.whitelist()
 def send_proforma_email(proforma_name: str, recipients: str) -> None:
 	proforma = frappe.get_doc("Proforma Invoice", proforma_name)

erpnext/selling/doctype/proforma_invoice/test_proforma_invoice.py

@@ -61,6 +61,25 @@ class TestProformaInvoice(ERPNextTestSuite):
 		# partial (4 of 10): net 400 + 10% tax = 440
 		self.assertEqual(flt(proforma.grand_total), 440)
 
+	def test_amount_based_proforma(self):
+		"""Amount basis: qty stays ordered, rate is derived so the line totals the entered amount."""
+		sales_order = make_sales_order(qty=10)  # rate 100 -> ordered amount 1000
+		so_detail = sales_order.items[0].name
+
+		name = make_proforma_invoice(
+			sales_order.name,
+			json.dumps([{"so_detail": so_detail, "amount": 250}]),
+			based_on="Amount",
+		)
+		proforma = frappe.get_doc("Proforma Invoice", name)
+
+		self.assertEqual(proforma.based_on, "Amount")
+		item = proforma.items[0]
+		self.assertEqual(flt(item.qty), 10)
+		self.assertEqual(flt(item.rate), 25)
+		self.assertEqual(flt(item.amount), 250)
+		self.assertEqual(flt(proforma.grand_total), 250)
+
 	def test_feature_toggle_is_enforced(self):
 		sales_order = make_sales_order(qty=10)
 		frappe.db.set_single_value("Selling Settings", "enable_proforma_invoice", 0)

erpnext/selling/doctype/proforma_invoice_item/proforma_invoice_item.json

@@ -10,6 +10,8 @@
   "column_break_qty",
   "qty",
   "uom",
+  "rate",
+  "amount",
   "so_detail"
  ],
  "fields": [
@@ -49,6 +51,22 @@
    "options": "UOM",
    "read_only": 1
   },
+  {
+   "columns": 2,
+   "fieldname": "rate",
+   "fieldtype": "Currency",
+   "in_list_view": 1,
+   "label": "Rate",
+   "read_only": 1
+  },
+  {
+   "columns": 2,
+   "fieldname": "amount",
+   "fieldtype": "Currency",
+   "in_list_view": 1,
+   "label": "Amount",
+   "read_only": 1
+  },
   {
    "fieldname": "so_detail",
    "fieldtype": "Data",

erpnext/selling/doctype/proforma_invoice_item/proforma_invoice_item.py

@@ -13,12 +13,14 @@ class ProformaInvoiceItem(Document):
 	if TYPE_CHECKING:
 		from frappe.types import DF
 
+		amount: DF.Currency
 		item_code: DF.Link
 		item_name: DF.Data | None
 		parent: DF.Data
 		parentfield: DF.Data
 		parenttype: DF.Data
 		qty: DF.Float
+		rate: DF.Currency
 		so_detail: DF.Data | None
 		uom: DF.Link | None
 	# end: auto-generated types