fix: allow zero amount checkout with coupons

frontend/src/pages/Billing.vue

@@ -199,8 +199,15 @@
 								}}
 							</div>
 						</div>
-						<Button variant="solid" size="md" @click="generatePaymentLink()">
-							{{ __('Proceed to Payment') }}
+						<Button
+							variant="solid"
+							size="md"
+							class="ms-auto"
+							@click="generatePaymentLink()"
+						>
+							{{
+								isZeroAmount ? __('Enroll for Free') : __('Proceed to Payment')
+							}}
 						</Button>
 					</div>
 				</div>
@@ -326,16 +333,10 @@ const paymentLink = createResource({
 		let data = {
 			doctype: props.type == 'batch' ? 'LMS Batch' : 'LMS Course',
 			docname: props.name,
-			title: orderSummary.data.title,
-			amount: orderSummary.data.original_amount,
-			discount_amount: orderSummary.data.discount_amount || 0,
-			gst_amount: orderSummary.data.gst_applied || 0,
-			currency: orderSummary.data.currency,
 			address: billingDetails,
-			redirect_to: redirectTo.value,
 			payment_for_certificate: props.type == 'certificate',
 			coupon_code: appliedCoupon.value,
-			coupon: orderSummary.data.coupon,
+			country: billingDetails.country,
 		}
 		return data
 	},
@@ -458,14 +459,8 @@ const changeCurrency = (country) => {
 	orderSummary.reload()
 }
 
-const redirectTo = computed(() => {
-	if (props.type == 'course') {
-		return getLmsRoute(`courses/${props.name}`)
-	} else if (props.type == 'batch') {
-		return getLmsRoute(`batches/${props.name}`)
-	} else if (props.type == 'certificate') {
-		return getLmsRoute(`courses/${props.name}/certification`)
-	}
+const isZeroAmount = computed(() => {
+	return orderSummary.data && parseFloat(orderSummary.data.total_amount) <= 0
 })
 
 watch(billingDetails, () => {

lms/lms/payments.py

@@ -1,5 +1,11 @@
 import frappe
 
+from lms.lms.utils import (
+	complete_enrollment,
+	get_lms_route,
+	get_order_summary,
+)
+
 
 def get_payment_gateway():
 	return frappe.db.get_single_value("LMS Settings", "payment_gateway")
@@ -21,22 +27,25 @@ def validate_currency(payment_gateway, currency):
 def get_payment_link(
 	doctype: str,
 	docname: str,
-	title: str,
-	amount: float,
-	discount_amount: float,
-	gst_amount: float,
-	currency: str,
 	address: dict,
-	redirect_to: str,
 	payment_for_certificate: int,
-	coupon_code: str = None,
-	coupon: str = None,
+	coupon_code: str,
+	country: str,
 ):
 	payment_gateway = get_payment_gateway()
 	address = frappe._dict(address)
-	original_amount = amount
-	amount -= discount_amount
+	redirect_to = get_redirect_url(doctype, docname, payment_for_certificate)
+
+	details = frappe._dict(get_order_summary(doctype, docname, coupon=coupon_code, country=country))
+	title = details.title
+	currency = details.currency
+	original_amount = details.original_amount
+	discount_amount = details.get("discount_amount", 0)
+	gst_amount = details.get("gst_applied", 0)
+	amount = original_amount - discount_amount
 	amount_with_gst = get_amount_with_gst(amount, gst_amount)
+	coupon = details.get("coupon")
+	total_amount = amount_with_gst if amount_with_gst else amount
 
 	payment = record_payment(
 		address,
@@ -51,10 +60,16 @@ def get_payment_link(
 		coupon_code,
 		coupon,
 	)
+
+	if total_amount <= 0:
+		frappe.db.set_value("LMS Payment", payment.name, "payment_received", 1)
+		complete_enrollment(payment.name, doctype, docname)
+		return redirect_to
+
 	controller = get_controller(payment_gateway)
 
 	payment_details = {
-		"amount": amount_with_gst if amount_with_gst else amount,
+		"amount": total_amount,
 		"title": f"Payment for {doctype} {title} {docname}",
 		"description": f"{address.billing_name}'s payment for {title}",
 		"reference_doctype": doctype,
@@ -99,8 +114,8 @@ def record_payment(
 	amount_with_gst: float = 0,
 	discount_amount: float = 0,
 	payment_for_certificate: int = 0,
-	coupon_code: str = None,
-	coupon: str = None,
+	coupon_code: str | None = None,
+	coupon: str | None = None,
 ):
 	address = frappe._dict(address)
 	address_name = save_address(address)
@@ -138,6 +153,15 @@ def record_payment(
 	return payment_doc
 
 
+def get_redirect_url(doctype: str, docname: str, payment_for_certificate: int) -> str:
+	if int(payment_for_certificate):
+		return get_lms_route(f"courses/{docname}/certification")
+	elif doctype == "LMS Course":
+		return get_lms_route(f"courses/{docname}")
+	else:
+		return get_lms_route(f"batches/{docname}")
+
+
 def save_address(address: dict) -> str:
 	filters = {"email_id": frappe.session.user}
 	exists = frappe.db.exists("Address", filters)

lms/lms/utils.py

@@ -1864,17 +1864,21 @@ def update_payment_record(doctype: str, docname: str):
 	if len(request):
 		data = request[0].data
 		data = frappe._dict(json.loads(data))
-		payment_doc = get_payment_doc(data.payment)
 
 		update_payment_details(data)
-		update_coupon_redemption(payment_doc)
+		complete_enrollment(data.payment, doctype, docname)
 
-		if payment_doc.payment_for_certificate:
-			update_certificate_purchase(docname, data.payment)
-		elif doctype == "LMS Course":
-			enroll_in_course(docname, data.payment)
-		else:
-			enroll_in_batch(docname, data.payment)
+
+def complete_enrollment(payment_name: str, doctype: str, docname: str):
+	payment_doc = get_payment_doc(payment_name)
+	update_coupon_redemption(payment_doc)
+
+	if payment_doc.payment_for_certificate:
+		update_certificate_purchase(docname, payment_name)
+	elif doctype == "LMS Course":
+		enroll_in_course(docname, payment_name)
+	else:
+		enroll_in_batch(docname, payment_name)
 
 
 def get_integration_requests(doctype: str, docname: str):