feat: add pending student registration flow and pricing APIs.

Support public class lookup, user provisioning, installment pricing, and admin approval before final enrollment.

utils/registrationPricing.js

@@ -0,0 +1,94 @@
+'use strict';
+
+const { FULL_PAYMENT_DISCOUNT, CLASS_REQUEST_DEPOSIT_RATE } = require('../constants/registration');
+
+const getFinalTuition = (cls = {}) => {
+  const tuitionFee = Math.max(0, Number(cls.tuitionFee) || 0);
+  const classDiscount = cls.hasDiscount ? Math.max(0, Number(cls.discount) || 0) : 0;
+  return Math.max(0, tuitionFee - Math.min(classDiscount, tuitionFee));
+};
+
+const calculateMidpointDueDate = (cls = {}, course = {}) => {
+  const startDate = cls.startDate ? new Date(cls.startDate) : null;
+  if (!startDate || Number.isNaN(startDate.getTime())) return null;
+
+  const sectionCount = Math.max(1, Number(course.sectionCount) || 1);
+  const sessionsPerWeek = Math.max(1, (cls.days || []).length || 1);
+  const totalWeeks = sectionCount / sessionsPerWeek;
+  const weeksUntilDue = totalWeeks / 2;
+
+  const due = new Date(startDate);
+  due.setDate(due.getDate() + Math.round(weeksUntilDue * 7));
+  return due;
+};
+
+const calculateEnrollmentPricing = (cls = {}, course = {}, paymentPlan = 'full') => {
+  const tuitionFee = getFinalTuition(cls);
+
+  if (paymentPlan === 'installments') {
+    const totalAmount = tuitionFee;
+    const amountDueNow = Math.ceil(totalAmount / 2);
+    const secondInstallmentAmount = Math.max(0, totalAmount - amountDueNow);
+
+    return {
+      type: 'enrollment',
+      paymentPlan: 'installments',
+      tuitionFee,
+      classDiscount: cls.hasDiscount ? Math.max(0, Number(cls.discount) || 0) : 0,
+      paymentDiscount: 0,
+      totalAmount,
+      amountDueNow,
+      secondInstallmentAmount,
+      secondInstallmentDueDate: calculateMidpointDueDate(cls, course)
+    };
+  }
+
+  const paymentDiscount = Math.min(FULL_PAYMENT_DISCOUNT, tuitionFee);
+  const totalAmount = Math.max(0, tuitionFee - paymentDiscount);
+
+  return {
+    type: 'enrollment',
+    paymentPlan: 'full',
+    tuitionFee,
+    classDiscount: cls.hasDiscount ? Math.max(0, Number(cls.discount) || 0) : 0,
+    paymentDiscount,
+    totalAmount,
+    amountDueNow: totalAmount,
+    secondInstallmentAmount: 0,
+    secondInstallmentDueDate: null
+  };
+};
+
+const calculateClassRequestPricing = (cls = {}) => {
+  const tuitionFee = getFinalTuition(cls);
+  const amountDueNow = Math.ceil(tuitionFee * CLASS_REQUEST_DEPOSIT_RATE);
+
+  return {
+    type: 'class_request',
+    paymentPlan: 'deposit',
+    tuitionFee,
+    classDiscount: cls.hasDiscount ? Math.max(0, Number(cls.discount) || 0) : 0,
+    paymentDiscount: 0,
+    totalAmount: amountDueNow,
+    amountDueNow,
+    secondInstallmentAmount: 0,
+    secondInstallmentDueDate: null
+  };
+};
+
+const calculateRegistrationPricing = (cls = {}, course = {}, { type = 'enrollment', paymentPlan = 'full' } = {}) => {
+  if (type === 'class_request') {
+    return calculateClassRequestPricing(cls);
+  }
+  return calculateEnrollmentPricing(cls, course, paymentPlan);
+};
+
+module.exports = {
+  FULL_PAYMENT_DISCOUNT,
+  CLASS_REQUEST_DEPOSIT_RATE,
+  getFinalTuition,
+  calculateMidpointDueDate,
+  calculateEnrollmentPricing,
+  calculateClassRequestPricing,
+  calculateRegistrationPricing
+};

utils/registrationPricing.test.js

@@ -0,0 +1,46 @@
+'use strict';
+
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const {
+  calculateEnrollmentPricing,
+  calculateClassRequestPricing,
+  calculateMidpointDueDate
+} = require('./registrationPricing');
+
+test('full payment applies 500k discount', () => {
+  const result = calculateEnrollmentPricing(
+    { tuitionFee: 5_000_000, hasDiscount: false },
+    { sectionCount: 16 },
+    'full'
+  );
+  assert.equal(result.totalAmount, 4_500_000);
+  assert.equal(result.paymentDiscount, 500_000);
+  assert.equal(result.amountDueNow, 4_500_000);
+});
+
+test('installments charge full tuition with half due now', () => {
+  const result = calculateEnrollmentPricing(
+    { tuitionFee: 4_000_000, hasDiscount: false, startDate: '2026-09-01', days: [2, 4] },
+    { sectionCount: 16 },
+    'installments'
+  );
+  assert.equal(result.totalAmount, 4_000_000);
+  assert.equal(result.amountDueNow, 2_000_000);
+  assert.equal(result.secondInstallmentAmount, 2_000_000);
+  assert.ok(result.secondInstallmentDueDate);
+});
+
+test('class request deposit is 10 percent', () => {
+  const result = calculateClassRequestPricing({ tuitionFee: 3_000_000, hasDiscount: false });
+  assert.equal(result.amountDueNow, 300_000);
+  assert.equal(result.paymentPlan, 'deposit');
+});
+
+test('midpoint due date is halfway through course duration', () => {
+  const due = calculateMidpointDueDate(
+    { startDate: '2026-01-01', days: [2, 4] },
+    { sectionCount: 16 }
+  );
+  assert.equal(due.toISOString().slice(0, 10), '2026-01-29');
+});