fix(billing): stop back-office edits from changing Payple renewal charges

server/supabase/functions/payple-renew/paid-tier.test.ts

@@ -0,0 +1,111 @@
+import { latestPaidTierByUser, withPaidTier } from './paid-tier.ts'
+import {
+  type ChargeRequest,
+  normalizeRenewalCandidate,
+  type RenewalDeps,
+  type RenewalPaymentApplication,
+  renewSubscription,
+} from './renewal.ts'
+import { TIER_PRICE } from '../_shared/payple.ts'
+
+function assert(condition: boolean, message: string): asserts condition {
+  if (!condition) throw new Error(message)
+}
+
+const USER = 'user0019-0000-0000-0000-000000000000'
+const OTHER_USER = 'user0020-0000-0000-0000-000000000000'
+const ORDER = 'D3RO-20260928100000-user0019-cccccccc'
+
+/** A Payple Pro subscriber whose row tier a back-office edit rewrote to pro_plus. */
+const tamperedDueRow: Record<string, unknown> = {
+  user_id: USER,
+  tier: 'pro_plus',
+  payple_payer_id: 'payer-19',
+  provider_resource_id: 'payer-19',
+  current_period_end: '2026-09-27T00:00:00.000Z',
+  renewal_failures: 0,
+}
+
+const appliedOperations: Record<string, unknown>[] = [
+  { user_id: USER, requested_tier: 'pro', updated_at: '2026-08-27T00:00:05.000Z', created_at: '2026-08-27T00:00:00.000Z' },
+  { user_id: OTHER_USER, requested_tier: 'pro_plus', updated_at: '2026-09-01T00:00:00.000Z', created_at: '2026-09-01T00:00:00.000Z' },
+]
+
+function chargingHarness(): { deps: RenewalDeps; charges: ChargeRequest[]; applied: RenewalPaymentApplication[] } {
+  const charges: ChargeRequest[] = []
+  const applied: RenewalPaymentApplication[] = []
+  const deps: RenewalDeps = {
+    now: () => new Date('2026-09-28T01:00:00.000Z'),
+    newOrderId: () => ORDER,
+    store: {
+      reserveRenewal: () => Promise.resolve({ kind: 'created', operationId: 'op-19' }),
+      getOperation: () => Promise.resolve(null),
+      markOperation: () => Promise.resolve(true),
+      recordRenewalFailure: () => Promise.resolve(true),
+      applyRenewalPayment: (application) => {
+        applied.push(application)
+        return Promise.resolve({ applied: true, duplicate: false })
+      },
+    },
+    gateway: {
+      charge: (request) => {
+        charges.push(request)
+        return Promise.resolve({ orderId: request.orderId, total: String(request.amount) })
+      },
+      lookup: () => Promise.resolve({ kind: 'unknown' }),
+    },
+  }
+  return { deps, charges, applied }
+}
+
+// ── 회귀: 관리자 등급 수정이 다음 갱신 청구 금액을 바꾸던 버그 ─────────
+
+Deno.test('renewal charges the tier the customer last paid for, not an edited row tier', async () => {
+  const candidate = normalizeRenewalCandidate(
+    withPaidTier(tamperedDueRow, latestPaidTierByUser(appliedOperations)),
+  )
+  assert(candidate !== null, 'candidate is valid')
+  const { deps, charges, applied } = chargingHarness()
+
+  const result = await renewSubscription(deps, candidate)
+
+  assert(result.success, `renewal succeeds: ${JSON.stringify(result)}`)
+  assert(charges.length === 1, 'charged once')
+  assert(charges[0].amount === TIER_PRICE.pro, `charged the pro price, got ${charges[0].amount}`)
+  assert(applied.length === 1 && applied[0].candidate.tier === 'pro', 'entitlement renewed at the paid tier')
+})
+
+Deno.test('legacy subscriptions without a payment ledger entry keep their row tier', () => {
+  const row = { ...tamperedDueRow, user_id: 'legacy-user', tier: 'pro' }
+  const adjusted = withPaidTier(row, latestPaidTierByUser(appliedOperations))
+  assert(adjusted === row, 'row is returned unchanged')
+  assert(normalizeRenewalCandidate(adjusted)?.tier === 'pro', 'legacy tier kept')
+})
+
+Deno.test('latest applied payment operation wins per user', () => {
+  const tiers = latestPaidTierByUser([
+    { user_id: USER, requested_tier: 'pro', updated_at: '2026-07-01T00:00:00.000Z', created_at: '2026-07-01T00:00:00.000Z' },
+    { user_id: USER, requested_tier: 'pro_plus', updated_at: '2026-09-01T00:00:00.000Z', created_at: '2026-09-01T00:00:00.000Z' },
+    { user_id: USER, requested_tier: 'pro', updated_at: '2026-08-01T00:00:00.000Z', created_at: '2026-08-01T00:00:00.000Z' },
+  ])
+  assert(tiers.get(USER) === 'pro_plus', 'most recently applied upgrade is charged')
+})
+
+Deno.test('same applied time falls back to the later created operation', () => {
+  const tiers = latestPaidTierByUser([
+    { user_id: USER, requested_tier: 'pro_plus', updated_at: '2026-09-01T00:00:00.000Z', created_at: '2026-08-31T00:00:00.000Z' },
+    { user_id: USER, requested_tier: 'pro', updated_at: '2026-09-01T00:00:00.000Z', created_at: '2026-09-01T00:00:00.000Z' },
+  ])
+  assert(tiers.get(USER) === 'pro', 'later-created operation wins the tie')
+})
+
+Deno.test('malformed ledger rows are ignored', () => {
+  const tiers = latestPaidTierByUser([
+    { user_id: USER, requested_tier: 'free', updated_at: '2026-09-01T00:00:00.000Z' },
+    { user_id: USER, requested_tier: null, updated_at: '2026-09-02T00:00:00.000Z' },
+    { user_id: USER, requested_tier: 'pro_plus', updated_at: 'not-a-date' },
+    { user_id: 42, requested_tier: 'pro', updated_at: '2026-09-03T00:00:00.000Z' },
+    { user_id: USER, requested_tier: 'pro', updated_at: '2026-08-01T00:00:00.000Z' },
+  ])
+  assert(tiers.size === 1 && tiers.get(USER) === 'pro', 'only the valid row counts')
+})