fix(billing): union departed ledger actors in org threshold settlement

Organization threshold billing now reads the period ledger per user and
unions the actors holding org-attributed rows with the current roster
before computing refresh deductions — the same actor set
calculateSubscriptionOverage and the cycle close use — so a departed
member's usage cannot be settled without their daily-refresh offset.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: icecrasher321

apps/sim/lib/billing/threshold-billing.test.ts

@@ -10,7 +10,7 @@ const {
   mockEnqueueOutboxEvent,
   mockGetEffectiveBillingStatus,
   mockGetHighestPrioritySubscription,
-  mockGetBillingPeriodUsageCost,
+  mockGetBillingPeriodUsageCostByUser,
   mockGetOrganizationSubscriptionUsable,
   mockHasUsableSubscriptionAccess,
   mockIsEnterprise,
@@ -26,7 +26,7 @@ const {
   mockEnqueueOutboxEvent: vi.fn(),
   mockGetEffectiveBillingStatus: vi.fn(),
   mockGetHighestPrioritySubscription: vi.fn(),
-  mockGetBillingPeriodUsageCost: vi.fn(),
+  mockGetBillingPeriodUsageCostByUser: vi.fn(),
   mockGetOrganizationSubscriptionUsable: vi.fn(),
   mockHasUsableSubscriptionAccess: vi.fn(),
   mockIsEnterprise: vi.fn(),
@@ -60,7 +60,7 @@ vi.mock('@/lib/billing/core/subscription', () => ({
 }))
 
 vi.mock('@/lib/billing/core/usage-log', () => ({
-  getBillingPeriodUsageCost: mockGetBillingPeriodUsageCost,
+  getBillingPeriodUsageCostByUser: mockGetBillingPeriodUsageCostByUser,
 }))
 
 vi.mock('@/lib/billing/cycle-close', () => ({
@@ -184,7 +184,7 @@ describe('checkAndBillOverageThreshold', () => {
     mockIsFree.mockReturnValue(false)
     mockIsEnterprise.mockReturnValue(false)
     mockIsOrgScopedSubscription.mockReturnValue(false)
-    mockGetBillingPeriodUsageCost.mockResolvedValue(0)
+    mockGetBillingPeriodUsageCostByUser.mockResolvedValue(new Map())
     mockIsSubscriptionCycleCloseCurrent.mockResolvedValue(true)
   })
 
@@ -609,7 +609,12 @@ describe('checkAndBillOverageThreshold', () => {
     mockIsOrgScopedSubscription.mockReturnValue(true)
     mockIsOrganizationBillingBlocked.mockResolvedValue(false)
     mockGetOrganizationSubscriptionUsable.mockResolvedValue(usableOrgSubscription)
-    mockGetBillingPeriodUsageCost.mockResolvedValue(350)
+    mockGetBillingPeriodUsageCostByUser.mockResolvedValue(
+      new Map([
+        ['owner-1', 300],
+        ['departed-1', 50],
+      ])
+    )
     queueOrgReads()
     mockComputeOrgOverageAmount.mockResolvedValue({
       totalOverage: 250,
@@ -626,7 +631,7 @@ describe('checkAndBillOverageThreshold', () => {
       periodEnd: new Date('2026-06-01T00:00:00.000Z'),
       organizationId: userSubscription.referenceId,
       pooledLedgerUsage: 350,
-      memberIds: ['owner-1'],
+      memberIds: ['owner-1', 'departed-1'],
     })
     expect(dbChainMockFns.transaction).toHaveBeenCalled()
     expect(mockComputeOrgOverageAmount.mock.invocationCallOrder[0]).toBeLessThan(

apps/sim/lib/billing/threshold-billing.ts

@@ -13,7 +13,7 @@ import {
   getHighestPrioritySubscription,
   getOrganizationSubscriptionUsable,
 } from '@/lib/billing/core/subscription'
-import { type BillingEntity, getBillingPeriodUsageCost } from '@/lib/billing/core/usage-log'
+import { type BillingEntity, getBillingPeriodUsageCostByUser } from '@/lib/billing/core/usage-log'
 import { isSubscriptionCycleCloseCurrent } from '@/lib/billing/cycle-close'
 import { isEnterprise, isFree } from '@/lib/billing/plan-helpers'
 import {
@@ -615,13 +615,20 @@ async function checkAndBillOrganizationOverageThreshold(
       ownerId: usageSnapshot.ownerId,
     })
 
-    const ledgerUsage =
+    const orgUsageByUser =
       orgSubscription.periodStart && orgSubscription.periodEnd
-        ? await getBillingPeriodUsageCost(
+        ? await getBillingPeriodUsageCostByUser(
             { type: 'organization', id: organizationId },
             { start: orgSubscription.periodStart, end: orgSubscription.periodEnd }
           )
-        : 0
+        : new Map<string, number>()
+    let ledgerUsage = 0
+    for (const cost of orgUsageByUser.values()) ledgerUsage += cost
+    // Union current members with every actor holding org-attributed rows this
+    // period: a member who departed mid-period still bills here, so their
+    // daily-refresh consumption must offset the overage too — same actor set
+    // as `calculateSubscriptionOverage` and the cycle close.
+    const overageActorIds = [...new Set([...usageSnapshot.memberIds, ...orgUsageByUser.keys()])]
 
     const {
       totalOverage: currentOverage,
@@ -634,7 +641,7 @@ async function checkAndBillOrganizationOverageThreshold(
       periodEnd: orgSubscription.periodEnd ?? null,
       organizationId,
       pooledLedgerUsage: ledgerUsage,
-      memberIds: usageSnapshot.memberIds,
+      memberIds: overageActorIds,
     })
 
     if (currentOverage < threshold) {