fix(billing): re-arm limit dedup at zero usage and zero prior usage (full clear / wipe-rebuild)

Author: waleedlatif1

apps/sim/lib/billing/core/limit-notifications.test.ts

@@ -161,9 +161,28 @@ describe('maybeSendLimitThresholdEmail', () => {
     expect(sendEmailSpy).not.toHaveBeenCalled()
   })
 
-  it('skips when limit or usage is non-positive', async () => {
+  it('re-arms but does not send when usage is fully cleared (zero usage)', async () => {
     await maybeSendLimitThresholdEmail({ ...baseUserParams, currentUsage: 0, limit: 5 })
+    expect(dbUpdateSpy).toHaveBeenCalledTimes(1) // re-arm only
+    expect(mockClaim).not.toHaveBeenCalled()
+    expect(sendEmailSpy).not.toHaveBeenCalled()
+  })
+
+  it('re-arms then sends on wipe-then-rebuild (priorUsage 0)', async () => {
+    // prior 0% (empty table) → current 90%: re-arm + claim + send.
+    await maybeSendLimitThresholdEmail({
+      ...baseUserParams,
+      currentUsage: 4.5,
+      limit: 5,
+      priorUsage: 0,
+    })
+    expect(dbUpdateSpy).toHaveBeenCalledTimes(2)
+    expect(sendEmailSpy).toHaveBeenCalledTimes(1)
+  })
+
+  it('skips when the limit is non-positive', async () => {
     await maybeSendLimitThresholdEmail({ ...baseUserParams, currentUsage: 4, limit: 0 })
+    expect(dbUpdateSpy).not.toHaveBeenCalled()
     expect(sendEmailSpy).not.toHaveBeenCalled()
   })
 })

apps/sim/lib/billing/core/limit-notifications.ts

@@ -129,12 +129,14 @@ export async function maybeSendLimitThresholdEmail(params: {
 }): Promise<void> {
   try {
     if (!isBillingEnabled) return
-    if (params.limit <= 0 || params.currentUsage <= 0) return
+    // A non-positive limit can't yield a percentage; a zero/negative `currentUsage`
+    // still needs to re-arm below, so it is handled by the `desired === 0` return.
+    if (params.limit <= 0) return
 
     const { category, scope } = params
-    const percent = (params.currentUsage / params.limit) * 100
+    const percent = Math.max(0, (params.currentUsage / params.limit) * 100)
     const priorPercent =
-      params.priorUsage != null && params.priorUsage > 0
+      params.priorUsage != null && params.priorUsage >= 0
         ? (params.priorUsage / params.limit) * 100
         : percent
     const desired = thresholdFor(percent)