fix(website): monotonic timestamp ride IDs, zero-budget cursor guard, and modal input preservation

- Guard advancePlaybackIndex against spuriously advancing when budgetMs <= 0 on duplicate timestamps
- Use monotonic millisecond timestamp in commitGroupRide to eliminate timestamp corruption and collision hazards
- Preserve CreateGroupRideModal form inputs on failed commit so users do not lose typed data
- Add regression tests in vitest suites for zero-budget duplicate timestamps, timestamp fidelity, and input preservation

website/components/group-rides/group-rides-management.tsx

@@ -183,7 +183,7 @@ type MyRidesFilter = 'all' | 'organized' | 'joined';
 interface CreateRideModalProps {
   isOpen: boolean;
   onClose: () => void;
-  onCreateRide: (ride: GroupRideSummary) => void | Promise<void>;
+  onCreateRide: (ride: GroupRideSummary) => void | boolean | Promise<void | boolean>;
 }
 
 function CreateGroupRideModal({ isOpen, onClose, onCreateRide }: CreateRideModalProps) {
@@ -326,8 +326,10 @@ function CreateGroupRideModal({ isOpen, onClose, onCreateRide }: CreateRideModal
 
     setIsSubmitting(true);
     try {
-      await onCreateRide(newRide);
-      onClose();
+      const outcome = await onCreateRide(newRide);
+      if (outcome !== false) {
+        onClose();
+      }
     } finally {
       setIsSubmitting(false);
     }
@@ -1014,9 +1016,9 @@ export function GroupRidesManagement({
   }, [currentUser?.uid]);
 
   // Handlers for Add, Alter, Remove, Join, Leave
-  const handleCreateRide = async (newRide: GroupRideSummary & { visibility?: string; clubId?: string; clubName?: string }) => {
+  const handleCreateRide = async (newRide: GroupRideSummary & { visibility?: string; clubId?: string; clubName?: string }): Promise<boolean> => {
     // Prevent duplicate submissions while a create is already in flight.
-    if (creatingRideRef.current) return;
+    if (creatingRideRef.current) return false;
 
     const uid = currentUser?.uid;
     // Check authentication and persistence availability BEFORE touching UI state, so an
@@ -1024,7 +1026,7 @@ export function GroupRidesManagement({
     // never saved. They get an actionable error instead.
     if (!uid || !firestore) {
       showAlert('Sign in to create a group ride — it could not be saved.', 'error');
-      return;
+      return false;
     }
 
     creatingRideRef.current = true;
@@ -1055,12 +1057,15 @@ export function GroupRidesManagement({
         };
         setRides((prev) => (prev.some((r) => r.id === result.rideId) ? prev : [rideWithOrganizer, ...prev]));
         showAlert(`Created new group ride "${newRide.title}"! Ride Code: ${result.rideId}`, 'success');
+        return true;
       } else if (result.reason === 'commit-failed') {
         console.error('Failed to persist group ride to Firestore:', result.error);
         showAlert('Could not create the ride. Please check your connection and try again.', 'error');
+        return false;
       } else {
         // unauthenticated / unavailable discovered inside the helper (defensive — guarded above).
         showAlert('Could not create the ride right now. Please try again.', 'error');
+        return false;
       }
     } finally {
       creatingRideRef.current = false;

website/lib/create-group-ride.ts

@@ -37,10 +37,10 @@ export interface CommitGroupRideDeps {
  * - unavailable: no Firestore handle
  * - commit-failed: the write was attempted but rejected (nothing persisted)
  */
-let rideIdCounter = 0;
+let lastRideTimestamp = 0;
 
 export function resetRideIdCounter(): void {
-  rideIdCounter = 0;
+  lastRideTimestamp = 0;
 }
 
 export async function commitGroupRide(
@@ -52,9 +52,10 @@ export async function commitGroupRide(
   if (!deps.firestore) return { ok: false, reason: 'unavailable' };
 
   const now = deps.now ?? new Date();
-  const seq = ++rideIdCounter;
-  const seqSuffix = seq > 1 ? `${seq}` : '';
-  const rideId = `ride_${now.getTime()}${seqSuffix}_${uid.substring(0, Math.min(6, uid.length))}`;
+  const rawMs = now.getTime();
+  const timestamp = Math.max(rawMs, lastRideTimestamp + 1);
+  lastRideTimestamp = timestamp;
+  const rideId = `ride_${timestamp}_${uid.substring(0, Math.min(6, uid.length))}`;
 
   const payload = buildWebGroupRidePayload(newRide, {
     rideId,

website/lib/telemetry-track.ts

@@ -62,22 +62,26 @@ export function advancePlaybackIndex(
   budgetMs: number
 ): { index: number; remainingMs: number } {
   if (points.length === 0) return { index: 0, remainingMs: 0 };
-  let i = Math.max(0, Math.min(fromIndex, points.length - 1));
-  let budget = Number.isFinite(budgetMs) ? Math.max(0, budgetMs) : 0;
-  while (i < points.length - 1) {
-    const connected = areTelemetryPointsConnected(points[i], points[i + 1]);
+  const i = Math.max(0, Math.min(fromIndex, points.length - 1));
+  if (!Number.isFinite(budgetMs) || budgetMs <= 0) {
+    return { index: i, remainingMs: 0 };
+  }
+  let budget = budgetMs;
+  let curr = i;
+  while (curr < points.length - 1) {
+    const connected = areTelemetryPointsConnected(points[curr], points[curr + 1]);
     const rawDt = connected
-      ? Date.parse(points[i + 1].timestamp) - Date.parse(points[i].timestamp)
+      ? Date.parse(points[curr + 1].timestamp) - Date.parse(points[curr].timestamp)
       : 50;
     const dt = Number.isFinite(rawDt) ? Math.max(0, rawDt) : 50;
     if (budget >= dt) {
       budget -= dt;
-      i++;
+      curr++;
     } else {
       break;
     }
   }
-  return { index: i, remainingMs: i < points.length - 1 ? budget : 0 };
+  return { index: curr, remainingMs: curr < points.length - 1 ? budget : 0 };
 }
 
 /** Leaflet's geographic API is [latitude, longitude], never normalized screen pixels. */

website/tests/create-group-ride.test.ts

@@ -1,5 +1,5 @@
-import { describe, it, expect, vi } from 'vitest';
-import { commitGroupRide } from '../lib/create-group-ride';
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { commitGroupRide, resetRideIdCounter } from '../lib/create-group-ride';
 import type { WebGroupRideInput } from '../lib/group-ride-payload';
 
 const baseRide: WebGroupRideInput = {
@@ -41,6 +41,10 @@ function makeDeps(overrides: Partial<Parameters<typeof commitGroupRide>[1]> = {}
 }
 
 describe('commitGroupRide (WEB Phase 1 — persisted ride creation)', () => {
+  beforeEach(() => {
+    resetRideIdCounter();
+  });
+
   it('refuses to create for an unauthenticated user (no uid) and never writes', async () => {
     const { deps, commitSpy } = makeDeps({ uid: undefined });
     const res = await commitGroupRide(baseRide, deps);
@@ -101,6 +105,24 @@ describe('commitGroupRide (WEB Phase 1 — persisted ride creation)', () => {
     }
   });
 
+  it('preserves clean timestamps without string suffix corruption on successive rides', async () => {
+    const t1 = new Date('2026-10-14T12:00:00.000Z');
+    const t2 = new Date('2026-10-14T12:05:00.000Z');
+    const { deps: deps1 } = makeDeps({ now: t1 });
+    const { deps: deps2 } = makeDeps({ now: t2 });
+
+    const res1 = await commitGroupRide(baseRide, deps1);
+    const res2 = await commitGroupRide(baseRide, deps2);
+
+    expect(res1.ok).toBe(true);
+    expect(res2.ok).toBe(true);
+    if (res1.ok && res2.ok) {
+      // Must equal exact millisecond timestamp, NOT corrupted with appended counter digits
+      expect(res1.rideId).toBe(`ride_${t1.getTime()}_rider-`);
+      expect(res2.rideId).toBe(`ride_${t2.getTime()}_rider-`);
+    }
+  });
+
   it('handles permission-denied or rejected commit cleanly without throwing', async () => {
     const permDenied = new Error('permission-denied: caller lacks organizer permission');
     const { deps } = makeDeps({

website/tests/group-rides-page.test.tsx

@@ -488,6 +488,9 @@ describe('Group Rides Interactive Page & Components', () => {
 
       await screen.findByText(/Could not create the ride/i);
       expect(screen.queryByRole('heading', { name: /Doomed Ride/i })).toBeNull();
+      // Form inputs remain preserved in the modal so the user does not lose their typed data
+      expect(screen.getByLabelText<HTMLInputElement>(/ride title/i).value).toBe('Doomed Ride');
+      expect(screen.getByLabelText<HTMLInputElement>(/region \/ city/i).value).toBe('Nowhere');
     });
 
     it('enforces commit-before-UI: never inserts into UI state while commit is in-flight', async () => {

website/tests/telemetry-playback-sync.test.ts

@@ -97,6 +97,17 @@ describe('replay regression tests: irregular timestamps', () => {
     expect(r.remainingMs).toBe(0);
   });
 
+  it('does not advance on zero or negative budget even if adjacent samples have identical timestamp (dt === 0)', () => {
+    const dups = [mk(0), mk(0), mk(50)];
+    const rZero = advancePlaybackIndex(dups, 0, 0);
+    expect(rZero.index).toBe(0);
+    expect(rZero.remainingMs).toBe(0);
+
+    const rNeg = advancePlaybackIndex(dups, 0, -10);
+    expect(rNeg.index).toBe(0);
+    expect(rNeg.remainingMs).toBe(0);
+  });
+
   it('treats inverted / backwards timestamps as disconnected (50 ms step) instead of looping or stalling', () => {
     // Sample 2 is out of order (timestamp goes backwards)
     const backwards = [mk(0), mk(50), mk(30), mk(100)];