Editing Openai/691a5ca1-2b1c-8010-8cbd-8797f95aa8d9 (section)

==== Given your offline-first + no push requirements, I’d treat this as a hybrid of: ====
* Manual “Start/Stop Driving” (primary source of truth)
* Motion + Location (used for validation and correction, not as the sole trigger)
* Periodic BGTasks to reconcile history and send “late” notifications if needed

===== 1. User taps Start Driving - Start an in-app “session”: - drivingSession.startDate = Date() - enable background location with allowsBackgroundLocationUpdates = true and activityType = .automotiveNavigation (or .otherNavigation if review is picky) - start CMMotionActivityManager.startActivityUpdates on a background queue =====
# While alive (foreground or kept alive by location): - Your “engine” consumes: - Location updates (speed, GPS validity) - Motion activity (.automotive, .stationary, confidence) - It maintains an accumulatedDrivingSeconds counter for the active session.
# When accumulated driving reaches 4 hours: - Schedule a local notification via UNUserNotificationCenter. - (Optionally also schedule earlier “pre-break” notifications at e.g. 3h30.)
# When user taps Stop Driving: - Close that session in SwiftData, record endDate, total driving seconds. - Stop background location + stop motion updates.

This is essentially exactly what navigation / running apps do, just with different output.

: 

===== You can’t force iOS to keep you alive forever. So plan for: =====
* Suspended but not killed: you may still get some location wakeups; process them and let your engine tick forward. But you can’t depend on high-frequency updates.
* Killed (by system or user): everything stops. Here’s where Core Motion history + BGTasks come in.

On next relaunch (or BGTask wake):
# Use CMMotionActivityManager.queryActivityStarting(from:to:to:handler:) to fetch activity segments since the last time you reconciled.devfright.com<ref>{{cite web|title=devfright.com|url=https://www.devfright.com/how-to-use-the-cmmotionactivitymanager/|publisher=devfright.com|access-date=2025-11-17}}</ref>
# Filter segments where activity.automotive == true and confidence is .medium/.high.
# Reconstruct driving intervals and: - Merge them with your stored sessions (manual Start/Stop windows). - Adjust any session that looks “off” (e.g. user forgot to tap Start but you see 2h of automotive → you can offer to auto-fill it next time they open the app).
# If from that reconstruction you see: - “User crossed 4h of continuous driving X minutes ago and we didn’t notify”: - Send a late notification (“You’ve been driving for about 4 hours. Time for a break?”).

This is not perfect to the minute—but it’s honest, offline, and uses the tools Apple actually gives you.

===== You can register a BGAppRefreshTask: =====
* On sceneWillResignActive, schedule a refresh task for, say, 30–60 min in the future.
* In the task handler: - Run the same Core Motion history reconciliation. - Update SwiftData. - If you see they’re well past 4 hours (and no notification has fired yet), send one now.

You have to accept:
* BGTasks are not guaranteed to fire on schedule. They’re “when the system feels like it”.Apple Developer<ref>{{cite web|title=Apple Developer|url=https://developer.apple.com/documentation/backgroundtasks/bgtaskscheduler|publisher=Apple Developer|access-date=2025-11-17}}</ref>
* This is more “nudge the user if they forget the app exists”, not “tachograph-level compliance.”

So the real-time guarantee only exists while you’re alive under a background mode; outside of that, it’s “best effort”.