bincio-rec/CLAUDE.md

bincio-rec

GPS activity recorder for the bincio ecosystem. Companion to bincio-autarchive (archive/sync app): rec makes the data, autarchive stores and syncs it.

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Concept

A focused, minimal recording app for cycling, running, hiking, and walking. Records GPS track + BLE sensor data, saves to GPX, optionally uploads directly to a bincio-activity server. Future: live navigation / turn-by-turn instructions.

The app does one thing well: record. No browsing, no analysis — that's autarchive's job.

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Ecosystem

bincio-rec          →  writes GPX files to shared storage
bincio-autarchive   →  imports GPX, stores locally, syncs to server
bincio-activity     →  server: parses GPX, stores activities, serves API
bincio-auth         →  auth service: issues JWTs for all bincio apps

bincio-rec can also upload directly to bincio-activity via /api/upload/raw (same endpoint autarchive uses), with instance URL + API token configured in settings.

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Tech Stack

Expo Prebuild (not managed Expo, not bare RN).

• Managed Expo ruled out: BLE requires native modules
• Bare RN ruled out: Expo library ecosystem is valuable (location, notifications, file system)
• Prebuild gives full native access while keeping Expo tooling and EAS Build

Key libraries:

• expo-location + expo-task-manager — background GPS recording
• react-native-ble-plx — BLE sensors (HR, power, cadence)
• @maplibre/maplibre-react-native — live track map, future navigation
• expo-notifications — km milestone alerts, future navigation cues
• expo-keep-awake — keep screen on during recording (user-toggleable)
• expo-file-system — write GPX/JSON to shared storage
• expo-sqlite — local DB for past recordings list

Target: Android first, iOS second.

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v1 Screens

1. Sensor pairing — scan BLE, pair HR monitor / power meter / cadence sensor; persisted
2. Recording — start / pause / resume / stop
   • Live stats: elapsed time, distance, current+avg speed, HR, power, cadence, elevation gain
   • Map with track drawn in real time
   • Keep-awake toggle
3. Post-recording summary — stats overview, title field, save / discard
4. Saved recordings — list of past sessions; tap to export GPX or upload to server
5. Settings — bincio instance URL + API token; km notification toggle; upload format

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Output Format

GPX with Garmin trackpoint extensions — one <trkpt> per second with:

• lat/lon/elevation from GPS
• <gpxtpx:hr> — heart rate
• <gpxtpx:power> — power (watts)
• <gpxtpx:cad> — cadence (rpm)

bincio-activity already parses this format via bincio.extract.parsers.

Files saved to a user-accessible location (iOS Files app / Android shared storage) so bincio-autarchive can import them manually.

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Known Platform Concerns

• Android battery optimization: aggressive OEMs (Xiaomi, Samsung, Huawei) kill background tasks. Prompt user to whitelist bincio-rec in battery settings on first launch. Every recording app has this problem — no framework-level fix.
• iOS background location: requires location background mode in Info.plist and "Always" location permission. Fine for sideloading/TestFlight; App Store submission requires clear justification.
• iOS foreground notifications: notification sounds are suppressed when app is in foreground — use expo-av audio cue instead for km alerts while screen is on.

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Out of Scope (v1)

• Navigation / turn-by-turn routing
• Auto-pause (stop lights, etc.)
• Structured workouts / intervals
• Offline maps
• Live tracking / sharing

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v1 Completion Plan

Scaffold is done (all screens, navigation, store, services, GPX, DB, upload). Items below are what remains before v1 is shippable.

1 — Quick fixes ✅

• Keep-awake toggle — wired to keepAwake store state via activateKeepAwakeAsync / deactivateKeepAwake; toggle button visible in controls bar
• Sensor button on Recording screen — "⚡ Sensors" button overlaid on map area navigates to SensorPairing modal
• GPS pause/resume — handlePause calls stopGpsRecording(), handleResume calls startGpsRecording()
• Track view — TrackView component renders recorded lat/lon points as a scaled SVG polyline on a dark background (no tile server needed); replaces the grey placeholder

2 — BLE ✅

• Android runtime permissions — requestBlePermissions() requests BLUETOOTH_SCAN + BLUETOOTH_CONNECT on Android 12+ (API 31+) before scanning
• Cadence CSC parsing — stateful parsing in parseCscMeasurement(): tracks previous crank revolution count + event time (uint16, 1/1024 s), computes RPM from delta with uint16 rollover handling
• BLE persistence — savePairedDevice / loadPairedDevices / removePairedDevice in ble.ts via AsyncStorage; SensorPairingScreen shows saved sensors at top, auto-attempts reconnect on mount, Forget button removes a device

3 — Km notifications ✅

• Permission request — requestNotificationPermissions() called in App.tsx on mount; foreground notification handler set at module level so iOS shows banners while app is active
• Milestone tracker — module-level runningDistanceMeters / lastNotifiedKm / prevPoint in gps.ts, reset on each startGpsRecording(); each incoming location adds haversine distance and fires a notification when a new km is crossed, gated on the kmNotifications AsyncStorage setting

4 — Android battery optimization prompt (1–2 hours)

• On first launch, detect if the app is affected by battery optimization (expo-intent-launcher) and show a one-time prompt directing the user to whitelist bincio-rec; persist dismissal in AsyncStorage so it only shows once

5 — Map (optional upgrade)

The track view from section 1 already shows the GPX polyline scaled to fit the screen. MapLibre can be added later for a real basemap (streets/terrain), but is not required for v1.

• MapLibre basemap — replace TrackView SVG with <MapLibreGL.MapView> + a tile source (e.g. OpenFreeMap); call MapLibreGL.setAccessToken(null) for raster-free usage
• Camera follow — add <MapLibreGL.Camera> that follows trackPoints[last] during recording
• Line layer — replace SVG polyline with <MapLibreGL.ShapeSource> + <MapLibreGL.LineLayer>