rippr/docs/V3-BACKLOG.md

> **Carried forward from the native repo** (`~/dojo/rippr/docs/v3/BACKLOG.md`) when the
> Flutter port completed. Two items below have changed status since it was written:
>
> - **Compose UI tests** — no longer a gap. The port has 15 widget tests plus 4
>   integration tests; see `docs/port/PARITY-AUDIT.md`.
> - **Elevation gain accuracy** — the algorithm is now proven bit-identical across Kotlin
>   and Dart (`tool/parity/run.sh`), so any future tuning can be checked against the
>   original rather than guessed at. The instruction below still stands: **do not tune it
>   blind.**
>
> Everything else carries over unchanged, including the v3 ideas and the
> "must not regress" list.

---

# v3 backlog

Everything known-outstanding as of v2.0.1, with enough context to pick up cold.
Nothing here is committed to — it is a menu, roughly ordered by value.

**Before planning anything: run the real-ride checklist in
[the real-ride checklist](port/REAL-RIDE-CHECKLIST.md).** Several items below may turn out to be non-issues, and
others may appear that nobody has thought of.

---

## 1. Carried over from v2 — the honest debt

### Elevation gain accuracy · *needs real data first*

~30 m of phantom gain per ten stationary minutes against synthetic ±8 m uniform noise. Real
GPS altitude error is *correlated* rather than uniform, so the true behaviour is unknown.

The current implementation is a 15-sample moving average plus reversal hysteresis (see
[ARCHITECTURE.md](ARCHITECTURE.md)). A naive version reported 1498 m over a parked
bike, so the guard rails matter.

**Do not tune this blind.** Record a flat ride, check whether the reported gain is
plausible, and only then adjust. If it needs work, options are a longer smoothing window, a
larger threshold, or using barometric pressure where available (much more accurate than GPS
altitude, and most phones have the sensor).

### Compose UI tests · *the largest coverage gap*

Zero UI tests across six screens. Everything was verified by manual screenshot. Worth
covering: navigation record→trips→detail→back, rotation/state retention, empty states,
`NotFound`, chart degradation below two points, selection mode enabling Merge only at two.

### Unmeasured, and probably should be

- **Battery drain** over a multi-hour ride — never measured, and it is the thing most likely
  to make the app unusable in practice
- **Map memory across repeated navigation** — the osmdroid lifecycle is a known hazard and
  the wiring was never leak-tested
- **GPX import into Strava/Garmin** — validated against an XML parser, but schema validity
  does not guarantee a consumer accepts it

---

## 2. The original v3 candidate — live group ride view

Deferred from v2 as "needs real server work". This was in the **v1** brief's goal
statement, so it has been the intended destination all along.

Already in place:
- `TelemetryUploader` — batched POST, retry, offline-safe, cannot stall recording
- `synced` column and backlog semantics
- `trip_id` / `segment_id` per point, so a server can reconstruct rides and pauses
- `Config.deviceId` — stable per-install id to distinguish riders

Missing:
- **A server.** Nothing exists. This is the actual work.
- **UI for the endpoint** — currently only reachable via `Config.setUploadEndpoint()`
- Other riders' positions on a map, and a live map at all (see below)
- Auth, rider identity, group membership

**Worth deciding early:** this is the point where Rippr stops being a local-only app. That
brings hosting, privacy, and location-sharing consent into scope.

---

## 3. Live map on the recording screen — **decision reversed**

v2 deliberately shipped no live map, on the reasoning that the phone rides in a pocket.
Dylan has since asked for one — for visual appeal, and because **people may mount the phone
on the handlebars** to watch the route live. Treat the v2 stance as superseded.

**The handlebar case changes the premise, not just the feature.** v1 and v2 were both built
around "start it, pocket it, stop it". A mounted phone is a different product with different
constraints, and it is worth deciding explicitly whether that becomes a first-class mode:

- **Screen on for the whole ride** — battery goes from "a background service" to "a
  service plus a lit screen plus continuous map rendering". Measure before committing.
- **Sunlight legibility** — the current dark theme is chosen for glanceability, but daylight
  behind a visor is a different problem.
- **Glove-sized targets** — already partly handled (72dp buttons); a map needs the same care.
- **Keep-screen-awake** handling, and what happens on a call or notification.

What still holds regardless:

- **`TrackingService` must never reference a map.** Rendering belongs to the Compose
  lifecycle of a visible screen, not the service.
- **No tile fetch or redraw while backgrounded**, even in mounted mode.

---

## 4. Activity type per ride

Promoted out of the ideas list, because it turned out to be a **positioning decision**
rather than a feature. See [LAUNCH.md](LAUNCH.md).

Everything user-facing says motorcycle, but the recording pipeline never did: it records
positions, speeds and altitudes, and nothing in it cares what you are sitting on. Dylan
already rides both bikes and motorcycles.

**Why it matters beyond the feature:** it decides the store category, the screenshots and
who ever finds the app. Cyclists are a far larger audience than motorcyclists and are
already used to paying for ride apps. That question is much cheaper to settle before a
store listing exists than after.

### Schema

An `activity` column on `Trip`, stored as a text enum like `TripState`:

```
motorcycle · bicycle · scooter · skateboard · running · walking · other
```

This is the **first real migration** the port will ship. The destructive fallback is gone
for good, so it needs `m.addColumn(trips, trips.activity)` with a default of `motorcycle`
for existing rows, `schemaVersion` bumped to 2, and a migration test that opens a v1
database and asserts the rides survive. Getting that path right once matters more than the
feature does — every later schema change depends on it.

### Type should drive defaults, not just labels

This is where the real value is, and it is easy to miss:

| Setting | Why it differs |
|---|---|
| Speed noise floor (1.5 km/h) | Fine for a motorcycle; wrong for walking, where real movement lives near it |
| Speed histogram bucket (10 km/h) | Useless for running — everything lands in one bucket. Wants ~1 km/h. |
| Accuracy gate (50 m) | A motorcycle at speed can tolerate looser fixes than a walker |
| Elevation smoothing window | Tuned at 15 samples for 2 Hz road speed; a slower activity covers less ground per sample |
| Map fit zoom | A 2 km walk and a 200 km ride want different defaults |

Treat these as a per-activity profile rather than scattering `if (activity == …)` through
the code.

### Do not put a picker in front of Start

The founding premise is press-and-go with gloves on. A modal asking "what are you doing?"
before recording begins would undo that.

Better: **default to the last activity used**, and make it editable on the trip detail
screen afterwards, next to rename. Most people do the same thing most days, and the one
time they don't, they can fix it after.

### Follow-ons, once the column exists

- **Filter and group the trips list** by activity
- **GPX `<type>` on `<trk>`** — Strava and Garmin read it, so an exported ride imports as
  the right activity instead of defaulting to something wrong
- Per-activity totals, if a stats screen ever appears

---

## 5. Smaller items

| Item | Notes |
|---|---|
| **Trip splitting** | Merge exists; split does not. The natural counterpart. |
| **SAF export** | Dropped in T16 as unnecessary — share sheet covers it. Add if a real need appears. |
| **Auto-pause** | Detect a stop and pause automatically. Rejected in v2 as unreliable in traffic; revisit only with real ride data showing it would help. |
| **Distance units** | Metric only, hardcoded. Trivial to add a preference. |
| **Settings screen** | None exists. `Config` has endpoint, deviceId, mapEnabled — the map toggle currently lives on trip detail because one switch did not justify a screen. |
| **Offline tile pre-download** | osmdroid caches what it renders; a mountain ride with no signal shows blank tiles. Respect OSM's usage policy — no bulk prefetch of their public servers. |
| **Notification live stats** | Show distance/duration in the ongoing notification, readable without unlocking. |
| **Crash reporting** | None. A recorder that dies mid-ride currently leaves no trace beyond logcat. |

---

## 6. Ideas

Terse on purpose. Unshaped, to be consolidated later.

- **Live map while recording.** More visually appealing than a numbers screen. Reverses the
  v2 decision — see section 3 for the constraints that survive it.
- **Pick a real theme.** The current look is functional dark + safety orange, chosen to
  match the icon. Decide on an actual visual identity and push the UI toward something
  polished rather than merely clean.
- **User sign-up and accounts.** Register people, give their data somewhere to live.
  Prerequisite for anything cloud-side, and pairs with the group-ride server in section 2.
- **Paid cloud backup.** Ongoing storage of rides over time. Needs accounts first, plus a
  decision on hosting, pricing, and what happens to data when someone stops paying.
- **Waypoint route planning.** Drop a series of pins on the map to "draw" a route, get
  distance and estimates back, and save it to ride later. This is *pre*-ride planning —
  a genuinely new mode alongside recording, not an extension of it. Needs its own entity
  (`Route` + `Waypoint`), separate from `Trip`, since a plan is not a recording.
  Straight-line pin-to-pin distance is easy and reuses `Geo.haversineMeters`; snapping to
  actual roads needs a routing service (OSRM, GraphHopper, Valhalla — self-hostable) and is
  a much larger step. Natural follow-ons: follow a planned route on the live map, and
  compare a recorded ride against the plan afterwards.

### Threads running through these

Sign-up, cloud backup and group ride are one programme, not three: they all need a server,
identity, and a privacy stance. Worth scoping together rather than separately.

Activity type (now section 4) and theming are independent and much cheaper — either could
ship alone, and activity type is the natural first v3 task because it forces the migration
path to be proven while the stakes are still low.

Live map, handlebar mounting and waypoint following also cluster: all three assume a
visible screen during the ride, and all three want the same map component. Route planning
is the odd one out — it needs no ride in progress at all and could be built entirely
standalone.

---

## 7. Things that must not regress

Hard-won and easy to undo by accident. Each has a comment in the code explaining why.

1. **The unbounded `Channel` + single batched writer.** Do not write to the database from
   the location callback.
2. **Points stamped with `tripId`/`segmentId` at creation.** Refactoring this into a
   write-time lookup breaks the pause guarantee silently.
3. **Recording state derived from the database.** Never reintroduce an in-memory flag.
4. **`fallbackToDestructiveMigration()` stays removed.** Any schema change ships a
   `Migration` against `app/schemas/com.rippr.data.AppDatabase/2.json`.
5. **Decimation is render-only.** It must never reach storage or export.
6. **`RipprTheme`'s `Surface`.** It sets `LocalContentColor`; without it, text without an
   explicit colour renders black-on-black and disappears.
7. **The map zoom clamp.** `zoomToBoundingBox` ignores `maxZoomLevel`; a short ride will
   render an empty grid without it.
8. **Instrumented tests use in-memory databases.** One previously wiped the real device
   database in `setUp`.

---

## 8. Reading order for picking this up cold

1. [../README.md](../README.md) — what the app is and its current state
2. [ARCHITECTURE.md](ARCHITECTURE.md) — why it is built this way
3. `~/dojo/rippr/docs/v2/PROGRESS.md` (native repo) — every bug found during v2 and how
4. [the real-ride checklist](port/REAL-RIDE-CHECKLIST.md) — **especially "What the emulator cannot verify"**
5. `~/dojo/rippr/docs/DEVELOPMENT.md` (native repo) — when you actually need to build something

The v2 planning approach worked well and is worth repeating: one document per task with
goal, context, design, acceptance criteria and risks, written *before* implementing, plus a
running progress log recording what actually went wrong. Several bugs were caught precisely
because the risk had been written down first — and one (the osmdroid lifecycle) was written
down and then walked into anyway, which is its own lesson.