# Offline Strategy

## Offline requirement

Offline use must cover riding-critical information, not only maps.

## Offline pack contents

A trip offline pack should include:

- route geometry,
- route alternatives,
- daily stages,
- elevation profile,
- selected vector/raster map area,
- route-corridor POIs,
- emergency/bailout POIs,
- local rule cards,
- cached weather forecast at departure,
- saved bookings/deep links/addresses,
- user notes,
- GPX/TCX/FIT exports,
- report queue for later upload.

## Pack scope

Use a corridor-based pack:

```text
primary corridor: 5 km on either side of route
logistics corridor: 20 km around stage endpoints and bailout towns
map context: bounding box with simplification by zoom level
```

## Offline modes

### MVP offline mode

- Download planned route, POIs, stage plan, rules, and GPX.
- Allow map viewing if tile pack is present.
- Allow report capture and sync later.
- Allow basic distance-to-next-critical-thing calculation from cached data.

### Production offline mode

- Offline rerouting using a compact regional routing graph.
- Offline POI search.
- Offline rule lookup.
- Offline elevation sampling.
- Offline exports.

## Storage model

Mobile app storage:

- SQLite for structured trip data and POIs.
- File storage for tile packs and exports.
- Key-value storage for user preferences and sync state.

## Pack versioning

Each offline pack should include:

```json
{
  "pack_id": "pack_123",
  "trip_id": "trip_123",
  "created_at": "2026-06-30T00:00:00Z",
  "data_versions": {
    "osm_extract": "geofabrik-europe-germany-2026-06-29",
    "poi_index": "2026-06-29",
    "rules": "2026-06-01",
    "weather_cached_at": "2026-06-30T06:00:00Z"
  },
  "bbox": [6.0, 47.0, 15.0, 55.0],
  "route_buffer_km": 5,
  "expires_at": "2026-07-14T00:00:00Z"
}
```

## User-facing warnings

Before departure, show:

- which items are available offline,
- which items are stale,
- which route sections lack cached POIs,
- whether offline rerouting is available,
- which exports are saved.