# County Sprints frontend/leaderboard update

Replace these files in the project:

- `src/main.rs`
- `src/model.rs`
- `src/db.rs`
- `src/leaderboard.rs`
- `src/web.rs`
- `migrations/0001_initial.sql`

No change is required to the working `src/intervals.rs`.

The existing `src/webhook.rs` can keep calling:

```rust
crate::process_activity(state_clone, athlete_id, activity_id.clone()).await
```

`process_activity()` now loads the athlete's OAuth access token itself. The development sync uses the explicit API-key client, so the personal development key is not written to the database.

## Database

The migration is intentionally a complete replacement because the database can be reset during development.

The new schema adds:

- `leaderboard_groups`
- `leaderboard_group_members`
- indexes for activity/crossing queries

## Leaderboard location matching

Leaderboard rows are grouped by:

- 10-minute time bucket
- source county
- destination county
- spatial cluster with a 10 metre DBSCAN radius

The crossing geometry is transformed to EPSG:3857 before the 10 metre clustering calculation so the distance is measured in metres rather than degrees.

## Frontend

The frontend now provides:

- Leaflet map for each leaderboard group
- small map for every individual crossing
- activity detail page at `/activity/{activity_id}`
- activity map containing all crossings
- browser-local timestamp formatting using `Intl.DateTimeFormat`
- leaderboard group management at `/groups`
- group selection on the main leaderboard

The map uses Leaflet and OpenStreetMap tiles. Leaflet's current stable 1.x documentation describes the same map/tile-layer APIs used here. citeturn0search2turn0search9