Add NearestStations Card & Location monitor

src/lib/geohash.svelte.ts

@@ -0,0 +1,90 @@
+import { OwlClient, ValidationError, ApiError } from './owlClient';
+import type { ApiStationsNearestStations } from '@owlboard/owlboard-ts';
+
+class NearestStationsState {
+	list = $state<ApiStationsNearestStations.StationsNearestStations[]>([]);
+	currentHash = $state('');
+	loading = $state(true);
+	error = $state<string | null>(null);
+
+	private geoConfig: PositionOptions = {
+		enableHighAccuracy: false,
+		timeout: 30000,
+		maximumAge: 120000
+	};
+
+	constructor() {
+		if (typeof window !== 'undefined' && 'geolocation' in navigator) {
+			this.jumpstart();
+			this.initWatcher();
+		}
+	}
+
+	private jumpstart() {
+		navigator.geolocation.getCurrentPosition(
+			(pos) => this.handleUpdate(pos.coords.latitude, pos.coords.longitude),
+			(err) => this.handleError(err),
+			this.geoConfig
+		);
+	}
+
+	private initWatcher() {
+		navigator.geolocation.watchPosition(
+			(pos) => this.handleUpdate(pos.coords.latitude, pos.coords.longitude),
+			(err) => this.handleError(err),
+			this.geoConfig
+		);
+	}
+
+	private async handleUpdate(lat: number, lon: number) {
+		const newHash = OwlClient.stationData.generateGeohash(lat, lon);
+		if (newHash !== this.currentHash) {
+			this.loading = true;
+
+			try {
+				const result = await OwlClient.stationData.getNearestStations(newHash);
+				this.list = result.data;
+				this.error = null;
+				this.currentHash = newHash;
+			} catch (e) {
+				this.handleApiError(e);
+			} finally {
+				this.loading = false;
+			}
+		}
+	}
+
+	private handleError(err: GeolocationPositionError) {
+		if (err.code === 1) {
+			this.error = 'Location access denied by device';
+		} else {
+			this.error = 'Waiting for GPS signal...';
+		}
+	}
+
+	private handleApiError(e: unknown) {
+		if (e instanceof ValidationError) {
+			this.error = `Request Error: ${e.reason} (Field: ${e.field})`;
+		} else if (e instanceof ApiError) {
+			switch (e.status) {
+				case 404:
+					this.error = 'No stations found nearby';
+					break;
+				case 429:
+					this.error = 'Too many requests, will retry';
+					break;
+				case 500:
+					this.error = 'Server Error, will retry';
+					break;
+				default:
+					this.error = `Service error: ${e.code}`;
+			}
+		} else {
+			this.error = 'Connection lost, waiting for signal';
+		}
+
+		console.error('OwlBoard API Error:', e);
+	}
+}
+
+export const nearestStationsState = new NearestStationsState();