adds routing engine

web/src/lib/stores/valhalla_store.ts

@@ -0,0 +1,79 @@
+import { ValhallaRoute, type ValhallaResponse } from "$lib/models/valhalla";
+import { ClientResponseError } from "pocketbase";
+
+
+
+export const route: ValhallaRoute = new ValhallaRoute();
+
+
+export function clearRoute() {
+    route.geometry.coordinates = [];
+}
+
+export async function calculateRouteBetween(startLat: number, startLon: number, endLat: number, endLon: number) {
+    const requestBody = {
+        "directions_type": "none",
+        "locations": [{ "lat": startLat, "lon": startLon }, { "lat": endLat, "lon": endLon }],
+        "costing": "pedestrian", "costing_options": { "pedestrian": { "max_hiking_difficulty": 6, "use_ferry": 0 } }
+    }
+    const r = await fetch("/api/v1/valhalla", { method: "POST", body: JSON.stringify(requestBody) })
+    if (!r.ok) {
+        throw new ClientResponseError(await r.json())
+    }
+    const response: ValhallaResponse = await r.json();
+
+    appendToRoute(response);
+}
+
+function appendToRoute(valhallaResponse: any) {
+    const routeGeometry = decodeShape(valhallaResponse.trip.legs[0].shape);
+
+    for (const point of routeGeometry) {
+        route.geometry.coordinates.push([point[1], point[0]])
+    }
+}
+
+
+function decodeShape(shape: string, precision: number = 6) {
+    var index = 0,
+        lat = 0,
+        lng = 0,
+        coordinates = [],
+        shift = 0,
+        result = 0,
+        byte = null,
+        latitude_change,
+        longitude_change,
+        factor = Math.pow(10, precision);
+
+    while (index < shape.length) {
+        byte = null;
+        shift = 0;
+        result = 0;
+
+        do {
+            byte = shape.charCodeAt(index++) - 63;
+            result |= (byte & 0x1f) << shift;
+            shift += 5;
+        } while (byte >= 0x20);
+
+        latitude_change = ((result & 1) ? ~(result >> 1) : (result >> 1));
+
+        shift = result = 0;
+
+        do {
+            byte = shape.charCodeAt(index++) - 63;
+            result |= (byte & 0x1f) << shift;
+            shift += 5;
+        } while (byte >= 0x20);
+
+        longitude_change = ((result & 1) ? ~(result >> 1) : (result >> 1));
+
+        lat += latitude_change;
+        lng += longitude_change;
+
+        coordinates.push([lat / factor, lng / factor]);
+    }
+
+    return coordinates;
+};