feat: fetch metadata from pmtiles

src/lib/services/TileMeta.ts

@@ -1,5 +1,8 @@
-import { map } from "$lib/components/lnv/map.svelte";
 import { lineString, pointToLineDistance } from "@turf/turf";
+import { FSSource, hasPMTiles } from "./OfflineTiles";
+import { PMTiles } from "pmtiles";
+import { VectorTile } from "@mapbox/vector-tile";
+import Protobuf from "pbf";
 
 function getFeatureDistance(f: GeoJSON.Feature, point: [number, number]) {
 	if (f.geometry.type === "LineString") {
@@ -16,11 +19,17 @@ function getFeatureDistance(f: GeoJSON.Feature, point: [number, number]) {
 	}
 }
 
-export function getTransportationMeta(coord: WorldLocation) {
-	if(!map.value) return null;
-	const features = map.value.querySourceFeatures("openmaptiles", {
-		sourceLayer: "transportation"
-	});
+export async function getMeta(coord: WorldLocation, layer: string) {
+	const zxy = coordToTile(coord, 14);
+	const tile = await fetchTile(zxy.z, zxy.x, zxy.y);
+	const layerData = tile.layers[layer];
+	if (!layerData) return null;
+
+	const features: GeoJSON.Feature[] = [];
+	for (let i = 0; i < layerData.length; i++) {
+		const feature = layerData.feature(i);
+		features.push(feature.toGeoJSON(zxy.x, zxy.y, zxy.z));
+	}
 	const filtered = features.filter((f) => f.geometry.type === "LineString" || f.geometry.type == "MultiLineString");
 	if(filtered.length === 0) return null;
 	const nearest = filtered.reduce((a, b) => {
@@ -47,3 +56,74 @@ export function getSpeed(maxspeed: string): number | null {
 	if(maxspeed === "walk") return 7; // https://wiki.openstreetmap.org/wiki/Proposed_features/maxspeed_walk
 	return IMPLICIT_SPEEDS[maxspeed as keyof typeof IMPLICIT_SPEEDS] || null;
 }
+
+function coordToTile(coord: WorldLocation, zoom: number) {
+	const z = zoom;
+	const x = Math.floor(((coord.lon + 180) / 360) * Math.pow(2, z));
+	const y = Math.floor(
+		((1 -
+			Math.log(
+				Math.tan((coord.lat * Math.PI) / 180) +
+					1 / Math.cos((coord.lat * Math.PI) / 180)
+			) /
+				Math.PI) /
+			2) *
+			Math.pow(2, z)
+	);
+	return { z, x, y };
+}
+
+class Cache<T> {
+	data: Map<string, T>;
+	size: number;
+
+	constructor(size: number) {
+		this.data = new Map<string, T>();
+		this.size = size;
+	}
+
+	get(key: string): T | undefined {
+		if (this.data.has(key)) {
+			const value = this.data.get(key)!;
+			this.data.delete(key);
+			this.data.set(key, value);
+			return value;
+		}
+		return this.data.get(key);
+	}
+
+	has(key: string): boolean {
+		return this.data.has(key);
+	}
+
+	set(key: string, value: T): void {
+		this.data.set(key, value);
+		if (this.data.size > this.size) {
+			const firstKey = this.data.keys().next().value;
+			if (firstKey) {
+				this.data.delete(firstKey);
+			}
+		}
+	}
+}
+
+const tileCache = new Cache<VectorTile>(5);
+
+export async function fetchTile(z: number, x: number, y: number) {
+	const cacheKey = `${z}/${x}/${y}`;
+	if (tileCache.has(cacheKey)) {
+		return tileCache.get(cacheKey)!;
+	}
+	const pmtiles = (await hasPMTiles("tiles"))
+		? new PMTiles(new FSSource("tiles"))
+		: new PMTiles("https://trafficcue-tiles.picoscratch.de/germany.pmtiles");
+	const tile = (await pmtiles.getZxy(z, x, y));
+	if (!tile) {
+		console.log(tile);
+		throw new Error(`Tile not found: z${z} x${x} y${y}`);
+	}
+	const data = tile.data;
+	const vectorTile = new VectorTile(new Protobuf(data));
+	tileCache.set(cacheKey, vectorTile);
+	return vectorTile;
+}