Add StationDataModule, implementing getNearestStations & a Geohash generator method

src/lib/validation.ts

@@ -1,6 +1,7 @@
 /**
-* Checks if a string is a valid CRS
+* Checks if a string is a valid CRS (Syntactically Only)
 * using byte level checking for max performance
+* @param CRS The CRS Code to be validated
 */
 export const IsValidCrs = (CRS: string): boolean => {
     if (CRS.length !== 3) return false;
@@ -15,8 +16,9 @@ export const IsValidCrs = (CRS: string): boolean => {
 }
 
 /**
- * Checks if a string is a valid TIPLOC
+ * Checks if a string is a valid TIPLOC (Syntactically Only)
  * using byte level checking for max performance
+ * @param TIPLOC The TIPLOC to be validated
  */
 export const IsValidTiploc = (TIPLOC: string): boolean => {
     const l = TIPLOC.length;
@@ -33,9 +35,10 @@ export const IsValidTiploc = (TIPLOC: string): boolean => {
 }
 
 /**
- * Checks if a string is a valid PIS Code
+ * Checks if a string is a valid PIS Code (Syntactically Only)
  * using byte level checking for max performance
  * ONLY GWR (4-digit) CODES SUPPORTED
+ * @param PIS The PIS Code to be validated
  */
 export const IsValidPis = (PIS: string): boolean => {
     if (PIS.length !== 4) return false;
@@ -44,4 +47,15 @@ export const IsValidPis = (PIS: string): boolean => {
         if (!(char >= 48 && char <= 57)) return false;
     }
     return true;
+}
+
+/**
+ * Validates Geohash string against standard b32 alphabet
+ * (Syntactically Only validation)
+ * @param hash The geohash to be validated
+ * @param maxLen Defaults to 6 - which is enforced by the server, should not need changing
+ */
+export const IsValidGeoHash = (hash: string, maxLen: number = 6): boolean => {
+    const geoHashRegex = new RegExp(`^[0-9bcdefghjkmnpqrstuvwxyz]{1,${maxLen}}$`, 'i');
+    return geoHashRegex.test(hash);
 }

src/modules/pis.ts

@@ -1,6 +1,6 @@
 import { ApiPisObject } from '@owlboard/api-schema-types';
 import type { BaseClient, ApiResult } from '../lib/base.js';
-import { IsValidCrs, IsValidTiploc, IsValidPis } from '../lib/validation.js';
+import { IsValidCrs, IsValidPis } from '../lib/validation.js';
 import { ValidationError } from '../lib/errors.js';
 
 export class PisModule {

src/modules/stationData.ts

@@ -0,0 +1,37 @@
+import { ApiStationsNearestStations } from '@owlboard/api-schema-types';
+import type { BaseClient, ApiResult } from '../lib/base.js';
+import { IsValidGeoHash } from '../lib/validation.js';
+import { ValidationError } from '../lib/errors.js';
+import Geohash from 'latlon-geohash';
+
+export class StationDataModule {
+    constructor(private client: BaseClient) {}
+
+    /**
+     * Generates a 6-char Geohash for the given co-ordinates
+     * @param lt Latitude
+     * @param ln Longitude
+     * @returns Geohash as string
+     */
+    static generateGeohash(lt: number, ln: number): string {
+        return Geohash.encode(lt, ln, 6);
+    }
+
+    /**
+     * 
+     * @param geohash Geohash as string (up to six characters), generate using this.generateGeohash()
+     * @returns Nearest Stations API Response (CRS, Name)
+     */
+    async getNearestStations(geohash: string): Promise<ApiResult<ApiStationsNearestStations.StationsNearestStations[]>> {
+        if (!IsValidGeoHash(geohash)) {
+            throw new ValidationError("hash", "Invalid Geohash requested");
+        }
+
+        const path = `/stationData/nearest/${geohash}`;
+        return this.client.request<ApiStationsNearestStations.StationsNearestStations[]>(path, {
+            method: 'GET',
+        })
+    }
+
+    // getStationSate(crs: string){}
+}