Cache calculated watering scale when using data from Dark Sky

WateringScaleCache.ts

@@ -0,0 +1,69 @@
+import * as NodeCache from "node-cache";
+import { GeoCoordinates, PWS } from "./types";
+import { AdjustmentOptions } from "./routes/adjustmentMethods/AdjustmentMethod";
+import * as moment from "moment-timezone";
+import * as geoTZ from "geo-tz";
+import { Moment } from "moment-timezone/moment-timezone";
+
+export default class WateringScaleCache {
+	private readonly cache: NodeCache = new NodeCache();
+
+	/**
+	 * Stores the results of a watering scale calculation. The scale will be cached until the end of the day in the local
+	 * timezone of the specified coordinates. If a scale has already been cached for the specified calculation parameters,
+	 * this method will have no effect.
+	 * @param adjustmentMethodId The ID of the AdjustmentMethod used to calculate this watering scale. This value should
+	 * have the appropriate bits set for any restrictions that were used.
+	 * @param coordinates The coordinates the watering scale was calculated for.
+	 * @param pws The PWS used to calculate the watering scale, or undefined if one was not used.
+	 * @param adjustmentOptions Any user-specified adjustment options that were used when calculating the watering scale.
+	 * @param wateringScale The results of the watering scale calculation.
+	 */
+	public storeWateringScale(
+		adjustmentMethodId: number,
+		coordinates: GeoCoordinates,
+		pws: PWS,
+		adjustmentOptions: AdjustmentOptions,
+		wateringScale: CachedScale
+	): void {
+		// The end of the day in the controller's timezone.
+		const expirationDate: Moment = moment().tz( geoTZ( coordinates[ 0 ], coordinates[ 1 ] )[ 0 ] ).endOf( "day" );
+		const ttl: number = ( expirationDate.unix() - moment().unix() );
+		const key = this.makeKey( adjustmentMethodId, coordinates, pws, adjustmentOptions );
+		this.cache.set( key, wateringScale, ttl );
+	}
+
+	/**
+	 * Retrieves a cached scale that was previously calculated with the given parameters.
+	 * @param adjustmentMethodId The ID of the AdjustmentMethod used to calculate this watering scale. This value should
+	 * have the appropriate bits set for any restrictions that were used.
+	 * @param coordinates The coordinates the watering scale was calculated for.
+	 * @param pws The PWS used to calculate the watering scale, or undefined if one was not used.
+	 * @param adjustmentOptions Any user-specified adjustment options that were used when calculating the watering scale.
+	 * @return The cached result of the watering scale calculation, or undefined if no values were cached.
+	 */
+	public getWateringScale(
+		adjustmentMethodId: number,
+		coordinates: GeoCoordinates,
+		pws: PWS,
+		adjustmentOptions: AdjustmentOptions
+	): CachedScale | undefined {
+		const key = this.makeKey( adjustmentMethodId, coordinates, pws, adjustmentOptions );
+		return this.cache.get( key );
+	}
+
+	private makeKey(
+		adjustmentMethodId: number,
+		coordinates: GeoCoordinates,
+		pws: PWS,
+		adjustmentOptions: AdjustmentOptions
+	): string {
+		return `${ adjustmentMethodId }#${ coordinates.join( "," ) }#${ pws ? pws.id : "" }#${ JSON.stringify( adjustmentOptions ) }`
+	}
+}
+
+export interface CachedScale {
+	scale: number;
+	rawData: object;
+	rainDelay: number;
+}