fix timezone issues

src/config.ts

@@ -6,6 +6,8 @@ export const Config = {
 	api_key: process.env.API_KEY,
 	port: process.env.PORT || "8080",
 
+	timezone: process.env.TIMEZONE || "Europe/Berlin",
+
 	gadgetbridge: {
 		db_path:
 			process.env.GADGETBRIDGE_DB_PATH || "src/gadgetbridge/db/Gadgetbridge.db",

src/gadgetbridge/client.ts

@@ -25,29 +25,32 @@ export class GadgetbridgeClient {
 		return db;
 	}
 
-	getStepsPerDay(fromTimestamp: number, toTimestamp: number): StepRow[] {
+	getStepsPerDay(fromTimestamp: number, toTimestamp: number, utcOffset: string): StepRow[] {
 		const stmt = this.db.prepare(`
 			SELECT date, SUM(steps) AS steps
 			FROM (
 				SELECT
-					DATE(TIMESTAMP, 'unixepoch', 'localtime') AS date,
+					DATE(TIMESTAMP, 'unixepoch', ?) AS date,
 					STEPS AS steps
 				FROM HUAMI_EXTENDED_ACTIVITY_SAMPLE
 				WHERE TIMESTAMP >= ? AND TIMESTAMP < ?
 				UNION ALL
 				SELECT date, steps
 				FROM old.steps
-				WHERE date >= DATE(?, 'unixepoch', 'localtime')
-				  AND date < DATE(?, 'unixepoch', 'localtime')
+				WHERE date >= DATE(?, 'unixepoch', ?)
+				  AND date < DATE(?, 'unixepoch', ?)
 			)
 			GROUP BY date
 			ORDER BY date
 		`);
 		return stmt.all(
+			utcOffset,
 			fromTimestamp,
 			toTimestamp,
 			fromTimestamp,
+			utcOffset,
 			toTimestamp,
+			utcOffset,
 		) as StepRow[];
 	}
 }

src/gadgetbridge/public-routes.ts

@@ -34,13 +34,7 @@ export async function publicGadgetbridgeRoutes(
 		async (request, reply) => {
 			const { from, to } = request.query as any;
 
-			const fromDate = new Date(`${from}T00:00:00`);
-			const toDate = new Date(`${to}T00:00:00`);
-
-			const service_result = gadgetbridgeService.getStepsForTimespan(
-				fromDate,
-				toDate,
-			);
+			const service_result = gadgetbridgeService.getStepsForTimespan(from, to);
 
 			if (!service_result.successful) {
 				reply.code(418);

src/gadgetbridge/service.ts

@@ -1,14 +1,24 @@
 import { BaseService, type ServiceResult, type StepRow } from "@dpu/shared";
+import { DateTime } from "luxon";
+import { Config } from "../config.js";
 import type { GadgetbridgeClient } from "./client.js";
 
 export class GadgetbridgeService extends BaseService<GadgetbridgeClient> {
-	getStepsForTimespan(from: Date, to: Date): ServiceResult<StepRow[] | string> {
+	getStepsForTimespan(from: string, to: string): ServiceResult<StepRow[] | string> {
 		try {
-			const fromTs = Math.floor(from.getTime() / 1000);
-			// Add one day to make `to` inclusive
-			const toTs = Math.floor(to.getTime() / 1000) + 86400;
+			const tz = Config.timezone;
+			const fromDt = DateTime.fromISO(from, { zone: tz }).startOf("day");
+			const toDt = DateTime.fromISO(to, { zone: tz }).startOf("day").plus({ days: 1 });
 
-			const rows = this.getClient().getStepsPerDay(fromTs, toTs);
+			const fromTs = Math.floor(fromDt.toSeconds());
+			const toTs = Math.floor(toDt.toSeconds());
+
+			const offsetMinutes = fromDt.offset;
+			const sign = offsetMinutes >= 0 ? "+" : "-";
+			const abs = Math.abs(offsetMinutes);
+			const utcOffset = `${sign}${String(Math.floor(abs / 60)).padStart(2, "0")}:${String(abs % 60).padStart(2, "0")}`;
+
+			const rows = this.getClient().getStepsPerDay(fromTs, toTs, utcOffset);
 			return this.getSuccessfulResult(rows);
 		} catch (error) {
 			return this.getErrorResult(