initial commit

fluxer_api/src/utils/GeoUtils.ts

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+/*
+ * Copyright (C) 2026 Fluxer Contributors
+ *
+ * This file is part of Fluxer.
+ *
+ * Fluxer is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Fluxer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with Fluxer. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+export function calculateDistance(lat1: number, lon1: number, lat2: number, lon2: number): number {
+	const R = 6371;
+	const dLat = ((lat2 - lat1) * Math.PI) / 180;
+	const dLon = ((lon2 - lon1) * Math.PI) / 180;
+	const a =
+		Math.sin(dLat / 2) * Math.sin(dLat / 2) +
+		Math.cos((lat1 * Math.PI) / 180) * Math.cos((lat2 * Math.PI) / 180) * Math.sin(dLon / 2) * Math.sin(dLon / 2);
+	const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
+	return R * c;
+}
+
+export function parseCoordinate(value?: string | null): number | null {
+	if (value == null) {
+		return null;
+	}
+	const parsed = Number.parseFloat(value);
+	return Number.isFinite(parsed) ? parsed : null;
+}