From db6ba00ded958ccff5f5c8aa2f81abe7051b2858 Mon Sep 17 00:00:00 2001
From: Tim Howitz <tim.howitz@dyson.com>
Date: Sun, 25 May 2025 11:46:42 +0100
Subject: [PATCH] Added linking of nearest observatories to earthquakes

---
 src/app/api/import-earthquakes/route.ts | 54 ++++++++++++++++++++++---
 1 file changed, 49 insertions(+), 5 deletions(-)

diff --git a/src/app/api/import-earthquakes/route.ts b/src/app/api/import-earthquakes/route.ts
index a42c6fb..bafe541 100644
--- a/src/app/api/import-earthquakes/route.ts
+++ b/src/app/api/import-earthquakes/route.ts
@@ -6,6 +6,7 @@ import { prisma } from "@utils/prisma";
 import { getRandomNumber } from "@utils/maths";
 
 const csvFilePath = path.resolve(process.cwd(), "public/earthquakes.csv");
+const DISTANCE_THRESHOLD_KM = 500; // Max distance for observatory matching
 
 type CsvRow = {
 	Date: string;
@@ -18,6 +19,18 @@ type CsvRow = {
 	Depth: string;
 };
 
+// Haversine formula to calculate distance between two points (in km)
+function getDistance(lat1: number, lon1: number, lat2: number, lon2: number): number {
+	const R = 6371; // Earth's radius in km
+	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 async function POST() {
 	try {
 		const fileContent = await fs.readFile(csvFilePath, "utf8");
@@ -28,12 +41,15 @@ export async function POST() {
 
 		const failedImports: { row: CsvRow; reason: string }[] = [];
 
+		// Fetch all observatories once to avoid repeated queries
+		const observatories = await prisma.observatory.findMany({
+			select: { id: true, latitude: true, longitude: true },
+		});
+
 		const earthquakes = await Promise.all(
 			records.map(async (row) => {
 				const creators = await prisma.user.findMany({
-					where: {
-						role: { in: ["SCIENTIST", "ADMIN"] },
-					},
+					where: { role: { in: ["SCIENTIST", "ADMIN"] } },
 				});
 				const randomCreator = creators.length > 0 ? creators[getRandomNumber(0, creators.length - 1)] : null;
 
@@ -42,16 +58,43 @@ export async function POST() {
 					return null;
 				}
 
+				const eqLat = parseFloat(row.Latitude);
+				const eqLon = parseFloat(row.Longitude);
+
+				// Find observatories within distance threshold
+				let nearbyObservatories = observatories
+					.map((obs) => ({
+						id: obs.id,
+						distance: getDistance(eqLat, eqLon, obs.latitude, obs.longitude),
+					}))
+					.filter((obs) => obs.distance <= DISTANCE_THRESHOLD_KM)
+					.map((obs) => ({ id: obs.id }));
+
+				// If no observatories within range, find the nearest one
+				if (nearbyObservatories.length === 0) {
+					const nearest = observatories.reduce(
+						(min, obs) => {
+							const distance = getDistance(eqLat, eqLon, obs.latitude, obs.longitude);
+							return distance < min.distance ? { id: obs.id, distance } : min;
+						},
+						{ id: -1, distance: Infinity }
+					);
+					if (nearest.id !== -1) {
+						nearbyObservatories = [{ id: nearest.id }];
+					}
+				}
+
 				return {
 					date: new Date(row.Date),
 					code: row.Code,
 					magnitude: parseFloat(row.Magnitude),
 					type: row.Type,
-					latitude: parseFloat(row.Latitude),
-					longitude: parseFloat(row.Longitude),
+					latitude: eqLat,
+					longitude: eqLon,
 					location: row.Location,
 					depth: row.Depth,
 					creatorId: randomCreator.id,
+					observatories: { connect: nearbyObservatories },
 				};
 			})
 		);
@@ -60,6 +103,7 @@ export async function POST() {
 			(earthquake): earthquake is NonNullable<typeof earthquake> => earthquake !== null
 		);
 
+		// Bulk insert earthquakes with observatory connections
 		await prisma.earthquake.createMany({
 			data: validEarthquakes,
 		});