Feat(util function): 사용자 위치와 관련된 유틸 함수 구현

- 위치 정보를 허용하는지, 사용자가 학교 내부에 있는지 확인하는 함수 구현

src/utils/map/user-location.ts

@@ -0,0 +1,34 @@
+import { NO_PROVIDE_LOCATION, PKNU_MAP_CENTER } from '@constants/pknu-map';
+import { Location } from '@type/map';
+
+const degreeToRadian = (deg: number) => deg * (Math.PI / 180);
+
+const getHaversineDistance = (lat: number, lng: number) => {
+  const R = 6371000;
+
+  const dLat = degreeToRadian(PKNU_MAP_CENTER.LAT - lat);
+  const dLon = degreeToRadian(PKNU_MAP_CENTER.LNG - lng);
+
+  const halfSideLength =
+    Math.sin(dLat / 2) * Math.sin(dLat / 2) +
+    Math.cos(degreeToRadian(PKNU_MAP_CENTER.LAT)) *
+      Math.cos(degreeToRadian(lat)) *
+      Math.sin(dLon / 2) *
+      Math.sin(dLon / 2);
+
+  const angularDistance =
+    2 * Math.atan2(Math.sqrt(halfSideLength), Math.sqrt(1 - halfSideLength));
+
+  return R * angularDistance;
+};
+
+export const hasLocationPermission = (location: Location | null) => {
+  return (
+    location && JSON.stringify(location) !== JSON.stringify(NO_PROVIDE_LOCATION)
+  );
+};
+
+export const isUserInShcool = (lat: number, lng: number) => {
+  const maxDistance = 450;
+  return getHaversineDistance(lat, lng) <= maxDistance;
+};