Feat: S2 기반 위치 관리 기능 구현

build.gradle

@@ -22,6 +22,7 @@ configurations {
 
 repositories {
 	mavenCentral()
+	maven { url 'https://jitpack.io' }
 }
 
 dependencies {
@@ -60,6 +61,9 @@ dependencies {
 	implementation 'dev.langchain4j:langchain4j:1.0.0-beta1'
 	implementation 'dev.langchain4j:langchain4j-google-ai-gemini:1.0.0-beta1'
 
+	// S2
+	implementation 'com.github.google:s2-geometry-library-java:2.0.0'
+
 	// etc
 	implementation group: 'org.springdoc', name: 'springdoc-openapi-starter-webmvc-ui', version: '2.7.0'
 	implementation 'net.javacrumbs.shedlock:shedlock-spring:5.1.0'

src/main/java/com/knu/ddip/common/exception/GlobalExceptionHandler.java

@@ -1,6 +1,7 @@
 package com.knu.ddip.common.exception;
 
 import com.knu.ddip.auth.exception.*;
+import com.knu.ddip.location.exception.LocationNotFoundException;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.HttpStatusCode;
 import org.springframework.http.ProblemDetail;
@@ -67,4 +68,12 @@ public ResponseEntity<ProblemDetail> handleTokenStolenException(TokenStolenExcep
         return ResponseEntity.status(HttpStatusCode.valueOf(462)).body(problemDetail);
     }
 
+    @ExceptionHandler(LocationNotFoundException.class)
+    public ResponseEntity<ProblemDetail> handleLocationNotFoundException(LocationNotFoundException e) {
+
+        ProblemDetail problemDetail = ProblemDetail.forStatusAndDetail(HttpStatus.NOT_FOUND, e.getMessage());
+        problemDetail.setTitle("Location Not Found");
+        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(problemDetail);
+    }
+
 }

src/main/java/com/knu/ddip/location/application/dto/GetNeighborsRequest.java

@@ -0,0 +1,20 @@
+package com.knu.ddip.location.application.dto;
+
+import lombok.Builder;
+
+import java.util.UUID;
+
+@Builder
+public record GetNeighborsRequest(
+        UUID userId, // 테스트용 파라미터
+        double lat,
+        double lng
+) {
+    public static GetNeighborsRequest of(UUID userId, double lat, double lng) {
+        return GetNeighborsRequest.builder()
+                .userId(userId)
+                .lat(lat)
+                .lng(lng)
+                .build();
+    }
+}

src/main/java/com/knu/ddip/location/application/dto/UpdateMyLocationRequest.java

@@ -0,0 +1,20 @@
+package com.knu.ddip.location.application.dto;
+
+import lombok.Builder;
+
+import java.util.UUID;
+
+@Builder
+public record UpdateMyLocationRequest(
+        UUID userId, // 테스트용 파라미터
+        double lat,
+        double lng
+) {
+    public static UpdateMyLocationRequest of(UUID userId, double lat, double lng) {
+        return UpdateMyLocationRequest.builder()
+                .userId(userId)
+                .lat(lat)
+                .lng(lng)
+                .build();
+    }
+}

src/main/java/com/knu/ddip/location/application/scheduler/LocationScheduler.java

@@ -0,0 +1,59 @@
+package com.knu.ddip.location.application.scheduler;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.data.redis.connection.RedisConnection;
+import org.springframework.data.redis.connection.RedisConnectionFactory;
+import org.springframework.data.redis.core.Cursor;
+import org.springframework.data.redis.core.RedisTemplate;
+import org.springframework.data.redis.core.ScanOptions;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Component;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Set;
+
+@Component
+@RequiredArgsConstructor
+public class LocationScheduler {
+
+    private final RedisTemplate redisTemplate;
+
+    @Scheduled(cron = "0 0 * * * *") // 매 정시
+    public void cleanupExpiredUserLocations() {
+        long now = System.currentTimeMillis();
+        ScanOptions scan = ScanOptions.scanOptions()
+                .match("cell:*:expiry")
+                .build();
+
+        RedisConnectionFactory connectionFactory = redisTemplate.getConnectionFactory();
+
+        if (connectionFactory == null) return;
+
+        try (
+                RedisConnection conn = connectionFactory.getConnection();
+                Cursor<byte[]> cursor = conn.keyCommands().scan(scan)
+        ) {
+            while (cursor.hasNext()) {
+                // 1. key 생성
+                byte[] expiryKey = cursor.next();
+                String expiryKeyStr = new String(expiryKey, StandardCharsets.UTF_8);
+                String usersKeyStr = expiryKeyStr.replace(":expiry", ":users");
+                byte[] usersKey = usersKeyStr.getBytes(StandardCharsets.UTF_8);
+
+                // 2. 만료된 멤버 수집 (-inf ~ now)
+                Set<byte[]> expired = conn.zSetCommands()
+                        .zRangeByScore(expiryKey, Double.NEGATIVE_INFINITY, (double) now);
+                if (expired == null || expired.isEmpty()) continue;
+
+                // 3. 파이프라인으로 SREM + ZREM
+                conn.openPipeline();
+                for (byte[] member : expired) {
+                    conn.sRem(usersKey, member);                 // SET에서 제거
+                    conn.zSetCommands().zRem(expiryKey, member); // ZSET에서도 제거
+                }
+                conn.closePipeline();
+            }
+        }
+    }
+
+}

src/main/java/com/knu/ddip/location/application/service/LocationRepository.java

@@ -0,0 +1,24 @@
+package com.knu.ddip.location.application.service;
+
+import java.util.List;
+import java.util.Optional;
+
+public interface LocationRepository {
+    void deleteAll();
+
+    void saveAll(List<String> cellIds);
+
+    Optional<String> findCellIdByUserId(String encodedUserId);
+
+    void deleteUserIdByCellId(String encodedUserId, String cellIdByUserId);
+
+    void saveUserIdByCellId(String encodedUserId, String cellId);
+
+    void saveCellIdByUserId(String encodedUserId, String cellId);
+
+    void validateLocationByCellId(String cellId);
+
+    List<String> findAllLocationsByCellIdIn(List<String> cellIds);
+
+    List<String> findUserIdsByCellId(String targetCellId);
+}

src/main/java/com/knu/ddip/location/application/service/LocationService.java

@@ -0,0 +1,146 @@
+package com.knu.ddip.location.application.service;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.common.geometry.S2CellId;
+import com.knu.ddip.location.application.dto.UpdateMyLocationRequest;
+import com.knu.ddip.location.application.util.S2Converter;
+import com.knu.ddip.location.application.util.UuidBase64Utils;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
+
+@Slf4j
+@Service
+@Transactional(readOnly = true)
+@RequiredArgsConstructor
+public class LocationService {
+
+    private final LocationRepository locationRepository;
+
+    private final ObjectMapper objectMapper;
+
+    public static final int LEVEL = 17;
+    public static final String KNU_GEOJSON_FEATURE_FILENAME = "geojson/cells.geojson";
+
+    // KNU GeoJSON 파일을 읽어서 각 Feature를 DB에 저장
+    @Transactional
+    public void loadAndSaveGeoJsonFeatures() {
+        try {
+            // resources 폴더에서 파일 읽기
+            ClassPathResource resource = new ClassPathResource(KNU_GEOJSON_FEATURE_FILENAME);
+            String geoJsonContent = new String(Files.readAllBytes(resource.getFile().toPath()));
+
+            // 기존 데이터 삭제
+            locationRepository.deleteAll();
+
+            // JSON 파싱
+            JsonNode rootNode = objectMapper.readTree(geoJsonContent);
+            JsonNode featuresNode = rootNode.get("features");
+            List<String> cellIds = StreamSupport.stream(featuresNode.spliterator(), false)
+                    .map(featureNode -> featureNode.get("properties").get("id").asText())
+                    .collect(Collectors.toList());
+
+            locationRepository.saveAll(cellIds);
+
+            log.info("총 {}개의 S2Cell Feature가 저장되었습니다.", cellIds.size());
+        } catch (IOException e) {
+            e.printStackTrace();
+            log.error(e.getMessage());
+        }
+    }
+
+    public void saveUserLocation(UUID userId, UpdateMyLocationRequest request) {
+        S2CellId cellIdObj = S2Converter.toCellId(request.lat(), request.lng(), LEVEL);
+        String cellId = cellIdObj.toToken();
+
+        String encodedUserId = UuidBase64Utils.uuidToBase64String(userId);
+
+        // 이전 유저 위치 정보 삭제 후 저장
+        // 예전 위치 있으면 -> 현재 위치와 다르면 삭제 후 저장
+        // 예전 위치 있으면 -> 현재 위치와 같으면 바로 리턴
+        // 예전 위치 없으면 -> 저장
+
+        // 예전 위치 있으면
+        Optional<String> cellIdByUserIdOptional = locationRepository.findCellIdByUserId(encodedUserId);
+        if (cellIdByUserIdOptional.isPresent()) {
+            String cellIdByUserId = cellIdByUserIdOptional.get();
+            // 현재 위치와 같으면 바로 리턴
+            if (cellId.equals(cellIdByUserId)) return;
+            // 이전 위치 삭제
+            locationRepository.deleteUserIdByCellId(encodedUserId, cellIdByUserId);
+        }
+
+        // 경북대 내부에 위치하는지 확인
+        locationRepository.validateLocationByCellId(cellId);
+
+        // 현재 위치 저장
+        // 유저의 현재 cellId 저장
+        locationRepository.saveCellIdByUserId(encodedUserId, cellId);
+        // 현재 cellId에 포함된 유저 저장
+        locationRepository.saveUserIdByCellId(encodedUserId, cellId);
+    }
+
+    // 요청 전송 시 이웃 userIds 조회
+    public List<UUID> getNeighborRecipientUserIds(UUID myUserId, double lat, double lng) {
+        S2CellId cellIdObj = S2Converter.toCellId(lat, lng, LEVEL);
+        String cellId = cellIdObj.toToken();
+
+        // 경북대 내부에 위치하는지 확인
+        locationRepository.validateLocationByCellId(cellId);
+
+        // 이웃 cellIds 가져오기
+        List<S2CellId> neighbors = new ArrayList<>();
+        cellIdObj.getAllNeighbors(LEVEL, neighbors);
+        List<String> neighborCellIds = neighbors.stream()
+                .map(S2CellId::toToken)
+                .collect(Collectors.toList());
+
+        // 경북대 내부에 위치하는 이웃 cellIds만 가져오기
+        List<String> targetCellIds = locationRepository.findAllLocationsByCellIdIn(neighborCellIds);
+        targetCellIds.add(cellId);
+
+        // targetCellId의 userIds만 가져오기
+        List<UUID> userIds = targetCellIds.stream()
+                .map(locationRepository::findUserIdsByCellId)
+                .flatMap(List::stream)
+                .map(UuidBase64Utils::base64StringToUuid)
+                .filter(userId -> !userId.equals(myUserId))
+                .collect(Collectors.toList());
+
+        return userIds;
+    }
+
+    // 초기 화면에서 인접한 요청 가져오기 (현재는 인접한 cellId 가져오는 것만 구현)
+    public List<String> getNeighborCellIds(double lat, double lng) {
+        S2CellId cellIdObj = S2Converter.toCellId(lat, lng, LEVEL);
+        String cellId = cellIdObj.toToken();
+
+        // 경북대 내부에 위치하는지 확인
+        locationRepository.validateLocationByCellId(cellId);
+
+        // 이웃 cellIds 가져오기
+        List<S2CellId> neighbors = new ArrayList<>();
+        cellIdObj.getAllNeighbors(LEVEL, neighbors);
+        List<String> neighborCellIds = neighbors.stream()
+                .map(S2CellId::toToken)
+                .collect(Collectors.toList());
+
+        // 경북대 내부에 위치하는 이웃 cellIds만 가져오기
+        List<String> targetCellIds = locationRepository.findAllLocationsByCellIdIn(neighborCellIds);
+        targetCellIds.add(cellId);
+
+        return targetCellIds;
+    }
+}

src/main/java/com/knu/ddip/location/application/util/S2Converter.java

@@ -0,0 +1,12 @@
+package com.knu.ddip.location.application.util;
+
+import com.google.common.geometry.S2CellId;
+import com.google.common.geometry.S2LatLng;
+
+public abstract class S2Converter {
+
+    public static S2CellId toCellId(double lat, double lng, int level) {
+        S2LatLng latLng = S2LatLng.fromDegrees(lat, lng);
+        return S2CellId.fromLatLng(latLng).parent(level);
+    }
+}

src/main/java/com/knu/ddip/location/application/util/UuidBase64Utils.java

@@ -0,0 +1,27 @@
+package com.knu.ddip.location.application.util;
+
+import java.nio.ByteBuffer;
+import java.util.Base64;
+import java.util.UUID;
+
+import static java.util.Base64.getUrlDecoder;
+import static java.util.Base64.getUrlEncoder;
+
+public abstract class UuidBase64Utils {
+
+    private static final Base64.Encoder B64_URL = getUrlEncoder().withoutPadding();
+    private static final Base64.Decoder B64_DEC = getUrlDecoder();
+
+    public static String uuidToBase64String(UUID uuid) {
+        ByteBuffer bb = ByteBuffer.allocate(16)
+                .putLong(uuid.getMostSignificantBits())
+                .putLong(uuid.getLeastSignificantBits());
+        return B64_URL.encodeToString(bb.array());
+    }
+
+    public static UUID base64StringToUuid(String string) {
+        byte[] bytes = B64_DEC.decode(string);
+        ByteBuffer bb = ByteBuffer.wrap(bytes);
+        return new UUID(bb.getLong(), bb.getLong());
+    }
+}

src/main/java/com/knu/ddip/location/exception/LocationNotFoundException.java

@@ -0,0 +1,7 @@
+package com.knu.ddip.location.exception;
+
+public class LocationNotFoundException extends RuntimeException {
+    public LocationNotFoundException(String message) {
+        super(message);
+    }
+}

src/main/java/com/knu/ddip/location/infrastructure/entity/LocationEntity.java

@@ -0,0 +1,35 @@
+package com.knu.ddip.location.infrastructure.entity;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+import lombok.*;
+import org.springframework.data.domain.Persistable;
+
+@Entity
+@Getter
+@Builder
+@AllArgsConstructor(access = AccessLevel.PRIVATE)
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@Table(name = "LOCATIONS")
+public class LocationEntity implements Persistable<String> {
+
+    @Id
+    private String cellId;
+
+    public static LocationEntity create(String cellId) {
+        return LocationEntity.builder()
+                .cellId(cellId)
+                .build();
+    }
+
+    @Override
+    public String getId() {
+        return cellId;
+    }
+
+    @Override
+    public boolean isNew() {
+        return cellId == null;
+    }
+}