feat: 인기 게시글 기능 구현 완료

src/main/java/page/clab/api/domain/community/board/adapter/in/web/HotBoardsRetrievalController.java

@@ -0,0 +1,36 @@
+package page.clab.api.domain.community.board.adapter.in.web;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import lombok.RequiredArgsConstructor;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+import page.clab.api.domain.community.board.application.dto.response.BoardListResponseDto;
+import page.clab.api.domain.community.board.application.port.in.RetrieveHotBoardsUseCase;
+import page.clab.api.global.common.dto.ApiResponse;
+
+import java.util.List;
+
+@RestController
+@RequestMapping("/api/v1/boards")
+@RequiredArgsConstructor
+@Tag(name = "Community - Board", description = "커뮤니티 게시판")
+public class HotBoardsRetrievalController {
+
+    private final RetrieveHotBoardsUseCase retrieveHotBoardsUseCase;
+
+    @Operation(summary = "[G] 커뮤니티 인기 게시글 목록 조회", description = "ROLE_GUEST 이상의 권한이 필요함<br>" +
+            "인기게시글 선정 전략별 조회가 가능함<br>" +
+            "- DEFAULT : 반응 순 기본 전략<br>")
+    @PreAuthorize("hasRole('GUEST')")
+    @GetMapping("/hot")
+    public ApiResponse<List<BoardListResponseDto>> retrieveHotBoards(
+            @RequestParam(name = "strategyName", defaultValue = "DEFAULT") String strategyName
+    ) {
+        List<BoardListResponseDto> boards = retrieveHotBoardsUseCase.retrieveHotBoards(strategyName);
+        return ApiResponse.success(boards);
+    }
+}

src/main/java/page/clab/api/domain/community/board/adapter/out/persistence/BoardPersistenceAdapter.java

@@ -10,6 +10,10 @@
 import page.clab.api.domain.community.board.domain.BoardCategory;
 import page.clab.api.global.exception.NotFoundException;
 
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.stream.Collectors;
+
 @Component
 @RequiredArgsConstructor
 public class BoardPersistenceAdapter implements
@@ -40,6 +44,20 @@ public Board findByIdRegardlessOfDeletion(Long boardId) {
                 .orElseThrow(() -> new NotFoundException("[Board] id: " + boardId + "에 해당하는 게시글이 존재하지 않습니다."));
     }
 
+    @Override
+    public List<Board> findAllWithinDateRange(LocalDateTime startDate, LocalDateTime endDate) {
+        return boardRepository.findAllWithinDateRange(startDate, endDate).stream()
+                .map(boardMapper::toDomain)
+                .collect(Collectors.toList());
+    }
+
+    @Override
+    public List<Board> findAll() {
+        return boardRepository.findAll().stream()
+                .map(boardMapper::toDomain)
+                .collect(Collectors.toList());
+    }
+
     @Override
     public Page<Board> findAllByCategory(BoardCategory category, Pageable pageable) {
         return boardRepository.findAllByCategory(category, pageable)

src/main/java/page/clab/api/domain/community/board/adapter/out/persistence/BoardRepository.java

@@ -1,5 +1,6 @@
 package page.clab.api.domain.community.board.adapter.out.persistence;
 
+import java.time.LocalDateTime;
 import java.util.List;
 import java.util.Optional;
 import org.springframework.data.domain.Page;
@@ -16,6 +17,9 @@ public interface BoardRepository extends JpaRepository<BoardJpaEntity, Long> {
     @Query("SELECT b FROM BoardJpaEntity b WHERE b.memberId = ?1 AND b.isDeleted = false")
     Page<BoardJpaEntity> findAllByMemberIdAndIsDeletedFalse(String memberId, Pageable pageable);
 
+    @Query("SELECT b FROM BoardJpaEntity b WHERE b.createdAt BETWEEN :start AND :end AND b.isDeleted = false")
+    List<BoardJpaEntity> findAllWithinDateRange(LocalDateTime start, LocalDateTime end);
+
     Page<BoardJpaEntity> findAllByCategory(BoardCategory category, Pageable pageable);
 
     @Query(value = "SELECT b.* FROM board b WHERE b.is_deleted = true", nativeQuery = true)

src/main/java/page/clab/api/domain/community/board/adapter/out/persistence/RedisHotBoardPersistenceAdapter.java

@@ -0,0 +1,58 @@
+package page.clab.api.domain.community.board.adapter.out.persistence;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.data.redis.core.RedisTemplate;
+import org.springframework.stereotype.Component;
+import page.clab.api.domain.community.board.application.port.out.RegisterHotBoardPort;
+import page.clab.api.domain.community.board.application.port.out.RemoveHotBoardPort;
+import page.clab.api.domain.community.board.application.port.out.RetrieveHotBoardPort;
+
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+
+@Component
+@RequiredArgsConstructor
+public class RedisHotBoardPersistenceAdapter implements
+        RegisterHotBoardPort,
+        RetrieveHotBoardPort,
+        RemoveHotBoardPort {
+
+    private static final String HOT_BOARDS_PREFIX = "hotBoards";
+
+    private final RedisTemplate<String, String> redisTemplate;
+
+    @Override
+    public void save(String boardId, String strategyName) {
+        String key = getRedisKey(strategyName);
+        redisTemplate.opsForList().rightPush(key, boardId);
+    }
+
+    @Override
+    public List<String> findByHotBoardStrategy(String strategyName) {
+        String key = getRedisKey(strategyName);
+        List<String> hotBoards = redisTemplate.opsForList().range(key, 0, -1);
+        return (hotBoards != null) ? hotBoards : List.of();
+    }
+
+    @Override
+    public void clearHotBoard() {
+        String pattern = HOT_BOARDS_PREFIX + ":*";
+        Set<String> keys = redisTemplate.keys(pattern);
+        if (keys == null) {
+            return;
+        }
+        keys.stream()
+                .filter(Objects::nonNull)
+                .forEach(key -> {
+                    Long size = redisTemplate.opsForList().size(key);
+                    if (size != null && size > 0) {
+                        redisTemplate.delete(key);
+                    }
+                });
+    }
+
+    private String getRedisKey(String strategyName) {
+        return String.format("%s:%s", HOT_BOARDS_PREFIX, strategyName);
+    }
+}

src/main/java/page/clab/api/domain/community/board/application/port/in/RetrieveHotBoardsUseCase.java

@@ -0,0 +1,9 @@
+package page.clab.api.domain.community.board.application.port.in;
+
+import page.clab.api.domain.community.board.application.dto.response.BoardListResponseDto;
+
+import java.util.List;
+
+public interface RetrieveHotBoardsUseCase {
+    List<BoardListResponseDto> retrieveHotBoards(String strategyName);
+}

src/main/java/page/clab/api/domain/community/board/application/port/out/RegisterHotBoardPort.java

@@ -0,0 +1,5 @@
+package page.clab.api.domain.community.board.application.port.out;
+
+public interface RegisterHotBoardPort {
+    void save(String boardId, String strategyName);
+}

src/main/java/page/clab/api/domain/community/board/application/port/out/RemoveHotBoardPort.java

@@ -0,0 +1,5 @@
+package page.clab.api.domain.community.board.application.port.out;
+
+public interface RemoveHotBoardPort {
+    void clearHotBoard();
+}

src/main/java/page/clab/api/domain/community/board/application/port/out/RetrieveBoardPort.java

@@ -5,12 +5,19 @@
 import page.clab.api.domain.community.board.domain.Board;
 import page.clab.api.domain.community.board.domain.BoardCategory;
 
+import java.time.LocalDateTime;
+import java.util.List;
+
 public interface RetrieveBoardPort {
 
     Board getById(Long boardId);
 
     Board findByIdRegardlessOfDeletion(Long boardId);
 
+    List<Board> findAllWithinDateRange(LocalDateTime startDate, LocalDateTime endDate);
+
+    List<Board> findAll();
+
     Page<Board> findAll(Pageable pageable);
 
     Page<Board> findAllByCategory(BoardCategory category, Pageable pageable);

src/main/java/page/clab/api/domain/community/board/application/port/out/RetrieveHotBoardPort.java

@@ -0,0 +1,7 @@
+package page.clab.api.domain.community.board.application.port.out;
+
+import java.util.List;
+
+public interface RetrieveHotBoardPort {
+    List<String> findByHotBoardStrategy(String strategyName);
+}

src/main/java/page/clab/api/domain/community/board/application/service/DefaultHotBoardSelectionStrategy.java

@@ -0,0 +1,87 @@
+package page.clab.api.domain.community.board.application.service;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+import page.clab.api.domain.community.board.application.port.out.RetrieveBoardEmojiPort;
+import page.clab.api.domain.community.board.application.port.out.RetrieveBoardPort;
+import page.clab.api.domain.community.board.domain.Board;
+import page.clab.api.domain.community.board.domain.HotBoardSelectionStrategies;
+import page.clab.api.external.community.comment.application.port.ExternalRetrieveCommentUseCase;
+
+import java.time.DayOfWeek;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.Collectors;
+
+@Service(HotBoardSelectionStrategies.DEFAULT)
+@RequiredArgsConstructor
+public class DefaultHotBoardSelectionStrategy implements HotBoardSelectionStrategy {
+
+    private final RetrieveBoardPort retrieveBoardPort;
+    private final RetrieveBoardEmojiPort retrieveBoardEmojiPort;
+    private final ExternalRetrieveCommentUseCase externalRetrieveCommentUseCase;
+
+    @Transactional
+    @Override
+    public List<Board> getHotBoards() {
+        // 만약 게시글의 총 개수가 5개보다 적다면 모든 게시글 반환
+        List<Board> allBoards = retrieveBoardPort.findAll();
+        if (allBoards.size() < 5) {
+            return sortBoardsByReactionAndDateWithLimit(allBoards.size(), allBoards);
+        }
+
+        List<Board> hotBoards = getHotBoardsForWeek(1, 5);
+
+        int weeksAgo = 2;
+        // 필요한 수량을 확보할 때까지 반복해서 이전 주로 이동하여 인기 게시글 보충
+        while (hotBoards.size() < 5) {
+            List<Board> additionalBoards = getLatestHotBoardForWeek(weeksAgo++, 5 - hotBoards.size());
+            if (additionalBoards != null && !additionalBoards.isEmpty()) {
+                hotBoards.addAll(additionalBoards);
+            }
+        }
+
+        return hotBoards;
+    }
+
+    private List<Board> getHotBoardsForWeek(int weeksAgo, int size) {
+        LocalDateTime startOfWeek = LocalDate.now().minusWeeks(weeksAgo).with(DayOfWeek.MONDAY).atStartOfDay();
+        LocalDateTime endOfWeek = LocalDate.now().minusWeeks(weeksAgo).with(DayOfWeek.SUNDAY).atTime(23, 59, 59);
+
+        List<Board> boardsForWeek = retrieveBoardPort.findAllWithinDateRange(startOfWeek, endOfWeek);
+
+        return sortBoardsByReactionAndDateWithLimit(size, boardsForWeek);
+    }
+
+    private List<Board> sortBoardsByReactionAndDateWithLimit(int size, List<Board> boardsForWeek) {
+        if (boardsForWeek == null) {
+            return null;
+        }
+
+        return boardsForWeek.stream()
+                .sorted(Comparator
+                        .comparingInt(this::getTotalReactionCount).reversed()
+                        .thenComparing(Board::getCreatedAt, Comparator.reverseOrder()))
+                .limit(size)
+                .collect(Collectors.toList());
+    }
+
+    private List<Board> getLatestHotBoardForWeek(int weeksAgo, int size) {
+
+        List<Board> topHotBoardsForWeek = getHotBoardsForWeek(weeksAgo, size);
+
+        return topHotBoardsForWeek.stream()
+                .sorted(Comparator.comparing(Board::getCreatedAt).reversed())
+                .toList();
+    }
+
+    private int getTotalReactionCount(Board board) {
+        Long commentCount = externalRetrieveCommentUseCase.countByBoardId(board.getId());
+        int emojiCount = retrieveBoardEmojiPort.findEmojiClickCountsByBoardId(board.getId(), null).size();
+
+        return commentCount.intValue() + emojiCount;
+    }
+}

src/main/java/page/clab/api/domain/community/board/application/service/HotBoardRegisterService.java

@@ -0,0 +1,63 @@
+package page.clab.api.domain.community.board.application.service;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+import page.clab.api.domain.community.board.application.port.out.RegisterHotBoardPort;
+import page.clab.api.domain.community.board.application.port.out.RemoveHotBoardPort;
+import page.clab.api.domain.community.board.domain.Board;
+import page.clab.api.domain.community.board.domain.HotBoardSelectionStrategies;
+
+import java.util.List;
+import java.util.Map;
+
+@Service
+@RequiredArgsConstructor
+public class HotBoardRegisterService {
+
+    private final Map<String, HotBoardSelectionStrategy> strategyMap;
+    private final RegisterHotBoardPort registerHotBoardPort;
+    private final RemoveHotBoardPort removeHotBoardPort;
+
+    /**
+     * 주어진 전략을 기반으로 인기 게시글을 등록합니다.
+     * <p>
+     * 지정된 전략을 기반으로 인기 게시글을 선정하고, 이를 Redis에 저장합니다.
+     *
+     * @param strategyName 인기 게시글 선정 전략 이름
+     * @return 인기 게시글 ID 리스트
+     */
+    @Transactional
+    public List<String> registerHotBoards(String strategyName) {
+        HotBoardSelectionStrategy strategy = strategyMap.get(strategyName);
+        List<String> hotBoardIds = getHotBoardIds(strategy);
+        hotBoardIds.forEach(id -> registerHotBoardPort.save(id, strategyName));
+        return hotBoardIds;
+    }
+
+    /**
+     * 기본 전략을 이용하여 인기 게시글을 등록합니다.
+     * <p>
+     * 매주 월요일 자정에 실행되도록 스케줄링되어 있습니다. 먼저 기존 인기 게시글을 초기화한 뒤,
+     * 기본 전략을 이용하여 선정된 인기 게시글을 Redis에 저장합니다.
+     */
+    @Transactional
+    @Scheduled(cron = "0 0 0 * * MON") // 매주 월요일 00:00 실행
+    public void registerDefaultHotBoards() {
+        HotBoardSelectionStrategy strategy = strategyMap.get(HotBoardSelectionStrategies.DEFAULT);
+
+        removeHotBoardPort.clearHotBoard(); // 저장된 지난 모든 인기 게시글 초기화
+
+        List<String> hotBoardIds = getHotBoardIds(strategy);
+        hotBoardIds.forEach(id ->
+                registerHotBoardPort.save(id, HotBoardSelectionStrategies.DEFAULT));
+    }
+
+    private static List<String> getHotBoardIds(HotBoardSelectionStrategy strategy) {
+        return strategy.getHotBoards().stream()
+                .map(Board::getId)
+                .map(String::valueOf)
+                .toList();
+    }
+}