[FEAT] 읽은책 캘린더 조회 구현

src/main/java/com/moongeul/backend/api/bookshelf/controller/DoneReadBookshelfController.java

@@ -1,12 +1,14 @@
 package com.moongeul.backend.api.bookshelf.controller;
 
+import com.moongeul.backend.api.bookshelf.dto.DoneReadCalendarResponseDTO;
 import com.moongeul.backend.api.bookshelf.dto.DoneReadBookshelfResponseDTO;
 import com.moongeul.backend.api.bookshelf.service.DoneReadBookshelfService;
 import com.moongeul.backend.common.response.ApiResponse;
 import com.moongeul.backend.common.response.SuccessStatus;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.responses.ApiResponses;
 import io.swagger.v3.oas.annotations.tags.Tag;
+import jakarta.validation.constraints.Max;
 import jakarta.validation.constraints.Min;
 import lombok.RequiredArgsConstructor;
 import org.springframework.http.ResponseEntity;
@@ -42,5 +44,25 @@ public ResponseEntity<ApiResponse<DoneReadBookshelfResponseDTO>> getDoneReadBook
         DoneReadBookshelfResponseDTO doneReadBookshelfResponseDTO = doneReadBookshelfService.getDoneReadBooks(userDetails.getUsername(), page, size);
         return ApiResponse.success(SuccessStatus.GET_DONE_READ_BOOKS_SUCCESS, doneReadBookshelfResponseDTO);
     }
-}
 
+    @Operation(
+            summary = "읽은 책 캘린더 조회 API",
+            description = "입력한 연/월 기준으로 일자별 읽은 책 정보를 조회합니다. " +
+                    "같은 날짜에 여러 권이 있으면 가장 최근에 작성된 기록의 표지를 대표로 반환하고 count로 개수를 제공합니다."
+    )
+    @ApiResponses({
+            @io.swagger.v3.oas.annotations.responses.ApiResponse(responseCode = "200", description = "읽은 책 캘린더 조회 성공"),
+            @io.swagger.v3.oas.annotations.responses.ApiResponse(responseCode = "400", description = "잘못된 요청 파라미터"),
+            @io.swagger.v3.oas.annotations.responses.ApiResponse(responseCode = "404", description = "사용자를 찾을 수 없습니다.")
+    })
+    @GetMapping("/calendar")
+    public ResponseEntity<ApiResponse<DoneReadCalendarResponseDTO>> getDoneReadCalendar(
+            @AuthenticationPrincipal UserDetails userDetails,
+            @RequestParam @Min(value = 1, message = "연도는 1 이상이어야 합니다.") Integer year,
+            @RequestParam @Min(value = 1, message = "월은 1 이상이어야 합니다.") @Max(value = 12, message = "월은 12 이하여야 합니다.") Integer month) {
+
+        DoneReadCalendarResponseDTO doneReadCalendar = doneReadBookshelfService.getDoneReadCalendar(
+                userDetails.getUsername(), year, month);
+        return ApiResponse.success(SuccessStatus.GET_DONE_READ_CALENDAR_SUCCESS, doneReadCalendar);
+    }
+}

src/main/java/com/moongeul/backend/api/bookshelf/dto/DoneReadCalendarDayDTO.java

@@ -0,0 +1,18 @@
+package com.moongeul.backend.api.bookshelf.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+public class DoneReadCalendarDayDTO {
+    private Integer day; // 일자
+    private Long postId; // 대표 기록 ID
+    private String isbn; // 대표 도서 ISBN
+    private String bookImage; // 대표 도서 표지
+    private Integer count; // 해당 일자의 읽은 책 수
+}

src/main/java/com/moongeul/backend/api/bookshelf/dto/DoneReadCalendarResponseDTO.java

@@ -0,0 +1,18 @@
+package com.moongeul.backend.api.bookshelf.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+import java.util.List;
+
+@Getter
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+public class DoneReadCalendarResponseDTO {
+    private Integer year; // 조회 연도
+    private Integer month; // 조회 월
+    private List<DoneReadCalendarDayDTO> data; // 일자별 캘린더 데이터
+}

src/main/java/com/moongeul/backend/api/bookshelf/service/DoneReadBookshelfService.java

@@ -1,12 +1,16 @@
 package com.moongeul.backend.api.bookshelf.service;
 
 import com.moongeul.backend.api.book.entity.Book;
+import com.moongeul.backend.api.bookshelf.dto.DoneReadCalendarDayDTO;
+import com.moongeul.backend.api.bookshelf.dto.DoneReadCalendarResponseDTO;
 import com.moongeul.backend.api.bookshelf.dto.DoneReadBookshelfItemDTO;
 import com.moongeul.backend.api.bookshelf.dto.DoneReadBookshelfResponseDTO;
 import com.moongeul.backend.api.bookshelf.entity.DoneReadBookshelf;
 import com.moongeul.backend.api.bookshelf.repository.DoneReadBookshelfRepository;
 import com.moongeul.backend.api.member.entity.Member;
 import com.moongeul.backend.api.member.repository.MemberRepository;
+import com.moongeul.backend.api.post.entity.Post;
+import com.moongeul.backend.api.post.repository.PostRepository;
 import com.moongeul.backend.common.exception.NotFoundException;
 import com.moongeul.backend.common.response.ErrorStatus;
 import lombok.RequiredArgsConstructor;
@@ -17,7 +21,12 @@
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.YearMonth;
+import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Map;
 
 @Slf4j
 @Service
@@ -26,6 +35,7 @@ public class DoneReadBookshelfService {
 
     private final DoneReadBookshelfRepository doneReadBookshelfRepository;
     private final MemberRepository memberRepository;
+    private final PostRepository postRepository;
 
     @Transactional(readOnly = true)
     public DoneReadBookshelfResponseDTO getDoneReadBooks(String email, Integer page, Integer size) {
@@ -58,6 +68,75 @@ public DoneReadBookshelfResponseDTO getDoneReadBooks(String email, Integer page,
                 .build();
     }
 
+    // 읽은 책 캘린더 조회
+    @Transactional(readOnly = true)
+    public DoneReadCalendarResponseDTO getDoneReadCalendar(String email, Integer year, Integer month) {
+
+        Member member = memberRepository.findByEmail(email)
+                .orElseThrow(() -> new NotFoundException(ErrorStatus.USER_NOTFOUND_EXCEPTION.getMessage()));
+
+        YearMonth yearMonth = YearMonth.of(year, month);
+        LocalDate startDate = yearMonth.atDay(1);
+        LocalDate endDate = yearMonth.atEndOfMonth();
+
+        List<Post> posts = postRepository.findCalendarPostsByMemberAndReadDateBetweenOrderByReadDateAscCreatedAtDesc(
+                member, startDate, endDate);
+
+        Map<LocalDate, CalendarDayAggregate> calendarMap = new LinkedHashMap<>();
+
+        for (Post post : posts) {
+            LocalDate readDate = post.getReadDate();
+            if (readDate == null) {
+                continue;
+            }
+
+            CalendarDayAggregate aggregate = calendarMap.get(readDate);
+            if (aggregate == null) {
+                calendarMap.put(readDate, new CalendarDayAggregate(
+                        post.getId(),
+                        post.getBook().getIsbn(),
+                        post.getBook().getBookImage(),
+                        post.getCreatedAt(),
+                        1
+                ));
+                continue;
+            }
+
+            aggregate.count++;
+            boolean isMoreRecent = aggregate.latestCreatedAt == null
+                    || (post.getCreatedAt() != null && post.getCreatedAt().isAfter(aggregate.latestCreatedAt));
+            boolean isSameTimeButLargerId = post.getCreatedAt() != null
+                    && aggregate.latestCreatedAt != null
+                    && post.getCreatedAt().isEqual(aggregate.latestCreatedAt)
+                    && aggregate.postId != null
+                    && post.getId() != null
+                    && post.getId() > aggregate.postId;
+
+            if (isMoreRecent || isSameTimeButLargerId) {
+                aggregate.postId = post.getId();
+                aggregate.isbn = post.getBook().getIsbn();
+                aggregate.bookImage = post.getBook().getBookImage();
+                aggregate.latestCreatedAt = post.getCreatedAt();
+            }
+        }
+
+        List<DoneReadCalendarDayDTO> calendarData = calendarMap.entrySet().stream()
+                .map(entry -> DoneReadCalendarDayDTO.builder()
+                        .day(entry.getKey().getDayOfMonth())
+                        .postId(entry.getValue().postId)
+                        .isbn(entry.getValue().isbn)
+                        .bookImage(entry.getValue().bookImage)
+                        .count(entry.getValue().count)
+                        .build())
+                .toList();
+
+        return DoneReadCalendarResponseDTO.builder()
+                .year(year)
+                .month(month)
+                .data(calendarData)
+                .build();
+    }
+
     private DoneReadBookshelfItemDTO convertToItemDTO(DoneReadBookshelf doneReadBookshelf) {
         Book book = doneReadBookshelf.getArticle().getBook();
 
@@ -72,5 +151,20 @@ private DoneReadBookshelfItemDTO convertToItemDTO(DoneReadBookshelf doneReadBook
                 .postCount(doneReadBookshelf.getPostCount())
                 .build();
     }
-}
 
+    private static class CalendarDayAggregate {
+        private Long postId;
+        private String isbn;
+        private String bookImage;
+        private LocalDateTime latestCreatedAt;
+        private Integer count;
+
+        private CalendarDayAggregate(Long postId, String isbn, String bookImage, LocalDateTime latestCreatedAt, Integer count) {
+            this.postId = postId;
+            this.isbn = isbn;
+            this.bookImage = bookImage;
+            this.latestCreatedAt = latestCreatedAt;
+            this.count = count;
+        }
+    }
+}

src/main/java/com/moongeul/backend/api/post/repository/PostRepository.java

@@ -1,6 +1,7 @@
 package com.moongeul.backend.api.post.repository;
 
 import com.moongeul.backend.api.book.entity.Book;
+import com.moongeul.backend.api.member.entity.Member;
 import com.moongeul.backend.api.member.entity.ReadingTasteType;
 import com.moongeul.backend.api.post.entity.Post;
 import org.springframework.data.domain.Page;
@@ -9,6 +10,7 @@
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.query.Param;
 
+import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.util.List;
 
@@ -68,4 +70,13 @@ List<Post> findWeeklyRecommendationByReadingTasteType(
     // 카테고리별 기록 조회 (평점 낮은순)
     @Query("SELECT p FROM Post p WHERE p.category.id = :categoryId ORDER BY p.rating ASC, p.createdAt DESC")
     Page<Post> findByCategoryIdOrderByRatingAsc(@Param("categoryId") Long categoryId, Pageable pageable);
+
+    // 읽은 날짜 기준 월별 게시글 조회 (일자 오름차순, 같은 일자 내 최신 작성순)
+    @Query("SELECT p FROM Post p JOIN FETCH p.book " +
+            "WHERE p.member = :member AND p.readDate BETWEEN :startDate AND :endDate " +
+            "ORDER BY p.readDate ASC, p.createdAt DESC")
+    List<Post> findCalendarPostsByMemberAndReadDateBetweenOrderByReadDateAscCreatedAtDesc(
+            @Param("member") Member member,
+            @Param("startDate") LocalDate startDate,
+            @Param("endDate") LocalDate endDate);
 }

src/main/java/com/moongeul/backend/common/response/SuccessStatus.java

@@ -44,6 +44,7 @@ public enum SuccessStatus {
 	REMOVE_WISH_READ_BOOK_SUCCESS(HttpStatus.OK, "읽고 싶은 책 삭제 성공"),
 	GET_WISH_READ_BOOKS_SUCCESS(HttpStatus.OK, "읽고 싶은 책장 조회 성공"),
 	GET_DONE_READ_BOOKS_SUCCESS(HttpStatus.OK, "읽은 책장 조회 성공"),
+	GET_DONE_READ_CALENDAR_SUCCESS(HttpStatus.OK, "읽은 책 캘린더 조회 성공"),
 
 	/* POST */
 	GET_ALL_POST_SUCCESS(HttpStatus.OK, "기록(게시글) 전체 조회 성공"),