Add recent post and comment context APIs

backend/src/main/java/com/openisle/controller/CommentController.java

@@ -1,11 +1,13 @@
 package com.openisle.controller;
 
+import com.openisle.dto.CommentContextDto;
 import com.openisle.dto.CommentDto;
 import com.openisle.dto.CommentRequest;
 import com.openisle.dto.PostChangeLogDto;
 import com.openisle.dto.TimelineItemDto;
 import com.openisle.mapper.CommentMapper;
 import com.openisle.mapper.PostChangeLogMapper;
+import com.openisle.mapper.PostMapper;
 import com.openisle.model.Comment;
 import com.openisle.model.CommentSort;
 import com.openisle.service.*;
@@ -40,6 +42,7 @@ public class CommentController {
   private final PointService pointService;
   private final PostChangeLogService changeLogService;
   private final PostChangeLogMapper postChangeLogMapper;
+  private final PostMapper postMapper;
 
   @Value("${app.captcha.enabled:false}")
   private boolean captchaEnabled;
@@ -184,6 +187,37 @@ public class CommentController {
     return itemDtoList;
   }
 
+  @GetMapping("/comments/{commentId}/context")
+  @Operation(
+    summary = "Comment context",
+    description = "Get a comment along with its previous comments and related post"
+  )
+  @ApiResponse(
+    responseCode = "200",
+    description = "Comment context",
+    content = @Content(schema = @Schema(implementation = CommentContextDto.class))
+  )
+  public ResponseEntity<CommentContextDto> getCommentContext(@PathVariable Long commentId) {
+    log.debug("getCommentContext called for comment {}", commentId);
+    Comment comment = commentService.getComment(commentId);
+    CommentContextDto dto = new CommentContextDto();
+    dto.setPost(postMapper.toSummaryDto(comment.getPost()));
+    dto.setTargetComment(commentMapper.toDtoWithReplies(comment));
+    dto.setPreviousComments(
+      commentService
+        .getCommentsBefore(comment)
+        .stream()
+        .map(commentMapper::toDtoWithReplies)
+        .collect(Collectors.toList())
+    );
+    log.debug(
+      "getCommentContext returning {} previous comments for comment {}",
+      dto.getPreviousComments().size(),
+      commentId
+    );
+    return ResponseEntity.ok(dto);
+  }
+
   @DeleteMapping("/comments/{id}")
   @Operation(summary = "Delete comment", description = "Delete a comment")
   @ApiResponse(responseCode = "200", description = "Deleted")

backend/src/main/java/com/openisle/controller/PostController.java

@@ -224,6 +224,26 @@ public class PostController {
       .collect(Collectors.toList());
   }
 
+  @GetMapping("/recent")
+  @Operation(
+    summary = "Recent posts",
+    description = "List posts created within the specified number of minutes"
+  )
+  @ApiResponse(
+    responseCode = "200",
+    description = "Recent posts",
+    content = @Content(
+      array = @ArraySchema(schema = @Schema(implementation = PostSummaryDto.class))
+    )
+  )
+  public List<PostSummaryDto> recentPosts(@RequestParam("minutes") int minutes) {
+    return postService
+      .listRecentPosts(minutes)
+      .stream()
+      .map(postMapper::toSummaryDto)
+      .collect(Collectors.toList());
+  }
+
   @GetMapping("/ranking")
   @Operation(summary = "Ranking posts", description = "List posts by view rankings")
   @ApiResponse(

backend/src/main/java/com/openisle/dto/CommentContextDto.java

@@ -0,0 +1,15 @@
+package com.openisle.dto;
+
+import java.util.List;
+import lombok.Data;
+
+/**
+ * DTO representing the context of a comment including its post and previous comments.
+ */
+@Data
+public class CommentContextDto {
+
+  private PostSummaryDto post;
+  private CommentDto targetComment;
+  private List<CommentDto> previousComments;
+}

backend/src/main/java/com/openisle/repository/CommentRepository.java

@@ -3,6 +3,7 @@ package com.openisle.repository;
 import com.openisle.model.Comment;
 import com.openisle.model.Post;
 import com.openisle.model.User;
+import java.time.LocalDateTime;
 import java.util.List;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
@@ -10,6 +11,10 @@ import org.springframework.data.jpa.repository.JpaRepository;
 public interface CommentRepository extends JpaRepository<Comment, Long> {
   List<Comment> findByPostAndParentIsNullOrderByCreatedAtAsc(Post post);
   List<Comment> findByParentOrderByCreatedAtAsc(Comment parent);
+  List<Comment> findByPostAndCreatedAtLessThanOrderByCreatedAtAsc(
+    Post post,
+    LocalDateTime createdAt
+  );
   List<Comment> findByAuthorOrderByCreatedAtDesc(User author, Pageable pageable);
   List<Comment> findByContentContainingIgnoreCase(String keyword);
 

backend/src/main/java/com/openisle/repository/PostRepository.java

@@ -19,6 +19,10 @@ public interface PostRepository extends JpaRepository<Post, Long> {
   List<Post> findByStatusOrderByCreatedAtDesc(PostStatus status, Pageable pageable);
   List<Post> findByStatusOrderByViewsDesc(PostStatus status);
   List<Post> findByStatusOrderByViewsDesc(PostStatus status, Pageable pageable);
+  List<Post> findByStatusAndCreatedAtGreaterThanEqualOrderByCreatedAtDesc(
+    PostStatus status,
+    LocalDateTime createdAt
+  );
   List<Post> findByAuthorAndStatusOrderByCreatedAtDesc(
     User author,
     PostStatus status,

backend/src/main/java/com/openisle/service/CommentService.java

@@ -266,6 +266,27 @@ public class CommentService {
     return replies;
   }
 
+  public Comment getComment(Long commentId) {
+    log.debug("getComment called for id {}", commentId);
+    return commentRepository
+      .findById(commentId)
+      .orElseThrow(() -> new com.openisle.exception.NotFoundException("Comment not found"));
+  }
+
+  public List<Comment> getCommentsBefore(Comment comment) {
+    log.debug("getCommentsBefore called for comment {}", comment.getId());
+    List<Comment> comments = commentRepository.findByPostAndCreatedAtLessThanOrderByCreatedAtAsc(
+      comment.getPost(),
+      comment.getCreatedAt()
+    );
+    log.debug(
+      "getCommentsBefore returning {} comments for comment {}",
+      comments.size(),
+      comment.getId()
+    );
+    return comments;
+  }
+
   public List<Comment> getRecentCommentsByUser(String username, int limit) {
     log.debug("getRecentCommentsByUser called for user {} with limit {}", username, limit);
     User user = userRepository

backend/src/main/java/com/openisle/service/PostService.java

@@ -770,6 +770,18 @@ public class PostService {
     return listPostsByCategories(null, null, null);
   }
 
+  public List<Post> listRecentPosts(int minutes) {
+    if (minutes <= 0) {
+      throw new IllegalArgumentException("Minutes must be positive");
+    }
+    LocalDateTime since = LocalDateTime.now().minusMinutes(minutes);
+    List<Post> posts = postRepository.findByStatusAndCreatedAtGreaterThanEqualOrderByCreatedAtDesc(
+      PostStatus.PUBLISHED,
+      since
+    );
+    return sortByPinnedAndCreated(posts);
+  }
+
   public List<Post> listPostsByViews(Integer page, Integer pageSize) {
     return listPostsByViews(null, null, page, pageSize);
   }