refactor: extract post dtos

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

@@ -0,0 +1,14 @@
+package com.openisle.dto;
+
+import lombok.Data;
+
+/**
+ * DTO representing a post or comment author.
+ */
+@Data
+public class AuthorDto {
+    private Long id;
+    private String username;
+    private String avatar;
+}
+

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

@@ -0,0 +1,16 @@
+package com.openisle.dto;
+
+import lombok.Data;
+
+/**
+ * DTO representing a post category.
+ */
+@Data
+public class CategoryDto {
+    private Long id;
+    private String name;
+    private String description;
+    private String icon;
+    private String smallIcon;
+}
+

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

@@ -0,0 +1,21 @@
+package com.openisle.dto;
+
+import lombok.Data;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+/**
+ * DTO representing a comment and its nested replies.
+ */
+@Data
+public class CommentDto {
+    private Long id;
+    private String content;
+    private LocalDateTime createdAt;
+    private AuthorDto author;
+    private List<CommentDto> replies;
+    private List<ReactionDto> reactions;
+    private int reward;
+}
+

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

@@ -0,0 +1,16 @@
+package com.openisle.dto;
+
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+
+import java.util.List;
+
+/**
+ * Detailed DTO for a post, including comments.
+ */
+@Data
+@EqualsAndHashCode(callSuper = true)
+public class PostDetailDto extends PostSummaryDto {
+    private List<CommentDto> comments;
+}
+

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

@@ -0,0 +1,18 @@
+package com.openisle.dto;
+
+import lombok.Data;
+
+import java.util.List;
+
+/**
+ * Request body for creating or updating a post.
+ */
+@Data
+public class PostRequest {
+    private Long categoryId;
+    private String title;
+    private String content;
+    private List<Long> tagIds;
+    private String captcha;
+}
+

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

@@ -0,0 +1,30 @@
+package com.openisle.dto;
+
+import com.openisle.model.PostStatus;
+import lombok.Data;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+/**
+ * Lightweight DTO for listing posts without comments.
+ */
+@Data
+public class PostSummaryDto {
+    private Long id;
+    private String title;
+    private String content;
+    private LocalDateTime createdAt;
+    private AuthorDto author;
+    private CategoryDto category;
+    private List<TagDto> tags;
+    private long views;
+    private PostStatus status;
+    private LocalDateTime pinnedAt;
+    private LocalDateTime lastReplyAt;
+    private List<ReactionDto> reactions;
+    private List<AuthorDto> participants;
+    private boolean subscribed;
+    private int reward;
+}
+

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

@@ -0,0 +1,18 @@
+package com.openisle.dto;
+
+import com.openisle.model.ReactionType;
+import lombok.Data;
+
+/**
+ * DTO representing a reaction on a post or comment.
+ */
+@Data
+public class ReactionDto {
+    private Long id;
+    private ReactionType type;
+    private String user;
+    private Long postId;
+    private Long commentId;
+    private int reward;
+}
+

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

@@ -0,0 +1,16 @@
+package com.openisle.dto;
+
+import lombok.Data;
+
+/**
+ * DTO representing a tag.
+ */
+@Data
+public class TagDto {
+    private Long id;
+    private String name;
+    private String description;
+    private String icon;
+    private String smallIcon;
+}
+