fix: add view history logic

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

@@ -34,6 +34,7 @@ public class UserController {
   private final TagService tagService;
   private final SubscriptionService subscriptionService;
   private final LevelService levelService;
+  private final PostReadService postReadService;
   private final JwtService jwtService;
   private final UserMapper userMapper;
   private final TagMapper tagMapper;
@@ -53,6 +54,9 @@ public class UserController {
   @Value("${app.user.tags-limit:50}")
   private int defaultTagsLimit;
 
+  @Value("${app.user.read-posts-limit:50}")
+  private int defaultReadPostsLimit;
+
   @GetMapping("/me")
   @SecurityRequirement(name = "JWT")
   @Operation(summary = "Current user", description = "Get current authenticated user information")
@@ -211,6 +215,33 @@ public class UserController {
       .collect(java.util.stream.Collectors.toList());
   }
 
+  @GetMapping("/{identifier}/read-posts")
+  @SecurityRequirement(name = "JWT")
+  @Operation(summary = "User read posts", description = "Get post read history (self only)")
+  @ApiResponse(
+    responseCode = "200",
+    description = "Post read history",
+    content = @Content(array = @ArraySchema(schema = @Schema(implementation = PostReadDto.class)))
+  )
+  public ResponseEntity<java.util.List<PostReadDto>> userReadPosts(
+    @PathVariable("identifier") String identifier,
+    @RequestParam(value = "limit", required = false) Integer limit,
+    Authentication auth
+  ) {
+    User user = userService.findByIdentifier(identifier).orElseThrow();
+    if (auth == null || !auth.getName().equals(user.getUsername())) {
+      return ResponseEntity.status(403).body(java.util.List.of());
+    }
+    int l = limit != null ? limit : defaultReadPostsLimit;
+    return ResponseEntity.ok(
+      postReadService
+        .getRecentReadsByUser(user.getUsername(), l)
+        .stream()
+        .map(userMapper::toPostReadDto)
+        .collect(java.util.stream.Collectors.toList())
+    );
+  }
+
   @GetMapping("/{identifier}/hot-posts")
   @Operation(summary = "User hot posts", description = "Get most reacted posts by user")
   @ApiResponse(

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

@@ -0,0 +1,12 @@
+package com.openisle.dto;
+
+import java.time.LocalDateTime;
+import lombok.Data;
+
+/** DTO for a user's post read record. */
+@Data
+public class PostReadDto {
+
+  private PostMetaDto post;
+  private LocalDateTime lastReadAt;
+}

backend/src/main/java/com/openisle/mapper/UserMapper.java

@@ -3,6 +3,7 @@ package com.openisle.mapper;
 import com.openisle.dto.*;
 import com.openisle.model.Comment;
 import com.openisle.model.Post;
+import com.openisle.model.PostRead;
 import com.openisle.model.User;
 import com.openisle.service.*;
 import java.util.stream.Collectors;
@@ -115,4 +116,11 @@ public class UserMapper {
     }
     return dto;
   }
+
+  public PostReadDto toPostReadDto(PostRead read) {
+    PostReadDto dto = new PostReadDto();
+    dto.setPost(toMetaDto(read.getPost()));
+    dto.setLastReadAt(read.getLastReadAt());
+    return dto;
+  }
 }

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

@@ -3,11 +3,14 @@ package com.openisle.repository;
 import com.openisle.model.Post;
 import com.openisle.model.PostRead;
 import com.openisle.model.User;
+import java.util.List;
 import java.util.Optional;
+import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
 
 public interface PostReadRepository extends JpaRepository<PostRead, Long> {
   Optional<PostRead> findByUserAndPost(User user, Post post);
+  List<PostRead> findByUserOrderByLastReadAtDesc(User user, Pageable pageable);
   long countByUser(User user);
   void deleteByPost(Post post);
 }

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

@@ -7,7 +7,10 @@ import com.openisle.repository.PostReadRepository;
 import com.openisle.repository.PostRepository;
 import com.openisle.repository.UserRepository;
 import java.time.LocalDateTime;
+import java.util.List;
 import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
 
 @Service
@@ -43,6 +46,14 @@ public class PostReadService {
       );
   }
 
+  public List<PostRead> getRecentReadsByUser(String username, int limit) {
+    User user = userRepository
+      .findByUsername(username)
+      .orElseThrow(() -> new com.openisle.exception.NotFoundException("User not found"));
+    Pageable pageable = PageRequest.of(0, limit);
+    return postReadRepository.findByUserOrderByLastReadAtDesc(user, pageable);
+  }
+
   public long countReads(String username) {
     User user = userRepository
       .findByUsername(username)