feat: add draft post support

src/main/java/com/openisle/controller/DraftController.java

@@ -0,0 +1,67 @@
+package com.openisle.controller;
+
+import com.openisle.model.Draft;
+import com.openisle.service.DraftService;
+import lombok.Data;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.core.Authentication;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+@RestController
+@RequestMapping("/api/drafts")
+@RequiredArgsConstructor
+public class DraftController {
+    private final DraftService draftService;
+
+    @PostMapping
+    public ResponseEntity<DraftDto> saveDraft(@RequestBody DraftRequest req, Authentication auth) {
+        Draft draft = draftService.saveDraft(auth.getName(), req.getCategoryId(), req.getTitle(), req.getContent(), req.getTagIds());
+        return ResponseEntity.ok(toDto(draft));
+    }
+
+    @GetMapping("/me")
+    public ResponseEntity<DraftDto> getMyDraft(Authentication auth) {
+        return draftService.getDraft(auth.getName())
+                .map(d -> ResponseEntity.ok(toDto(d)))
+                .orElseGet(() -> ResponseEntity.noContent().build());
+    }
+
+    @DeleteMapping("/me")
+    public ResponseEntity<?> deleteMyDraft(Authentication auth) {
+        draftService.deleteDraft(auth.getName());
+        return ResponseEntity.ok().build();
+    }
+
+    private DraftDto toDto(Draft draft) {
+        DraftDto dto = new DraftDto();
+        dto.setId(draft.getId());
+        dto.setTitle(draft.getTitle());
+        dto.setContent(draft.getContent());
+        if (draft.getCategory() != null) {
+            dto.setCategoryId(draft.getCategory().getId());
+        }
+        dto.setTagIds(draft.getTags().stream().map(com.openisle.model.Tag::getId).collect(Collectors.toList()));
+        return dto;
+    }
+
+    @Data
+    private static class DraftRequest {
+        private String title;
+        private String content;
+        private Long categoryId;
+        private List<Long> tagIds;
+    }
+
+    @Data
+    private static class DraftDto {
+        private Long id;
+        private String title;
+        private String content;
+        private Long categoryId;
+        private List<Long> tagIds;
+    }
+}

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

@@ -7,6 +7,7 @@ import com.openisle.service.CommentService;
 import com.openisle.service.PostService;
 import com.openisle.service.ReactionService;
 import com.openisle.service.CaptchaService;
+import com.openisle.service.DraftService;
 import lombok.Data;
 import lombok.RequiredArgsConstructor;
 import org.springframework.http.ResponseEntity;
@@ -26,6 +27,7 @@ public class PostController {
     private final CommentService commentService;
     private final ReactionService reactionService;
     private final CaptchaService captchaService;
+    private final DraftService draftService;
 
     @Value("${app.captcha.enabled:false}")
     private boolean captchaEnabled;
@@ -40,6 +42,7 @@ public class PostController {
         }
         Post post = postService.createPost(auth.getName(), req.getCategoryId(),
                 req.getTitle(), req.getContent(), req.getTagIds());
+        draftService.deleteDraft(auth.getName());
         return ResponseEntity.ok(toDto(post));
     }
 

src/main/java/com/openisle/model/Draft.java

@@ -0,0 +1,41 @@
+package com.openisle.model;
+
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+import java.util.HashSet;
+import java.util.Set;
+
+@Entity
+@Getter
+@Setter
+@NoArgsConstructor
+@Table(name = "drafts", uniqueConstraints = {
+        @UniqueConstraint(columnNames = {"author_id"})
+})
+public class Draft {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    private String title;
+
+    @Column(columnDefinition = "TEXT")
+    private String content;
+
+    @ManyToOne(fetch = FetchType.LAZY, optional = false)
+    @JoinColumn(name = "author_id")
+    private User author;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "category_id")
+    private Category category;
+
+    @ManyToMany(fetch = FetchType.LAZY)
+    @JoinTable(name = "draft_tags",
+            joinColumns = @JoinColumn(name = "draft_id"),
+            inverseJoinColumns = @JoinColumn(name = "tag_id"))
+    private Set<Tag> tags = new HashSet<>();
+}

src/main/java/com/openisle/repository/DraftRepository.java

@@ -0,0 +1,12 @@
+package com.openisle.repository;
+
+import com.openisle.model.Draft;
+import com.openisle.model.User;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import java.util.Optional;
+
+public interface DraftRepository extends JpaRepository<Draft, Long> {
+    Optional<Draft> findByAuthor(User author);
+    void deleteByAuthor(User author);
+}

src/main/java/com/openisle/service/DraftService.java

@@ -0,0 +1,58 @@
+package com.openisle.service;
+
+import com.openisle.model.Category;
+import com.openisle.model.Draft;
+import com.openisle.model.Tag;
+import com.openisle.model.User;
+import com.openisle.repository.CategoryRepository;
+import com.openisle.repository.DraftRepository;
+import com.openisle.repository.TagRepository;
+import com.openisle.repository.UserRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+
+@Service
+@RequiredArgsConstructor
+public class DraftService {
+    private final DraftRepository draftRepository;
+    private final UserRepository userRepository;
+    private final CategoryRepository categoryRepository;
+    private final TagRepository tagRepository;
+
+    public Draft saveDraft(String username, Long categoryId, String title, String content, List<Long> tagIds) {
+        User user = userRepository.findByUsername(username)
+                .orElseThrow(() -> new IllegalArgumentException("User not found"));
+        Draft draft = draftRepository.findByAuthor(user).orElse(new Draft());
+        draft.setAuthor(user);
+        draft.setTitle(title);
+        draft.setContent(content);
+        if (categoryId != null) {
+            Category category = categoryRepository.findById(categoryId)
+                    .orElseThrow(() -> new IllegalArgumentException("Category not found"));
+            draft.setCategory(category);
+        } else {
+            draft.setCategory(null);
+        }
+        Set<Tag> tags = new HashSet<>();
+        if (tagIds != null && !tagIds.isEmpty()) {
+            tags.addAll(tagRepository.findAllById(tagIds));
+        }
+        draft.setTags(tags);
+        return draftRepository.save(draft);
+    }
+
+    public Optional<Draft> getDraft(String username) {
+        return userRepository.findByUsername(username)
+                .flatMap(draftRepository::findByAuthor);
+    }
+
+    public void deleteDraft(String username) {
+        userRepository.findByUsername(username)
+                .ifPresent(draftRepository::deleteByAuthor);
+    }
+}