[feat] #5 게시물 비즈니스 로직 구현

src/main/java/org/sopt/seminar/domain/post/service/PostService.java

@@ -0,0 +1,84 @@
+package org.sopt.seminar.domain.post.service;
+
+import lombok.RequiredArgsConstructor;
+import org.sopt.seminar.domain.member.domain.Member;
+import org.sopt.seminar.domain.member.repository.MemberRepository;
+import org.sopt.seminar.domain.post.domain.Category;
+import org.sopt.seminar.domain.post.domain.Post;
+import org.sopt.seminar.domain.post.dto.request.PostSaveOrUpdateRequest;
+import org.sopt.seminar.domain.post.dto.response.PostGetResponse;
+import org.sopt.seminar.domain.post.dto.response.PostSaveResponse;
+import org.sopt.seminar.domain.post.repository.CategoryRepository;
+import org.sopt.seminar.domain.post.repository.PostRepository;
+import org.springframework.data.domain.Pageable;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.util.List;
+
+import static org.sopt.seminar.domain.post.domain.Category.createCategory;
+import static org.sopt.seminar.domain.post.domain.Post.createPost;
+
+@RequiredArgsConstructor
+@Transactional(readOnly = true)
+@Service
+public class PostService {
+    private final MemberRepository memberRepository;
+    private final PostRepository postRepository;
+    private final CategoryRepository categoryRepository;
+
+    @Transactional
+    public PostSaveResponse savePost(Long memberId, PostSaveOrUpdateRequest postSaveOrUpdateRequest) {
+        Member findMember = findMember(memberId);
+        Category savedCategory = createCategoryAndGetSavedCategory(postSaveOrUpdateRequest);
+        Post savedPost = createPostAndGetSavedPost(postSaveOrUpdateRequest, findMember, savedCategory);
+        return PostSaveResponse.of(savedPost);
+    }
+
+    public PostGetResponse getPost(Long postId) {
+        Post findPost = findPost(postId);
+        return PostGetResponse.of(findPost);
+    }
+
+    public List<PostGetResponse> getPosts(Long memberId, Pageable pageable) {
+        return postRepository.findAllByMemberId(memberId, pageable)
+                .stream()
+                .map(PostGetResponse::of)
+                .toList();
+    }
+
+    @Transactional
+    public void updatePost(Long postId, PostSaveOrUpdateRequest postSaveOrUpdateRequest) {
+        Post findPost = findPost(postId);
+        Category category = findPost.getCategory();
+        updatePostAndCategory(postSaveOrUpdateRequest, findPost, category);
+    }
+
+    @Transactional
+    public void deletePost(Long postId) {
+        postRepository.deleteById(postId);
+    }
+
+    private Member findMember(Long memberId) {
+        return memberRepository.findByIdOrThrow(memberId);
+    }
+
+    private Category createCategoryAndGetSavedCategory(PostSaveOrUpdateRequest postSaveOrUpdateRequest) {
+        Category category = createCategory(postSaveOrUpdateRequest.categoryContent());
+        return categoryRepository.save(category);
+    }
+
+    private Post createPostAndGetSavedPost(PostSaveOrUpdateRequest postSaveOrUpdateRequest, Member member, Category category) {
+        Post post = createPost(postSaveOrUpdateRequest.title(), postSaveOrUpdateRequest.postContent(), category, member);
+        return postRepository.save(post);
+    }
+
+    private Post findPost(Long postId) {
+        return postRepository.findByIdOrThrow(postId);
+    }
+
+    private void updatePostAndCategory(PostSaveOrUpdateRequest postSaveOrUpdateRequest, Post post, Category category) {
+        post.updateTitleAndContent(postSaveOrUpdateRequest.title(), postSaveOrUpdateRequest.postContent());
+        category.updateContent(postSaveOrUpdateRequest.categoryContent());
+    }
+}