feat: add search module

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

@@ -0,0 +1,96 @@
+package com.openisle.controller;
+
+import com.openisle.model.Post;
+import com.openisle.model.Comment;
+import com.openisle.model.User;
+import com.openisle.service.SearchService;
+import lombok.Data;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+@RestController
+@RequestMapping("/api/search")
+@RequiredArgsConstructor
+public class SearchController {
+    private final SearchService searchService;
+
+    @GetMapping("/users")
+    public List<UserDto> searchUsers(@RequestParam String keyword) {
+        return searchService.searchUsers(keyword).stream()
+                .map(this::toUserDto)
+                .collect(Collectors.toList());
+    }
+
+    @GetMapping("/posts")
+    public List<PostDto> searchPosts(@RequestParam String keyword) {
+        return searchService.searchPosts(keyword).stream()
+                .map(this::toPostDto)
+                .collect(Collectors.toList());
+    }
+
+    @GetMapping("/posts/content")
+    public List<PostDto> searchPostsByContent(@RequestParam String keyword) {
+        return searchService.searchPostsByContent(keyword).stream()
+                .map(this::toPostDto)
+                .collect(Collectors.toList());
+    }
+
+    @GetMapping("/posts/title")
+    public List<PostDto> searchPostsByTitle(@RequestParam String keyword) {
+        return searchService.searchPostsByTitle(keyword).stream()
+                .map(this::toPostDto)
+                .collect(Collectors.toList());
+    }
+
+    @GetMapping("/global")
+    public List<SearchResultDto> global(@RequestParam String keyword) {
+        return searchService.globalSearch(keyword).stream()
+                .map(r -> {
+                    SearchResultDto dto = new SearchResultDto();
+                    dto.setType(r.type());
+                    dto.setId(r.id());
+                    dto.setText(r.text());
+                    return dto;
+                })
+                .collect(Collectors.toList());
+    }
+
+    private UserDto toUserDto(User user) {
+        UserDto dto = new UserDto();
+        dto.setId(user.getId());
+        dto.setUsername(user.getUsername());
+        return dto;
+    }
+
+    private PostDto toPostDto(Post post) {
+        PostDto dto = new PostDto();
+        dto.setId(post.getId());
+        dto.setTitle(post.getTitle());
+        return dto;
+    }
+
+    @Data
+    private static class UserDto {
+        private Long id;
+        private String username;
+    }
+
+    @Data
+    private static class PostDto {
+        private Long id;
+        private String title;
+    }
+
+    @Data
+    private static class SearchResultDto {
+        private String type;
+        private Long id;
+        private String text;
+    }
+}

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

@@ -12,4 +12,5 @@ public interface CommentRepository extends JpaRepository<Comment, Long> {
     List<Comment> findByPostAndParentIsNullOrderByCreatedAtAsc(Post post);
     List<Comment> findByParentOrderByCreatedAtAsc(Comment parent);
     List<Comment> findByAuthorOrderByCreatedAtDesc(User author, Pageable pageable);
+    List<Comment> findByContentContainingIgnoreCase(String keyword);
 }

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

@@ -15,4 +15,7 @@ public interface PostRepository extends JpaRepository<Post, Long> {
     List<Post> findByAuthorAndStatusOrderByCreatedAtDesc(User author, PostStatus status, Pageable pageable);
     List<Post> findByCategoryInAndStatus(List<Category> categories, PostStatus status);
     List<Post> findByCategoryInAndStatus(List<Category> categories, PostStatus status, Pageable pageable);
+    List<Post> findByTitleContainingIgnoreCaseOrContentContainingIgnoreCaseAndStatus(String titleKeyword, String contentKeyword, PostStatus status);
+    List<Post> findByContentContainingIgnoreCaseAndStatus(String keyword, PostStatus status);
+    List<Post> findByTitleContainingIgnoreCaseAndStatus(String keyword, PostStatus status);
 }

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

@@ -7,4 +7,5 @@ import java.util.Optional;
 public interface UserRepository extends JpaRepository<User, Long> {
     Optional<User> findByUsername(String username);
     Optional<User> findByEmail(String email);
+    java.util.List<User> findByUsernameContainingIgnoreCase(String keyword);
 }

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

@@ -0,0 +1,60 @@
+package com.openisle.service;
+
+import com.openisle.model.Post;
+import com.openisle.model.PostStatus;
+import com.openisle.model.Comment;
+import com.openisle.model.User;
+import com.openisle.repository.PostRepository;
+import com.openisle.repository.CommentRepository;
+import com.openisle.repository.UserRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+import java.util.stream.Stream;
+
+@Service
+@RequiredArgsConstructor
+public class SearchService {
+    private final UserRepository userRepository;
+    private final PostRepository postRepository;
+    private final CommentRepository commentRepository;
+
+    public List<User> searchUsers(String keyword) {
+        return userRepository.findByUsernameContainingIgnoreCase(keyword);
+    }
+
+    public List<Post> searchPosts(String keyword) {
+        return postRepository
+                .findByTitleContainingIgnoreCaseOrContentContainingIgnoreCaseAndStatus(keyword, keyword, PostStatus.PUBLISHED);
+    }
+
+    public List<Post> searchPostsByContent(String keyword) {
+        return postRepository
+                .findByContentContainingIgnoreCaseAndStatus(keyword, PostStatus.PUBLISHED);
+    }
+
+    public List<Post> searchPostsByTitle(String keyword) {
+        return postRepository
+                .findByTitleContainingIgnoreCaseAndStatus(keyword, PostStatus.PUBLISHED);
+    }
+
+    public List<Comment> searchComments(String keyword) {
+        return commentRepository.findByContentContainingIgnoreCase(keyword);
+    }
+
+    public List<SearchResult> globalSearch(String keyword) {
+        Stream<SearchResult> users = searchUsers(keyword).stream()
+                .map(u -> new SearchResult("user", u.getId(), u.getUsername()));
+        Stream<SearchResult> posts = searchPosts(keyword).stream()
+                .map(p -> new SearchResult("post", p.getId(), p.getTitle()));
+        Stream<SearchResult> titles = searchPostsByTitle(keyword).stream()
+                .map(p -> new SearchResult("post_title", p.getId(), p.getTitle()));
+        Stream<SearchResult> comments = searchComments(keyword).stream()
+                .map(c -> new SearchResult("comment", c.getId(), c.getContent()));
+        return Stream.concat(Stream.concat(Stream.concat(users, posts), titles), comments)
+                .toList();
+    }
+
+    public record SearchResult(String type, Long id, String text) {}
+}