add search function, still not working as intended tho

BE/src/main/java/org/example/controllers/PostController.java

@@ -57,9 +57,7 @@ public class PostController {
         }
     }
     @PostMapping
-    public Post createPost(
-
-                            @RequestParam("title") String title,
+    public Post createPost(@RequestParam("title") String title,
                            @RequestParam("content") String content,
                            @RequestParam(value = "imageFile", required = false) MultipartFile imageFile,
                            @RequestParam(value = "videoFile", required = false) MultipartFile videoFile) throws IOException {

BE/src/main/java/org/example/controllers/SearchController.java

@@ -0,0 +1,26 @@
+package org.example.controllers;
+
+import org.example.objects.SearchDTO;
+import org.example.services.PostService;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+@RestController
+@RequestMapping("/api/search")
+public class SearchController {
+    private final PostService postService;
+
+    public SearchController(PostService postService) {
+        this.postService = postService;
+    }
+
+
+    @GetMapping("/search_result")
+    public ResponseEntity<List<SearchDTO>> searchRelatedTopics(@RequestParam String key){
+        List<SearchDTO> searchResult  =  postService.searchRelatedTopics(key);
+        return new ResponseEntity<>(searchResult, HttpStatus.OK);
+    }
+}

BE/src/main/java/org/example/models/Post.java

@@ -16,7 +16,6 @@ import java.util.UUID;
 @Getter
 @Node
 public class Post {
-
     @Id
     @GeneratedValue
     private Long id;

BE/src/main/java/org/example/models/UserPostResult.java

@@ -1 +0,0 @@
-

BE/src/main/java/org/example/objects/SearchDTO.java

@@ -0,0 +1,27 @@
+package org.example.objects;
+
+public class SearchDTO {
+    private String username;
+    private String title;
+    
+    public SearchDTO(String username, String title) {
+        this.username = username;
+        this.title = title;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+}

BE/src/main/java/org/example/repositories/PostRepository.java

@@ -3,6 +3,7 @@ package org.example.repositories;
 import org.example.controllers.UserController;
 import org.example.models.Image;
 import org.example.models.Post;
+import org.example.objects.SearchDTO;
 import org.example.queryresults.PostQueryResult;
 import org.springframework.data.neo4j.repository.Neo4jRepository;
 import org.springframework.data.neo4j.repository.query.Query;
@@ -48,6 +49,7 @@ public interface PostRepository extends Neo4jRepository<Post,Long> {
                 ")\n" +
                 "RETURN p")
         Post updatePost(@Param("postId") Long postId, @Param("title") String title, @Param("content") String content, @Param("imageFile")MultipartFile imageFile, @Param("videoFile") MultipartFile videoFile);
+
         @Query("MATCH (u:User {username: $username}), (p:Post) WHERE ID(p)=$postId CREATE (u)-[:LIKES]->(p)")
         void createLike(@Param("username") String username,@Param("postId") Long postId);
 
@@ -57,4 +59,9 @@ public interface PostRepository extends Neo4jRepository<Post,Long> {
         @Query("MATCH (user:User {username: $username}),(post:Post )"+"where ID(post)=$postId"+ " CREATE (user)-[:createPost ]->(post)"+
                 "RETURN user, post")
         PostQueryResult createPostRelationship(@Param("username") String username,@Param("postId") Long postId);
+
+        @Query("OPTIONAL MATCH (p:Post), (u:User) " +
+                "WHERE toLower(p.title) CONTAINS toLower($input) OR toLower(u.username) CONTAINS toLower($input) " +
+                "RETURN p, u;")
+        List<SearchDTO> search(@Param("input") String input);
 }

BE/src/main/java/org/example/services/PostService.java

@@ -7,6 +7,7 @@ import org.example.models.Image;
 import org.example.models.Post;
 import org.example.models.User;
 import org.example.models.Video;
+import org.example.objects.SearchDTO;
 import org.example.queryresults.PostQueryResult;
 import org.example.repositories.PostRepository;
 import org.example.repositories.UserRepository;
@@ -185,4 +186,8 @@ public class PostService {
         return video;
     }
 
+    @Transactional
+    public List<SearchDTO> searchRelatedTopics(String input){
+        return postRepository.search(input);
+    }
 }