From 1544b37ed3cf00b654c617419c1414af5a199ff4 Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Sun, 27 Jul 2025 10:46:59 +0300
Subject: [PATCH] feat: implement listing posts in a hierarchical  structure

---
 .../wesal/controller/CommentController.java   |  2 +-
 .../wesal/wesal/dto/CommentResponseDTO.java   | 12 +++++++
 .../wesal/wesal/service/CommentService.java   | 32 ++++++++++++++++---
 3 files changed, 40 insertions(+), 6 deletions(-)

diff --git a/backend/src/main/java/online/wesal/wesal/controller/CommentController.java b/backend/src/main/java/online/wesal/wesal/controller/CommentController.java
index ce80e91..dda0124 100644
--- a/backend/src/main/java/online/wesal/wesal/controller/CommentController.java
+++ b/backend/src/main/java/online/wesal/wesal/controller/CommentController.java
@@ -69,7 +69,7 @@ public class CommentController {
     }
     
     @GetMapping("/list")
-    @Operation(summary = "Get comments for post", description = "Get all comments for a specific post ordered by creation date")
+    @Operation(summary = "Get comments for post", description = "Get all comments for a specific post in hierarchical structure with nested replies")
     public ResponseEntity<ApiResponse<List<CommentResponseDTO>>> getCommentsByPostId(
             @RequestParam Long postId,
             Authentication authentication) {
diff --git a/backend/src/main/java/online/wesal/wesal/dto/CommentResponseDTO.java b/backend/src/main/java/online/wesal/wesal/dto/CommentResponseDTO.java
index 3c10c2c..5c8c92a 100644
--- a/backend/src/main/java/online/wesal/wesal/dto/CommentResponseDTO.java
+++ b/backend/src/main/java/online/wesal/wesal/dto/CommentResponseDTO.java
@@ -3,6 +3,8 @@ package online.wesal.wesal.dto;
 import online.wesal.wesal.entity.Comment;
 import online.wesal.wesal.entity.User;
 import java.time.LocalDateTime;
+import java.util.List;
+import java.util.ArrayList;
 
 public class CommentResponseDTO {
     
@@ -15,6 +17,7 @@ public class CommentResponseDTO {
     private String displayReplyComment;
     private CreatorDTO replyUser;
     private Integer level;
+    private List<CommentResponseDTO> replies;
     
     public CommentResponseDTO() {}
     
@@ -28,6 +31,7 @@ public class CommentResponseDTO {
         this.displayReplyComment = comment.getDisplayReplyComment() != null ? String.valueOf(comment.getDisplayReplyComment()) : null;
         this.replyUser = replyUser != null ? new CreatorDTO(replyUser) : null;
         this.level = comment.getLevel();
+        this.replies = new ArrayList<>();
     }
     
     public String getId() {
@@ -101,4 +105,12 @@ public class CommentResponseDTO {
     public void setLevel(Integer level) {
         this.level = level;
     }
+    
+    public List<CommentResponseDTO> getReplies() {
+        return replies;
+    }
+    
+    public void setReplies(List<CommentResponseDTO> replies) {
+        this.replies = replies;
+    }
 }
\ No newline at end of file
diff --git a/backend/src/main/java/online/wesal/wesal/service/CommentService.java b/backend/src/main/java/online/wesal/wesal/service/CommentService.java
index f0c84d0..da084f6 100644
--- a/backend/src/main/java/online/wesal/wesal/service/CommentService.java
+++ b/backend/src/main/java/online/wesal/wesal/service/CommentService.java
@@ -11,6 +11,7 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
@@ -105,10 +106,31 @@ public class CommentService {
         Map<Long, User> users = userRepository.findAllById(creatorIds.stream().distinct().collect(Collectors.toList())).stream()
                 .collect(Collectors.toMap(User::getId, user -> user));
         
-        return comments.stream()
-                .map(comment -> new CommentResponseDTO(comment, 
-                    users.get(comment.getCreatorId()),
-                    comment.getReplyUser() != null ? users.get(comment.getReplyUser()) : null))
-                .collect(Collectors.toList());
+        Map<Long, CommentResponseDTO> commentMap = comments.stream()
+                .collect(Collectors.toMap(
+                    Comment::getId,
+                    comment -> new CommentResponseDTO(comment, 
+                        users.get(comment.getCreatorId()),
+                        comment.getReplyUser() != null ? users.get(comment.getReplyUser()) : null)
+                ));
+        
+        List<CommentResponseDTO> rootComments = new ArrayList<>();
+        
+        for (Comment comment : comments) {
+            CommentResponseDTO dto = commentMap.get(comment.getId());
+            
+            if (comment.getDisplayReplyComment() == null) {
+                rootComments.add(dto);
+            } else {
+                CommentResponseDTO parent = commentMap.get(comment.getDisplayReplyComment());
+                if (parent != null) {
+                    parent.getReplies().add(dto);
+                } else {
+                    rootComments.add(dto);
+                }
+            }
+        }
+        
+        return rootComments;
     }
 }
\ No newline at end of file