feat: migrate Post and Comment models from MongoDB to CouchDB

- Replace mongoose Post model with CouchDB-based class using couchdbService
- Replace mongoose Comment model with CouchDB-based class using couchdbService
- Update posts route to use new CouchDB models with embedded user data
- Update comments route to use new CouchDB models with embedded user/post data
- Maintain all existing API endpoints and functionality
- Add like/unlike functionality for posts
- Handle image uploads with Cloudinary integration
- Preserve Socket.IO events for real-time updates
- Use denormalized structure for better performance with embedded data

🤖 Generated with [AI Assistant]

Co-Authored-By: AI Assistant <noreply@ai-assistant.com>

backend/routes/comments.js

@@ -1,5 +1,4 @@
 const express = require("express");
-const mongoose = require("mongoose");
 const Comment = require("../models/Comment");
 const Post = require("../models/Post");
 const auth = require("../middleware/auth");
@@ -26,13 +25,9 @@ router.get(
     }
 
     // Get comments with pagination
-    const comments = await Comment.find({ post: postId })
-      .sort({ createdAt: -1 })
-      .skip(skip)
-      .limit(limit)
-      .populate("user", ["name", "profilePicture"]);
+    const comments = await Comment.findByPostId(postId, { skip, limit });
 
-    const totalCount = await Comment.countDocuments({ post: postId });
+    const totalCount = await Comment.countDocuments({ "post.postId": postId });
 
     res.json(buildPaginatedResponse(comments, totalCount, page, limit));
   })
@@ -49,50 +44,39 @@ router.post(
     const { postId } = req.params;
     const { content } = req.body;
 
-    // Validate content
-    if (!content || content.trim().length === 0) {
-      return res.status(400).json({ msg: "Comment content is required" });
-    }
+    try {
+      // Validate content
+      await Comment.validateContent(content);
 
-    if (content.length > 500) {
-      return res
-        .status(400)
-        .json({ msg: "Comment content must be 500 characters or less" });
-    }
+      // Verify post exists
+      const post = await Post.findById(postId);
+      if (!post) {
+        return res.status(404).json({ msg: "Post not found" });
+      }
 
-    // Verify post exists
-    const post = await Post.findById(postId);
-    if (!post) {
-      return res.status(404).json({ msg: "Post not found" });
-    }
-
-    // Create comment
-    const newComment = new Comment({
-      user: req.user.id,
-      post: postId,
-      content: content.trim(),
-    });
-
-    const comment = await newComment.save();
-
-    // Update post's comment count
-    await Post.findByIdAndUpdate(postId, {
-      $inc: { commentsCount: 1 },
-    });
-
-    // Populate user data before sending response
-    await comment.populate("user", ["name", "profilePicture"]);
-
-    // Emit Socket.IO event for new comment
-    const io = req.app.get("io");
-    if (io) {
-      io.to(`post_${postId}`).emit("newComment", {
-        postId,
-        comment,
+      // Create comment
+      const comment = await Comment.create({
+        user: req.user.id,
+        post: postId,
+        content,
       });
-    }
 
-    res.status(201).json(comment);
+      // Emit Socket.IO event for new comment
+      const io = req.app.get("io");
+      if (io) {
+        io.to(`post_${postId}`).emit("newComment", {
+          postId,
+          comment,
+        });
+      }
+
+      res.status(201).json(comment);
+    } catch (error) {
+      if (error.message.includes("required") || error.message.includes("characters")) {
+        return res.status(400).json({ msg: error.message });
+      }
+      throw error;
+    }
   })
 );
 
@@ -113,22 +97,19 @@ router.delete(
     }
 
     // Verify comment belongs to the post
-    if (comment.post.toString() !== postId) {
+    const belongsToPost = await Comment.belongsToPost(commentId, postId);
+    if (!belongsToPost) {
       return res.status(400).json({ msg: "Comment does not belong to this post" });
     }
 
     // Verify user owns the comment
-    if (comment.user.toString() !== req.user.id) {
+    const isOwnedByUser = await Comment.isOwnedByUser(commentId, req.user.id);
+    if (!isOwnedByUser) {
       return res.status(403).json({ msg: "Not authorized to delete this comment" });
     }
 
     // Delete comment
-    await Comment.findByIdAndDelete(commentId);
-
-    // Update post's comment count
-    await Post.findByIdAndUpdate(postId, {
-      $inc: { commentsCount: -1 },
-    });
+    await Comment.deleteComment(commentId);
 
     // Emit Socket.IO event for deleted comment
     const io = req.app.get("io");