Implement conversation handling in sendMessage controller

backend/controllers/message.controller.js

@@ -1,11 +1,36 @@
+import Conversation from "../models/conversation.model.js"; // .js is mandatory for proper working of ES6 modules
+
 export const sendMessage = async (req, res) => {
     // res.send('Send Message Route');
     // console.log('Message sent by userId', req.params.id);
     try {
-        const {id: recieverId} = req.params;
         const {message} = req.body;
-        const senderId = req.user._id;
-        console.log('Message sent by userId', senderId);
+        const {id: recieverId} = req.params;
+        const senderId = req.user._id; // because we used protectRoute middleware in the route
+        // console.log('Message sent by userId', senderId);
+
+        let conversation = await Conversation.findOne({
+            participants: {$all: [senderId, recieverId]} // participants array contains senderId and recieverId $all is used to check if both are present
+        }); // this will find the conversation between sender and reciever
+
+        if(!conversation) {
+            conversation = await Conversation.create({
+                participants: [senderId, recieverId]
+            });
+        }; // this will create a new conversation if it does not exist
+
+        const newMessage = {
+            sender : senderId,
+            reciever : recieverId,
+            message
+        }// this will create a new message
+
+        if(newMessage){
+            conversation.messages.push(newMessage._id);
+        }// this will push the new message to the conversation messages array
+
+        res.status(201).json({newMessage, conversation});
+
     } catch (error) {
         console.log("Error in sendMessages controller : ",error.message);
         res.status(500).json({message: "Internal Server Error During Sending Message"});  

backend/routes/message.routes.js

@@ -4,6 +4,7 @@ import protectRoute from "../middleware/protectRoute.js";
 
 const router = express.Router();
 
-router.post("/send/:id", protectRoute,sendMessage); 
+router.post("/send/:id", protectRoute,sendMessage);  
+// protectRoute is a middleware to protect the route so that we can use req.user._id in the controller
 
 export default router;

package.json

@@ -5,7 +5,7 @@
   "scripts": {
     "server": "nodemon backend/server.js"
   },
-  "type": "module",
+  "type": "module", 
   "keywords": [],
   "author": "",
   "license": "ISC",