Atisa 204 llm

.gitignore

@@ -40,3 +40,4 @@ tests/ui-test/chromedriver.exe
 tests/ui-test/screenshot/**
 report.*.json
 *.tsbuildinfo
+.env

llm-backend-poc/backend.js

@@ -0,0 +1,51 @@
+require("dotenv").config();
+const express = require("express"); // to build HTTP servers in Node.js
+const cors = require("cors"); //middleware, allows the frontend (which runs on one port) to talk to the backend (which runs on a different port)
+const bodyParser = require("body-parser"); // parses the JSON body of incoming HTTP requests so that data is accessible 
+const { OpenAI } = require("openai");
+
+const app = express(); // creates instance of the express app, which will be the server
+const port = 3001;
+
+const openai = new OpenAI({ apiKey: process.env.OPENAI_API_KEY });
+
+app.use(cors()); // Enable CORS so frontend can send requests to backend
+app.use(bodyParser.json()); // tells express to automatically parse incoming request bodies as JSON. Without, req.body.message would be undefined
+
+// LLM's behavior
+const systemMessage = {
+  role: "system",
+  content:
+    "You only answer questions related to programming, software development, or your own capabilities. If a user asks about anything else (like politics, personal opinions, religion, etc), politely decline and redirect them to ask about code or AI-related questions.",
+};
+
+// creates route to handle chat requests
+app.post("/chat", async (req, res) => {
+  const userMessage = req.body.message;
+  if (!userMessage) return res.status(400).json({ error: "No message sent" });
+
+  // creates the message that will be sent to OpenAI. It contains the system role/context and the user input
+  const messages = [systemMessage, { role: "user", content: userMessage }];
+
+  // sends the message to OpenAI and waits for the response
+  try {
+    const completion = await openai.chat.completions.create({
+      model: "gpt-4.1-mini",
+      messages,
+    });
+
+    const reply = completion.choices[0].message.content; // extracts the reply from OpenAI
+    return res.json({ reply }); // sends reply to frontend (in JSON format)
+  } 
+
+  // error handling
+  catch (err) {
+    console.error("Error from OpenAI:", err);
+    return res.status(500).json({ error: "Something went wrong" });
+  }
+});
+
+// tells app to start listening on port 3001
+app.listen(port, () => {
+  console.log(`LLM backend server running on http://localhost:${port}`);
+});