added: grade, subject and chapter in new chat, fixed that shitty card bug

backend/src/routes/chat.js

@@ -0,0 +1,132 @@
+import express from "express";
+import { streamChatResponse } from "../services/ai.js";
+import { createSession, addMessage, getMessages, getSession, listSessions } from "../stores/sessionStore.js";
+
+const router = express.Router();
+
+/**
+ * POST /api/chat — Send a message and stream back an AI response.
+ *
+ * Request body:
+ * {
+ *   text: "What is photosynthesis?",
+ *   chatId: "optional_existing_session_id",
+ *   grade: "Grade 10",
+ *   subject: "Biology",
+ *   chapter: "Nutrition in Plants"
+ * }
+ */
+router.post("/", async (req, res) => {
+  const { text, chatId, grade, subject, chapter } = req.body;
+
+  // Validate input
+  if (!text || !text.trim()) {
+    return res.status(400).json({ error: "Message text is required" });
+  }
+
+  // Resolve or create session
+  let session;
+  if (chatId) {
+    session = getSession(chatId);
+    if (!session) {
+      return res.status(404).json({ error: "Session not found" });
+    }
+  } else {
+    session = createSession(grade, subject, chapter);
+  }
+
+  const currentChatId = session.id;
+
+  // Get conversation history
+  const chatMessages = getMessages(currentChatId);
+
+  // Add user message to history
+  const userMsg = {
+    id: `user_${Date.now()}`,
+    role: "user",
+    text: text.trim(),
+    timestamp: new Date().toISOString(),
+  };
+  addMessage(currentChatId, userMsg);
+
+  // Set SSE headers
+  res.setHeader("Content-Type", "text/event-stream");
+  res.setHeader("Cache-Control", "no-cache");
+  res.setHeader("Connection", "keep-alive");
+  res.setHeader("X-Accel-Buffering", "no");
+
+  let assistantText = "";
+  let errorOccurred = false;
+
+  // Stream the AI response
+  try {
+    await streamChatResponse(
+      chatMessages,
+      grade || session.grade,
+      subject || session.subject,
+      chapter || session.chapter,
+      (chunk) => {
+        assistantText += chunk;
+        // Send chunk as SSE event
+        res.write(`data: ${JSON.stringify({ type: "chunk", content: chunk })}\n\n`);
+      },
+      (err) => {
+        errorOccurred = true;
+        res.write(`data: ${JSON.stringify({ type: "error", message: err })}\n\n`);
+        res.end();
+      }
+    );
+
+    // Send end event
+    res.write(`data: ${JSON.stringify({ type: "done" })}\n\n`);
+
+    // Save assistant message to history
+    const assistantMsg = {
+      id: `assistant_${Date.now()}`,
+      role: "assistant",
+      text: assistantText,
+      timestamp: new Date().toISOString(),
+    };
+    addMessage(currentChatId, assistantMsg);
+  } catch (err) {
+    res.write(`data: ${JSON.stringify({ type: "error", message: err.message })}\n\n`);
+  } finally {
+    res.end();
+  }
+});
+
+/**
+ * GET /api/chat/:chatId — Get conversation messages for a session
+ */
+router.get("/:chatId", (req, res) => {
+  const { chatId } = req.params;
+  const session = getSession(chatId);
+
+  if (!session) {
+    return res.status(404).json({ error: "Session not found" });
+  }
+
+  const msgHistory = getMessages(chatId);
+
+  res.json({
+    session: {
+      id: session.id,
+      grade: session.grade,
+      subject: session.subject,
+      chapter: session.chapter,
+      createdAt: session.createdAt,
+      updatedAt: session.updatedAt,
+    },
+    messages: msgHistory,
+  });
+});
+
+/**
+ * GET /api/chat/sessions — List all chat sessions
+ */
+router.get("/sessions", (_req, res) => {
+  const sessions = listSessions();
+  res.json(sessions);
+});
+
+export default router;