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

2026-08-18 04:44:10 -04:00
parent ab88ae30f1
commit 93a35a7343
24 changed files with 2683 additions and 66 deletions
@@ -0,0 +1,18 @@
+# AI Provider: "openai" | "anthropic" | "google"
+AI_PROVIDER=openai
+
+# OpenAI
+OPENAI_API_KEY=sk-your-key-here
+OPENAI_MODEL=gpt-4o
+
+# Anthropic (optional)
+ANTHROPIC_API_KEY=sk-ant-your-key-here
+ANTHROPIC_MODEL=claude-sonnet-4-20250514
+
+# Google (optional)
+GOOGLE_API_KEY=your-google-api-key-here
+GOOGLE_MODEL=gemini-2.0-flash
+
+# Server
+PORT=3001
+CORS_ORIGIN=http://localhost:5173
@@ -0,0 +1,2 @@
+node_modules/
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+      "integrity": "sha512-BNGbWLfd0eUPabhkXUVm0j8uuvREyTh5ovRa/dyow/BqAbZJyC+5fU+IzQOzmAKzYqYRAISoRhdQr3eIZ/PXqg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.8"
+      }
+    },
+    "node_modules/wrappy": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz",
+      "integrity": "sha512-l4Sp/DRseor9wL6EvV2+TuQn63dMkPjZ/sp9XkghTEbV9KlPS1xUsZ3u7/IQO4wxtcFB4bgpQPRcR3QCvezPcQ==",
+      "license": "ISC"
+    }
+  }
+}
@@ -0,0 +1,16 @@
+{
+  "name": "padhle-backend",
+  "version": "0.1.0",
+  "type": "module",
+  "description": "AI-powered educational chat backend for padhle",
+  "scripts": {
+    "dev": "node --watch src/index.js",
+    "start": "node src/index.js"
+  },
+  "dependencies": {
+    "cors": "^2.8.5",
+    "express": "^5.1.0",
+    "openai": "^5.11.0",
+    "dotenv": "^16.6.0"
+  }
+}
@@ -0,0 +1,35 @@
+import dotenv from "dotenv";
+import cors from "cors";
+import express from "express";
+import chatRoutes from "./routes/chat.js";
+import sessionRoutes from "./routes/sessions.js";
+
+dotenv.config();
+
+const app = express();
+const PORT = process.env.PORT || 3001;
+const CORS_ORIGIN = process.env.CORS_ORIGIN || "http://localhost:5173";
+
+// Middleware
+app.use(cors({ origin: CORS_ORIGIN, credentials: true }));
+app.use(express.json());
+
+// Health check
+app.get("/health", (_req, res) => {
+  res.json({ status: "ok", provider: process.env.AI_PROVIDER });
+});
+
+// Routes
+app.use("/api/chat", chatRoutes);
+app.use("/api/sessions", sessionRoutes);
+
+// 404 handler
+app.use((_req, res) => {
+  res.status(404).json({ error: "Endpoint not found" });
+});
+
+app.listen(PORT, () => {
+  console.log(`\n  📚 padhle backend running on http://localhost:${PORT}`);
+  console.log(`  Provider: ${process.env.AI_PROVIDER || "openai"}`);
+  console.log(`  Frontend: ${CORS_ORIGIN}\n`);
+});
@@ -0,0 +1,132 @@
+import express from "express";
+import { streamChatResponse } from "../services/ai.js";
+import { createSession, addMessage, getMessages, getSession, listSessions } from "../stores/sessionStore.js";
+
+const router = express.Router();
+
+/**
+ * POST /api/chat — Send a message and stream back an AI response.
+ *
+ * Request body:
+ * {
+ *   text: "What is photosynthesis?",
+ *   chatId: "optional_existing_session_id",
+ *   grade: "Grade 10",
+ *   subject: "Biology",
+ *   chapter: "Nutrition in Plants"
+ * }
+ */
+router.post("/", async (req, res) => {
+  const { text, chatId, grade, subject, chapter } = req.body;
+
+  // Validate input
+  if (!text || !text.trim()) {
+    return res.status(400).json({ error: "Message text is required" });
+  }
+
+  // Resolve or create session
+  let session;
+  if (chatId) {
+    session = getSession(chatId);
+    if (!session) {
+      return res.status(404).json({ error: "Session not found" });
+    }
+  } else {
+    session = createSession(grade, subject, chapter);
+  }
+
+  const currentChatId = session.id;
+
+  // Get conversation history
+  const chatMessages = getMessages(currentChatId);
+
+  // Add user message to history
+  const userMsg = {
+    id: `user_${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;
@@ -0,0 +1,58 @@
+import express from "express";
+import { listSessions, getSession, deleteSession, clearMessages, createSession } from "../stores/sessionStore.js";
+
+const router = express.Router();
+
+/**
+ * GET /api/sessions — List all sessions
+ */
+router.get("/", (_req, res) => {
+  const sessions = listSessions();
+  res.json(sessions);
+});
+
+/**
+ * POST /api/sessions — Create a new session
+ */
+router.post("/", (req, res) => {
+  const { grade, subject, chapter } = req.body;
+  const session = createSession(grade, subject, chapter);
+  res.status(201).json(session);
+});
+
+/**
+ * GET /api/sessions/:id — Get a single session
+ */
+router.get("/:id", (req, res) => {
+  const session = getSession(req.params.id);
+  if (!session) {
+    return res.status(404).json({ error: "Session not found" });
+  }
+  res.json(session);
+});
+
+/**
+ * DELETE /api/sessions/:id — Delete a session
+ */
+router.delete("/:id", (req, res) => {
+  const deleted = deleteSession(req.params.id);
+  if (!deleted) {
+    return res.status(404).json({ error: "Session not found" });
+  }
+  res.json({ message: "Session deleted", id: req.params.id });
+});
+
+/**
+ * PATCH /api/sessions/:id/clear — Clear messages but keep session
+ */
+router.patch("/:id/clear", (req, res) => {
+  const { id } = req.params;
+  const session = getSession(id);
+  if (!session) {
+    return res.status(404).json({ error: "Session not found" });
+  }
+  clearMessages(id);
+  res.json({ message: "Messages cleared", id });
+});
+
+export default router;
@@ -0,0 +1,295 @@
+import OpenAI from "openai";
+import dotenv from "dotenv";
+
+dotenv.config();
+
+const provider = process.env.AI_PROVIDER || "openai";
+
+// --- OpenAI client ---
+const openai = new OpenAI({
+  apiKey: process.env.OPENAI_API_KEY,
+});
+
+// --- Anthropic (via OpenAI SDK compatible endpoint or raw) ---
+const ANTHROPIC_BASE_URL = "https://api.anthropic.com";
+
+// --- Google (via OpenAI SDK compatible endpoint) ---
+const GOOGLE_BASE_URL = "https://generativelanguage.googleapis.com/v1beta/openai/";
+
+/**
+ * Build the system prompt based on grade/subject/chapter context.
+ */
+function buildSystemPrompt(grade, subject, chapter) {
+  const context = [];
+
+  if (grade && grade !== "General") context.push(`You are teaching students in grade ${grade}.`);
+  if (subject && subject !== "General") context.push(`The subject is ${subject}.`);
+  if (chapter && chapter !== "General") context.push(`The relevant chapter is ${chapter}.`);
+
+  context.push(
+    "You are padhle, an AI tutor designed to help students learn.",
+    "Be clear, patient, and encouraging. Use simple language appropriate for the student's grade level.",
+    "When explaining concepts, use examples, analogies, and step-by-step breakdowns.",
+    "If a question is outside the selected subject/chapter, politely redirect to the topic or answer briefly while noting the scope.",
+    "Never just give answers for homework — explain the reasoning so the student learns.",
+    "Format your responses using markdown: headings for structure, bullet points for lists, and code blocks for examples."
+  );
+
+  return context.join("\n");
+}
+
+/**
+ * Build the messages array for the AI call.
+ */
+function buildMessages(chatMessages, grade, subject, chapter) {
+  const systemMsg = {
+    role: "system",
+    content: buildSystemPrompt(grade, subject, chapter),
+  };
+
+  const userMessages = chatMessages.map((m) => ({
+    role: m.role === "user" ? "user" : "assistant",
+    content: m.text,
+  }));
+
+  return [systemMsg, ...userMessages];
+}
+
+/**
+ * Call OpenAI and stream the response via a callback.
+ */
+async function streamOpenai(messages, onChunk, onError) {
+  const stream = await openai.chat.completions.create({
+    model: process.env.OPENAI_MODEL || "gpt-4o",
+    messages,
+    stream: true,
+    max_tokens: 2048,
+  });
+
+  let fullResponse = "";
+  for await (const chunk of stream) {
+    const content = chunk.choices[0]?.delta?.content || "";
+    if (content) {
+      fullResponse += content;
+      onChunk(content);
+    }
+  }
+
+  return fullResponse;
+}
+
+/**
+ * Call Anthropic and stream the response.
+ */
+async function streamAnthropic(messages, onChunk, onError) {
+  const userMsgs = messages.filter((m) => m.role === "user");
+  const systemMsg = messages.find((m) => m.role === "system");
+
+  const body = {
+    model: process.env.ANTHROPIC_MODEL || "claude-sonnet-4-20250514",
+    max_tokens: 2048,
+    system: systemMsg?.content || "",
+    messages: userMsgs.map((m) => ({ role: "user", content: m.content })),
+    stream: true,
+  };
+
+  const response = await fetch(ANTHROPIC_BASE_URL, {
+    method: "POST",
+    headers: {
+      "Content-Type": "application/json",
+      "x-api-key": process.env.ANTHROPIC_API_KEY,
+      "anthropic-version": "2023-06-01",
+    },
+    body: JSON.stringify(body),
+  });
+
+  if (!response.ok) {
+    const err = await response.text();
+    onError(`Anthropic API error: ${err}`);
+    return "";
+  }
+
+  const reader = response.body.getReader();
+  const decoder = new TextDecoder();
+  let fullResponse = "";
+  let buffer = "";
+
+  while (true) {
+    const { done, value } = await reader.read();
+    if (done) break;
+
+    buffer += decoder.decode(value, { stream: true });
+    const lines = buffer.split("\n");
+    buffer = lines.pop() || "";
+
+    for (const line of lines) {
+      const trimmed = line.trim();
+      if (!trimmed.startsWith("data: ")) continue;
+      const jsonStr = trimmed.slice(6);
+      if (jsonStr === "[DONE]") continue;
+
+      try {
+        const json = JSON.parse(jsonStr);
+        const content = json.delta?.text || "";
+        if (content) {
+          fullResponse += content;
+          onChunk(content);
+        }
+      } catch {}
+    }
+  }
+
+  return fullResponse;
+}
+
+/**
+ * Call Google Gemini and stream the response.
+ */
+async function streamGoogle(messages, onChunk, onError) {
+  const model = process.env.GOOGLE_MODEL || "gemini-2.0-flash";
+  const apiKey = process.env.GOOGLE_API_KEY;
+  const url = `${GOOGLE_BASE_URL}${apiKey}/chat/models/${model}:streamGenerateContent?key=${apiKey}`;
+
+  const systemMsg = messages.find((m) => m.role === "system");
+  const userMsgs = messages.filter((m) => m.role !== "system");
+
+  // Convert messages to Gemini format
+  const contents = userMsgs.map((m) => ({
+    role: m.role === "user" ? "user" : "model",
+    parts: [{ text: m.content }],
+  }));
+
+  const body = {
+    contents,
+    systemInstruction: systemMsg ? { parts: [{ text: systemMsg.content }] } : undefined,
+    generationConfig: { maxOutputTokens: 2048 },
+  };
+
+  const response = await fetch(url, {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify(body),
+  });
+
+  if (!response.ok) {
+    const err = await response.text();
+    onError(`Google AI error: ${err}`);
+    return "";
+  }
+
+  const reader = response.body.getReader();
+  const decoder = new TextDecoder();
+  let fullResponse = "";
+  let buffer = "";
+
+  while (true) {
+    const { done, value } = await reader.read();
+    if (done) break;
+
+    buffer += decoder.decode(value, { stream: true });
+    const lines = buffer.split("\n");
+    buffer = lines.pop() || "";
+
+    for (const line of lines) {
+      const trimmed = line.trim();
+      if (!trimmed) continue;
+
+      try {
+        const json = JSON.parse(trimmed);
+        const candidates = json.candidates?.[0];
+        const parts = candidates?.content?.parts;
+        const text = parts?.[0]?.text || "";
+        if (text) {
+          fullResponse += text;
+          onChunk(text);
+        }
+      } catch {}
+    }
+  }
+
+  return fullResponse;
+}
+
+/**
+ * Stream a chat response.
+ * @param {Array} chatMessages - Array of {role, text} messages
+ * @param {string} grade
+ * @param {string} subject
+ * @param {string} chapter
+ * @param {Function} onChunk - Called with each text chunk
+ * @param {Function} onError - Called on error
+ * @returns {Promise<string>} The full response text
+ */
+export async function streamChatResponse(chatMessages, grade, subject, chapter, onChunk, onError) {
+  const messages = buildMessages(chatMessages, grade, subject, chapter);
+
+  switch (provider) {
+    case "anthropic":
+      return streamAnthropic(messages, onChunk, onError);
+    case "google":
+      return streamGoogle(messages, onChunk, onError);
+    case "openai":
+    default:
+      return streamOpenai(messages, onChunk, onError);
+  }
+}
+
+/**
+ * Get a non-streaming response (fallback for simple queries).
+ */
+export async function getChatResponse(chatMessages, grade, subject, chapter) {
+  const messages = buildMessages(chatMessages, grade, subject, chapter);
+
+  let response;
+  switch (provider) {
+    case "anthropic": {
+      const userMsgs = messages.filter((m) => m.role === "user");
+      const systemMsg = messages.find((m) => m.role === "system");
+      const res = await fetch(ANTHROPIC_BASE_URL, {
+        method: "POST",
+        headers: {
+          "Content-Type": "application/json",
+          "x-api-key": process.env.ANTHROPIC_API_KEY,
+          "anthropic-version": "2023-06-01",
+        },
+        body: JSON.stringify({
+          model: process.env.ANTHROPIC_MODEL || "claude-sonnet-4-20250514",
+          max_tokens: 2048,
+          system: systemMsg?.content || "",
+          messages: userMsgs.map((m) => ({ role: "user", content: m.content })),
+        }),
+      });
+      const data = await res.json();
+      return data.content?.[0]?.text || "No response";
+    }
+    case "google": {
+      const systemMsg = messages.find((m) => m.role === "system");
+      const userMsgs = messages.filter((m) => m.role !== "system");
+      const contents = userMsgs.map((m) => ({
+        role: m.role === "user" ? "user" : "model",
+        parts: [{ text: m.content }],
+      }));
+      const url = `${GOOGLE_BASE_URL}${process.env.GOOGLE_API_KEY}/chat/models/${process.env.GOOGLE_MODEL || "gemini-2.0-flash"}:generateContent?key=${process.env.GOOGLE_API_KEY}`;
+      const res = await fetch(url, {
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+        body: JSON.stringify({
+          contents,
+          systemInstruction: systemMsg ? { parts: [{ text: systemMsg.content }] } : undefined,
+          generationConfig: { maxOutputTokens: 2048 },
+        }),
+      });
+      const data = await res.json();
+      return data.candidates?.[0]?.content?.parts?.[0]?.text || "No response";
+    }
+    case "openai":
+    default: {
+      const res = await openai.chat.completions.create({
+        model: process.env.OPENAI_MODEL || "gpt-4o",
+        messages,
+        max_tokens: 2048,
+      });
+      return res.choices?.[0]?.message?.content || "No response";
+    }
+  }
+}
@@ -0,0 +1,114 @@
+/**
+ * In-memory session store.
+ * Each session holds a chatId, metadata (grade/subject/chapter),
+ * and a list of messages. Swappable for a DB backend later.
+ */
+
+const sessions = new Map();
+const messages = new Map(); // chatId -> [Message]
+
+function generateId() {
+  return `chat_${Date.now()}_${Math.random().toString(36).slice(2, 9)}`;
+}
+
+/**
+ * Create a new chat session
+ */
+export function createSession(grade, subject, chapter) {
+  const chatId = generateId();
+  const session = {
+    id: chatId,
+    grade: grade || "General",
+    subject: subject || "General",
+    chapter: chapter || "General",
+    preview: "New Chat",
+    createdAt: new Date().toISOString(),
+    updatedAt: new Date().toISOString(),
+    messageCount: 0,
+  };
+
+  sessions.set(chatId, session);
+  messages.set(chatId, []);
+
+  return session;
+}
+
+/**
+ * Get a session by ID
+ */
+export function getSession(chatId) {
+  return sessions.get(chatId) || null;
+}
+
+/**
+ * Get all sessions (most recent first)
+ */
+export function listSessions() {
+  const all = Array.from(sessions.values());
+  return all.sort((a, b) => new Date(b.updatedAt) - new Date(a.updatedAt));
+}
+
+/**
+ * Get messages for a chat
+ */
+export function getMessages(chatId) {
+  return messages.get(chatId) || [];
+}
+
+/**
+ * Add a message to a chat session
+ */
+export function addMessage(chatId, message) {
+  const msgs = messages.get(chatId);
+  if (msgs) {
+    msgs.push(message);
+  }
+
+  // Update session metadata
+  const session = sessions.get(chatId);
+  if (session) {
+    session.updatedAt = new Date().toISOString();
+    session.messageCount = msgs ? msgs.length : 0;
+
+    // Set preview from the first user message
+    if (session.messageCount <= 1 && message.role === "user") {
+      session.preview = message.text.substring(0, 60) + (message.text.length > 60 ? "..." : "");
+    }
+  }
+
+  return message;
+}
+
+/**
+ * Delete a session and its messages
+ */
+export function deleteSession(chatId) {
+  const deleted = sessions.delete(chatId);
+  messages.delete(chatId);
+  return deleted;
+}
+
+/**
+ * Clear all messages for a session (keep session metadata)
+ */
+export function clearMessages(chatId) {
+  messages.set(chatId, []);
+  const session = sessions.get(chatId);
+  if (session) {
+    session.messageCount = 0;
+    session.updatedAt = new Date().toISOString();
+  }
+}
+
+/**
+ * Get stats (for monitoring)
+ */
+export function getStats() {
+  return {
+    activeSessions: sessions.size,
+    totalMessages: Array.from(messages.values()).reduce(
+      (sum, msgs) => sum + msgs.length,
+      0
+    ),
+  };
+}