feat: add GenAI implementation guide and demo ask flows

readme.md

@@ -33,6 +33,19 @@ If your PR aligns with our development direction and passes checks we’ll merge
 
 ---
 
+## GenAI Implementation Guide
+
+The API now includes a public guide endpoint for planning a LangChain-based GenAI feature.
+
+- `GET /api/v1/gen-ai-implementation` returns the full guide for single-agent, multi-agent, and LangGraph approaches.
+- `GET /api/v1/gen-ai-implementation?mode=single` returns only the single-agent blueprint.
+- `GET /api/v1/gen-ai-implementation?mode=multi` returns the multi-agent blueprint.
+- `GET /api/v1/gen-ai-implementation?mode=langgraph` returns the LangGraph blueprint.
+
+The response is structured so a UI can render hero copy, theme data, comparison cards, and implementation steps.
+
+---
+
 ## Found a Bug or Issue?
 
 If you encounter any problems or have suggestions:

src/__tests__/gen-ai-implementation.test.js

@@ -0,0 +1,115 @@
+import request from 'supertest';
+import app from '../app.js';
+
+describe('GenAI Implementation API Routes', () => {
+    describe('GET /api/v1/gen-ai-implementation', () => {
+        it('should return the full implementation guide by default', async () => {
+            const response = await request(app)
+                .get('/api/v1/gen-ai-implementation')
+                .expect(200);
+
+            expect(response.body.success).toBe(true);
+            expect(response.body.message).toBe(
+                'GenAI implementation guide retrieved successfully'
+            );
+            expect(response.body.data).toHaveProperty('feature');
+            expect(response.body.data).toHaveProperty('uiTheme');
+            expect(response.body.data).toHaveProperty('overview');
+            expect(response.body.data).toHaveProperty('implementationModes');
+            expect(response.body.data.implementationModes).toHaveProperty('single');
+            expect(response.body.data.implementationModes).toHaveProperty('multi');
+            expect(response.body.data.implementationModes).toHaveProperty(
+                'langgraph'
+            );
+        });
+
+        it('should return a single-agent guide when requested', async () => {
+            const response = await request(app)
+                .get('/api/v1/gen-ai-implementation?mode=single')
+                .expect(200);
+
+            expect(response.body.success).toBe(true);
+            expect(response.body.data.implementation.slug).toBe('single');
+            expect(response.body.data.implementation.title).toBe(
+                'Single-Agent LangChain'
+            );
+        });
+
+        it('should return a LangGraph guide when requested', async () => {
+            const response = await request(app)
+                .get('/api/v1/gen-ai-implementation?mode=langgraph')
+                .expect(200);
+
+            expect(response.body.success).toBe(true);
+            expect(response.body.data.implementation.slug).toBe('langgraph');
+            expect(response.body.data.implementation.codeSnippet).toContain(
+                'StateGraph'
+            );
+        });
+
+        it('should return 400 for invalid mode values', async () => {
+            const response = await request(app)
+                .get('/api/v1/gen-ai-implementation?mode=unknown')
+                .expect(400);
+
+            expect(response.body.success).toBe(false);
+            expect(response.body.message).toBe(
+                'Invalid mode. Use single, multi, langgraph, or all.'
+            );
+        });
+    });
+
+    describe('POST /api/v1/gen-ai-implementation/*/ask', () => {
+        it('should return single-agent demo output', async () => {
+            const response = await request(app)
+                .post('/api/v1/gen-ai-implementation/single/ask')
+                .send({ question: 'How to start with LangChain?' })
+                .expect(200);
+
+            expect(response.body.success).toBe(true);
+            expect(response.body.message).toBe(
+                'Single-agent demo response generated successfully'
+            );
+            expect(response.body.data.mode).toBe('single');
+            expect(response.body.data).toHaveProperty('response');
+        });
+
+        it('should return multi-agent demo output', async () => {
+            const response = await request(app)
+                .post('/api/v1/gen-ai-implementation/multi/ask')
+                .send({ question: 'How to design multi-agent pipeline?' })
+                .expect(200);
+
+            expect(response.body.success).toBe(true);
+            expect(response.body.message).toBe(
+                'Multi-agent demo response generated successfully'
+            );
+            expect(response.body.data.mode).toBe('multi');
+            expect(response.body.data).toHaveProperty('researchNotes');
+        });
+
+        it('should return langgraph demo output', async () => {
+            const response = await request(app)
+                .post('/api/v1/gen-ai-implementation/langgraph/ask')
+                .send({ question: 'How to add retries in workflow?' })
+                .expect(200);
+
+            expect(response.body.success).toBe(true);
+            expect(response.body.message).toBe(
+                'LangGraph demo response generated successfully'
+            );
+            expect(response.body.data.mode).toBe('langgraph');
+            expect(response.body.data).toHaveProperty('graphTrace');
+        });
+
+        it('should return 400 when question is missing', async () => {
+            const response = await request(app)
+                .post('/api/v1/gen-ai-implementation/single/ask')
+                .send({ question: '' })
+                .expect(400);
+
+            expect(response.body.success).toBe(false);
+            expect(response.body.message).toBe('Question is required.');
+        });
+    });
+});

src/app.js

@@ -33,12 +33,14 @@ import userRoutes from './routes/user.routes.js';
 import productRoutes from './routes/product.routes.js';
 import cartRoutes from './routes/cart.routes.js';
 import paymentRoutes from './routes/payment.routes.js';
+import genAiImplementationRoutes from './routes/gen-ai-implementation.routes.js';
 
 app.use('/api/v1/auth', authRoutes);
 app.use('/api/v1/users', userRoutes);
 app.use('/api/v1/store/products', productRoutes);
 app.use('/api/v1/store/cart', cartRoutes);
 app.use('/api/v1/payments', paymentRoutes);
+app.use('/api/v1/gen-ai-implementation', genAiImplementationRoutes);
 
 // // Simple route for checking server status
 app.get('/', (req, res) => {

src/config/config.js

@@ -27,10 +27,10 @@ const _config = {
 };
 
 let finalConfig;
-if (process.env.NODE_ENV === 'testing') {
-  finalConfig = _config; // Don't freeze in testing mode
-} else {
+if (process.env.NODE_ENV === 'production') {
   finalConfig = Object.freeze(_config);
+} else {
+  finalConfig = _config; // Keep config mutable outside production for tests and local overrides
 }
 
 export default finalConfig;

src/config/email.config.js

@@ -1,18 +1,31 @@
 import nodemailer from 'nodemailer';
 import { google } from 'googleapis';
 import config from './config.js';
+import AppError from '../utils/appError.js';
 
 const OAuth2 = google.auth.OAuth2;
 
-const oAuth2Client = new OAuth2(
-  config.GOOGLE_CLIENT_ID,
-  config.GOOGLE_CLIENT_SECRET,
-  'https://developers.google.com/oauthplayground'
-);
+export const createTransporter = async () => {
+  if (
+    !config.GOOGLE_CLIENT_ID ||
+    !config.GOOGLE_CLIENT_SECRET ||
+    !config.GOOGLE_REFRESH_TOKEN ||
+    !config.GMAIL_USER
+  ) {
+    throw new AppError(
+      'Email service is not configured. Set GOOGLE_CLIENT_ID, GOOGLE_CLIENT_SECRET, GOOGLE_REFRESH_TOKEN, and GMAIL_USER.',
+      503
+    );
+  }
 
-oAuth2Client.setCredentials({ refresh_token: config.GOOGLE_REFRESH_TOKEN });
+  const oAuth2Client = new OAuth2(
+    config.GOOGLE_CLIENT_ID,
+    config.GOOGLE_CLIENT_SECRET,
+    'https://developers.google.com/oauthplayground'
+  );
+
+  oAuth2Client.setCredentials({ refresh_token: config.GOOGLE_REFRESH_TOKEN });
 
-export const createTransporter = async () => {
   const { token } = await oAuth2Client.getAccessToken();
 
   return nodemailer.createTransport({