Trainer AI

AI-assisted workout and meal planning with session tracking. Built with Next.js App Router, TypeScript, Tailwind, and MongoDB/Cosmos.

Architecture

flowchart LR
  browser[Browser] --> next[Next.js App Router]
  next --> ui[Pages + Client Components]
  next --> api[API Routes]
  api --> db[(MongoDB / Cosmos)]
  api --> ai[AI Providers]
  ui --> analytics[GA4 + GTM]

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Local setup

1. Use Node.js 20 (nvm recommended).
   • nvm use 20.19.6
2. Install dependencies.
   • npm install
3. Configure environment variables.
   • cp .env.example .env
   • Fill in required values.
4. Start the dev server.
   • npm run dev

Environment variables

Required:

• MONGODB_URI - MongoDB connection string.
• JWT_SECRET - secret used to sign auth cookies.

Optional (AI providers):

• GEMINI_API_KEY
• OPENROUTER_API_KEY
• MISTRAL_API_KEY
• GROQ_API_KEY
• CEREBRAS_API_KEY

Optional (analytics):

• NEXT_PUBLIC_GA_ID
• NEXT_PUBLIC_GTM_ID

Optional (OAuth):

• GOOGLE_CLIENT_ID
• GOOGLE_CLIENT_SECRET
• FACEBOOK_CLIENT_ID
• FACEBOOK_CLIENT_SECRET
• APPLE_CLIENT_ID
• APPLE_CLIENT_SECRET

API endpoints

Auth:

• POST /api/auth/signup - create account and set auth cookie.
• POST /api/auth/login - authenticate and set auth cookie.
• POST /api/auth/logout - clear auth cookie.
• GET /api/auth/oauth/:provider - start OAuth flow.
• GET /api/auth/oauth/:provider/callback - OAuth callback handler.

User:

• GET /api/me/profile - fetch profile.
• PUT /api/me/profile - update or create profile.
• GET /api/me/settings - fetch settings.
• PUT /api/me/settings - update settings.
• POST /api/me/avatar - upload profile avatar.
• PUT /api/me/password - change password.

Plans:

• GET /api/plans/active - fetch active workout/diet plan.
• POST /api/plans/generate-workout - generate workout plan.
• POST /api/plans/workout-image - regenerate exercise image.
• POST /api/plans/generate-diet - generate diet plan.
• POST /api/plans/diet-image - regenerate diet image.

AI models:

• GET /api/ai-models - list AI models.
• POST /api/ai-models - create AI model config.
• GET /api/ai-models/:id - get model details.
• PUT /api/ai-models/:id - update model.
• DELETE /api/ai-models/:id - delete model.

Messages:

• GET /api/messages - list AI messages.
• POST /api/messages - send message.
• POST /api/messages/rate - rate a response.

Workout sessions:

• POST /api/workout-sessions - create a workout session.
• GET /api/workout-sessions - list sessions.
• GET /api/workout-sessions/:id - get a session.
• PATCH /api/workout-sessions/:id - update a session.

Scripts

• npm run dev - local dev server.
• npm run build - production build.
• npm run start - serve production build.
• npm run lint - lint.
• npm run test - Jest unit/API tests.
• npm run test:watch - Jest watch mode.
• npm run e2e - Playwright end-to-end tests (starts dev server).
• npm run e2e:ui - Playwright UI mode.

Testing notes

• Playwright uses a local dev server and sets E2E_MOCKS=true to avoid DB dependencies in some flows.
• Install Playwright browsers once: npx playwright install.