🔧 One-Shot Static Prompt for LLM (Production-Ready Tango Catalog App)

You are a senior full-stack engineer. Build a production-ready <TechStack> application that displays the Tango Card Catalog.
All OAuth and catalog fetching must run server-side only.
Generate fully runnable code, fix build/runtime errors, and output everything in one shot.

STEP 0 — Collect Requirements

Ask the user one question at a time:

1. Frontend framework? (React, Vue, Svelte, etc.)
2. Backend framework? (Node/Express, Flask, Spring Boot, etc.)
3. Number of grid columns for the catalog?

Then request credentials and create a .env file with:

• TANGO_CLIENT_ID
• TANGO_CLIENT_SECRET
• TANGO_USERNAME
• TANGO_PASSWORD

STEP 1 — Server-Side OAuth Flow

Implement backend OAuth:

POST https://sandbox-auth.tangocard.com/oauth/token
Headers:

• Accept: application/json
• Content-Type: application/x-www-form-urlencoded

Body:

• `grant_type=password'
• 'scope=raas.all'
• 'audience=https://api.tangocard.com/'
• 'client_id=CLIENT_ID_FROM_ENV'
• 'client_secret=CLIENT_SECRET_FROM_ENV'
• 'username=USERNAME_FROM_ENV'
• 'password=PASSWORD_FROM_ENV`

Rules:

• Parse: access_token, token_type, expires_in, scope
• Throw descriptive errors for missing fields or non-200 responses
• Handle passwords containing quotes/special characters

STEP 2 — Fetch Tango Catalog

Request catalog using token:

GET https://integration-api.tangocard.com/raas/v2/catalogs?verbose=true
Headers:

• Accept: application/json
• Authorization: Bearer <access_token>

Rules:

• Normalize imageUrls (array, map, or missing)
• Fallback gracefully for missing images/description

STEP 3 — UI Requirements

Create a BrandCard component with:

• Image (priority: 200w-326ppi → 130w-326ppi → 80w-326ppi)
• brandName
• Amount

On click → open modal showing:

• Short description
• Amount options

Catalog grid uses the user-selected column count.

STEP 4 — Production Behavior

• Cache or revalidate catalog every 10 minutes
• Avoid exposing secrets to client bundles
• Strong error handling for:
  • Network failures
  • OAuth 4xx/5xx
  • Catalog 4xx/5xx
  • JSON parsing errors
• Keep dependencies minimal

STEP 5 — Output Requirements

Output complete runnable code, including:

• Full backend + frontend
• All components, routes, configs
• .env usage
• README.md with:
  • Setup instructions
  • Environment variable details
  • Install + start commands
  • One single command to start the full app

Rules:

• No pseudocode
• Every file must contain full real code
• The app must run on a clean machine without modification

STEP 6 — Execute Code

Simulate running all commands in a terminal and fix any build/runtime errors before the final output