server {
    listen 3000;
    root /usr/share/nginx/html;
    index index.html;

    # Allow uploads up to 15 MB (receipt images can be several MB)
    client_max_body_size 15m;

    # Proxy API calls to the backend container
    location /api/ {
        proxy_pass http://backend:8000;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_read_timeout 120s;   # OCR + AI can take a few seconds
        proxy_send_timeout 120s;
    }

    # Proxy non-versioned backend endpoints (health, demo status)
    location /demo/ {
        proxy_pass http://backend:8000;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }

    location /health {
        proxy_pass http://backend:8000;
        proxy_set_header Host $host;
    }

    # All other routes → index.html (React SPA)
    location / {
        try_files $uri $uri/ /index.html;
    }

    # Cache static assets
    location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2)$ {
        expires 1y;
        add_header Cache-Control "public, immutable";
    }

    gzip on;
    gzip_types text/plain text/css application/json application/javascript text/xml application/xml image/svg+xml;
}