server {
    listen 80;
    server_name _;
    root /usr/share/nginx/html;
    index index.html;

    # Backend API dentro de la misma base HTTPS (evita mixed content).
    location /auth/ {
        proxy_pass http://backend:8074/auth/;
        proxy_http_version 1.1;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }

    location /exam/ {
        proxy_pass http://backend:8074/exam/;
        proxy_http_version 1.1;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }

    location = /health {
        proxy_pass http://backend:8074/health;
        proxy_http_version 1.1;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }

    # SPA: cualquier ruta desconocida sirve index.html (React Router).
    location / {
        try_files $uri $uri/ /index.html;
    }

    # Cache de assets con hash.
    location /assets/ {
        expires 1y;
        add_header Cache-Control "public, immutable";
    }

    gzip on;
    gzip_types text/css application/javascript application/json image/svg+xml;
    gzip_min_length 1024;
}