server {
    listen 80;
    server_name cdn.urmic.org;

    # Redirect HTTP to HTTPS
    return 301 https://$host$request_uri;
}

server {
    listen 443 ssl http2;
    server_name cdn.urmic.org;

    # SSL settings (use certbot or your provider)
    ssl_certificate /etc/letsencrypt/live/cdn.urmic.org/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/cdn.urmic.org/privkey.pem;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers HIGH:!aNULL:!MD5;
    ssl_prefer_server_ciphers on;
    ssl_session_cache shared:SSL:10m;
    ssl_session_timeout 10m;

    if ($request_method !~ ^(GET|HEAD|POST|OPTIONS)$) {
        return 444;
    }

    # Root CDN content
    root /var/www/cdn.urmic.org;
    index index.html;

    # Rate Limiting (Anti-DDoS)
    limit_req zone=req_limit_per_ip burst=10 nodelay;

    # Connection limiting
    limit_conn_zone $binary_remote_addr zone=conn_limit_per_ip:10m;
    limit_conn conn_limit_per_ip 10;

    # Basic Security Headers
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-XSS-Protection "1; mode=block" always;
    add_header Referrer-Policy "no-referrer-when-downgrade";
    add_header Content-Security-Policy "default-src 'self' cdn.urmic.org;";

    # Protect against large request bodies
    client_max_body_size 5M;

    # Logging
    access_log /var/log/nginx/cdn.urmic.org.access.log;
    error_log /var/log/nginx/cdn.urmic.org.error.log warn;

    # Cache Control (for static CDN files)
    location ~* \.(jpg|jpeg|png|gif|ico|css|js|woff|woff2|ttf|svg|eot|mp4|webm|ogg|avi)$ {
        expires 30d;
        access_log off;
        add_header Cache-Control "public, no-transform";
    }

    # General static file serving
    location / {
        try_files $uri $uri/ =404;
    }

    # Deny access to hidden files
    location ~ /\. {
        deny all;
    }
}