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

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_proxied expired no-cache no-store private auth;
    gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/xml application/javascript;

    # 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 "strict-origin-when-cross-origin" always;

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

    # SPA routing - send all requests to index.html
    location / {
        try_files $uri $uri/ /index.html;
    }

    # Health check endpoint
    location /health {
        access_log off;
        return 200 "healthy\n";
        add_header Content-Type text/plain;
    }

    # API proxy (optional - if needed)
    # location /api {
    #     proxy_pass http://backend:3000;
    #     proxy_http_version 1.1;
    #     proxy_set_header Upgrade $http_upgrade;
    #     proxy_set_header Connection 'upgrade';
    #     proxy_set_header Host $host;
    #     proxy_cache_bypass $http_upgrade;
    # }
}