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

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_min_length 256;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_types text/plain text/css text/xml text/javascript application/javascript application/xml+rss application/json image/svg+xml application/manifest+json;

    # Cache static app assets (immutable cache-busted files)
    location ~* ^/_next/static/ {
        expires 1y;
        add_header Cache-Control "public, immutable";
        add_header X-Content-Type-Options "nosniff" always;
    }

    # Cache images, fonts, icons
    location ~* \.(png|jpg|jpeg|gif|ico|svg|webp|woff|woff2|ttf|eot)$ {
        expires 30d;
        add_header Cache-Control "public";
    }

    # Service worker - must not be cached
    location = /sw.js {
        expires -1;
        add_header Cache-Control "no-store, no-cache, must-revalidate, proxy-revalidate";
        add_header X-Content-Type-Options "nosniff" always;
    }

    # Manifest - light caching
    location = /manifest.json {
        expires 1h;
        add_header Cache-Control "public, must-revalidate";
    }

    # SPA fallback - handles /, /login/, /map/, /settings/
    location / {
        try_files $uri $uri/ $uri/index.html /index.html;
    }

    # Security headers (applied globally)
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;
    add_header Permissions-Policy "geolocation=(self)" always;
}