server {
  listen 80;
  server_name _;

  root /usr/share/nginx/html;
  index index.html;

  # Don't cache the entrypoints / SW / manifest so updates roll out
  location = /index.html {
    add_header Cache-Control "no-cache, must-revalidate" always;
  }
  location = /sw.js {
    add_header Cache-Control "no-cache, must-revalidate" always;
    add_header Service-Worker-Allowed "/" always;
  }
  location = /manifest.webmanifest {
    add_header Cache-Control "no-cache" always;
    types { } default_type application/manifest+json;
  }

  # Static assets: short cache (the SW does the heavy caching)
  location /css/  { add_header Cache-Control "public, max-age=300"; try_files $uri =404; }
  location /js/   { add_header Cache-Control "public, max-age=300"; try_files $uri =404; }
  location /icons/ { add_header Cache-Control "public, max-age=86400"; try_files $uri =404; }

  # API: proxy to backend container
  location /api/ {
    proxy_pass         http://backend:3000/api/;
    proxy_http_version 1.1;
    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 30s;
  }

  # SPA fallback: any other path → index.html (History API routing)
  location / {
    try_files $uri $uri/ /index.html;
  }
}