server {
    listen 80;
    server_name localhost;
    client_max_body_size 50M;

    # Service worker and app shell must revalidate so PWA updates are detected
    location ~* ^/(sw\.js|workbox-.*\.js|manifest\.webmanifest|version\.json)$ {
        root /usr/share/nginx/html;
        add_header Cache-Control "no-cache, no-store, must-revalidate";
    }

    location = /index.html {
        root /usr/share/nginx/html;
        add_header Cache-Control "no-cache, must-revalidate";
    }

    location / {
        root /usr/share/nginx/html;
        index index.html index.htm;
        try_files $uri $uri/ /index.html;
    }

    location /api/ {
        proxy_pass http://backend:5000/api/;
        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;
    }
}