server {
    listen 80;
    root /usr/share/nginx/html;
    index index.html;
    resolver 127.0.0.11 valid=10s ipv6=off;

    # Gzip compression — critical for large API responses (coverage ~26 MB → ~2-3 MB)
    gzip on;
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_types text/plain text/css text/xml application/json application/javascript application/rss+xml application/atom+xml image/svg+xml;
    gzip_min_length 256;

    # Proxy API calls through to the app service so live stats work
    location /api/ {
        set $backend_api_upstream http://backend:3000;
        proxy_pass $backend_api_upstream;
        proxy_http_version 1.1;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }

    # Proxy WebSocket connections to backend
    location /ws/ {
        set $backend_ws_upstream http://backend:3000;
        proxy_pass $backend_ws_upstream;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_read_timeout 86400;
    }
    location /ws {
        set $backend_ws_upstream http://backend:3000;
        proxy_pass $backend_ws_upstream;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_read_timeout 86400;
    }

    # SPA fallback — all routes serve index.html
    location / {
        try_files $uri $uri/ /index.html;
    }

    location /assets/ {
        expires 1y;
        add_header Cache-Control "public, immutable";
        try_files $uri =404;
    }

    location = /index.html {
        add_header Cache-Control "no-cache, no-store, must-revalidate";
    }
}