server {
    listen 3000;
    server_name _;

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

    # API + WebSocket 反向代理（含 WebSocket upgrade 支持）
    location /api/ {
        proxy_pass http://api-server:8000;
        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_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_read_timeout 3600s;
        proxy_send_timeout 3600s;
    }

    # 前端静态文件（注入运行时 API 配置，让前端走 nginx 代理而非直连 :8000）
    location / {
        try_files $uri $uri/ /index.html;
        sub_filter_once on;
        sub_filter '</head>' '<script>window.CONFIG={API_BASE_URL:window.location.origin};</script></head>';
    }

    # gzip 压缩
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/xml+rss application/json application/javascript;
}