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

    # gzip
    gzip on;
    gzip_types text/plain text/css application/json application/javascript text/xml application/xml text/javascript;
    gzip_min_length 256;

    # security headers
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-XSS-Protection "1; mode=block" always;

    # static assets with long cache
    location /assets/ {
        expires 7d;
        add_header Cache-Control "public, immutable";
    }

    location / {
        try_files $uri $uri/ /index.html;
        add_header Cache-Control "no-cache";
    }

    # SSE 长连接：禁用代理缓冲并放宽读写超时，避免 60s 空闲被掐断
    location ~ ^/api/(notifications/stream|attendance-records/import/dingtalk/stream|ai/chat/.*/stream)$ {
        proxy_pass http://backend:3000;
        proxy_http_version 1.1;
        proxy_set_header Connection "";
        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_buffering off;
        proxy_cache off;
        proxy_read_timeout 3600s;
        proxy_send_timeout 3600s;
        add_header X-Accel-Buffering no;
    }

    location /api/ {
        proxy_pass http://backend:3000/api/;
        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 60s;
    }
}