server {
    listen 80;
    server_name localhost;

    # Client body size limit
    client_max_body_size 10M;

    # Admin 后台静态文件
    location /admin {
        alias /usr/share/nginx/html/admin;
        index index.html;
        try_files $uri $uri/ /admin/index.html;

        # 缓存静态资源
        location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot)$ {
            expires 1y;
            add_header Cache-Control "public, immutable";
        }
    }

    # API 接口代理
    location /api/ {
        limit_req zone=api_limit burst=20 nodelay;
        limit_conn conn_limit 10;

        proxy_pass http://api_servers;
        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_set_header X-Forwarded-Proto $scheme;
        proxy_cache_bypass $http_upgrade;

        proxy_connect_timeout 60s;
        proxy_send_timeout 60s;
        proxy_read_timeout 60s;
    }

    # Health check
    location /health {
        proxy_pass http://api_servers;
        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;
    }

    # API 文档
    location /api-docs {
        proxy_pass http://api_servers;
        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;
    }

    # 上传文件访问
    location /uploads/ {
        proxy_pass http://api_servers;
        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_cache_valid 200 1d;
        expires 1d;
        add_header Cache-Control "public, immutable";
    }

    # 根路径重定向到 admin
    location = / {
        return 302 /admin;
    }

    # 禁止访问隐藏文件
    location ~ /\. {
        deny all;
        access_log off;
        log_not_found off;
    }

    # 错误页面
    error_page 500 502 503 504 /50x.html;
    location = /50x.html {
        root /usr/share/nginx/html;
        internal;
    }
}