cellbot/internal/plugins/mcstatus/ping.go

package mcstatus

import (
	"encoding/json"
	"fmt"
	"strings"
	"time"

	mcnet "github.com/Tnze/go-mc/net"
	pk "github.com/Tnze/go-mc/net/packet"
)

// ServerStatus 服务器状态信息
type ServerStatus struct {
	Host        string
	Port        int
	Latency     int64 // 延迟（毫秒）
	Version     Version
	Players     Players
	Description string // MOTD
	Favicon     string // Base64 编码的图标
}

// Version 版本信息
type Version struct {
	Name     string
	Protocol int
}

// Players 玩家信息
type Players struct {
	Online int
	Max    int
}

// Ping 查询 Minecraft 服务器状态
func Ping(host string, port int, timeout time.Duration) (*ServerStatus, error) {
	// 连接服务器
	startTime := time.Now()
	conn, err := mcnet.DialMC(fmt.Sprintf("%s:%d", host, port))
	if err != nil {
		return nil, fmt.Errorf("failed to connect: %w", err)
	}
	defer conn.Close()

	latency := time.Since(startTime).Milliseconds()

	// 发送握手包
	handshake := pk.Marshal(
		0x00,          // Handshake packet ID
		pk.VarInt(47), // Protocol version (1.8+)
		pk.String(host),
		pk.UnsignedShort(port),
		pk.VarInt(1), // Next state: Status
	)
	if err := conn.WritePacket(handshake); err != nil {
		return nil, fmt.Errorf("failed to send handshake: %w", err)
	}

	// 发送状态请求
	request := pk.Marshal(0x00) // Status request packet ID
	if err := conn.WritePacket(request); err != nil {
		return nil, fmt.Errorf("failed to send status request: %w", err)
	}

	// 读取响应
	var response pk.Packet
	if err := conn.ReadPacket(&response); err != nil {
		return nil, fmt.Errorf("failed to read response: %w", err)
	}

	// 解析响应
	var statusJSON pk.String
	if err := response.Scan(&statusJSON); err != nil {
		return nil, fmt.Errorf("failed to parse response: %w", err)
	}

	// 解析 JSON 响应
	var statusData map[string]interface{}
	if err := json.Unmarshal([]byte(statusJSON), &statusData); err != nil {
		return nil, fmt.Errorf("failed to parse JSON: %w", err)
	}

	status := &ServerStatus{
		Host:    host,
		Port:    port,
		Latency: latency,
	}

	// 解析 description
	if desc, ok := statusData["description"].(map[string]interface{}); ok {
		if text, ok := desc["text"].(string); ok {
			status.Description = text
		} else if text, ok := desc["extra"].([]interface{}); ok && len(text) > 0 {
			// 处理 extra 数组
			var descText strings.Builder
			for _, item := range text {
				if itemMap, ok := item.(map[string]interface{}); ok {
					if text, ok := itemMap["text"].(string); ok {
						descText.WriteString(text)
					}
				}
			}
			status.Description = descText.String()
		}
	} else if desc, ok := statusData["description"].(string); ok {
		status.Description = desc
	}

	// 解析 version
	if version, ok := statusData["version"].(map[string]interface{}); ok {
		if name, ok := version["name"].(string); ok {
			status.Version.Name = name
		}
		if protocol, ok := version["protocol"].(float64); ok {
			status.Version.Protocol = int(protocol)
		}
	}

	// 解析 players
	if players, ok := statusData["players"].(map[string]interface{}); ok {
		if online, ok := players["online"].(float64); ok {
			status.Players.Online = int(online)
		}
		if max, ok := players["max"].(float64); ok {
			status.Players.Max = int(max)
		}
	}

	// 解析 favicon
	if favicon, ok := statusData["favicon"].(string); ok {
		// 移除 data:image/png;base64, 前缀
		if strings.HasPrefix(favicon, "data:image/png;base64,") {
			status.Favicon = strings.TrimPrefix(favicon, "data:image/png;base64,")
		} else {
			status.Favicon = favicon
		}
	}

	return status, nil
}