package snmp

import (
	"context"
	"fmt"
	"strings"

	"github.com/shadow1ng/fscan/common"
	"github.com/shadow1ng/fscan/common/i18n"
	"github.com/shadow1ng/fscan/plugins/base"
)

// SNMPPlugin SNMP插件实现
type SNMPPlugin struct {
	*base.ServicePlugin
	exploiter *SNMPExploiter
}

// NewSNMPPlugin 创建SNMP插件
func NewSNMPPlugin() *SNMPPlugin {
	// 插件元数据
	metadata := &base.PluginMetadata{
		Name:        "snmp",
		Version:     "2.0.0",
		Author:      "fscan-team",
		Description: "SNMP网络管理协议服务扫描插件",
		Category:    "service",
		Ports:       []int{161}, // SNMP默认端口
		Protocols:   []string{"udp"},
		Tags:        []string{"snmp", "network-management", "weak-community", "information-disclosure"},
	}
	
	// 创建连接器和服务插件
	connector := NewSNMPConnector()
	servicePlugin := base.NewServicePlugin(metadata, connector)
	
	// 创建SNMP插件
	plugin := &SNMPPlugin{
		ServicePlugin: servicePlugin,
		exploiter:     NewSNMPExploiter(),
	}
	
	// 设置能力
	plugin.SetCapabilities([]base.Capability{
		base.CapWeakPassword,
		base.CapInformationLeak,
	})
	
	return plugin
}

// Scan 重写扫描方法，进行SNMP服务扫描
func (p *SNMPPlugin) Scan(ctx context.Context, info *common.HostInfo) (*base.ScanResult, error) {
	// 如果禁用了暴力破解，只进行服务识别
	if common.DisableBrute {
		return p.performServiceIdentification(ctx, info)
	}
	
	target := fmt.Sprintf("%s:%s", info.Host, info.Ports)
	
	// 优先尝试默认community字符串
	defaultCommunities := []*base.Credential{
		{Username: "public", Password: ""},
		{Username: "private", Password: ""},
		{Username: "cisco", Password: ""},
		{Username: "community", Password: ""},
	}
	
	// 先测试默认community
	for _, cred := range defaultCommunities {
		result, err := p.ScanCredential(ctx, info, cred)
		if err == nil && result.Success {
			// 认证成功
			common.LogSuccess(i18n.GetText("snmp_weak_community_success", target, cred.Username))
			
			return &base.ScanResult{
				Success:     true,
				Service:     "SNMP",
				Credentials: []*base.Credential{cred},
				Banner:      result.Banner,
				Extra: map[string]interface{}{
					"service":   "SNMP",
					"port":      info.Ports,
					"community": cred.Username,
					"type":      "weak-community",
				},
			}, nil
		}
	}
	
	// 生成其他凭据进行暴力破解
	credentials := p.generateCredentials()
	
	// 遍历凭据进行测试
	for _, cred := range credentials {
		result, err := p.ScanCredential(ctx, info, cred)
		if err == nil && result.Success {
			// 认证成功
			common.LogSuccess(i18n.GetText("snmp_weak_community_success", target, cred.Username))
			
			return &base.ScanResult{
				Success:     true,
				Service:     "SNMP",
				Credentials: []*base.Credential{cred},
				Banner:      result.Banner,
				Extra: map[string]interface{}{
					"service":   "SNMP",
					"port":      info.Ports,
					"community": cred.Username,
					"type":      "weak-community",
				},
			}, nil
		}
	}
	
	// 所有凭据都失败，但可能识别到了SNMP服务
	return p.performServiceIdentification(ctx, info)
}

// generateCredentials 生成SNMP凭据（community字符串）
func (p *SNMPPlugin) generateCredentials() []*base.Credential {
	var credentials []*base.Credential
	
	// 获取SNMP community字典
	communities := common.Userdict["snmp"]
	if len(communities) == 0 {
		// 常见的SNMP community字符串
		communities = []string{
			"admin", "manager", "secret", "read", "write", "test", 
			"monitor", "guest", "default", "root", "snmp", "router", 
			"switch", "network", "public1", "private1", "v1", "v2c",
		}
	}
	
	// 生成community凭据
	for _, community := range communities {
		credentials = append(credentials, &base.Credential{
			Username: community,
			Password: "",
		})
	}
	
	// 如果有密码字典，也作为community使用
	passwords := common.Passwords
	if len(passwords) > 0 {
		for _, password := range passwords {
			// 替换密码中的占位符
			actualPassword := strings.Replace(password, "{user}", "snmp", -1)
			if actualPassword != "" && actualPassword != "snmp" {
				credentials = append(credentials, &base.Credential{
					Username: actualPassword,
					Password: "",
				})
			}
		}
	}
	
	return credentials
}

// Exploit 使用exploiter执行利用
func (p *SNMPPlugin) Exploit(ctx context.Context, info *common.HostInfo, creds *base.Credential) (*base.ExploitResult, error) {
	return p.exploiter.Exploit(ctx, info, creds)
}

// GetExploitMethods 获取利用方法
func (p *SNMPPlugin) GetExploitMethods() []base.ExploitMethod {
	return p.exploiter.GetExploitMethods()
}

// IsExploitSupported 检查利用支持
func (p *SNMPPlugin) IsExploitSupported(method base.ExploitType) bool {
	return p.exploiter.IsExploitSupported(method)
}

// performServiceIdentification 执行SNMP服务识别（-nobr模式）
func (p *SNMPPlugin) performServiceIdentification(ctx context.Context, info *common.HostInfo) (*base.ScanResult, error) {
	target := fmt.Sprintf("%s:%s", info.Host, info.Ports)
	
	// 尝试识别SNMP服务
	connector := NewSNMPConnector()
	conn, err := connector.Connect(ctx, info)
	
	if err == nil && conn != nil {
		if snmpConn, ok := conn.(*SNMPConnection); ok {
			// 记录服务识别成功
			common.LogSuccess(i18n.GetText("snmp_service_identified", target, snmpConn.info))
			
			connector.Close(conn)
			return &base.ScanResult{
				Success: true,
				Service: "SNMP",
				Banner:  snmpConn.info,
				Extra: map[string]interface{}{
					"service":   "SNMP",
					"port":      info.Ports,
					"info":      snmpConn.info,
					"protocol":  "SNMP",
					"community": snmpConn.community,
				},
			}, nil
		}
	}
	
	// 如果无法识别为SNMP，返回失败
	return &base.ScanResult{
		Success: false,
		Error:   fmt.Errorf("无法识别为SNMP服务"),
	}, nil
}

// =============================================================================
// 插件注册
// =============================================================================

// RegisterSNMPPlugin 注册SNMP插件
func RegisterSNMPPlugin() {
	factory := base.NewSimplePluginFactory(
		&base.PluginMetadata{
			Name:        "snmp",
			Version:     "2.0.0",
			Author:      "fscan-team",
			Description: "SNMP网络管理协议服务扫描插件",
			Category:    "service",
			Ports:       []int{161}, // SNMP默认端口
			Protocols:   []string{"udp"},
			Tags:        []string{"snmp", "network-management", "weak-community", "information-disclosure"},
		},
		func() base.Plugin {
			return NewSNMPPlugin()
		},
	)
	
	base.GlobalPluginRegistry.Register("snmp", factory)
}

// 自动注册
func init() {
	RegisterSNMPPlugin()
}