package services

import (
	"context"
	"fmt"
	"net"
	"strconv"
	"strings"
	"time"

	"github.com/gocql/gocql"
	"github.com/shadow1ng/fscan/common"
	"github.com/shadow1ng/fscan/common/i18n"
)

// CassandraPlugin Cassandra数据库扫描插件 - 基于gocql库
type CassandraPlugin struct {
	name  string
	ports []int
}

// NewCassandraPlugin 创建Cassandra插件
func NewCassandraPlugin() *CassandraPlugin {
	return &CassandraPlugin{
		name:  "cassandra",
		ports: []int{9042, 9160, 7000, 7001}, // CQL端口 + Thrift端口 + 集群通信端口
	}
}

// GetName 实现Plugin接口
func (p *CassandraPlugin) GetName() string {
	return p.name
}

// GetPorts 实现Plugin接口
func (p *CassandraPlugin) GetPorts() []int {
	return p.ports
}

// Scan 执行Cassandra扫描 - CQL协议弱密码检测
func (p *CassandraPlugin) Scan(ctx context.Context, info *common.HostInfo) *ScanResult {
	target := fmt.Sprintf("%s:%s", info.Host, info.Ports)

	// 如果禁用暴力破解，只做服务识别
	if common.DisableBrute {
		return p.identifyService(ctx, info)
	}

	// 生成测试凭据
	credentials := GenerateCredentials("cassandra")
	if len(credentials) == 0 {
		// Cassandra默认凭据
		credentials = []Credential{
			{Username: "cassandra", Password: "cassandra"},
			{Username: "admin", Password: "admin"},
			{Username: "admin", Password: ""},
			{Username: "root", Password: "root"},
			{Username: "user", Password: "user"},
		}
	}

	// 逐个测试凭据
	for _, cred := range credentials {
		// 检查Context是否被取消
		select {
		case <-ctx.Done():
			return &ScanResult{
				Success: false,
				Service: "cassandra",
				Error:   ctx.Err(),
			}
		default:
		}

		// 测试凭据
		if p.testCredential(ctx, info, cred) {
			// Cassandra认证成功
			common.LogSuccess(i18n.GetText("cassandra_scan_success", target, cred.Username, cred.Password))

			return &ScanResult{
				Success:  true,
				Service:  "cassandra",
				Username: cred.Username,
				Password: cred.Password,
			}
		}
	}

	// 所有凭据都失败
	return &ScanResult{
		Success: false,
		Service: "cassandra",
		Error:   fmt.Errorf("未发现弱密码"),
	}
}

// testCredential 测试单个凭据 - 使用gocql进行CQL认证
func (p *CassandraPlugin) testCredential(ctx context.Context, info *common.HostInfo, cred Credential) bool {
	// 解析端口
	port, err := strconv.Atoi(info.Ports)
	if err != nil {
		return false
	}

	// 创建Cassandra集群配置
	cluster := gocql.NewCluster(info.Host)
	cluster.Port = port
	
	// 设置连接参数
	timeout := time.Duration(common.Timeout) * time.Second
	cluster.Timeout = timeout
	cluster.ConnectTimeout = timeout
	cluster.ProtoVersion = 4
	cluster.Consistency = gocql.One

	// 设置认证信息
	if cred.Username != "" || cred.Password != "" {
		cluster.Authenticator = gocql.PasswordAuthenticator{
			Username: cred.Username,
			Password: cred.Password,
		}
	}

	// 支持代理连接
	if common.Socks5Proxy != "" {
		cluster.Dialer = &cassandraProxyDialer{timeout: timeout}
	}

	// 设置重试策略
	cluster.RetryPolicy = &gocql.SimpleRetryPolicy{NumRetries: 2}

	// 创建会话
	session, err := p.createSessionWithTimeout(ctx, cluster)
	if err != nil {
		return false
	}
	defer session.Close()

	// 执行简单查询验证连接
	return p.validateConnection(ctx, session)
}

// createSessionWithTimeout 在超时控制下创建Cassandra会话
func (p *CassandraPlugin) createSessionWithTimeout(ctx context.Context, cluster *gocql.ClusterConfig) (*gocql.Session, error) {
	// 创建会话通道以支持Context超时
	sessionChan := make(chan struct {
		session *gocql.Session
		err     error
	}, 1)

	// 在goroutine中创建会话
	go func() {
		session, err := cluster.CreateSession()
		select {
		case <-ctx.Done():
			if session != nil {
				session.Close()
			}
		case sessionChan <- struct {
			session *gocql.Session
			err     error
		}{session, err}:
		}
	}()

	// 等待会话创建或Context取消
	select {
	case result := <-sessionChan:
		return result.session, result.err
	case <-ctx.Done():
		return nil, fmt.Errorf("创建会话超时: %v", ctx.Err())
	}
}

// validateConnection 验证Cassandra连接 - 执行系统查询
func (p *CassandraPlugin) validateConnection(ctx context.Context, session *gocql.Session) bool {
	// 使用通道支持Context超时
	resultChan := make(chan bool, 1)

	go func() {
		// 尝试执行系统查询
		// 先尝试查询节点信息，如果失败再尝试本地信息
		var dummy interface{}
		
		err := session.Query("SELECT peer FROM system.peers LIMIT 1").WithContext(ctx).Scan(&dummy)
		if err != nil {
			// 如果peer查询失败，尝试查询本地节点信息
			err = session.Query("SELECT now() FROM system.local").WithContext(ctx).Scan(&dummy)
		}

		select {
		case <-ctx.Done():
		case resultChan <- (err == nil):
		}
	}()

	// 等待查询结果或Context取消
	select {
	case success := <-resultChan:
		return success
	case <-ctx.Done():
		return false
	}
}

// identifyService 服务识别 - 尝试连接Cassandra但不认证
func (p *CassandraPlugin) identifyService(ctx context.Context, info *common.HostInfo) *ScanResult {
	target := fmt.Sprintf("%s:%s", info.Host, info.Ports)

	// 解析端口
	port, err := strconv.Atoi(info.Ports)
	if err != nil {
		return &ScanResult{
			Success: false,
			Service: "cassandra",
			Error:   fmt.Errorf("无效的端口号: %s", info.Ports),
		}
	}

	// 创建基本集群配置（无认证）
	cluster := gocql.NewCluster(info.Host)
	cluster.Port = port
	
	timeout := time.Duration(common.Timeout) * time.Second
	cluster.Timeout = timeout
	cluster.ConnectTimeout = timeout
	cluster.ProtoVersion = 4

	// 支持代理
	if common.Socks5Proxy != "" {
		cluster.Dialer = &cassandraProxyDialer{timeout: timeout}
	}

	// 尝试创建会话
	session, err := p.createSessionWithTimeout(ctx, cluster)
	if err != nil {
		// 检查错误类型，判断是否为认证问题
		if p.isAuthenticationError(err) {
			// 认证错误说明服务存在但需要密码
			common.LogSuccess(i18n.GetText("cassandra_service_identified", target, "Cassandra (需要认证)"))
			return &ScanResult{
				Success: true,
				Service: "cassandra",
				Banner:  "Cassandra (需要认证)",
			}
		}

		return &ScanResult{
			Success: false,
			Service: "cassandra",
			Error:   err,
		}
	}
	defer session.Close()

	// 连接成功，获取Cassandra版本信息
	banner := p.getCassandraVersion(ctx, session)
	common.LogSuccess(i18n.GetText("cassandra_service_identified", target, banner))

	return &ScanResult{
		Success: true,
		Service: "cassandra",
		Banner:  banner,
	}
}

// getCassandraVersion 获取Cassandra版本信息
func (p *CassandraPlugin) getCassandraVersion(ctx context.Context, session *gocql.Session) string {
	// 尝试查询系统版本信息
	var releaseVersion string
	err := session.Query("SELECT release_version FROM system.local").WithContext(ctx).Scan(&releaseVersion)
	if err == nil && releaseVersion != "" {
		return fmt.Sprintf("Cassandra %s", releaseVersion)
	}

	// 如果无法获取版本，返回通用描述
	return "Cassandra (版本未知)"
}

// isAuthenticationError 判断是否为认证错误
func (p *CassandraPlugin) isAuthenticationError(err error) bool {
	if err == nil {
		return false
	}
	
	errStr := err.Error()
	// 检查常见的认证错误信息
	authErrors := []string{
		"authentication",
		"password",
		"credentials",
		"unauthorized",
		"login",
	}

	for _, authErr := range authErrors {
		if strings.Contains(strings.ToLower(errStr), authErr) {
			return true
		}
	}
	
	return false
}

// cassandraProxyDialer 代理拨号器
type cassandraProxyDialer struct {
	timeout time.Duration
}

// DialContext 实现gocql.Dialer接口
func (d *cassandraProxyDialer) DialContext(ctx context.Context, network, addr string) (net.Conn, error) {
	return common.WrapperTcpWithContext(ctx, network, addr)
}

// init 自动注册插件
func init() {
	RegisterPlugin("cassandra", func() Plugin {
		return NewCassandraPlugin()
	})
}