package smtp

import (
	"context"
	"fmt"
	"net"
	"net/smtp"
	"strconv"
	"time"

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

// SMTPConnector SMTP连接器实现
type SMTPConnector struct {
	host string
	port int
}

// SMTPConnection SMTP连接结构
type SMTPConnection struct {
	client   *smtp.Client
	username string
	password string
	info     string
	host     string
}

// NewSMTPConnector 创建SMTP连接器
func NewSMTPConnector() *SMTPConnector {
	return &SMTPConnector{}
}

// Connect 建立SMTP连接
func (c *SMTPConnector) Connect(ctx context.Context, info *common.HostInfo) (interface{}, error) {
	// 解析端口
	port, err := strconv.Atoi(info.Ports)
	if err != nil {
		return nil, fmt.Errorf("无效的端口号: %s", info.Ports)
	}

	c.host = info.Host
	c.port = port

	timeout := time.Duration(common.Timeout) * time.Second
	addr := fmt.Sprintf("%s:%s", info.Host, info.Ports)

	// 结果通道
	type connResult struct {
		conn   *SMTPConnection
		err    error
		banner string
	}
	resultChan := make(chan connResult, 1)

	// 在协程中尝试连接
	go func() {
		// 建立TCP连接
		tcpConn, err := net.DialTimeout("tcp", addr, timeout)
		if err != nil {
			select {
			case <-ctx.Done():
			case resultChan <- connResult{nil, err, ""}:
			}
			return
		}

		// 设置连接超时
		tcpConn.SetDeadline(time.Now().Add(timeout))

		// 创建SMTP客户端
		client, err := smtp.NewClient(tcpConn, info.Host)
		if err != nil {
			tcpConn.Close()
			select {
			case <-ctx.Done():
			case resultChan <- connResult{nil, err, ""}:
			}
			return
		}

		// 获取服务器信息
		banner := "SMTP Service (Detected)"

		// 创建连接对象
		smtpConn := &SMTPConnection{
			client: client,
			info:   banner,
			host:   info.Host,
		}

		select {
		case <-ctx.Done():
			client.Close()
		case resultChan <- connResult{smtpConn, nil, banner}:
		}
	}()

	// 等待连接结果
	select {
	case result := <-resultChan:
		if result.err != nil {
			return nil, result.err
		}
		return result.conn, nil
	case <-ctx.Done():
		return nil, ctx.Err()
	}
}

// Authenticate 进行SMTP认证
func (c *SMTPConnector) Authenticate(ctx context.Context, conn interface{}, cred *base.Credential) error {
	smtpConn, ok := conn.(*SMTPConnection)
	if !ok {
		return fmt.Errorf("无效的SMTP连接类型")
	}

	// 如果是空用户名和密码，测试匿名访问
	if cred.Username == "" && cred.Password == "" {
		// 尝试匿名发送测试邮件
		return c.testAnonymousAccess(smtpConn)
	}

	// 结果通道
	type authResult struct {
		err error
	}
	resultChan := make(chan authResult, 1)

	// 在协程中尝试认证
	go func() {
		// 尝试PLAIN认证
		auth := smtp.PlainAuth("", cred.Username, cred.Password, smtpConn.host)
		err := smtpConn.client.Auth(auth)

		if err == nil {
			// 认证成功，测试MAIL FROM权限
			mailErr := smtpConn.client.Mail("test@test.com")
			if mailErr != nil {
				err = fmt.Errorf("认证成功但缺少发送权限: %v", mailErr)
			}
		}

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

	// 等待认证结果
	select {
	case result := <-resultChan:
		if result.err != nil {
			return fmt.Errorf(i18n.GetText("smtp_auth_failed"), result.err)
		}

		// 更新连接信息
		smtpConn.username = cred.Username
		smtpConn.password = cred.Password
		return nil
	case <-ctx.Done():
		return ctx.Err()
	}
}

// testAnonymousAccess 测试匿名访问
func (c *SMTPConnector) testAnonymousAccess(smtpConn *SMTPConnection) error {
	// 尝试匿名发送测试邮件
	err := smtpConn.client.Mail("test@test.com")
	if err != nil {
		return fmt.Errorf("SMTP服务不支持匿名访问: %v", err)
	}
	return nil
}

// Close 关闭SMTP连接
func (c *SMTPConnector) Close(conn interface{}) error {
	if smtpConn, ok := conn.(*SMTPConnection); ok {
		if smtpConn.client != nil {
			smtpConn.client.Close()
		}
		return nil
	}
	return fmt.Errorf("无效的SMTP连接类型")
}

// GetConnectionInfo 获取连接信息
func (conn *SMTPConnection) GetConnectionInfo() map[string]interface{} {
	info := map[string]interface{}{
		"protocol": "SMTP",
		"service":  "SMTP",
		"info":     conn.info,
	}

	if conn.username != "" {
		info["username"] = conn.username
		info["authenticated"] = true
	}

	return info
}

// IsAlive 检查连接是否仍然有效
func (conn *SMTPConnection) IsAlive() bool {
	if conn.client == nil {
		return false
	}

	// 简单的NOOP命令测试连接
	err := conn.client.Noop()
	return err == nil
}

// GetServerInfo 获取服务器信息
func (conn *SMTPConnection) GetServerInfo() string {
	return conn.info
}