package ftp

import (
	"context"
	"fmt"
	"time"

	ftplib "github.com/jlaffaye/ftp"
	"github.com/shadow1ng/fscan/common"
	"github.com/shadow1ng/fscan/plugins/base"
)

// FTPConnector FTP连接器实现
type FTPConnector struct {
	host string
	port string
}

// NewFTPConnector 创建FTP连接器
func NewFTPConnector() *FTPConnector {
	return &FTPConnector{}
}

// Connect 连接到FTP服务
func (c *FTPConnector) Connect(ctx context.Context, info *common.HostInfo) (interface{}, error) {
	c.host = info.Host
	c.port = info.Ports
	
	// 构建连接地址
	target := fmt.Sprintf("%s:%s", c.host, c.port)
	
	// 创建FTP连接配置
	config := &FTPConfig{
		Target:  target,
		Timeout: time.Duration(common.Timeout) * time.Second,
	}
	
	return config, nil
}

// Authenticate 认证
func (c *FTPConnector) Authenticate(ctx context.Context, conn interface{}, cred *base.Credential) error {
	config, ok := conn.(*FTPConfig)
	if !ok {
		return fmt.Errorf("无效的连接类型")
	}
	
	// 在goroutine中建立FTP连接，支持Context取消
	resultChan := make(chan struct {
		ftpConn *ftplib.ServerConn
		err     error
	}, 1)
	
	go func() {
		ftpConn, err := ftplib.DialTimeout(config.Target, config.Timeout)
		select {
		case <-ctx.Done():
			if ftpConn != nil {
				ftpConn.Quit()
			}
		case resultChan <- struct {
			ftpConn *ftplib.ServerConn
			err     error
		}{ftpConn, err}:
		}
	}()
	
	// 等待连接结果或Context取消
	var ftpConn *ftplib.ServerConn
	var err error
	select {
	case result := <-resultChan:
		ftpConn, err = result.ftpConn, result.err
		if err != nil {
			return fmt.Errorf("FTP连接失败: %v", err)
		}
	case <-ctx.Done():
		return fmt.Errorf("FTP连接超时: %v", ctx.Err())
	}
	
	defer ftpConn.Quit()
	
	// 在goroutine中进行登录认证
	loginChan := make(chan error, 1)
	
	go func() {
		err := ftpConn.Login(cred.Username, cred.Password)
		select {
		case <-ctx.Done():
		case loginChan <- err:
		}
	}()
	
	// 等待登录结果或Context取消
	select {
	case err := <-loginChan:
		if err != nil {
			return fmt.Errorf("FTP认证失败: %v", err)
		}
		return nil
	case <-ctx.Done():
		return fmt.Errorf("FTP认证超时: %v", ctx.Err())
	}
}

// Close 关闭连接
func (c *FTPConnector) Close(conn interface{}) error {
	// FTP配置无需显式关闭
	return nil
}

// FTPConfig FTP连接配置
type FTPConfig struct {
	Target  string
	Timeout time.Duration
}