package services

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

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

type RsyncPlugin struct {
	name  string
	ports []int
}

func NewRsyncPlugin() *RsyncPlugin {
	return &RsyncPlugin{
		name:  "rsync",
		ports: []int{873},
	}
}

func (p *RsyncPlugin) GetName() string {
	return p.name
}

func (p *RsyncPlugin) GetPorts() []int {
	return p.ports
}

func (p *RsyncPlugin) Scan(ctx context.Context, info *common.HostInfo) *ScanResult {
	target := fmt.Sprintf("%s:%s", info.Host, info.Ports)

	if common.DisableBrute {
		return p.identifyService(ctx, info)
	}

	if result := p.testUnauthorizedAccess(ctx, info); result != nil && result.Success {
		common.LogSuccess(fmt.Sprintf("Rsync %s 未授权访问", target))
		return result
	}

	credentials := GenerateCredentials("rsync")
	if len(credentials) == 0 {
		return &ScanResult{
			Success: false,
			Service: "rsync",
			Error:   fmt.Errorf("没有可用的测试凭据"),
		}
	}

	for _, cred := range credentials {
		if p.testCredential(ctx, info, cred) {
			common.LogSuccess(fmt.Sprintf("Rsync %s %s:%s", target, cred.Username, cred.Password))

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

	return &ScanResult{
		Success: false,
		Service: "rsync",
		Error:   fmt.Errorf("未发现弱密码"),
	}
}


func (p *RsyncPlugin) testUnauthorizedAccess(ctx context.Context, info *common.HostInfo) *ScanResult {
	conn := p.connectToRsync(ctx, info)
	if conn == nil {
		return nil
	}
	defer conn.Close()

	modules := p.getModules(conn)
	if len(modules) > 0 {
		return &ScanResult{
			Success: true,
			Service: "rsync",
			Banner:  "未授权访问",
		}
	}

	return nil
}

func (p *RsyncPlugin) testCredential(ctx context.Context, info *common.HostInfo, cred Credential) bool {
	return false
}

func (p *RsyncPlugin) connectToRsync(ctx context.Context, info *common.HostInfo) net.Conn {
	target := fmt.Sprintf("%s:%s", info.Host, info.Ports)
	timeout := time.Duration(common.Timeout) * time.Second

	conn, err := net.DialTimeout("tcp", target, timeout)
	if err != nil {
		return nil
	}

	conn.SetDeadline(time.Now().Add(timeout))
	return conn
}

func (p *RsyncPlugin) getModules(conn net.Conn) []string {
	timeout := time.Duration(common.Timeout) * time.Second
	
	conn.SetWriteDeadline(time.Now().Add(timeout))
	if _, err := conn.Write([]byte("\n")); err != nil {
		return nil
	}

	conn.SetReadDeadline(time.Now().Add(timeout))
	scanner := bufio.NewScanner(conn)
	
	var modules []string
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" {
			continue
		}
		
		if strings.HasPrefix(line, "@RSYNCD: EXIT") {
			break
		}
		
		if strings.HasPrefix(line, "@RSYNCD:") {
			continue
		}
		
		modules = append(modules, line)
	}

	return modules
}

func (p *RsyncPlugin) identifyService(ctx context.Context, info *common.HostInfo) *ScanResult {
	target := fmt.Sprintf("%s:%s", info.Host, info.Ports)

	conn := p.connectToRsync(ctx, info)
	if conn == nil {
		return &ScanResult{
			Success: false,
			Service: "rsync",
			Error:   fmt.Errorf("无法连接到Rsync服务"),
		}
	}
	defer conn.Close()

	timeout := time.Duration(common.Timeout) * time.Second
	
	conn.SetWriteDeadline(time.Now().Add(timeout))
	if _, err := conn.Write([]byte("\n")); err != nil {
		return &ScanResult{
			Success: false,
			Service: "rsync",
			Error:   err,
		}
	}

	conn.SetReadDeadline(time.Now().Add(timeout))
	response := make([]byte, 1024)
	n, err := conn.Read(response)
	if err != nil {
		return &ScanResult{
			Success: false,
			Service: "rsync",
			Error:   err,
		}
	}

	responseStr := string(response[:n])
	var banner string
	
	if strings.Contains(responseStr, "@RSYNCD") {
		lines := strings.Split(responseStr, "\n")
		for _, line := range lines {
			if strings.HasPrefix(line, "@RSYNCD:") {
				banner = fmt.Sprintf("Rsync服务 (%s)", strings.TrimSpace(line))
				break
			}
		}
		if banner == "" {
			banner = "Rsync文件同步服务"
		}
	} else {
		return &ScanResult{
			Success: false,
			Service: "rsync",
			Error:   fmt.Errorf("无法识别为Rsync服务"),
		}
	}

	common.LogSuccess(fmt.Sprintf("Rsync %s %s", target, banner))

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

func init() {
	// 使用高效注册方式：直接传递端口信息，避免实例创建
	RegisterPluginWithPorts("rsync", func() Plugin {
		return NewRsyncPlugin()
	}, []int{873})
}