package fwd

import (
	"context"
	"io"
	"log/slog"
	"net"
	"proxy-server/pkg/utils"
	"proxy-server/server/fwd/socks"
	"proxy-server/server/pkg/orm"
	"proxy-server/server/web/models"
	"time"

	"github.com/pkg/errors"
)

type NoAuthAuthenticator struct {
}

func (a *NoAuthAuthenticator) Method() socks.AuthMethod {
	return socks.NoAuth
}

func (a *NoAuthAuthenticator) Authenticate(ctx context.Context, reader io.Reader, writer io.Writer) (*socks.Authentication, error) {

	// 获取用户地址
	conn, ok := writer.(net.Conn)
	if !ok {
		return nil, errors.New("noAuth 认证失败，无法获取连接信息")
	}
	addr := conn.RemoteAddr().String()
	client, _, err := net.SplitHostPort(addr)
	if err != nil {
		return nil, errors.Wrap(err, "noAuth 认证失败")
	}
	slog.Debug("用户的地址为 " + client)

	// 获取服务
	server, ok := ctx.Value("service").(*socks.Server)
	if !ok {
		return nil, errors.New("noAuth 认证失败，无法获取服务信息")
	}
	node := server.Name
	slog.Debug("服务的名称为 " + server.Name)

	// 查询权限记录
	slog.Info("用户 " + client + " 请求连接到 " + node)
	var channels []models.Channel
	err = orm.DB.
		Joins("INNER JOIN public.nodes n ON channels.node_id = n.id AND n.name = ?", node).
		Joins("INNER JOIN public.users u ON channels.user_id = u.id").
		Joins("INNER JOIN public.user_ips ip ON u.id = ip.user_id AND ip.ip_address = ?", client).
		Where(&models.Channel{
			AuthIp: true,
		}).
		Find(&channels).Error
	if err != nil {
		return nil, errors.New("noAuth 查询用户权限失败")
	}

	// 记录应该只有一条
	channel, err := orm.MaySingle(channels)
	if err != nil {
		return nil, errors.Wrap(err, "noAuth 没有权限")
	}

	// 检查是否需要密码认证
	if channel.AuthPass {
		return nil, errors.New("noAuth 没有权限，需要密码认证")
	}

	// 检查权限是否过期
	timeout := channel.Expiration.Sub(time.Now()).Seconds()
	slog.Info("用户剩余时间", "timeout", timeout)
	if timeout <= 0 {
		return nil, errors.New("noAuth 权限已过期")
	}
	slog.Debug("权限剩余时间", slog.Uint64("timeout", uint64(timeout)))

	return &socks.Authentication{
		Method:  socks.NoAuth,
		Timeout: uint(timeout),
		Payload: socks.Payload{
			ID: channel.UserId,
		},
	}, nil
}

type UserPassAuthenticator struct {
}

func (a *UserPassAuthenticator) Method() socks.AuthMethod {
	return socks.UserPassAuth
}

func (a *UserPassAuthenticator) Authenticate(ctx context.Context, reader io.Reader, writer io.Writer) (*socks.Authentication, error) {

	// 检查认证版本
	slog.Debug("验证认证版本")
	v, err := utils.ReadByte(reader)
	if err != nil {
		return nil, errors.Wrap(err, "读取版本号失败")
	}
	if v != socks.AuthVersion {
		_, err := writer.Write([]byte{socks.Version, socks.AuthFailure})
		if err != nil {
			return nil, errors.Wrap(err, "响应认证失败")
		}
		return nil, errors.New("认证版本参数不正确")
	}

	// 读取账号
	slog.Debug("验证用户账号")
	uLen, err := utils.ReadByte(reader)
	if err != nil {
		return nil, errors.Wrap(err, "读取用户名长度失败")
	}
	usernameBuf, err := utils.ReadBuffer(reader, int(uLen))
	if err != nil {
		return nil, errors.Wrap(err, "读取用户名失败")
	}
	username := string(usernameBuf)

	// 读取密码
	pLen, err := utils.ReadByte(reader)
	if err != nil {
		return nil, errors.Wrap(err, "读取密码长度失败")
	}
	passwordBuf, err := utils.ReadBuffer(reader, int(pLen))
	if err != nil {
		return nil, errors.Wrap(err, "读取密码失败")
	}
	password := string(passwordBuf)

	// 查询通道配置
	var channel models.Channel
	err = orm.DB.
		Where(&models.Channel{
			Username: username,
			AuthPass: true,
		}).
		First(&channel).Error
	if err != nil {
		return nil, errors.Wrap(err, "查询用户失败")
	}

	// 检查密码 todo 哈希
	if channel.Password != password {
		return nil, errors.New("密码错误")
	}

	// 检查权限是否过期
	timeout := channel.Expiration.Sub(time.Now()).Seconds()
	slog.Info("用户剩余时间", "timeout", timeout)
	if timeout <= 0 {
		return nil, errors.New("权限已过期")
	}

	// 如果用户设置了双验证则检查 ip 是否在白名单中
	if channel.AuthIp {
		slog.Debug("验证用户 ip")

		// 获取用户地址
		conn, ok := writer.(net.Conn)
		if !ok {
			return nil, errors.New("无法获取连接信息")
		}
		addr := conn.RemoteAddr().String()
		client, _, err := net.SplitHostPort(addr)
		if err != nil {
			return nil, errors.Wrap(err, "无法获取连接信息")
		}

		// 查询通道配置
		var ips []models.UserIp
		err = orm.DB.
			Where(&models.UserIp{
				UserId:    channel.UserId,
				IpAddress: client,
			}).
			Find(&ips).Error
		if err != nil {
			return nil, errors.Wrap(err, "查询用户 ip 失败")
		}

		// 检查是否在白名单中
		if len(ips) == 0 {
			return nil, errors.New("没有权限")
		}
	}

	// 响应认证成功
	_, err = writer.Write([]byte{socks.AuthVersion, socks.AuthSuccess})
	if err != nil {
		slog.Error("响应认证失败", "err", err)
		return nil, err
	}

	return &socks.Authentication{
		Method:  socks.UserPassAuth,
		Timeout: uint(timeout),
		Payload: socks.Payload{
			ID: channel.UserId,
		},
	}, nil
}