package socks5

import (
	"io"
)

// PasswordNegotiationRequest is the password negotiation reqeust packet
type PasswordNegotiationRequest struct {
	UsernameLen byte
	Username    string
	PasswordLen byte
	Password    string
}

// NewPasswordNegotiationRequest returns new password negotiation request packet
func NewPasswordNegotiationRequest(username string, password string) *PasswordNegotiationRequest {
	return &PasswordNegotiationRequest{
		UsernameLen: byte(len(username)),
		Username:    username,
		PasswordLen: byte(len(password)),
		Password:    password,
	}
}

// NewPasswordNegotiationRequestFrom reads password negotiation request packet from reader
func NewPasswordNegotiationRequestFrom(r io.Reader) (*PasswordNegotiationRequest, error) {
	buf := make([]byte, 2)
	if _, err := io.ReadFull(r, buf); err != nil {
		return nil, err
	}

	if buf[0] != PasswordVersion {
		return nil, ErrPasswordAuthVersion
	}

	if buf[1] == 0 {
		return nil, ErrBadRequest
	}

	usernameBuf := make([]byte, int(buf[1])+1)
	if _, err := io.ReadFull(r, usernameBuf); err != nil {
		return nil, err
	}

	var passwordBuf []byte
	if usernameBuf[int(buf[1])] != 0 {
		passwordBuf = make([]byte, int(usernameBuf[int(buf[1])]))
		if _, err := io.ReadFull(r, passwordBuf); err != nil {
			return nil, err
		}
	}

	return &PasswordNegotiationRequest{
		UsernameLen: buf[1],
		Username:    string(usernameBuf[:int(buf[1])]),
		PasswordLen: usernameBuf[int(buf[1])],
		Password:    string(passwordBuf),
	}, nil
}

// WriteTo writes password negotiation request packet
func (s *PasswordNegotiationRequest) WriteTo(w io.Writer) (int64, error) {
	buf := []byte{PasswordVersion, s.UsernameLen}
	buf = append(buf, []byte(s.Username)...)
	buf = append(buf, s.PasswordLen)
	buf = append(buf, []byte(s.Password)...)

	n, err := w.Write(buf)
	if err != nil {
		return int64(n), err
	}

	return int64(n), nil
}

// PasswordNegotiationReply is the password negotiation reply packet
type PasswordNegotiationReply struct {
	Status PasswordStatus
}

// NewPasswordNegotiationReply returns password negotiation reply packet
func NewPasswordNegotiationReply(status PasswordStatus) *PasswordNegotiationReply {
	return &PasswordNegotiationReply{
		Status: status,
	}
}

// NewPasswordNegotiationReplyFrom reads password negotiation reply packet from reader
func NewPasswordNegotiationReplyFrom(r io.Reader) (*PasswordNegotiationReply, error) {
	buf := make([]byte, 2)
	if _, err := io.ReadFull(r, buf); err != nil {
		return nil, err
	}

	if buf[0] != PasswordVersion {
		return nil, ErrPasswordAuthVersion
	}

	rep := &PasswordNegotiationReply{
		Status: PasswordStatus(buf[1]),
	}

	return rep, nil
}

// WriteTo writes password negotiation reply packet
func (s *PasswordNegotiationReply) WriteTo(w io.Writer) (int64, error) {
	n, err := w.Write([]byte{PasswordVersion, byte(s.Status)})
	if err != nil {
		return int64(n), err
	}

	return int64(n), nil
}