package socks5

import (
	"errors"
)

const (
	// Version is the protocol version
	Version byte = 0x05
	// Reserved is the reserved field value
	Reserved byte = 0x00
	// PasswordVersion is the username/password auth protocol version
	PasswordVersion byte = 0x01
	// DatagramStandalone is the standalone datagram fragment field value
	DatagramStandalone byte = 0x00
)

// AuthMethod is the auth method
type AuthMethod byte

// Auth methods
const (
	AuthMethodNone         AuthMethod = 0x00
	AuthMethodGSSAPI       AuthMethod = 0x01
	AuthMethodPassword     AuthMethod = 0x02
	AuthMethodNotSupported AuthMethod = 0xFF
)

func (am AuthMethod) String() string {
	return authMethodNames[am]
}

var authMethodNames = map[AuthMethod]string{
	AuthMethodNone:         "none",
	AuthMethodGSSAPI:       "gssapi",
	AuthMethodPassword:     "password",
	AuthMethodNotSupported: "not supported",
}

// PasswordStatus is the password auth status
type PasswordStatus byte

// Password statuses
const (
	PasswordStatusSuccess PasswordStatus = 0x00
	PasswordStatusFailure PasswordStatus = 0x01
)

func (ps PasswordStatus) String() string {
	return passwordStatusNames[ps]
}

var passwordStatusNames = map[PasswordStatus]string{
	PasswordStatusSuccess: "success",
	PasswordStatusFailure: "failure",
}

// Command is the command
type Command byte

// Commands
const (
	CommandConnect      Command = 0x01
	CommandBind         Command = 0x02
	CommandUDPAssociate Command = 0x03
)

func (c Command) String() string {
	return commandNames[c]
}

var commandNames = map[Command]string{
	CommandConnect:      "connect",
	CommandBind:         "bind",
	CommandUDPAssociate: "udp associate",
}

// ATYP is the address type
type ATYP byte

// Address types
const (
	ATYPIPv4 ATYP = 0x01
	ATYPFQDN ATYP = 0x03
	ATYPIPv6 ATYP = 0x04
)

func (a ATYP) String() string {
	return atypNames[a]
}

var atypNames = map[ATYP]string{
	ATYPIPv4: "ipv4",
	ATYPFQDN: "fqdn",
	ATYPIPv6: "ipv6",
}

// ReplyStatus is the reply status
type ReplyStatus byte

// Reply statuses
const (
	ReplyStatusSuccess             ReplyStatus = 0x00
	ReplyStatusServerFailure       ReplyStatus = 0x01
	ReplyStatusNotAllowed          ReplyStatus = 0x02
	ReplyStatusNetworkUnreachable  ReplyStatus = 0x03
	ReplyStatusHostUnreachable     ReplyStatus = 0x04
	ReplyStatusConnectionRefused   ReplyStatus = 0x05
	ReplyStatusTTLExpired          ReplyStatus = 0x06
	ReplyStatusCommandNotSupported ReplyStatus = 0x07
	ReplyStatusAddressNotSupported ReplyStatus = 0x08
)

func (rs ReplyStatus) String() string {
	return replyStatusNames[rs]
}

var replyStatusNames = map[ReplyStatus]string{
	ReplyStatusSuccess:             "success",
	ReplyStatusServerFailure:       "server failure",
	ReplyStatusNotAllowed:          "not allowed",
	ReplyStatusNetworkUnreachable:  "network unreachable",
	ReplyStatusHostUnreachable:     "host unreachable",
	ReplyStatusConnectionRefused:   "connection refused",
	ReplyStatusTTLExpired:          "TTL expired",
	ReplyStatusCommandNotSupported: "command not supported",
	ReplyStatusAddressNotSupported: "address not supported",
}

var (
	// ErrVersion is the protocol version error
	ErrVersion = errors.New("invalid protocol version")
	// ErrBadReply is the bad reply error
	ErrBadReply = errors.New("bad reply")
	// ErrBadRequest is the bad request error
	ErrBadRequest = errors.New("bad request")
	// ErrBadDatagram is the bad datagram error
	ErrBadDatagram = errors.New("bad datagram")
	// ErrFragmentedDatagram us the fragmented datagram error
	ErrFragmentedDatagram = errors.New("fragmented datagram")
	// ErrIPAuth is the invalid ip error
	ErrIPAuth = errors.New("invalid ip auth")
	// ErrPasswordAuth is the invalid username or password error
	ErrPasswordAuth = errors.New("invalid username or password")
	// ErrAuthMethodNotSupported is the error when auth method not supported
	ErrAuthMethodNotSupported = errors.New("auth method not supported")
	// ErrCommandNotSupported is the error when command not supported
	ErrCommandNotSupported = errors.New("command not supported")
	// ErrPasswordAuthVersion is the password auth version error
	ErrPasswordAuthVersion = errors.New("invalid password auth version")
)