package packet

const (
	OctetLen       = 8
	MaxASNsSegment = 255
	BGP4Version    = 4
	MinOpenLen     = 29

	MarkerLen         = 16
	HeaderLen         = 19
	MinLen            = 19
	MaxLen            = 4096
	NLRIMaxLen        = 5
	LargeCommunityLen = 12

	OpenMsg         = 1
	UpdateMsg       = 2
	NotificationMsg = 3
	KeepaliveMsg    = 4

	MessageHeaderError      = 1
	OpenMessageError        = 2
	UpdateMessageError      = 3
	HoldTimeExpired         = 4
	FiniteStateMachineError = 5
	Cease                   = 6

	// Msg Header Errors
	ConnectionNotSync = 1
	BadMessageLength  = 2
	BadMessageType    = 3

	// Open Msg Errors
	UnsupportedVersionNumber     = 1
	BadPeerAS                    = 2
	BadBGPIdentifier             = 3
	UnsupportedOptionalParameter = 4
	DeprecatedOpenMsgError5      = 5
	UnacceptableHoldTime         = 6

	// Update Msg Errors
	MalformedAttributeList    = 1
	UnrecognizedWellKnownAttr = 2
	MissingWellKnonAttr       = 3
	AttrFlagsError            = 4
	AttrLengthError           = 5
	InvalidOriginAttr         = 6
	DeprecatedUpdateMsgError7 = 7
	InvalidNextHopAttr        = 8
	OptionalAttrError         = 9
	InvalidNetworkField       = 10
	MalformedASPath           = 11

	// Notification Msg Subcodes
	AdministrativeShutdown = 2
	AdministrativeReset    = 4

	// Attribute Type Codes
	OriginAttr         = 1
	ASPathAttr         = 2
	NextHopAttr        = 3
	MEDAttr            = 4
	LocalPrefAttr      = 5
	AtomicAggrAttr     = 6
	AggregatorAttr     = 7
	CommunitiesAttr    = 8
	AS4PathAttr        = 17
	AS4AggregatorAttr  = 18
	LargeCommunityAttr = 32

	// ORIGIN values
	IGP        = 0
	EGP        = 1
	INCOMPLETE = 2

	// ASPath Segment Types
	ASSet      = 1
	ASSequence = 2

	// NOTIFICATION Cease error SubCodes (RFC4486)
	MaxPrefReached                = 1
	AdminShut                     = 2
	PeerDeconfigured              = 3
	AdminReset                    = 4
	ConnectionRejected            = 5
	OtherConfigChange             = 8
	ConnectionCollisionResolution = 7
	OutOfResoutces                = 8

	IPv4AFI               = 1
	UnicastSAFI           = 1
	CapabilitiesParamType = 2
	AddPathCapabilityCode = 69
	AddPathReceive        = 1
	AddPathSend           = 2
	AddPathSendReceive    = 3
)

type BGPError struct {
	ErrorCode    uint8
	ErrorSubCode uint8
	ErrorStr     string
}

func (b BGPError) Error() string {
	return b.ErrorStr
}

type BGPMessage struct {
	Header *BGPHeader
	Body   interface{}
}

type BGPHeader struct {
	Length uint16
	Type   uint8
}

type BGPOpen struct {
	Version       uint8
	AS            uint16
	HoldTime      uint16
	BGPIdentifier uint32
	OptParmLen    uint8
	OptParams     []OptParam
}

type BGPNotification struct {
	ErrorCode    uint8
	ErrorSubcode uint8
}

type BGPUpdate struct {
	WithdrawnRoutesLen uint16
	WithdrawnRoutes    *NLRI
	TotalPathAttrLen   uint16
	PathAttributes     *PathAttribute
	NLRI               *NLRI
}

type BGPUpdateAddPath struct {
	WithdrawnRoutesLen uint16
	WithdrawnRoutes    *NLRIAddPath
	TotalPathAttrLen   uint16
	PathAttributes     *PathAttribute
	NLRI               *NLRIAddPath
}

type PathAttribute struct {
	Length         uint16
	Optional       bool
	Transitive     bool
	Partial        bool
	ExtendedLength bool
	TypeCode       uint8
	Value          interface{}
	Next           *PathAttribute
}

type NLRI struct {
	IP     uint32
	Pfxlen uint8
	Next   *NLRI
}

type NLRIAddPath struct {
	PathIdentifier uint32
	IP             uint32
	Pfxlen         uint8
	Next           *NLRIAddPath
}

type ASPath []ASPathSegment
type ASPathSegment struct {
	Type  uint8
	Count uint8
	ASNs  []uint32
}

type Aggretator struct {
	Addr uint32
	ASN  uint16
}