package netlink

import (
	"fmt"
	"net"
	"time"
)

// XfrmStateAlgo represents the algorithm to use for the ipsec encryption.
type XfrmStateAlgo struct {
	Name        string
	Key         []byte
	TruncateLen int // Auth only
	ICVLen      int // AEAD only
}

func (a XfrmStateAlgo) String() string {
	base := fmt.Sprintf("{Name: %s, Key: 0x%x", a.Name, a.Key)
	if a.TruncateLen != 0 {
		base = fmt.Sprintf("%s, Truncate length: %d", base, a.TruncateLen)
	}
	if a.ICVLen != 0 {
		base = fmt.Sprintf("%s, ICV length: %d", base, a.ICVLen)
	}
	return fmt.Sprintf("%s}", base)
}

// EncapType is an enum representing the optional packet encapsulation.
type EncapType uint8

const (
	XFRM_ENCAP_ESPINUDP_NONIKE EncapType = iota + 1
	XFRM_ENCAP_ESPINUDP
)

func (e EncapType) String() string {
	switch e {
	case XFRM_ENCAP_ESPINUDP_NONIKE:
		return "espinudp-non-ike"
	case XFRM_ENCAP_ESPINUDP:
		return "espinudp"
	}
	return "unknown"
}

// XfrmStateEncap represents the encapsulation to use for the ipsec encryption.
type XfrmStateEncap struct {
	Type            EncapType
	SrcPort         int
	DstPort         int
	OriginalAddress net.IP
}

func (e XfrmStateEncap) String() string {
	return fmt.Sprintf("{Type: %s, Srcport: %d, DstPort: %d, OriginalAddress: %v}",
		e.Type, e.SrcPort, e.DstPort, e.OriginalAddress)
}

// XfrmStateLimits represents the configured limits for the state.
type XfrmStateLimits struct {
	ByteSoft    uint64
	ByteHard    uint64
	PacketSoft  uint64
	PacketHard  uint64
	TimeSoft    uint64
	TimeHard    uint64
	TimeUseSoft uint64
	TimeUseHard uint64
}

// XfrmStateStats represents the current number of bytes/packets
// processed by this State, the State's installation and first use
// time and the replay window counters.
type XfrmStateStats struct {
	ReplayWindow uint32
	Replay       uint32
	Failed       uint32
	Bytes        uint64
	Packets      uint64
	AddTime      uint64
	UseTime      uint64
}

// XfrmReplayState represents the sequence number states for
// "legacy" anti-replay mode.
type XfrmReplayState struct {
	OSeq   uint32
	Seq    uint32
	BitMap uint32
}

func (r XfrmReplayState) String() string {
	return fmt.Sprintf("{OSeq: 0x%x, Seq: 0x%x, BitMap: 0x%x}",
		r.OSeq, r.Seq, r.BitMap)
}

// XfrmState represents the state of an ipsec policy. It optionally
// contains an XfrmStateAlgo for encryption and one for authentication.
type XfrmState struct {
	Dst           net.IP
	Src           net.IP
	Proto         Proto
	Mode          Mode
	Spi           int
	Reqid         int
	ReplayWindow  int
	Limits        XfrmStateLimits
	Statistics    XfrmStateStats
	Mark          *XfrmMark
	OutputMark    *XfrmMark
	Ifid          int
	Auth          *XfrmStateAlgo
	Crypt         *XfrmStateAlgo
	Aead          *XfrmStateAlgo
	Encap         *XfrmStateEncap
	ESN           bool
	DontEncapDSCP bool
	OSeqMayWrap   bool
	Replay        *XfrmReplayState
	Selector      *XfrmPolicy
}

func (sa XfrmState) String() string {
	return fmt.Sprintf("Dst: %v, Src: %v, Proto: %s, Mode: %s, SPI: 0x%x, ReqID: 0x%x, ReplayWindow: %d, Mark: %v, OutputMark: %v, Ifid: %d, Auth: %v, Crypt: %v, Aead: %v, Encap: %v, ESN: %t, DontEncapDSCP: %t, OSeqMayWrap: %t, Replay: %v",
		sa.Dst, sa.Src, sa.Proto, sa.Mode, sa.Spi, sa.Reqid, sa.ReplayWindow, sa.Mark, sa.OutputMark, sa.Ifid, sa.Auth, sa.Crypt, sa.Aead, sa.Encap, sa.ESN, sa.DontEncapDSCP, sa.OSeqMayWrap, sa.Replay)
}
func (sa XfrmState) Print(stats bool) string {
	if !stats {
		return sa.String()
	}
	at := time.Unix(int64(sa.Statistics.AddTime), 0).Format(time.UnixDate)
	ut := "-"
	if sa.Statistics.UseTime > 0 {
		ut = time.Unix(int64(sa.Statistics.UseTime), 0).Format(time.UnixDate)
	}
	return fmt.Sprintf("%s, ByteSoft: %s, ByteHard: %s, PacketSoft: %s, PacketHard: %s, TimeSoft: %d, TimeHard: %d, TimeUseSoft: %d, TimeUseHard: %d, Bytes: %d, Packets: %d, "+
		"AddTime: %s, UseTime: %s, ReplayWindow: %d, Replay: %d, Failed: %d",
		sa.String(), printLimit(sa.Limits.ByteSoft), printLimit(sa.Limits.ByteHard), printLimit(sa.Limits.PacketSoft), printLimit(sa.Limits.PacketHard),
		sa.Limits.TimeSoft, sa.Limits.TimeHard, sa.Limits.TimeUseSoft, sa.Limits.TimeUseHard, sa.Statistics.Bytes, sa.Statistics.Packets, at, ut,
		sa.Statistics.ReplayWindow, sa.Statistics.Replay, sa.Statistics.Failed)
}

func printLimit(lmt uint64) string {
	if lmt == ^uint64(0) {
		return "(INF)"
	}
	return fmt.Sprintf("%d", lmt)
}
