package netlink

import (
	"net"
	"syscall"
)

// Link represents a link device from netlink. Shared link attributes
// like name may be retrieved using the Attrs() method. Unique data
// can be retrieved by casting the object to the proper type.
type Link interface {
	Attrs() *LinkAttrs
	Type() string
}

type (
	NsPid int
	NsFd  int
)

// LinkAttrs represents data shared by most link types
type LinkAttrs struct {
	Index        int
	MTU          int
	TxQLen       int // Transmit Queue Length
	Name         string
	HardwareAddr net.HardwareAddr
	Flags        net.Flags
	ParentIndex  int         // index of the parent link device
	MasterIndex  int         // must be the index of a bridge
	Namespace    interface{} // nil | NsPid | NsFd
	Alias        string
}

// NewLinkAttrs returns LinkAttrs structure filled with default values
func NewLinkAttrs() LinkAttrs {
	return LinkAttrs{
		TxQLen: -1,
	}
}

// Device links cannot be created via netlink. These links
// are links created by udev like 'lo' and 'etho0'
type Device struct {
	LinkAttrs
}

func (device *Device) Attrs() *LinkAttrs {
	return &device.LinkAttrs
}

func (device *Device) Type() string {
	return "device"
}

// Dummy links are dummy ethernet devices
type Dummy struct {
	LinkAttrs
}

func (dummy *Dummy) Attrs() *LinkAttrs {
	return &dummy.LinkAttrs
}

func (dummy *Dummy) Type() string {
	return "dummy"
}

// Ifb links are advanced dummy devices for packet filtering
type Ifb struct {
	LinkAttrs
}

func (ifb *Ifb) Attrs() *LinkAttrs {
	return &ifb.LinkAttrs
}

func (ifb *Ifb) Type() string {
	return "ifb"
}

// Bridge links are simple linux bridges
type Bridge struct {
	LinkAttrs
}

func (bridge *Bridge) Attrs() *LinkAttrs {
	return &bridge.LinkAttrs
}

func (bridge *Bridge) Type() string {
	return "bridge"
}

// Vlan links have ParentIndex set in their Attrs()
type Vlan struct {
	LinkAttrs
	VlanId int
}

func (vlan *Vlan) Attrs() *LinkAttrs {
	return &vlan.LinkAttrs
}

func (vlan *Vlan) Type() string {
	return "vlan"
}

type MacvlanMode uint16

const (
	MACVLAN_MODE_DEFAULT MacvlanMode = iota
	MACVLAN_MODE_PRIVATE
	MACVLAN_MODE_VEPA
	MACVLAN_MODE_BRIDGE
	MACVLAN_MODE_PASSTHRU
	MACVLAN_MODE_SOURCE
)

// Macvlan links have ParentIndex set in their Attrs()
type Macvlan struct {
	LinkAttrs
	Mode MacvlanMode
}

func (macvlan *Macvlan) Attrs() *LinkAttrs {
	return &macvlan.LinkAttrs
}

func (macvlan *Macvlan) Type() string {
	return "macvlan"
}

// Macvtap - macvtap is a virtual interfaces based on macvlan
type Macvtap struct {
	Macvlan
}

func (macvtap Macvtap) Type() string {
	return "macvtap"
}

type TuntapMode uint16

const (
	TUNTAP_MODE_TUN TuntapMode = syscall.IFF_TUN
	TUNTAP_MODE_TAP TuntapMode = syscall.IFF_TAP
)

// Tuntap links created via /dev/tun/tap, but can be destroyed via netlink
type Tuntap struct {
	LinkAttrs
	Mode TuntapMode
}

func (tuntap *Tuntap) Attrs() *LinkAttrs {
	return &tuntap.LinkAttrs
}

func (tuntap *Tuntap) Type() string {
	return "tuntap"
}

// Veth devices must specify PeerName on create
type Veth struct {
	LinkAttrs
	PeerName string // veth on create only
}

func (veth *Veth) Attrs() *LinkAttrs {
	return &veth.LinkAttrs
}

func (veth *Veth) Type() string {
	return "veth"
}

// GenericLink links represent types that are not currently understood
// by this netlink library.
type GenericLink struct {
	LinkAttrs
	LinkType string
}

func (generic *GenericLink) Attrs() *LinkAttrs {
	return &generic.LinkAttrs
}

func (generic *GenericLink) Type() string {
	return generic.LinkType
}

type Vxlan struct {
	LinkAttrs
	VxlanId      int
	VtepDevIndex int
	SrcAddr      net.IP
	Group        net.IP
	TTL          int
	TOS          int
	Learning     bool
	Proxy        bool
	RSC          bool
	L2miss       bool
	L3miss       bool
	NoAge        bool
	GBP          bool
	Age          int
	Limit        int
	Port         int
	PortLow      int
	PortHigh     int
}

func (vxlan *Vxlan) Attrs() *LinkAttrs {
	return &vxlan.LinkAttrs
}

func (vxlan *Vxlan) Type() string {
	return "vxlan"
}

type IPVlanMode uint16

const (
	IPVLAN_MODE_L2 IPVlanMode = iota
	IPVLAN_MODE_L3
	IPVLAN_MODE_MAX
)

type IPVlan struct {
	LinkAttrs
	Mode IPVlanMode
}

func (ipvlan *IPVlan) Attrs() *LinkAttrs {
	return &ipvlan.LinkAttrs
}

func (ipvlan *IPVlan) Type() string {
	return "ipvlan"
}

// GreTap devices must specify LocalIP and RemoteIP on create
type Gretap struct {
	LinkAttrs
	Key      uint32
	LocalIP  net.IP
	RemoteIP net.IP
}

func (gretap *Gretap) Attrs() *LinkAttrs {
	return &gretap.LinkAttrs
}

func (gretap *Gretap) Type() string {
	return "gretap"
}

// iproute2 supported devices;
// vlan | veth | vcan | dummy | ifb | macvlan | macvtap |
// bridge | bond | ipoib | ip6tnl | ipip | sit | vxlan |
// gre | gretap | ip6gre | ip6gretap | vti | nlmon |
// bond_slave | ipvlan