// Modified for Tendermint
// Originally Copyright (c) 2013-2014 Conformal Systems LLC.
// https://github.com/conformal/btcd/blob/master/LICENSE

package peer

import (
    . "github.com/tendermint/tendermint/binary"
    "io"
    "net"
    "strconv"
)

/* NetAddress */

type NetAddress struct {
    IP          net.IP
    Port        UInt16
}

func NewNetAddressIPPort(ip net.IP, port UInt16) *NetAddress {
    na := NetAddress{
        IP:        ip,
        Port:      port,
    }
    return &na
}

func NewNetAddress(addr net.Addr) *NetAddress {
    tcpAddr, ok := addr.(*net.TCPAddr)
    if !ok { panic("addr is not a net.TCPAddr") }

    na := NewNetAddressIPPort(tcpAddr.IP, UInt16(tcpAddr.Port))
    return na
}

func ReadNetAddress(r io.Reader) *NetAddress {
    return &NetAddress{
        IP:         net.IP(ReadByteSlice(r)),
        Port:       ReadUInt16(r),
    }
}

func (na *NetAddress) WriteTo(w io.Writer) (n int64, err error) {
    n, err = WriteOnto(ByteSlice(na.IP.To16()), w, n, err)
    n, err = WriteOnto(na.Port,                 w, n, err)
    return
}

func (na *NetAddress) String() string {
    port := strconv.FormatUint(uint64(na.Port), 10)
    addr := net.JoinHostPort(na.IP.String(), port)
    return addr
}

func (na *NetAddress) Routable() bool {
    // TODO(oga) bitcoind doesn't include RFC3849 here, but should we?
    return na.Valid() && !(na.RFC1918() || na.RFC3927() || na.RFC4862() ||
                           na.RFC4193() || na.RFC4843() || na.Local())
}

// For IPv4 these are either a 0 or all bits set address. For IPv6 a zero
// address or one that matches the RFC3849 documentation address format.
func (na *NetAddress) Valid() bool {
    return na.IP != nil && !(na.IP.IsUnspecified() || na.RFC3849() ||
                             na.IP.Equal(net.IPv4bcast))
}

func (na *NetAddress) Local() bool {
    return na.IP.IsLoopback() || zero4.Contains(na.IP)
}

func (na *NetAddress) ReachabilityTo(o *NetAddress) int {
    const (
        Unreachable = 0
        Default     = iota
        Teredo
        Ipv6_weak
        Ipv4
        Ipv6_strong
        Private
    )
    if !na.Routable() {
        return Unreachable
    } else if na.RFC4380() {
        if !o.Routable() {
            return Default
        } else if o.RFC4380() {
            return Teredo
        } else if o.IP.To4() != nil {
            return Ipv4
        } else { // ipv6
            return Ipv6_weak
        }
    } else if na.IP.To4() != nil {
        if o.Routable() && o.IP.To4() != nil {
            return Ipv4
        }
        return Default
    } else /* ipv6 */ {
        var tunnelled bool
        // Is our v6 is tunnelled?
        if o.RFC3964() || o.RFC6052() || o.RFC6145() {
            tunnelled = true
        }
        if !o.Routable() {
            return Default
        } else if o.RFC4380() {
            return Teredo
        } else if o.IP.To4() != nil {
            return Ipv4
        } else if tunnelled {
            // only prioritise ipv6 if we aren't tunnelling it.
            return Ipv6_weak
        }
        return Ipv6_strong
    }
}

// RFC1918: IPv4 Private networks (10.0.0.0/8, 192.168.0.0/16, 172.16.0.0/12)
// RFC3849: IPv6 Documentation address  (2001:0DB8::/32)
// RFC3927: IPv4 Autoconfig (169.254.0.0/16)
// RFC3964: IPv6 6to4 (2002::/16)
// RFC4193: IPv6 unique local (FC00::/7)
// RFC4380: IPv6 Teredo tunneling (2001::/32)
// RFC4843: IPv6 ORCHID: (2001:10::/28)
// RFC4862: IPv6 Autoconfig (FE80::/64)
// RFC6052: IPv6 well known prefix (64:FF9B::/96)
// RFC6145: IPv6 IPv4 translated address ::FFFF:0:0:0/96
var rfc1918_10 =    net.IPNet{IP: net.ParseIP("10.0.0.0"),      Mask: net.CIDRMask(8, 32)}
var rfc1918_192 =   net.IPNet{IP: net.ParseIP("192.168.0.0"),   Mask: net.CIDRMask(16, 32)}
var rfc1918_172 =   net.IPNet{IP: net.ParseIP("172.16.0.0"),    Mask: net.CIDRMask(12, 32)}
var rfc3849 =       net.IPNet{IP: net.ParseIP("2001:0DB8::"),   Mask: net.CIDRMask(32, 128)}
var rfc3927 =       net.IPNet{IP: net.ParseIP("169.254.0.0"),   Mask: net.CIDRMask(16, 32)}
var rfc3964 =       net.IPNet{IP: net.ParseIP("2002::"),        Mask: net.CIDRMask(16, 128)}
var rfc4193 =       net.IPNet{IP: net.ParseIP("FC00::"),        Mask: net.CIDRMask(7, 128)}
var rfc4380 =       net.IPNet{IP: net.ParseIP("2001::"),        Mask: net.CIDRMask(32, 128)}
var rfc4843 =       net.IPNet{IP: net.ParseIP("2001:10::"),     Mask: net.CIDRMask(28, 128)}
var rfc4862 =       net.IPNet{IP: net.ParseIP("FE80::"),        Mask: net.CIDRMask(64, 128)}
var rfc6052 =       net.IPNet{IP: net.ParseIP("64:FF9B::"),     Mask: net.CIDRMask(96, 128)}
var rfc6145 =       net.IPNet{IP: net.ParseIP("::FFFF:0:0:0"),  Mask: net.CIDRMask(96, 128)}
var zero4 =         net.IPNet{IP: net.ParseIP("0.0.0.0"),       Mask: net.CIDRMask(8, 32)}

func (na *NetAddress) RFC1918() bool { return rfc1918_10.Contains(na.IP) ||
                                              rfc1918_192.Contains(na.IP) ||
                                              rfc1918_172.Contains(na.IP) }
func (na *NetAddress) RFC3849() bool { return rfc3849.Contains(na.IP) }
func (na *NetAddress) RFC3927() bool { return rfc3927.Contains(na.IP) }
func (na *NetAddress) RFC3964() bool { return rfc3964.Contains(na.IP) }
func (na *NetAddress) RFC4193() bool { return rfc4193.Contains(na.IP) }
func (na *NetAddress) RFC4380() bool { return rfc4380.Contains(na.IP) }
func (na *NetAddress) RFC4843() bool { return rfc4843.Contains(na.IP) }
func (na *NetAddress) RFC4862() bool { return rfc4862.Contains(na.IP) }
func (na *NetAddress) RFC6052() bool { return rfc6052.Contains(na.IP) }
func (na *NetAddress) RFC6145() bool { return rfc6145.Contains(na.IP) }