package netx

import (
	"net/netip"

	"go4.org/netipx"
)

const (
	ip4in6Legacy96 string = "::"
	ip4in6Modern96 string = "::ffff:"
)

var (
	// IPv4 documentation prefixes (RFC 5737)
	ipDoc4pfxs []netip.Prefix = []netip.Prefix{
		netip.MustParsePrefix("192.0.2.0/24"),
		netip.MustParsePrefix("198.51.100.0/24"),
		netip.MustParsePrefix("203.0.113.0/24"),
	}
	ipDoc4 *netipx.IPSet = MustIPSetFromNative(nil, ipDoc4pfxs, nil)
	// IPv6 documentation prefixes (RFC 3849, RFC 9637)
	ipDoc6pfxs []netip.Prefix = []netip.Prefix{
		netip.MustParsePrefix("2001:db8::/32"),
		netip.MustParsePrefix("3fff::/20"),
	}
	ipDoc6 *netipx.IPSet = MustIPSetFromNative(nil, ipDoc6pfxs, nil)
	// combined documentation prefixes
	ipDoc *netipx.IPSet = MustIPSetCombined(
		[]*netipx.IPSet{
			ipDoc4,
			ipDoc6,
		},
	)

	// CGNAT/LSN (RFC 6598)
	cgnat4 netip.Prefix = netip.MustParsePrefix("100.64.0.0/10")

	// IPv4-Compatible IPv6 Address, RFC 4291 § 2.5.5.1
	ip4in6Legacy netip.Prefix = netip.MustParsePrefix(ip4in6Legacy96 + "/96")
	// IPv4-Mapped IPv6 Address, RFC 4291 § 2.5.5.2
	ip4in6Modern netip.Prefix = netip.MustParsePrefix(ip4in6Modern96 + "0:0/96")
	// both
	ip4in6 *netipx.IPSet = MustIPSetFromNative(
		nil,
		[]netip.Prefix{
			ip4in6Legacy,
			ip4in6Modern,
		},
		nil,
	)
)