package outward

import (
	"errors"
	"net/netip"
	"reflect"
	"testing"
)

func prefixes(s ...string) []netip.Prefix {
	var out []netip.Prefix
	for _, p := range s {
		out = append(out, netip.MustParsePrefix(p))
	}
	return out
}

// **Each link facing outside says the networks it is attached to** (novox/hq ADR 0340 §7), as the
// network's address and prefix, never the machine's own address on it — and every one, public and
// link-local included, because which count is the controller's judgement and said with why.
func TestEachOutwardLinkSaysTheNetworksItIsOn(t *testing.T) {
	addrs := map[string][]netip.Prefix{
		"eth0": prefixes("192.168.1.10/24", "fe80::1/64", "fd12:3456:789a::5/64"),
		"eth1": prefixes("203.0.113.7/24"),
		// Not asked: the bridge is not a link facing outside.
		"docker0": prefixes("172.17.0.1/16"),
	}
	got, err := Networks([]string{"eth1", "eth0"}, func(link string) ([]netip.Prefix, error) { return addrs[link], nil })
	if err != nil {
		t.Fatal(err)
	}
	want := []Network{
		{Link: "eth0", Network: "192.168.1.0/24"},
		{Link: "eth0", Network: "fd12:3456:789a::/64"},
		{Link: "eth0", Network: "fe80::/64"},
		{Link: "eth1", Network: "203.0.113.0/24"},
	}
	if !reflect.DeepEqual(got, want) {
		t.Fatalf("got %+v\nwant %+v", got, want)
	}
}

// A link whose addresses cannot be read fails the whole, so the machine says the fact is unknown rather
// than reporting part of its networks as all of them.
func TestAnUnreadableLinkIsNotAPartialAccount(t *testing.T) {
	_, err := Networks([]string{"eth0"}, func(string) ([]netip.Prefix, error) { return nil, errors.New("denied") })
	if err == nil {
		t.Fatal("an unreadable link was reported as having no networks")
	}
}

// A link gone between reading the routing table and reading its addresses has no networks, and the
// rest are still said.
func TestALinkGoneSinceItWasListedHasNoNetworks(t *testing.T) {
	got, err := Networks([]string{"gone0"}, RealAddresses)
	if err != nil || len(got) != 0 {
		t.Fatalf("got %v, %v", got, err)
	}
}