package routetable_test

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

	"git.eeqj.de/sneak/routewatch/internal/routetable"
)

// Origin ASes that are not reserved, unlike asA, asB and asC, which are
// documentation AS numbers and so make bogon announcements.
const (
	asOne   = 1000
	asTwo   = 2000
	asThree = 3000
	asFour  = 4000
	asFive  = 5000

	// noKnownOrigin is the origin AS of a route whose path ends in an AS
	// set.
	noKnownOrigin = 0
	// privateUseAS and asTrans are reserved AS numbers.
	privateUseAS = 64512
	asTrans      = 23456

	// maxListed is how many bogon announcements and prefixes with more than
	// one origin AS the tests ask Overview for.
	maxListed = 10
)

// prefixRoute returns the PrefixRoute of prefix with origin AS asn, second
// seconds after the start.
func prefixRoute(prefix string, asn, second int) *routetable.PrefixRoute {
	return &routetable.PrefixRoute{
		Prefix: netip.MustParsePrefix(prefix), OriginASN: asn, Time: at(second),
	}
}

func TestOverviewOfAnEmptyTable(t *testing.T) {
	t.Parallel()

	got := routetable.New(routetable.Params{}).Overview(maxListed)
	if !reflect.DeepEqual(got, routetable.Overview{}) {
		t.Errorf("Overview() = %+v, want no figures", got)
	}
}

// TestOverviewNewestAndOldestRoutes checks that the newest and the oldest kept
// routes are found among every origin's kept routes, and that withdrawn routes
// no longer count.
func TestOverviewNewestAndOldestRoutes(t *testing.T) {
	t.Parallel()

	table := routetable.New(routetable.Params{})
	announceAll(table, "1.0.0.0/24", asOne, 20, peerA, peerB)
	// The oldest is the older of this origin's two kept routes.
	announceAll(table, "2.0.0.0/24", asTwo, 10, peerA, peerB)
	announceAll(table, "2001:4860::/32", asThree, 40, peerC)
	// Withdrawn routes, newer and older than every other.
	announceAll(table, "3.0.0.0/24", asOne, 50, peerA)
	announceAll(table, "4.0.0.0/24", asOne, 5, peerB)
	table.Withdraw(netip.MustParsePrefix("3.0.0.0/24"), peerA)
	table.Withdraw(netip.MustParsePrefix("4.0.0.0/24"), peerB)

	got := table.Overview(maxListed)

	want := prefixRoute("2001:4860::/32", asThree, 40)
	if !reflect.DeepEqual(got.NewestRoute, want) {
		t.Errorf("NewestRoute = %+v, want %+v", got.NewestRoute, want)
	}

	want = prefixRoute("2.0.0.0/24", asTwo, 10)
	if !reflect.DeepEqual(got.OldestRoute, want) {
		t.Errorf("OldestRoute = %+v, want %+v", got.OldestRoute, want)
	}
}

// TestOverviewPrefixesPerOrigin checks the AS that originates the most
// prefixes and the ASes that originate one.
func TestOverviewPrefixesPerOrigin(t *testing.T) {
	t.Parallel()

	table := routetable.New(routetable.Params{})
	// asOne and asTwo originate two prefixes each; the lower AS number counts.
	announceAll(table, "1.0.0.0/24", asTwo, 10, peerA)
	announceAll(table, "1.0.1.0/24", asTwo, 10, peerA)
	announceAll(table, "2.0.0.0/24", asOne, 10, peerA)
	announceAll(table, "2.0.1.0/24", asOne, 10, peerB)
	// Three ASes originate one prefix. asThree's route is the newest, and
	// asFive's origin keeps no route: peers B and C withdrew theirs.
	announceAll(table, "3.0.0.0/24", asThree, 30, peerA)
	announceAll(table, "4.0.0.0/24", asFour, 20, peerA)
	announceAll(table, "5.0.0.0/24", asFive, 40, peerA, peerB, peerC)
	table.Withdraw(netip.MustParsePrefix("5.0.0.0/24"), peerB)
	table.Withdraw(netip.MustParsePrefix("5.0.0.0/24"), peerC)

	got := table.Overview(maxListed)

	if got.MostPrefixesASN != asOne || got.MostPrefixes != 2 {
		t.Errorf("most prefixes: AS%d with %d, want AS%d with 2",
			got.MostPrefixesASN, got.MostPrefixes, asOne)
	}

	if got.SinglePrefixASes != 3 {
		t.Errorf("SinglePrefixASes = %d, want 3", got.SinglePrefixASes)
	}

	want := prefixRoute("3.0.0.0/24", asThree, 30)
	if !reflect.DeepEqual(got.NewestSinglePrefix, want) {
		t.Errorf("NewestSinglePrefix = %+v, want %+v", got.NewestSinglePrefix, want)
	}
}

// TestOverviewLeavesOutNoKnownOrigin checks that AS 0, which stands for no
// known origin, counts in neither the most nor the single-prefix figures. It
// originates one prefix, with a route newer than asOne's, and asOne would lose
// the tie for the most prefixes to it.
func TestOverviewLeavesOutNoKnownOrigin(t *testing.T) {
	t.Parallel()

	table := routetable.New(routetable.Params{})
	announceAll(table, "1.0.0.0/24", asOne, 10, peerA)
	announceAll(table, "2.0.0.0/24", noKnownOrigin, 20, peerA)

	got := table.Overview(maxListed)

	if got.MostPrefixesASN != asOne || got.SinglePrefixASes != 1 {
		t.Errorf("most prefixes AS%d, %d single-prefix ASes; want AS%d, 1",
			got.MostPrefixesASN, got.SinglePrefixASes, asOne)
	}

	want := prefixRoute("1.0.0.0/24", asOne, 10)
	if !reflect.DeepEqual(got.NewestSinglePrefix, want) {
		t.Errorf("NewestSinglePrefix = %+v, want %+v", got.NewestSinglePrefix, want)
	}
}

// TestOverviewBogons checks which routes are bogon announcements and why, in
// prefix order, and that a smaller maxListed lists fewer but counts them all.
func TestOverviewBogons(t *testing.T) {
	t.Parallel()

	table := routetable.New(routetable.Params{})
	// A reserved prefix, carried by two peers.
	announceAll(table, "192.168.0.0/16", asOne, 10, peerA, peerB)
	// A reserved origin AS.
	announceAll(table, "1.0.0.0/24", privateUseAS, 10, peerA)
	// Both.
	announceAll(table, "10.0.0.0/8", asTrans, 10, peerA)
	// Neither: a normal route, and a block that may be announced although it
	// lies inside a reserved one.
	announceAll(table, "1.0.1.0/24", asOne, 10, peerA)
	announceAll(table, "2001:4:112::/48", asTwo, 10, peerA)

	want := []routetable.Bogon{
		{
			Prefix: netip.MustParsePrefix("1.0.0.0/24"), OriginASN: privateUseAS,
			Peers: 1, Reasons: []string{"Private-Use (AS64512-AS65534)"},
		},
		{
			Prefix: netip.MustParsePrefix("10.0.0.0/8"), OriginASN: asTrans,
			Peers: 1,
			Reasons: []string{
				"Private-Use (10.0.0.0/8)", "AS_TRANS (AS23456)",
			},
		},
		{
			Prefix: netip.MustParsePrefix("192.168.0.0/16"), OriginASN: asOne,
			Peers: 2, Reasons: []string{"Private-Use (192.168.0.0/16)"},
		},
	}

	got := table.Overview(maxListed)
	if !reflect.DeepEqual(got.Bogons, want) || got.BogonCount != len(want) {
		t.Errorf("Overview(%d): %d bogons %+v, want %d %+v", maxListed,
			got.BogonCount, got.Bogons, len(want), want)
	}

	const fewer = 2

	got = table.Overview(fewer)
	if !reflect.DeepEqual(got.Bogons, want[:fewer]) || got.BogonCount != len(want) {
		t.Errorf("Overview(%d): %d bogons %+v, want %d %+v", fewer,
			got.BogonCount, got.Bogons, len(want), want[:fewer])
	}
}

// TestOverviewMultipleOrigins checks the prefixes with more than one origin
// AS, in prefix order, and that a smaller maxListed lists fewer but counts them
// all.
func TestOverviewMultipleOrigins(t *testing.T) {
	t.Parallel()

	table := routetable.New(routetable.Params{})
	announceAll(table, "2001:4860::/32", asThree, 10, peerA)
	announceAll(table, "2001:4860::/32", asTwo, 10, peerB)
	announceAll(table, "1.0.0.0/24", asOne, 10, peerA, peerB)
	announceAll(table, "1.0.0.0/24", asTwo, 30, peerC)
	// One origin only.
	announceAll(table, "2.0.0.0/24", asOne, 10, peerA, peerB)

	want := []routetable.MultipleOriginPrefix{
		{
			Prefix: netip.MustParsePrefix("1.0.0.0/24"),
			Origins: []routetable.OriginPeers{
				{ASN: asOne, Peers: 2}, {ASN: asTwo, Peers: 1},
			},
		},
		{
			Prefix: netip.MustParsePrefix("2001:4860::/32"),
			Origins: []routetable.OriginPeers{
				{ASN: asTwo, Peers: 1}, {ASN: asThree, Peers: 1},
			},
		},
	}

	got := table.Overview(maxListed)
	if !reflect.DeepEqual(got.MultipleOrigins, want) ||
		got.MultipleOriginCount != len(want) {
		t.Errorf("Overview(%d): %d prefixes %+v, want %d %+v", maxListed,
			got.MultipleOriginCount, got.MultipleOrigins, len(want), want)
	}

	got = table.Overview(1)
	if !reflect.DeepEqual(got.MultipleOrigins, want[:1]) ||
		got.MultipleOriginCount != len(want) {
		t.Errorf("Overview(1): %d prefixes %+v, want %d %+v",
			got.MultipleOriginCount, got.MultipleOrigins, len(want), want[:1])
	}
}