package basichost

import (
	"context"
	"fmt"
	"io"
	"reflect"
	"sort"
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/libp2p/go-libp2p/core/event"
	"github.com/libp2p/go-libp2p/core/host"
	"github.com/libp2p/go-libp2p/core/network"
	"github.com/libp2p/go-libp2p/core/peer"
	"github.com/libp2p/go-libp2p/core/peerstore"
	"github.com/libp2p/go-libp2p/core/protocol"
	"github.com/libp2p/go-libp2p/core/record"
	"github.com/libp2p/go-libp2p/p2p/host/autonat"
	"github.com/libp2p/go-libp2p/p2p/host/eventbus"
	swarmt "github.com/libp2p/go-libp2p/p2p/net/swarm/testing"
	"github.com/libp2p/go-libp2p/p2p/protocol/identify"

	ma "github.com/multiformats/go-multiaddr"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestHostDoubleClose(t *testing.T) {
	h1, err := NewHost(swarmt.GenSwarm(t), nil)
	require.NoError(t, err)
	h1.Close()
	h1.Close()
}

func TestHostSimple(t *testing.T) {
	ctx := context.Background()
	h1, err := NewHost(swarmt.GenSwarm(t), nil)
	require.NoError(t, err)
	defer h1.Close()
	h1.Start()
	h2, err := NewHost(swarmt.GenSwarm(t), nil)
	require.NoError(t, err)
	defer h2.Close()
	h2.Start()

	h2pi := h2.Peerstore().PeerInfo(h2.ID())
	require.NoError(t, h1.Connect(ctx, h2pi))

	piper, pipew := io.Pipe()
	h2.SetStreamHandler(protocol.TestingID, func(s network.Stream) {
		defer s.Close()
		w := io.MultiWriter(s, pipew)
		io.Copy(w, s) // mirror everything
	})

	s, err := h1.NewStream(ctx, h2pi.ID, protocol.TestingID)
	require.NoError(t, err)

	// write to the stream
	buf1 := []byte("abcdefghijkl")
	_, err = s.Write(buf1)
	require.NoError(t, err)

	// get it from the stream (echoed)
	buf2 := make([]byte, len(buf1))
	_, err = io.ReadFull(s, buf2)
	require.NoError(t, err)
	require.Equal(t, buf1, buf2)

	// get it from the pipe (tee)
	buf3 := make([]byte, len(buf1))
	_, err = io.ReadFull(piper, buf3)
	require.NoError(t, err)
	require.Equal(t, buf1, buf3)
}

func TestMultipleClose(t *testing.T) {
	h, err := NewHost(swarmt.GenSwarm(t), nil)
	require.NoError(t, err)

	require.NoError(t, h.Close())
	require.NoError(t, h.Close())
	require.NoError(t, h.Close())
}

func TestSignedPeerRecordWithNoListenAddrs(t *testing.T) {
	h, err := NewHost(swarmt.GenSwarm(t, swarmt.OptDialOnly), nil)
	require.NoError(t, err)
	defer h.Close()
	h.Start()

	require.Empty(t, h.Addrs(), "expected no listen addrs")
	// now add a listen addr
	require.NoError(t, h.Network().Listen(ma.StringCast("/ip4/0.0.0.0/tcp/0")))
	require.NotEmpty(t, h.Addrs(), "expected at least 1 listen addr")

	cab, ok := peerstore.GetCertifiedAddrBook(h.Peerstore())
	if !ok {
		t.Fatalf("peerstore doesn't support certified addrs")
	}
	// the signed record with the new addr is added async
	var env *record.Envelope
	require.Eventually(t, func() bool {
		env = cab.GetPeerRecord(h.ID())
		return env != nil
	}, 500*time.Millisecond, 10*time.Millisecond)
	rec, err := env.Record()
	require.NoError(t, err)
	require.NotEmpty(t, rec.(*peer.PeerRecord).Addrs)
}

func TestProtocolHandlerEvents(t *testing.T) {
	h, err := NewHost(swarmt.GenSwarm(t), nil)
	require.NoError(t, err)
	defer h.Close()

	sub, err := h.EventBus().Subscribe(&event.EvtLocalProtocolsUpdated{}, eventbus.BufSize(16))
	require.NoError(t, err)
	defer sub.Close()

	// the identify service adds new protocol handlers shortly after the host
	// starts. this helps us filter those events out, since they're unrelated
	// to the test.
	isIdentify := func(evt event.EvtLocalProtocolsUpdated) bool {
		for _, p := range evt.Added {
			if p == identify.ID || p == identify.IDPush {
				return true
			}
		}
		return false
	}

	nextEvent := func() event.EvtLocalProtocolsUpdated {
		for {
			select {
			case evt := <-sub.Out():
				next := evt.(event.EvtLocalProtocolsUpdated)
				if isIdentify(next) {
					continue
				}
				return next
			case <-time.After(5 * time.Second):
				t.Fatal("event not received in 5 seconds")
			}
		}
	}

	assert := func(added, removed []protocol.ID) {
		next := nextEvent()
		if !reflect.DeepEqual(added, next.Added) {
			t.Errorf("expected added: %v; received: %v", added, next.Added)
		}
		if !reflect.DeepEqual(removed, next.Removed) {
			t.Errorf("expected removed: %v; received: %v", removed, next.Removed)
		}
	}

	h.SetStreamHandler(protocol.TestingID, func(s network.Stream) {})
	assert([]protocol.ID{protocol.TestingID}, nil)
	h.SetStreamHandler("foo", func(s network.Stream) {})
	assert([]protocol.ID{"foo"}, nil)
	h.RemoveStreamHandler(protocol.TestingID)
	assert(nil, []protocol.ID{protocol.TestingID})
}

func TestHostAddrsFactory(t *testing.T) {
	maddr := ma.StringCast("/ip4/1.2.3.4/tcp/1234")
	addrsFactory := func(addrs []ma.Multiaddr) []ma.Multiaddr {
		return []ma.Multiaddr{maddr}
	}

	h, err := NewHost(swarmt.GenSwarm(t), &HostOpts{AddrsFactory: addrsFactory})
	require.NoError(t, err)
	defer h.Close()

	addrs := h.Addrs()
	if len(addrs) != 1 {
		t.Fatalf("expected 1 addr, got %+v", addrs)
	}
	if !addrs[0].Equal(maddr) {
		t.Fatalf("expected %s, got %s", maddr.String(), addrs[0].String())
	}

	autoNat, err := autonat.New(h, autonat.WithReachability(network.ReachabilityPublic))
	if err != nil {
		t.Fatalf("should be able to attach autonat: %v", err)
	}
	h.SetAutoNat(autoNat)
	addrs = h.Addrs()
	if len(addrs) != 1 {
		t.Fatalf("didn't expect change in returned addresses.")
	}
}

func TestLocalIPChangesWhenListenAddrChanges(t *testing.T) {
	// no listen addrs
	h, err := NewHost(swarmt.GenSwarm(t, swarmt.OptDialOnly), nil)
	require.NoError(t, err)
	h.Start()
	defer h.Close()

	h.addrMu.Lock()
	h.filteredInterfaceAddrs = nil
	h.allInterfaceAddrs = nil
	h.addrMu.Unlock()

	// change listen addrs and verify local IP addr is not nil again
	require.NoError(t, h.Network().Listen(ma.StringCast("/ip4/0.0.0.0/tcp/0")))
	h.SignalAddressChange()
	time.Sleep(1 * time.Second)

	h.addrMu.RLock()
	defer h.addrMu.RUnlock()
	require.NotEmpty(t, h.filteredInterfaceAddrs)
	require.NotEmpty(t, h.allInterfaceAddrs)
}

func TestAllAddrs(t *testing.T) {
	// no listen addrs
	h, err := NewHost(swarmt.GenSwarm(t, swarmt.OptDialOnly), nil)
	require.NoError(t, err)
	defer h.Close()
	require.Nil(t, h.AllAddrs())

	// listen on loopback
	laddr := ma.StringCast("/ip4/127.0.0.1/tcp/0")
	require.NoError(t, h.Network().Listen(laddr))
	require.Len(t, h.AllAddrs(), 1)
	firstAddr := h.AllAddrs()[0]
	require.Equal(t, "/ip4/127.0.0.1", ma.Split(firstAddr)[0].String())

	// listen on IPv4 0.0.0.0
	require.NoError(t, h.Network().Listen(ma.StringCast("/ip4/0.0.0.0/tcp/0")))
	// should contain localhost and private local addr along with previous listen address
	require.Len(t, h.AllAddrs(), 3)
	// Should still contain the original addr.
	require.True(t, ma.Contains(h.AllAddrs(), firstAddr), "should still contain the original addr")
}

// getHostPair gets a new pair of hosts.
// The first host initiates the connection to the second host.
func getHostPair(t *testing.T) (host.Host, host.Host) {
	t.Helper()

	h1, err := NewHost(swarmt.GenSwarm(t), nil)
	require.NoError(t, err)
	h1.Start()
	h2, err := NewHost(swarmt.GenSwarm(t), nil)
	require.NoError(t, err)
	h2.Start()

	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()
	h2pi := h2.Peerstore().PeerInfo(h2.ID())
	require.NoError(t, h1.Connect(ctx, h2pi))
	return h1, h2
}

func assertWait(t *testing.T, c chan protocol.ID, exp protocol.ID) {
	t.Helper()
	select {
	case proto := <-c:
		if proto != exp {
			t.Fatalf("should have connected on %s, got %s", exp, proto)
		}
	case <-time.After(time.Second * 5):
		t.Fatal("timeout waiting for stream")
	}
}

func TestHostProtoPreference(t *testing.T) {
	h1, h2 := getHostPair(t)
	defer h1.Close()
	defer h2.Close()

	const (
		protoOld   = "/testing"
		protoNew   = "/testing/1.1.0"
		protoMinor = "/testing/1.2.0"
	)

	connectedOn := make(chan protocol.ID)
	handler := func(s network.Stream) {
		connectedOn <- s.Protocol()
		s.Close()
	}

	// Prevent pushing identify information so this test works.
	h1.RemoveStreamHandler(identify.IDPush)

	h2.SetStreamHandler(protoOld, handler)

	s, err := h1.NewStream(context.Background(), h2.ID(), protoMinor, protoNew, protoOld)
	require.NoError(t, err)

	// force the lazy negotiation to complete
	_, err = s.Write(nil)
	require.NoError(t, err)

	assertWait(t, connectedOn, protoOld)
	s.Close()

	h2.SetStreamHandlerMatch(protoMinor, func(protocol.ID) bool { return true }, handler)
	// remembered preference will be chosen first, even when the other side newly supports it
	s2, err := h1.NewStream(context.Background(), h2.ID(), protoMinor, protoNew, protoOld)
	require.NoError(t, err)

	// required to force 'lazy' handshake
	_, err = s2.Write([]byte("hello"))
	require.NoError(t, err)

	assertWait(t, connectedOn, protoOld)
	s2.Close()

	s3, err := h1.NewStream(context.Background(), h2.ID(), protoMinor)
	require.NoError(t, err)

	// Force a lazy handshake as we may have received a protocol update by this point.
	_, err = s3.Write([]byte("hello"))
	require.NoError(t, err)

	assertWait(t, connectedOn, protoMinor)
	s3.Close()
}

func TestHostProtoMismatch(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	h1, h2 := getHostPair(t)
	defer h1.Close()
	defer h2.Close()

	h1.SetStreamHandler("/super", func(s network.Stream) {
		t.Error("shouldnt get here")
		s.Reset()
	})

	_, err := h2.NewStream(ctx, h1.ID(), "/foo", "/bar", "/baz/1.0.0")
	if err == nil {
		t.Fatal("expected new stream to fail")
	}
}

func TestHostProtoPreknowledge(t *testing.T) {
	h1, err := NewHost(swarmt.GenSwarm(t, swarmt.OptDialOnly), nil)
	require.NoError(t, err)
	defer h1.Close()

	h2, err := NewHost(swarmt.GenSwarm(t, swarmt.OptDisableTCP), nil)
	require.NoError(t, err)
	defer h2.Close()

	conn := make(chan protocol.ID)
	handler := func(s network.Stream) {
		conn <- s.Protocol()
		s.Close()
	}

	h2.SetStreamHandler("/super", handler)

	h1.Start()
	h2.Start()

	// Prevent pushing identify information so this test actually _uses_ the super protocol.
	h1.RemoveStreamHandler(identify.IDPush)

	h2pi := h2.Peerstore().PeerInfo(h2.ID())
	// Filter to only 1 address so that we don't have to think about parallel
	// connections in this test
	h2pi.Addrs = h2pi.Addrs[:1]
	require.NoError(t, h1.Connect(context.Background(), h2pi))

	// This test implicitly relies on 1 connection. If a background identify
	// completes after we set the stream handler below things break
	require.Len(t, h1.Network().ConnsToPeer(h2.ID()), 1)

	// wait for identify handshake to finish completely
	select {
	case <-h1.ids.IdentifyWait(h1.Network().ConnsToPeer(h2.ID())[0]):
	case <-time.After(time.Second * 5):
		t.Fatal("timed out waiting for identify")
	}

	select {
	case <-h2.ids.IdentifyWait(h2.Network().ConnsToPeer(h1.ID())[0]):
	case <-time.After(time.Second * 5):
		t.Fatal("timed out waiting for identify")
	}

	h2.SetStreamHandler("/foo", handler)

	require.Never(t, func() bool {
		protos, err := h1.Peerstore().GetProtocols(h2.ID())
		require.NoError(t, err)
		for _, p := range protos {
			if p == "/foo" {
				return true
			}
		}
		return false
	}, time.Second, 100*time.Millisecond)

	s, err := h1.NewStream(context.Background(), h2.ID(), "/foo", "/bar", "/super")
	require.NoError(t, err)

	select {
	case p := <-conn:
		t.Fatal("shouldn't have gotten connection yet, we should have a lazy stream: ", p)
	case <-time.After(time.Millisecond * 50):
	}

	_, err = s.Read(nil)
	require.NoError(t, err)
	assertWait(t, conn, "/super")

	s.Close()
}

func TestNewDialOld(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	h1, h2 := getHostPair(t)
	defer h1.Close()
	defer h2.Close()

	connectedOn := make(chan protocol.ID)
	h2.SetStreamHandler("/testing", func(s network.Stream) {
		connectedOn <- s.Protocol()
		s.Close()
	})

	s, err := h1.NewStream(ctx, h2.ID(), "/testing/1.0.0", "/testing")
	require.NoError(t, err)

	// force the lazy negotiation to complete
	_, err = s.Write(nil)
	require.NoError(t, err)
	assertWait(t, connectedOn, "/testing")

	require.Equal(t, s.Protocol(), protocol.ID("/testing"), "should have gotten /testing")
}

func TestNewStreamResolve(t *testing.T) {
	h1, err := NewHost(swarmt.GenSwarm(t), nil)
	require.NoError(t, err)
	h1.Start()
	h2, err := NewHost(swarmt.GenSwarm(t), nil)
	require.NoError(t, err)
	h2.Start()

	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()

	// Get the tcp port that h2 is listening on.
	h2pi := h2.Peerstore().PeerInfo(h2.ID())
	var dialAddr string
	const tcpPrefix = "/ip4/127.0.0.1/tcp/"
	for _, addr := range h2pi.Addrs {
		addrStr := addr.String()
		if strings.HasPrefix(addrStr, tcpPrefix) {
			port := addrStr[len(tcpPrefix):]
			dialAddr = "/dns4/localhost/tcp/" + port
			break
		}
	}
	assert.NotEqual(t, "", dialAddr)

	// Add the DNS multiaddr to h1's peerstore.
	maddr, err := ma.NewMultiaddr(dialAddr)
	require.NoError(t, err)
	h1.Peerstore().AddAddr(h2.ID(), maddr, time.Second)

	connectedOn := make(chan protocol.ID)
	h2.SetStreamHandler("/testing", func(s network.Stream) {
		connectedOn <- s.Protocol()
		s.Close()
	})

	// NewStream will make a new connection using the DNS address in h1's
	// peerstore.
	s, err := h1.NewStream(ctx, h2.ID(), "/testing/1.0.0", "/testing")
	require.NoError(t, err)

	// force the lazy negotiation to complete
	_, err = s.Write(nil)
	require.NoError(t, err)
	assertWait(t, connectedOn, "/testing")
}

func TestProtoDowngrade(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	h1, h2 := getHostPair(t)
	defer h1.Close()
	defer h2.Close()

	connectedOn := make(chan protocol.ID)
	h2.SetStreamHandler("/testing/1.0.0", func(s network.Stream) {
		defer s.Close()
		result, err := io.ReadAll(s)
		assert.NoError(t, err)
		assert.Equal(t, "bar", string(result))
		connectedOn <- s.Protocol()
	})

	s, err := h1.NewStream(ctx, h2.ID(), "/testing/1.0.0", "/testing")
	require.NoError(t, err)
	require.Equal(t, s.Protocol(), protocol.ID("/testing/1.0.0"), "should have gotten /testing/1.0.0, got %s", s.Protocol())

	_, err = s.Write([]byte("bar"))
	require.NoError(t, err)
	require.NoError(t, s.CloseWrite())

	assertWait(t, connectedOn, "/testing/1.0.0")
	require.NoError(t, s.Close())

	h1.Network().ClosePeer(h2.ID())
	h2.RemoveStreamHandler("/testing/1.0.0")
	h2.SetStreamHandler("/testing", func(s network.Stream) {
		defer s.Close()
		result, err := io.ReadAll(s)
		assert.NoError(t, err)
		assert.Equal(t, "foo", string(result))
		connectedOn <- s.Protocol()
	})

	// Give us a second to update our protocol list. This happens async through the event bus.
	// This is _almost_ instantaneous, but this test fails once every ~1k runs without this.
	time.Sleep(time.Millisecond)

	h2pi := h2.Peerstore().PeerInfo(h2.ID())
	require.NoError(t, h1.Connect(ctx, h2pi))

	s2, err := h1.NewStream(ctx, h2.ID(), "/testing/1.0.0", "/testing")
	require.NoError(t, err)
	require.Equal(t, s2.Protocol(), protocol.ID("/testing"), "should have gotten /testing, got %s, %s", s.Protocol(), s.Conn())

	_, err = s2.Write([]byte("foo"))
	require.NoError(t, err)
	require.NoError(t, s2.CloseWrite())

	assertWait(t, connectedOn, "/testing")
}

func TestAddrChangeImmediatelyIfAddressNonEmpty(t *testing.T) {
	ctx := context.Background()
	taddrs := []ma.Multiaddr{ma.StringCast("/ip4/1.2.3.4/tcp/1234")}

	starting := make(chan struct{})
	h, err := NewHost(swarmt.GenSwarm(t), &HostOpts{AddrsFactory: func(addrs []ma.Multiaddr) []ma.Multiaddr {
		<-starting
		return taddrs
	}})
	require.NoError(t, err)
	defer h.Close()

	sub, err := h.EventBus().Subscribe(&event.EvtLocalAddressesUpdated{})
	close(starting)
	if err != nil {
		t.Error(err)
	}
	defer sub.Close()
	h.Start()

	expected := event.EvtLocalAddressesUpdated{
		Diffs: true,
		Current: []event.UpdatedAddress{
			{Action: event.Added, Address: ma.StringCast("/ip4/1.2.3.4/tcp/1234")},
		},
		Removed: []event.UpdatedAddress{}}

	// assert we get expected event
	evt := waitForAddrChangeEvent(ctx, sub, t)
	if !updatedAddrEventsEqual(expected, evt) {
		t.Errorf("change events not equal: \n\texpected: %v \n\tactual: %v", expected, evt)
	}

	// assert it's on the signed record
	rc := peerRecordFromEnvelope(t, evt.SignedPeerRecord)
	require.Equal(t, taddrs, rc.Addrs)

	// assert it's in the peerstore
	ev := h.Peerstore().(peerstore.CertifiedAddrBook).GetPeerRecord(h.ID())
	require.NotNil(t, ev)
	rc = peerRecordFromEnvelope(t, ev)
	require.Equal(t, taddrs, rc.Addrs)
}

func TestStatefulAddrEvents(t *testing.T) {
	h, err := NewHost(swarmt.GenSwarm(t), nil)
	require.NoError(t, err)
	h.Start()
	defer h.Close()

	sub, err := h.EventBus().Subscribe(&event.EvtLocalAddressesUpdated{}, eventbus.BufSize(10))
	if err != nil {
		t.Error(err)
	}
	defer sub.Close()

	select {
	case v := <-sub.Out():
		assert.NotNil(t, v)
	case <-time.After(time.Second * 5):
		t.Error("timed out waiting for event")
	}
}

func TestHostAddrChangeDetection(t *testing.T) {
	// This test uses the address factory to provide several
	// sets of listen addresses for the host. It advances through
	// the sets by changing the currentAddrSet index var below.
	addrSets := [][]ma.Multiaddr{
		{},
		{ma.StringCast("/ip4/1.2.3.4/tcp/1234")},
		{ma.StringCast("/ip4/1.2.3.4/tcp/1234"), ma.StringCast("/ip4/2.3.4.5/tcp/1234")},
		{ma.StringCast("/ip4/2.3.4.5/tcp/1234"), ma.StringCast("/ip4/3.4.5.6/tcp/4321")},
	}

	// The events we expect the host to emit when SignalAddressChange is called
	// and the changes between addr sets are detected
	expectedEvents := []event.EvtLocalAddressesUpdated{
		{
			Diffs: true,
			Current: []event.UpdatedAddress{
				{Action: event.Added, Address: ma.StringCast("/ip4/1.2.3.4/tcp/1234")},
			},
			Removed: []event.UpdatedAddress{},
		},
		{
			Diffs: true,
			Current: []event.UpdatedAddress{
				{Action: event.Maintained, Address: ma.StringCast("/ip4/1.2.3.4/tcp/1234")},
				{Action: event.Added, Address: ma.StringCast("/ip4/2.3.4.5/tcp/1234")},
			},
			Removed: []event.UpdatedAddress{},
		},
		{
			Diffs: true,
			Current: []event.UpdatedAddress{
				{Action: event.Added, Address: ma.StringCast("/ip4/3.4.5.6/tcp/4321")},
				{Action: event.Maintained, Address: ma.StringCast("/ip4/2.3.4.5/tcp/1234")},
			},
			Removed: []event.UpdatedAddress{
				{Action: event.Removed, Address: ma.StringCast("/ip4/1.2.3.4/tcp/1234")},
			},
		},
	}

	var lk sync.Mutex
	currentAddrSet := 0
	addrsFactory := func(addrs []ma.Multiaddr) []ma.Multiaddr {
		lk.Lock()
		defer lk.Unlock()
		return addrSets[currentAddrSet]
	}

	ctx := context.Background()
	h, err := NewHost(swarmt.GenSwarm(t), &HostOpts{AddrsFactory: addrsFactory})
	require.NoError(t, err)
	h.Start()
	defer h.Close()

	sub, err := h.EventBus().Subscribe(&event.EvtLocalAddressesUpdated{}, eventbus.BufSize(10))
	require.NoError(t, err)
	defer sub.Close()

	// wait for the host background thread to start
	time.Sleep(1 * time.Second)
	// host should start with no addrs (addrSet 0)
	addrs := h.Addrs()
	if len(addrs) != 0 {
		t.Fatalf("expected 0 addrs, got %d", len(addrs))
	}

	// change addr, signal and assert event
	for i := 1; i < len(addrSets); i++ {
		lk.Lock()
		currentAddrSet = i
		lk.Unlock()
		h.SignalAddressChange()
		evt := waitForAddrChangeEvent(ctx, sub, t)
		if !updatedAddrEventsEqual(expectedEvents[i-1], evt) {
			t.Errorf("change events not equal: \n\texpected: %v \n\tactual: %v", expectedEvents[i-1], evt)
		}

		// assert it's on the signed record
		rc := peerRecordFromEnvelope(t, evt.SignedPeerRecord)
		require.Equal(t, addrSets[i], rc.Addrs)

		// assert it's in the peerstore
		ev := h.Peerstore().(peerstore.CertifiedAddrBook).GetPeerRecord(h.ID())
		require.NotNil(t, ev)
		rc = peerRecordFromEnvelope(t, ev)
		require.Equal(t, addrSets[i], rc.Addrs)
	}
}

func TestNegotiationCancel(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	h1, h2 := getHostPair(t)
	defer h1.Close()
	defer h2.Close()

	// pre-negotiation so we can make the negotiation hang.
	h2.Network().SetStreamHandler(func(s network.Stream) {
		<-ctx.Done() // wait till the test is done.
		s.Reset()
	})

	ctx2, cancel2 := context.WithCancel(ctx)
	defer cancel2()

	errCh := make(chan error, 1)
	go func() {
		s, err := h1.NewStream(ctx2, h2.ID(), "/testing")
		if s != nil {
			errCh <- fmt.Errorf("expected to fail negotiation")
			return
		}
		errCh <- err
	}()
	select {
	case err := <-errCh:
		t.Fatal(err)
	case <-time.After(10 * time.Millisecond):
		// ok, hung.
	}
	cancel2()

	select {
	case err := <-errCh:
		require.ErrorIs(t, err, context.Canceled)
	case <-time.After(500 * time.Millisecond):
		// failed to cancel
		t.Fatal("expected negotiation to be canceled")
	}
}

func waitForAddrChangeEvent(ctx context.Context, sub event.Subscription, t *testing.T) event.EvtLocalAddressesUpdated {
	t.Helper()
	for {
		select {
		case evt, more := <-sub.Out():
			if !more {
				t.Fatal("channel should not be closed")
			}
			return evt.(event.EvtLocalAddressesUpdated)
		case <-ctx.Done():
			t.Fatal("context should not have cancelled")
		case <-time.After(5 * time.Second):
			t.Fatal("timed out waiting for address change event")
		}
	}
}

// updatedAddrsEqual is a helper to check whether two lists of
// event.UpdatedAddress have the same contents, ignoring ordering.
func updatedAddrsEqual(a, b []event.UpdatedAddress) bool {
	if len(a) != len(b) {
		return false
	}

	// We can't use an UpdatedAddress directly as a map key, since
	// Multiaddr is an interface, and go won't know how to compare
	// for equality. So we convert to this little struct, which
	// stores the multiaddr as a string.
	type ua struct {
		action  event.AddrAction
		addrStr string
	}
	aSet := make(map[ua]struct{})
	for _, addr := range a {
		k := ua{action: addr.Action, addrStr: string(addr.Address.Bytes())}
		aSet[k] = struct{}{}
	}
	for _, addr := range b {
		k := ua{action: addr.Action, addrStr: string(addr.Address.Bytes())}
		_, ok := aSet[k]
		if !ok {
			return false
		}
	}
	return true
}

// updatedAddrEventsEqual is a helper to check whether two
// event.EvtLocalAddressesUpdated are equal, ignoring the ordering of
// addresses in the inner lists.
func updatedAddrEventsEqual(a, b event.EvtLocalAddressesUpdated) bool {
	return a.Diffs == b.Diffs &&
		updatedAddrsEqual(a.Current, b.Current) &&
		updatedAddrsEqual(a.Removed, b.Removed)
}

func peerRecordFromEnvelope(t *testing.T, ev *record.Envelope) *peer.PeerRecord {
	t.Helper()
	rec, err := ev.Record()
	if err != nil {
		t.Fatalf("error getting PeerRecord from event: %v", err)
		return nil
	}
	peerRec, ok := rec.(*peer.PeerRecord)
	if !ok {
		t.Fatalf("wrong type for peer record")
		return nil
	}
	return peerRec
}

func TestNormalizeMultiaddr(t *testing.T) {
	h1, err := NewHost(swarmt.GenSwarm(t), nil)
	require.NoError(t, err)
	defer h1.Close()

	require.Equal(t, "/ip4/1.2.3.4/udp/9999/quic-v1/webtransport", h1.NormalizeMultiaddr(ma.StringCast("/ip4/1.2.3.4/udp/9999/quic-v1/webtransport/certhash/uEgNmb28")).String())
}

func TestInferWebtransportAddrsFromQuic(t *testing.T) {
	type testCase struct {
		name string
		in   []string
		out  []string
	}

	testCases := []testCase{
		{
			name: "Happy Path",
			in:   []string{"/ip4/0.0.0.0/udp/9999/quic-v1", "/ip4/0.0.0.0/udp/9999/quic-v1/webtransport", "/ip4/1.2.3.4/udp/9999/quic-v1"},
			out:  []string{"/ip4/0.0.0.0/udp/9999/quic-v1", "/ip4/0.0.0.0/udp/9999/quic-v1/webtransport", "/ip4/1.2.3.4/udp/9999/quic-v1", "/ip4/1.2.3.4/udp/9999/quic-v1/webtransport"},
		},
		{
			name: "Happy Path With CertHashes",
			in:   []string{"/ip4/0.0.0.0/udp/9999/quic-v1", "/ip4/0.0.0.0/udp/9999/quic-v1/webtransport/certhash/uEgNmb28/certhash/uEgNmb28", "/ip4/1.2.3.4/udp/9999/quic-v1"},
			out:  []string{"/ip4/0.0.0.0/udp/9999/quic-v1", "/ip4/0.0.0.0/udp/9999/quic-v1/webtransport/certhash/uEgNmb28/certhash/uEgNmb28", "/ip4/1.2.3.4/udp/9999/quic-v1", "/ip4/1.2.3.4/udp/9999/quic-v1/webtransport"},
		},
		{
			name: "Already discovered",
			in:   []string{"/ip4/0.0.0.0/udp/9999/quic-v1", "/ip4/0.0.0.0/udp/9999/quic-v1/webtransport", "/ip4/1.2.3.4/udp/9999/quic-v1", "/ip4/1.2.3.4/udp/9999/quic-v1/webtransport"},
			out:  []string{"/ip4/0.0.0.0/udp/9999/quic-v1", "/ip4/0.0.0.0/udp/9999/quic-v1/webtransport", "/ip4/1.2.3.4/udp/9999/quic-v1", "/ip4/1.2.3.4/udp/9999/quic-v1/webtransport"},
		},
		{
			name: "Infer Many",
			in:   []string{"/ip4/0.0.0.0/udp/9999/quic-v1", "/ip4/0.0.0.0/udp/9999/quic-v1/webtransport", "/ip4/1.2.3.4/udp/9999/quic-v1", "/ip4/4.3.2.1/udp/9999/quic-v1"},
			out:  []string{"/ip4/0.0.0.0/udp/9999/quic-v1", "/ip4/0.0.0.0/udp/9999/quic-v1/webtransport", "/ip4/1.2.3.4/udp/9999/quic-v1", "/ip4/4.3.2.1/udp/9999/quic-v1", "/ip4/1.2.3.4/udp/9999/quic-v1/webtransport", "/ip4/4.3.2.1/udp/9999/quic-v1/webtransport"},
		},
		{
			name: "No Common listeners",
			in:   []string{"/ip4/0.0.0.0/udp/9999/quic-v1", "/ip4/0.0.0.0/udp/1111/quic-v1/webtransport", "/ip4/1.2.3.4/udp/9999/quic-v1"},
			out:  []string{"/ip4/0.0.0.0/udp/9999/quic-v1", "/ip4/0.0.0.0/udp/1111/quic-v1/webtransport", "/ip4/1.2.3.4/udp/9999/quic-v1"},
		},
		{
			name: "No WebTransport",
			in:   []string{"/ip4/0.0.0.0/udp/9999/quic-v1", "/ip4/1.2.3.4/udp/9999/quic-v1"},
			out:  []string{"/ip4/0.0.0.0/udp/9999/quic-v1", "/ip4/1.2.3.4/udp/9999/quic-v1"},
		},
	}

	// Make sure the testCases are all valid multiaddrs
	for _, tc := range testCases {
		for _, addr := range tc.in {
			_, err := ma.NewMultiaddr(addr)
			require.NoError(t, err)
		}
		for _, addr := range tc.out {
			_, err := ma.NewMultiaddr(addr)
			require.NoError(t, err)
		}
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			sort.StringSlice(tc.in).Sort()
			sort.StringSlice(tc.out).Sort()
			min := make([]ma.Multiaddr, 0, len(tc.in))
			for _, addr := range tc.in {
				min = append(min, ma.StringCast(addr))
			}
			outMa := inferWebtransportAddrsFromQuic(min)
			outStr := make([]string, 0, len(outMa))
			for _, addr := range outMa {
				outStr = append(outStr, addr.String())
			}
			require.Equal(t, tc.out, outStr)
		})

	}

}

func TestTrimHostAddrList(t *testing.T) {
	type testCase struct {
		name      string
		in        []ma.Multiaddr
		threshold int
		out       []ma.Multiaddr
	}

	tcpPublic := ma.StringCast("/ip4/1.1.1.1/tcp/1")
	quicPublic := ma.StringCast("/ip4/1.1.1.1/udp/1/quic-v1")

	tcpPrivate := ma.StringCast("/ip4/192.168.1.1/tcp/1")
	quicPrivate := ma.StringCast("/ip4/192.168.1.1/udp/1/quic-v1")

	tcpLocal := ma.StringCast("/ip4/127.0.0.1/tcp/1")
	quicLocal := ma.StringCast("/ip4/127.0.0.1/udp/1/quic-v1")

	testCases := []testCase{
		{
			name:      "Public preferred over private",
			in:        []ma.Multiaddr{tcpPublic, quicPrivate},
			threshold: len(tcpLocal.Bytes()),
			out:       []ma.Multiaddr{tcpPublic},
		},
		{
			name:      "Public and private preffered over local",
			in:        []ma.Multiaddr{tcpPublic, tcpPrivate, quicLocal},
			threshold: len(tcpPublic.Bytes()) + len(tcpPrivate.Bytes()),
			out:       []ma.Multiaddr{tcpPublic, tcpPrivate},
		},
		{
			name:      "quic preferred over tcp",
			in:        []ma.Multiaddr{tcpPublic, quicPublic},
			threshold: len(quicPublic.Bytes()),
			out:       []ma.Multiaddr{quicPublic},
		},
		{
			name:      "no filtering on large threshold",
			in:        []ma.Multiaddr{tcpPublic, quicPublic, quicLocal, tcpLocal, tcpPrivate},
			threshold: 10000,
			out:       []ma.Multiaddr{tcpPublic, quicPublic, quicLocal, tcpLocal, tcpPrivate},
		},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			got := trimHostAddrList(tc.in, tc.threshold)
			require.ElementsMatch(t, got, tc.out)
		})
	}
}