func TestToAndFromNetMessage(t *testing.T) {

	original := New(true)
	original.AddBlock(blocks.NewBlock([]byte("W")))
	original.AddBlock(blocks.NewBlock([]byte("E")))
	original.AddBlock(blocks.NewBlock([]byte("F")))
	original.AddBlock(blocks.NewBlock([]byte("M")))

	buf := new(bytes.Buffer)
	if err := original.ToNet(buf); err != nil {
		t.Fatal(err)
	}

	m2, err := FromNet(buf)
	if err != nil {
		t.Fatal(err)
	}

	keys := make(map[key.Key]bool)
	for _, b := range m2.Blocks() {
		keys[b.Key()] = true
	}

	for _, b := range original.Blocks() {
		if _, ok := keys[b.Key()]; !ok {
			t.Fail()
		}
	}
}

func TestSendMessageAsyncButWaitForResponse(t *testing.T) {
	net := VirtualNetwork(mockrouting.NewServer(), delay.Fixed(0))
	responderPeer := testutil.RandIdentityOrFatal(t)
	waiter := net.Adapter(testutil.RandIdentityOrFatal(t))
	responder := net.Adapter(responderPeer)

	var wg sync.WaitGroup

	wg.Add(1)

	expectedStr := "received async"

	responder.SetDelegate(lambda(func(
		ctx context.Context,
		fromWaiter peer.ID,
		msgFromWaiter bsmsg.BitSwapMessage) {

		msgToWaiter := bsmsg.New(true)
		msgToWaiter.AddBlock(blocks.NewBlock([]byte(expectedStr)))
		waiter.SendMessage(ctx, fromWaiter, msgToWaiter)
	}))

	waiter.SetDelegate(lambda(func(
		ctx context.Context,
		fromResponder peer.ID,
		msgFromResponder bsmsg.BitSwapMessage) {

		// TODO assert that this came from the correct peer and that the message contents are as expected
		ok := false
		for _, b := range msgFromResponder.Blocks() {
			if string(b.Data) == expectedStr {
				wg.Done()
				ok = true
			}
		}

		if !ok {
			t.Fatal("Message not received from the responder")
		}
	}))

	messageSentAsync := bsmsg.New(true)
	messageSentAsync.AddBlock(blocks.NewBlock([]byte("data")))
	errSending := waiter.SendMessage(
		context.Background(), responderPeer.ID(), messageSentAsync)
	if errSending != nil {
		t.Fatal(errSending)
	}

	wg.Wait() // until waiter delegate function is executed
}

func TestConsistentAccounting(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	sender := newEngine(ctx, "Ernie")
	receiver := newEngine(ctx, "Bert")

	// Send messages from Ernie to Bert
	for i := 0; i < 1000; i++ {

		m := message.New(false)
		content := []string{"this", "is", "message", "i"}
		m.AddBlock(blocks.NewBlock([]byte(strings.Join(content, " "))))

		sender.Engine.MessageSent(receiver.Peer, m)
		receiver.Engine.MessageReceived(sender.Peer, m)
	}

	// Ensure sender records the change
	if sender.Engine.numBytesSentTo(receiver.Peer) == 0 {
		t.Fatal("Sent bytes were not recorded")
	}

	// Ensure sender and receiver have the same values
	if sender.Engine.numBytesSentTo(receiver.Peer) != receiver.Engine.numBytesReceivedFrom(sender.Peer) {
		t.Fatal("Inconsistent book-keeping. Strategies don't agree")
	}

	// Ensure sender didn't record receving anything. And that the receiver
	// didn't record sending anything
	if receiver.Engine.numBytesSentTo(sender.Peer) != 0 || sender.Engine.numBytesReceivedFrom(receiver.Peer) != 0 {
		t.Fatal("Bert didn't send bytes to Ernie")
	}
}

func TestGetBlockFromPeerAfterPeerAnnounces(t *testing.T) {

	net := tn.VirtualNetwork(mockrouting.NewServer(), delay.Fixed(kNetworkDelay))
	block := blocks.NewBlock([]byte("block"))
	g := NewTestSessionGenerator(net)
	defer g.Close()

	peers := g.Instances(2)
	hasBlock := peers[0]
	defer hasBlock.Exchange.Close()

	if err := hasBlock.Exchange.HasBlock(block); err != nil {
		t.Fatal(err)
	}

	wantsBlock := peers[1]
	defer wantsBlock.Exchange.Close()

	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()
	received, err := wantsBlock.Exchange.GetBlock(ctx, block.Key())
	if err != nil {
		t.Log(err)
		t.Fatal("Expected to succeed")
	}

	if !bytes.Equal(block.Data, received.Data) {
		t.Fatal("Data doesn't match")
	}
}

func partnerWants(e *Engine, keys []string, partner peer.ID) {
	add := message.New(false)
	for i, letter := range keys {
		block := blocks.NewBlock([]byte(letter))
		add.AddEntry(block.Key(), math.MaxInt32-i)
	}
	e.MessageReceived(partner, add)
}

func partnerCancels(e *Engine, keys []string, partner peer.ID) {
	cancels := message.New(false)
	for _, k := range keys {
		block := blocks.NewBlock([]byte(k))
		cancels.Cancel(block.Key())
	}
	e.MessageReceived(partner, cancels)
}

func newMessageFromProto(pbm pb.Message) BitSwapMessage {
	m := newMsg(pbm.GetWantlist().GetFull())
	for _, e := range pbm.GetWantlist().GetEntries() {
		m.addEntry(key.Key(e.GetBlock()), int(e.GetPriority()), e.GetCancel())
	}
	for _, d := range pbm.GetBlocks() {
		b := blocks.NewBlock(d)
		m.AddBlock(b)
	}
	return m
}

func checkHandledInOrder(t *testing.T, e *Engine, keys []string) error {
	for _, k := range keys {
		next := <-e.Outbox()
		envelope := <-next
		received := envelope.Block
		expected := blocks.NewBlock([]byte(k))
		if received.Key() != expected.Key() {
			return errors.New(fmt.Sprintln("received", string(received.Data), "expected", string(expected.Data)))
		}
	}
	return nil
}

func TestSubscribeMany(t *testing.T) {
	e1 := blocks.NewBlock([]byte("1"))
	e2 := blocks.NewBlock([]byte("2"))

	n := New()
	defer n.Shutdown()
	ch := n.Subscribe(context.Background(), e1.Key(), e2.Key())

	n.Publish(e1)
	r1, ok := <-ch
	if !ok {
		t.Fatal("didn't receive first expected block")
	}
	assertBlocksEqual(t, e1, r1)

	n.Publish(e2)
	r2, ok := <-ch
	if !ok {
		t.Fatal("didn't receive second expected block")
	}
	assertBlocksEqual(t, e2, r2)
}

func TestCarryOnWhenDeadlineExpires(t *testing.T) {

	impossibleDeadline := time.Nanosecond
	fastExpiringCtx, cancel := context.WithTimeout(context.Background(), impossibleDeadline)
	defer cancel()

	n := New()
	defer n.Shutdown()
	block := blocks.NewBlock([]byte("A Missed Connection"))
	blockChannel := n.Subscribe(fastExpiringCtx, block.Key())

	assertBlockChannelNil(t, blockChannel)
}

func TestHasBlockReturnsNil(t *testing.T) {
	store := bstore()
	ex := Exchange(store)
	block := blocks.NewBlock([]byte("data"))

	err := ex.HasBlock(block)
	if err != nil {
		t.Fail()
	}

	if _, err := store.Get(block.Key()); err != nil {
		t.Fatal(err)
	}
}

func TestValueTypeMismatch(t *testing.T) {
	block := blocks.NewBlock([]byte("some data"))

	datastore := ds.NewMapDatastore()
	k := BlockPrefix.Child(block.Key().DsKey())
	datastore.Put(k, "data that isn't a block!")

	blockstore := NewBlockstore(ds_sync.MutexWrap(datastore))

	_, err := blockstore.Get(block.Key())
	if err != ValueTypeMismatch {
		t.Fatal(err)
	}
}

func TestDuplicates(t *testing.T) {
	b1 := blocks.NewBlock([]byte("1"))
	b2 := blocks.NewBlock([]byte("2"))

	n := New()
	defer n.Shutdown()
	ch := n.Subscribe(context.Background(), b1.Key(), b2.Key())

	n.Publish(b1)
	blockRecvd, ok := <-ch
	if !ok {
		t.Fail()
	}
	assertBlocksEqual(t, b1, blockRecvd)

	n.Publish(b1) // ignored duplicate

	n.Publish(b2)
	blockRecvd, ok = <-ch
	if !ok {
		t.Fail()
	}
	assertBlocksEqual(t, b2, blockRecvd)
}

func TestDuplicates(t *testing.T) {
	b := blocks.NewBlock([]byte("foo"))
	msg := New(true)

	msg.AddEntry(b.Key(), 1)
	msg.AddEntry(b.Key(), 1)
	if len(msg.Wantlist()) != 1 {
		t.Fatal("Duplicate in BitSwapMessage")
	}

	msg.AddBlock(b)
	msg.AddBlock(b)
	if len(msg.Blocks()) != 1 {
		t.Fatal("Duplicate in BitSwapMessage")
	}
}

func TestPublishSubscribe(t *testing.T) {
	blockSent := blocks.NewBlock([]byte("Greetings from The Interval"))

	n := New()
	defer n.Shutdown()
	ch := n.Subscribe(context.Background(), blockSent.Key())

	n.Publish(blockSent)
	blockRecvd, ok := <-ch
	if !ok {
		t.Fail()
	}

	assertBlocksEqual(t, blockRecvd, blockSent)

}

func TestElideDuplicateWrite(t *testing.T) {
	cd := &callbackDatastore{f: func() {}, ds: ds.NewMapDatastore()}
	bs := NewBlockstore(syncds.MutexWrap(cd))
	cachedbs, err := WriteCached(bs, 1)
	if err != nil {
		t.Fatal(err)
	}

	b1 := blocks.NewBlock([]byte("foo"))

	cachedbs.Put(b1)
	cd.SetFunc(func() {
		t.Fatal("write hit the datastore")
	})
	cachedbs.Put(b1)
}

func TestPutThenGetBlock(t *testing.T) {
	bs := NewBlockstore(ds_sync.MutexWrap(ds.NewMapDatastore()))
	block := blocks.NewBlock([]byte("some data"))

	err := bs.Put(block)
	if err != nil {
		t.Fatal(err)
	}

	blockFromBlockstore, err := bs.Get(block.Key())
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(block.Data, blockFromBlockstore.Data) {
		t.Fail()
	}
}

func newBlockStoreWithKeys(t *testing.T, d ds.Datastore, N int) (Blockstore, []key.Key) {
	if d == nil {
		d = ds.NewMapDatastore()
	}
	bs := NewBlockstore(ds_sync.MutexWrap(d))

	keys := make([]key.Key, N)
	for i := 0; i < N; i++ {
		block := blocks.NewBlock([]byte(fmt.Sprintf("some data %d", i)))
		err := bs.Put(block)
		if err != nil {
			t.Fatal(err)
		}
		keys[i] = block.Key()
	}
	return bs, keys
}

func TestPartnerWantsThenCancels(t *testing.T) {
	numRounds := 10
	if testing.Short() {
		numRounds = 1
	}
	alphabet := strings.Split("abcdefghijklmnopqrstuvwxyz", "")
	vowels := strings.Split("aeiou", "")

	type testCase [][]string
	testcases := []testCase{
		{
			alphabet, vowels,
		},
		{
			alphabet, stringsComplement(alphabet, vowels),
		},
	}

	bs := blockstore.NewBlockstore(dssync.MutexWrap(ds.NewMapDatastore()))
	for _, letter := range alphabet {
		block := blocks.NewBlock([]byte(letter))
		if err := bs.Put(block); err != nil {
			t.Fatal(err)
		}
	}

	for i := 0; i < numRounds; i++ {
		for _, testcase := range testcases {
			set := testcase[0]
			cancels := testcase[1]
			keeps := stringsComplement(set, cancels)

			e := NewEngine(context.Background(), bs)
			partner := testutil.RandPeerIDFatal(t)

			partnerWants(e, set, partner)
			partnerCancels(e, cancels, partner)
			if err := checkHandledInOrder(t, e, keeps); err != nil {
				t.Logf("run #%d of %d", i, numRounds)
				t.Fatal(err)
			}
		}
	}
}

func TestAppendBlock(t *testing.T) {

	strs := make([]string, 2)
	strs = append(strs, "Celeritas")
	strs = append(strs, "Incendia")

	m := New(true)
	for _, str := range strs {
		block := blocks.NewBlock([]byte(str))
		m.AddBlock(block)
	}

	// assert strings are in proto message
	for _, blockbytes := range m.ToProto().GetBlocks() {
		s := bytes.NewBuffer(blockbytes).String()
		if !contains(strs, s) {
			t.Fail()
		}
	}
}