package sync

import (
	"context"
	"sync"
	"testing"
	"time"

	"github.com/ethereum/go-ethereum/p2p/enr"
	"github.com/gogo/protobuf/proto"
	"github.com/libp2p/go-libp2p-core/network"
	"github.com/libp2p/go-libp2p-core/protocol"
	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
	"github.com/prysmaticlabs/go-ssz"
	mock "github.com/prysmaticlabs/prysm/beacon-chain/blockchain/testing"
	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
	"github.com/prysmaticlabs/prysm/beacon-chain/p2p/peers"
	p2ptest "github.com/prysmaticlabs/prysm/beacon-chain/p2p/testing"
	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
	"github.com/prysmaticlabs/prysm/shared/params"
	"github.com/prysmaticlabs/prysm/shared/testutil"
	"github.com/sirupsen/logrus"
)

func init() {
	logrus.SetLevel(logrus.DebugLevel)
}

func TestHelloRPCHandler_Disconnects_OnForkVersionMismatch(t *testing.T) {
	p1 := p2ptest.NewTestP2P(t)
	p2 := p2ptest.NewTestP2P(t)
	p1.Connect(p2)
	if len(p1.Host.Network().Peers()) != 1 {
		t.Error("Expected peers to be connected")
	}

	r := &Service{p2p: p1,
		chain: &mock.ChainService{
			Genesis:        time.Now(),
			ValidatorsRoot: [32]byte{'A'},
		}}
	pcl := protocol.ID("/testing")

	var wg sync.WaitGroup
	wg.Add(1)
	p2.Host.SetStreamHandler(pcl, func(stream network.Stream) {
		defer wg.Done()
		code, errMsg, err := ReadStatusCode(stream, p1.Encoding())
		if err != nil {
			t.Fatal(err)
		}
		if code == 0 {
			t.Error("Expected a non-zero code")
		}
		if errMsg != errWrongForkDigestVersion.Error() {
			t.Logf("Received error string len %d, wanted error string len %d", len(errMsg), len(errWrongForkDigestVersion.Error()))
			t.Errorf("Received unexpected message response in the stream: %s. Wanted %s.", errMsg, errWrongForkDigestVersion.Error())
		}
	})

	stream1, err := p1.Host.NewStream(context.Background(), p2.Host.ID(), pcl)
	if err != nil {
		t.Fatal(err)
	}

	err = r.statusRPCHandler(context.Background(), &pb.Status{ForkDigest: []byte("fake")}, stream1)
	if err != errWrongForkDigestVersion {
		t.Errorf("Expected error %v, got %v", errWrongForkDigestVersion, err)
	}

	if testutil.WaitTimeout(&wg, 1*time.Second) {
		t.Fatal("Did not receive stream within 1 sec")
	}

	if len(p1.Host.Network().Peers()) != 0 {
		t.Error("handler did not disconnect peer")
	}
}

func TestHelloRPCHandler_ReturnsHelloMessage(t *testing.T) {
	p1 := p2ptest.NewTestP2P(t)
	p2 := p2ptest.NewTestP2P(t)
	p1.Connect(p2)
	if len(p1.Host.Network().Peers()) != 1 {
		t.Error("Expected peers to be connected")
	}

	// Set up a head state with data we expect.
	headRoot, err := ssz.HashTreeRoot(&ethpb.BeaconBlock{Slot: 111})
	if err != nil {
		t.Fatal(err)
	}
	finalizedRoot, err := ssz.HashTreeRoot(&ethpb.BeaconBlock{Slot: 40})
	if err != nil {
		t.Fatal(err)
	}
	genesisState, err := state.GenesisBeaconState(nil, 0, &ethpb.Eth1Data{})
	if err != nil {
		t.Fatal(err)
	}
	if err := genesisState.SetSlot(111); err != nil {
		t.Fatal(err)
	}
	if err := genesisState.UpdateBlockRootAtIndex(111%params.BeaconConfig().SlotsPerHistoricalRoot, headRoot); err != nil {
		t.Fatal(err)
	}
	finalizedCheckpt := &ethpb.Checkpoint{
		Epoch: 5,
		Root:  finalizedRoot[:],
	}

	r := &Service{
		p2p: p1,
		chain: &mock.ChainService{
			State:               genesisState,
			FinalizedCheckPoint: finalizedCheckpt,
			Root:                headRoot[:],
			Fork: &pb.Fork{
				PreviousVersion: params.BeaconConfig().GenesisForkVersion,
				CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
			},
			ValidatorsRoot: [32]byte{'A'},
			Genesis:        time.Now(),
		},
	}
	digest, err := r.forkDigest()
	if err != nil {
		t.Fatal(err)
	}

	// Setup streams
	pcl := protocol.ID("/testing")
	var wg sync.WaitGroup
	wg.Add(1)
	p2.Host.SetStreamHandler(pcl, func(stream network.Stream) {
		defer wg.Done()
		expectSuccess(t, r, stream)
		out := &pb.Status{}
		if err := r.p2p.Encoding().DecodeWithLength(stream, out); err != nil {
			t.Fatal(err)
		}
		expected := &pb.Status{
			ForkDigest:     digest[:],
			HeadSlot:       genesisState.Slot(),
			HeadRoot:       headRoot[:],
			FinalizedEpoch: 5,
			FinalizedRoot:  finalizedRoot[:],
		}
		if !proto.Equal(out, expected) {
			t.Errorf("Did not receive expected message. Got %+v wanted %+v", out, expected)
		}
	})
	stream1, err := p1.Host.NewStream(context.Background(), p2.Host.ID(), pcl)
	if err != nil {
		t.Fatal(err)
	}

	err = r.statusRPCHandler(context.Background(), &pb.Status{ForkDigest: digest[:]}, stream1)
	if err != nil {
		t.Errorf("Unxpected error: %v", err)
	}

	if testutil.WaitTimeout(&wg, 1*time.Second) {
		t.Fatal("Did not receive stream within 1 sec")
	}
}

func TestHandshakeHandlers_Roundtrip(t *testing.T) {
	// Scenario is that p1 and p2 connect, exchange handshakes.
	// p2 disconnects and p1 should forget the handshake status.
	p1 := p2ptest.NewTestP2P(t)
	p2 := p2ptest.NewTestP2P(t)

	p1.LocalMetadata = &pb.MetaData{
		SeqNumber: 2,
		Attnets:   []byte{'A', 'B'},
	}

	p2.LocalMetadata = &pb.MetaData{
		SeqNumber: 2,
		Attnets:   []byte{'C', 'D'},
	}

	st, err := stateTrie.InitializeFromProto(&pb.BeaconState{
		Slot: 5,
	})
	if err != nil {
		t.Fatal(err)
	}
	r := &Service{
		p2p: p1,
		chain: &mock.ChainService{
			State:               st,
			FinalizedCheckPoint: &ethpb.Checkpoint{},
			Fork: &pb.Fork{
				PreviousVersion: params.BeaconConfig().GenesisForkVersion,
				CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
			},
			Genesis:        time.Now(),
			ValidatorsRoot: [32]byte{'A'},
		},
		ctx: context.Background(),
	}
	p1.Digest, err = r.forkDigest()
	if err != nil {
		t.Fatal(err)
	}

	r2 := &Service{
		p2p: p2,
	}
	p2.Digest, err = r.forkDigest()
	if err != nil {
		t.Fatal(err)
	}

	r.Start()

	// Setup streams
	pcl := protocol.ID("/eth2/beacon_chain/req/status/1/ssz")
	var wg sync.WaitGroup
	wg.Add(1)
	p2.Host.SetStreamHandler(pcl, func(stream network.Stream) {
		defer wg.Done()
		out := &pb.Status{}
		if err := r.p2p.Encoding().DecodeWithLength(stream, out); err != nil {
			t.Fatal(err)
		}
		log.WithField("status", out).Warn("received status")

		resp := &pb.Status{HeadSlot: 100, ForkDigest: p2.Digest[:]}

		if _, err := stream.Write([]byte{responseCodeSuccess}); err != nil {
			t.Fatal(err)
		}
		_, err := r.p2p.Encoding().EncodeWithLength(stream, resp)
		if err != nil {
			t.Fatal(err)
		}
		log.WithField("status", out).Warn("sending status")
		if err := stream.Close(); err != nil {
			t.Log(err)
		}
	})

	pcl = protocol.ID("/eth2/beacon_chain/req/ping/1/ssz")
	var wg2 sync.WaitGroup
	wg2.Add(1)
	p2.Host.SetStreamHandler(pcl, func(stream network.Stream) {
		defer wg2.Done()
		out := new(uint64)
		if err := r.p2p.Encoding().DecodeWithLength(stream, out); err != nil {
			t.Fatal(err)
		}
		if *out != 2 {
			t.Fatalf("Wanted 2 but got %d as our sequence number", *out)
		}
		err := r2.pingHandler(context.Background(), out, stream)
		if err != nil {
			t.Fatal(err)
		}
		if err := stream.Close(); err != nil {
			t.Fatal(err)
		}
	})

	numInactive1 := len(p1.Peers().Inactive())
	numActive1 := len(p1.Peers().Active())

	p1.Connect(p2)

	p1.Peers().Add(new(enr.Record), p2.Host.ID(), p2.Host.Addrs()[0], network.DirUnknown)
	p1.Peers().SetMetadata(p2.Host.ID(), p2.LocalMetadata)

	p2.Peers().Add(new(enr.Record), p1.Host.ID(), p1.Host.Addrs()[0], network.DirUnknown)
	p2.Peers().SetMetadata(p1.Host.ID(), p1.LocalMetadata)

	if testutil.WaitTimeout(&wg, 1*time.Second) {
		t.Fatal("Did not receive stream within 1 sec")
	}
	if testutil.WaitTimeout(&wg2, 1*time.Second) {
		t.Fatal("Did not receive stream within 1 sec")
	}

	// Wait for stream buffer to be read.
	time.Sleep(200 * time.Millisecond)

	numInactive2 := len(p1.Peers().Inactive())
	numActive2 := len(p1.Peers().Active())

	if numInactive2 != numInactive1 {
		t.Errorf("Number of inactive peers changed unexpectedly: was %d, now %d", numInactive1, numInactive2)
	}
	if numActive2 != numActive1+1 {
		t.Errorf("Number of active peers unexpected: wanted %d, found %d", numActive1+1, numActive2)
	}

	if err := p2.Disconnect(p1.PeerID()); err != nil {
		t.Fatal(err)
	}
	p1.Peers().SetConnectionState(p2.PeerID(), peers.PeerDisconnected)

	// Wait for disconnect event to trigger.
	time.Sleep(200 * time.Millisecond)

	numInactive3 := len(p1.Peers().Inactive())
	numActive3 := len(p1.Peers().Active())
	if numInactive3 != numInactive2+1 {
		t.Errorf("Number of inactive peers unexpected: wanted %d, found %d", numInactive2+1, numInactive3)
	}
	if numActive3 != numActive2-1 {
		t.Errorf("Number of active peers unexpected: wanted %d, found %d", numActive2-1, numActive3)
	}
}

func TestStatusRPCRequest_RequestSent(t *testing.T) {
	p1 := p2ptest.NewTestP2P(t)
	p2 := p2ptest.NewTestP2P(t)

	// Set up a head state with data we expect.
	headRoot, err := ssz.HashTreeRoot(&ethpb.BeaconBlock{Slot: 111})
	if err != nil {
		t.Fatal(err)
	}
	finalizedRoot, err := ssz.HashTreeRoot(&ethpb.BeaconBlock{Slot: 40})
	if err != nil {
		t.Fatal(err)
	}
	genesisState, err := state.GenesisBeaconState(nil, 0, &ethpb.Eth1Data{})
	if err != nil {
		t.Fatal(err)
	}
	if err := genesisState.SetSlot(111); err != nil {
		t.Fatal(err)
	}
	if err := genesisState.UpdateBlockRootAtIndex(111%params.BeaconConfig().SlotsPerHistoricalRoot, headRoot); err != nil {
		t.Fatal(err)
	}
	finalizedCheckpt := &ethpb.Checkpoint{
		Epoch: 5,
		Root:  finalizedRoot[:],
	}

	r := &Service{
		p2p: p1,
		chain: &mock.ChainService{
			State:               genesisState,
			FinalizedCheckPoint: finalizedCheckpt,
			Root:                headRoot[:],
			Fork: &pb.Fork{
				PreviousVersion: params.BeaconConfig().GenesisForkVersion,
				CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
			},
			Genesis:        time.Now(),
			ValidatorsRoot: [32]byte{'A'},
		},
		ctx: context.Background(),
	}

	// Setup streams
	pcl := protocol.ID("/eth2/beacon_chain/req/status/1/ssz")
	var wg sync.WaitGroup
	wg.Add(1)
	p2.Host.SetStreamHandler(pcl, func(stream network.Stream) {
		defer wg.Done()
		out := &pb.Status{}
		if err := r.p2p.Encoding().DecodeWithLength(stream, out); err != nil {
			t.Fatal(err)
		}
		digest, err := r.forkDigest()
		if err != nil {
			t.Fatal(err)
		}
		expected := &pb.Status{
			ForkDigest:     digest[:],
			HeadSlot:       genesisState.Slot(),
			HeadRoot:       headRoot[:],
			FinalizedEpoch: 5,
			FinalizedRoot:  finalizedRoot[:],
		}
		if !proto.Equal(out, expected) {
			t.Errorf("Did not receive expected message. Got %+v wanted %+v", out, expected)
		}
	})

	p1.AddConnectionHandler(r.sendRPCStatusRequest, r.sendGenericGoodbyeMessage)
	p1.Connect(p2)

	if testutil.WaitTimeout(&wg, 1*time.Second) {
		t.Fatal("Did not receive stream within 1 sec")
	}

	if len(p1.Host.Network().Peers()) != 1 {
		t.Error("Expected peers to continue being connected")
	}
}

func TestStatusRPCRequest_BadPeerHandshake(t *testing.T) {
	p1 := p2ptest.NewTestP2P(t)
	p2 := p2ptest.NewTestP2P(t)

	// Set up a head state with data we expect.
	headRoot, err := ssz.HashTreeRoot(&ethpb.BeaconBlock{Slot: 111})
	if err != nil {
		t.Fatal(err)
	}
	finalizedRoot, err := ssz.HashTreeRoot(&ethpb.BeaconBlock{Slot: 40})
	if err != nil {
		t.Fatal(err)
	}
	genesisState, err := state.GenesisBeaconState(nil, 0, &ethpb.Eth1Data{})
	if err != nil {
		t.Fatal(err)
	}
	if err := genesisState.SetSlot(111); err != nil {
		t.Fatal(err)
	}
	if err := genesisState.UpdateBlockRootAtIndex(111%params.BeaconConfig().SlotsPerHistoricalRoot, headRoot); err != nil {
		t.Fatal(err)
	}
	finalizedCheckpt := &ethpb.Checkpoint{
		Epoch: 5,
		Root:  finalizedRoot[:],
	}

	r := &Service{
		p2p: p1,
		chain: &mock.ChainService{
			State:               genesisState,
			FinalizedCheckPoint: finalizedCheckpt,
			Root:                headRoot[:],
			Fork: &pb.Fork{
				PreviousVersion: params.BeaconConfig().GenesisForkVersion,
				CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
			},
			Genesis:        time.Now(),
			ValidatorsRoot: [32]byte{'A'},
		},
		ctx: context.Background(),
	}

	r.Start()

	// Setup streams
	pcl := protocol.ID("/eth2/beacon_chain/req/status/1/ssz")
	var wg sync.WaitGroup
	wg.Add(1)
	p2.Host.SetStreamHandler(pcl, func(stream network.Stream) {
		defer wg.Done()
		out := &pb.Status{}
		if err := r.p2p.Encoding().DecodeWithLength(stream, out); err != nil {
			t.Fatal(err)
		}
		expected := &pb.Status{
			ForkDigest:     []byte{1, 1, 1, 1},
			HeadSlot:       genesisState.Slot(),
			HeadRoot:       headRoot[:],
			FinalizedEpoch: 5,
			FinalizedRoot:  finalizedRoot[:],
		}
		if _, err := stream.Write([]byte{responseCodeSuccess}); err != nil {
			log.WithError(err).Error("Failed to write to stream")
		}
		_, err := r.p2p.Encoding().EncodeWithLength(stream, expected)
		if err != nil {
			t.Errorf("Could not send status: %v", err)
		}
	})

	p1.Connect(p2)

	if testutil.WaitTimeout(&wg, time.Second) {
		t.Fatal("Did not receive stream within 1 sec")
	}
	time.Sleep(100 * time.Millisecond)

	connectionState, err := p1.Peers().ConnectionState(p2.PeerID())
	if err != nil {
		t.Fatal("Failed to obtain peer connection state")
	}
	if connectionState != peers.PeerDisconnected {
		t.Error("Expected peer to be disconnected")
	}

	badResponses, err := p1.Peers().BadResponses(p2.PeerID())
	if err != nil {
		t.Fatal("Failed to obtain peer connection state")
	}
	if badResponses != 1 {
		t.Errorf("Bad response was not bumped to one, instead it is %d", badResponses)
	}
}