package p2p

import (
	"context"
	"crypto/ecdsa"
	"fmt"
	"math/rand"
	"net"
	"os"
	"path"
	"strconv"
	"strings"
	"testing"
	"time"

	"github.com/ethereum/go-ethereum/p2p/discover"
	"github.com/ethereum/go-ethereum/p2p/enode"
	"github.com/ethereum/go-ethereum/p2p/enr"
	"github.com/kevinms/leakybucket-go"
	"github.com/libp2p/go-libp2p-core/host"
	"github.com/libp2p/go-libp2p-core/network"
	"github.com/libp2p/go-libp2p-core/peer"
	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
	"github.com/prysmaticlabs/go-bitfield"
	mock "github.com/prysmaticlabs/prysm/beacon-chain/blockchain/testing"
	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
	"github.com/prysmaticlabs/prysm/beacon-chain/p2p/peers"
	"github.com/prysmaticlabs/prysm/beacon-chain/p2p/peers/peerdata"
	"github.com/prysmaticlabs/prysm/beacon-chain/p2p/peers/scorers"
	testp2p "github.com/prysmaticlabs/prysm/beacon-chain/p2p/testing"
	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
	"github.com/prysmaticlabs/prysm/shared/bytesutil"
	"github.com/prysmaticlabs/prysm/shared/iputils"
	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
	"github.com/prysmaticlabs/prysm/shared/testutil/require"
	logTest "github.com/sirupsen/logrus/hooks/test"
)

var discoveryWaitTime = 1 * time.Second

func init() {
	rand.Seed(time.Now().Unix())
}

func createAddrAndPrivKey(t *testing.T) (net.IP, *ecdsa.PrivateKey) {
	ip, err := iputils.ExternalIPv4()
	require.NoError(t, err, "Could not get ip")
	ipAddr := net.ParseIP(ip)
	temp := t.TempDir()
	randNum := rand.Int()
	tempPath := path.Join(temp, strconv.Itoa(randNum))
	require.NoError(t, os.Mkdir(tempPath, 0700))
	pkey, err := privKey(&Config{DataDir: tempPath})
	require.NoError(t, err, "Could not get private key")
	return ipAddr, pkey
}

func TestCreateListener(t *testing.T) {
	port := 1024
	ipAddr, pkey := createAddrAndPrivKey(t)
	s := &Service{
		genesisTime:           time.Now(),
		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
		cfg:                   &Config{UDPPort: uint(port)},
	}
	listener, err := s.createListener(ipAddr, pkey)
	require.NoError(t, err)
	defer listener.Close()

	assert.Equal(t, true, listener.Self().IP().Equal(ipAddr), "IP address is not the expected type")
	assert.Equal(t, port, listener.Self().UDP(), "Incorrect port number")

	pubkey := listener.Self().Pubkey()
	XisSame := pkey.PublicKey.X.Cmp(pubkey.X) == 0
	YisSame := pkey.PublicKey.Y.Cmp(pubkey.Y) == 0

	if !(XisSame && YisSame) {
		t.Error("Pubkey is different from what was used to create the listener")
	}
}

func TestStartDiscV5_DiscoverAllPeers(t *testing.T) {
	port := 2000
	ipAddr, pkey := createAddrAndPrivKey(t)
	genesisTime := time.Now()
	genesisValidatorsRoot := make([]byte, 32)
	s := &Service{
		cfg:                   &Config{UDPPort: uint(port)},
		genesisTime:           genesisTime,
		genesisValidatorsRoot: genesisValidatorsRoot,
	}
	bootListener, err := s.createListener(ipAddr, pkey)
	require.NoError(t, err)
	defer bootListener.Close()

	bootNode := bootListener.Self()

	var listeners []*discover.UDPv5
	for i := 1; i <= 5; i++ {
		port = 3000 + i
		cfg := &Config{
			Discv5BootStrapAddr: []string{bootNode.String()},
			UDPPort:             uint(port),
		}
		ipAddr, pkey := createAddrAndPrivKey(t)
		s = &Service{
			cfg:                   cfg,
			genesisTime:           genesisTime,
			genesisValidatorsRoot: genesisValidatorsRoot,
		}
		listener, err := s.startDiscoveryV5(ipAddr, pkey)
		assert.NoError(t, err, "Could not start discovery for node")
		listeners = append(listeners, listener)
	}
	defer func() {
		// Close down all peers.
		for _, listener := range listeners {
			listener.Close()
		}
	}()

	// Wait for the nodes to have their local routing tables to be populated with the other nodes
	time.Sleep(discoveryWaitTime)

	lastListener := listeners[len(listeners)-1]
	nodes := lastListener.Lookup(bootNode.ID())
	if len(nodes) < 4 {
		t.Errorf("The node's local table doesn't have the expected number of nodes. "+
			"Expected more than or equal to %d but got %d", 4, len(nodes))
	}
}

func TestMultiAddrsConversion_InvalidIPAddr(t *testing.T) {
	addr := net.ParseIP("invalidIP")
	_, pkey := createAddrAndPrivKey(t)
	s := &Service{
		genesisTime:           time.Now(),
		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
	}
	node, err := s.createLocalNode(pkey, addr, 0, 0)
	require.NoError(t, err)
	multiAddr := convertToMultiAddr([]*enode.Node{node.Node()})
	assert.Equal(t, 0, len(multiAddr), "Invalid ip address converted successfully")
}

func TestMultiAddrConversion_OK(t *testing.T) {
	hook := logTest.NewGlobal()
	ipAddr, pkey := createAddrAndPrivKey(t)
	s := &Service{
		cfg: &Config{
			TCPPort: 0,
			UDPPort: 0,
		},
		genesisTime:           time.Now(),
		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
	}
	listener, err := s.createListener(ipAddr, pkey)
	require.NoError(t, err)
	defer listener.Close()

	_ = convertToMultiAddr([]*enode.Node{listener.Self()})
	require.LogsDoNotContain(t, hook, "Node doesn't have an ip4 address")
	require.LogsDoNotContain(t, hook, "Invalid port, the tcp port of the node is a reserved port")
	require.LogsDoNotContain(t, hook, "Could not get multiaddr")
}

func TestStaticPeering_PeersAreAdded(t *testing.T) {
	cfg := &Config{
		MaxPeers: 30,
	}
	port := 6000
	var staticPeers []string
	var hosts []host.Host
	// setup other nodes
	for i := 1; i <= 5; i++ {
		h, _, ipaddr := createHost(t, port+i)
		staticPeers = append(staticPeers, fmt.Sprintf("/ip4/%s/tcp/%d/p2p/%s", ipaddr, port+i, h.ID()))
		hosts = append(hosts, h)
	}

	defer func() {
		for _, h := range hosts {
			if err := h.Close(); err != nil {
				t.Log(err)
			}
		}
	}()

	cfg.TCPPort = 14500
	cfg.UDPPort = 14501
	cfg.StaticPeers = staticPeers
	cfg.StateNotifier = &mock.MockStateNotifier{}
	cfg.NoDiscovery = true
	s, err := NewService(context.Background(), cfg)
	require.NoError(t, err)

	exitRoutine := make(chan bool)
	go func() {
		s.Start()
		<-exitRoutine
	}()
	time.Sleep(50 * time.Millisecond)
	// Send in a loop to ensure it is delivered (busy wait for the service to subscribe to the state feed).
	for sent := 0; sent == 0; {
		sent = s.stateNotifier.StateFeed().Send(&feed.Event{
			Type: statefeed.Initialized,
			Data: &statefeed.InitializedData{
				StartTime:             time.Now(),
				GenesisValidatorsRoot: make([]byte, 32),
			},
		})
	}
	time.Sleep(4 * time.Second)
	peers := s.host.Network().Peers()
	assert.Equal(t, 5, len(peers), "Not all peers added to peerstore")
	require.NoError(t, s.Stop())
	exitRoutine <- true
}

func TestHostIsResolved(t *testing.T) {
	// As defined in RFC 2606 , example.org is a
	// reserved example domain name.
	exampleHost := "example.org"
	exampleIP := "93.184.216.34"

	s := &Service{
		cfg: &Config{
			HostDNS: exampleHost,
		},
		genesisTime:           time.Now(),
		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
	}
	ip, key := createAddrAndPrivKey(t)
	list, err := s.createListener(ip, key)
	require.NoError(t, err)

	newIP := list.Self().IP()
	assert.Equal(t, exampleIP, newIP.String(), "Did not resolve to expected IP")
}

func TestInboundPeerLimit(t *testing.T) {
	fakePeer := testp2p.NewTestP2P(t)
	s := &Service{
		cfg:       &Config{MaxPeers: 30},
		ipLimiter: leakybucket.NewCollector(ipLimit, ipBurst, false),
		peers: peers.NewStatus(context.Background(), &peers.StatusConfig{
			PeerLimit:    30,
			ScorerParams: &scorers.Config{},
		}),
		host: fakePeer.BHost,
	}

	for i := 0; i < 30; i++ {
		_ = addPeer(t, s.peers, peerdata.PeerConnectionState(ethpb.ConnectionState_CONNECTED))
	}

	require.Equal(t, true, s.isPeerAtLimit(false), "not at limit for outbound peers")
	require.Equal(t, false, s.isPeerAtLimit(true), "at limit for inbound peers")

	for i := 0; i < highWatermarkBuffer; i++ {
		_ = addPeer(t, s.peers, peerdata.PeerConnectionState(ethpb.ConnectionState_CONNECTED))
	}

	require.Equal(t, true, s.isPeerAtLimit(true), "not at limit for inbound peers")
}

func TestUDPMultiAddress(t *testing.T) {
	port := 6500
	ipAddr, pkey := createAddrAndPrivKey(t)
	genesisTime := time.Now()
	genesisValidatorsRoot := make([]byte, 32)
	s := &Service{
		cfg:                   &Config{UDPPort: uint(port)},
		genesisTime:           genesisTime,
		genesisValidatorsRoot: genesisValidatorsRoot,
	}
	listener, err := s.createListener(ipAddr, pkey)
	require.NoError(t, err)
	defer listener.Close()
	s.dv5Listener = listener

	multiAddresses, err := s.DiscoveryAddresses()
	require.NoError(t, err)
	require.Equal(t, true, len(multiAddresses) > 0)
	assert.Equal(t, true, strings.Contains(multiAddresses[0].String(), fmt.Sprintf("%d", port)))
	assert.Equal(t, true, strings.Contains(multiAddresses[0].String(), "udp"))
}

func TestMultipleDiscoveryAddresses(t *testing.T) {
	db, err := enode.OpenDB(t.TempDir())
	require.NoError(t, err)
	_, key := createAddrAndPrivKey(t)
	node := enode.NewLocalNode(db, key)
	node.Set(enr.IPv4{127, 0, 0, 1})
	node.Set(enr.IPv6{0x20, 0x01, 0x48, 0x60, 0, 0, 0x20, 0x01, 0, 0, 0, 0, 0, 0, 0x00, 0x68})
	s := &Service{dv5Listener: mockListener{localNode: node}}

	multiAddresses, err := s.DiscoveryAddresses()
	require.NoError(t, err)
	require.Equal(t, 2, len(multiAddresses))
	ipv4Found, ipv6Found := false, false
	for _, address := range multiAddresses {
		s := address.String()
		if strings.Contains(s, "ip4") {
			ipv4Found = true
		} else if strings.Contains(s, "ip6") {
			ipv6Found = true
		}
	}
	assert.Equal(t, true, ipv4Found, "IPv4 discovery address not found")
	assert.Equal(t, true, ipv6Found, "IPv6 discovery address not found")
}

func TestCorrectUDPVersion(t *testing.T) {
	assert.Equal(t, "udp4", udpVersionFromIP(net.IPv4zero), "incorrect network version")
	assert.Equal(t, "udp6", udpVersionFromIP(net.IPv6zero), "incorrect network version")
	assert.Equal(t, "udp4", udpVersionFromIP(net.IP{200, 20, 12, 255}), "incorrect network version")
	assert.Equal(t, "udp6", udpVersionFromIP(net.IP{22, 23, 24, 251, 17, 18, 0, 0, 0, 0, 12, 14, 212, 213, 16, 22}), "incorrect network version")
	// v4 in v6
	assert.Equal(t, "udp4", udpVersionFromIP(net.IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 212, 213, 16, 22}), "incorrect network version")
}

// addPeer is a helper to add a peer with a given connection state)
func addPeer(t *testing.T, p *peers.Status, state peerdata.PeerConnectionState) peer.ID {
	// Set up some peers with different states
	mhBytes := []byte{0x11, 0x04}
	idBytes := make([]byte, 4)
	_, err := rand.Read(idBytes)
	require.NoError(t, err)
	mhBytes = append(mhBytes, idBytes...)
	id, err := peer.IDFromBytes(mhBytes)
	require.NoError(t, err)
	p.Add(new(enr.Record), id, nil, network.DirInbound)
	p.SetConnectionState(id, state)
	p.SetMetadata(id, &pb.MetaData{
		SeqNumber: 0,
		Attnets:   bitfield.NewBitvector64(),
	})
	return id
}