package internal

import (
	"context"
	"fmt"
	"net"
	"net/netip"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/pion/transport/v3/stdnet"
	log "github.com/sirupsen/logrus"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
	"google.golang.org/grpc"
	"google.golang.org/grpc/keepalive"

	"github.com/netbirdio/netbird/client/internal/dns"
	"github.com/netbirdio/netbird/client/internal/peer"
	"github.com/netbirdio/netbird/client/internal/routemanager"
	"github.com/netbirdio/netbird/client/ssh"
	"github.com/netbirdio/netbird/client/system"
	nbdns "github.com/netbirdio/netbird/dns"
	"github.com/netbirdio/netbird/iface"
	"github.com/netbirdio/netbird/iface/bind"
	mgmt "github.com/netbirdio/netbird/management/client"
	mgmtProto "github.com/netbirdio/netbird/management/proto"
	"github.com/netbirdio/netbird/management/server"
	"github.com/netbirdio/netbird/management/server/activity"
	"github.com/netbirdio/netbird/route"
	signal "github.com/netbirdio/netbird/signal/client"
	"github.com/netbirdio/netbird/signal/proto"
	signalServer "github.com/netbirdio/netbird/signal/server"
	"github.com/netbirdio/netbird/util"
)

var (
	kaep = keepalive.EnforcementPolicy{
		MinTime:             15 * time.Second,
		PermitWithoutStream: true,
	}

	kasp = keepalive.ServerParameters{
		MaxConnectionIdle:     15 * time.Second,
		MaxConnectionAgeGrace: 5 * time.Second,
		Time:                  5 * time.Second,
		Timeout:               2 * time.Second,
	}
)

func TestEngine_SSH(t *testing.T) {

	if runtime.GOOS == "windows" {
		t.Skip("skipping TestEngine_SSH on Windows")
	}

	key, err := wgtypes.GeneratePrivateKey()
	if err != nil {
		t.Fatal(err)
		return
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	engine := NewEngine(ctx, cancel, &signal.MockClient{}, &mgmt.MockClient{}, &EngineConfig{
		WgIfaceName:  "utun101",
		WgAddr:       "100.64.0.1/24",
		WgPrivateKey: key,
		WgPort:       33100,
	}, MobileDependency{}, peer.NewRecorder("https://mgm"))

	engine.dnsServer = &dns.MockServer{
		UpdateDNSServerFunc: func(serial uint64, update nbdns.Config) error { return nil },
	}

	var sshKeysAdded []string
	var sshPeersRemoved []string

	sshCtx, cancel := context.WithCancel(context.Background())

	engine.sshServerFunc = func(hostKeyPEM []byte, addr string) (ssh.Server, error) {
		return &ssh.MockServer{
			Ctx: sshCtx,
			StopFunc: func() error {
				cancel()
				return nil
			},
			StartFunc: func() error {
				<-ctx.Done()
				return ctx.Err()
			},
			AddAuthorizedKeyFunc: func(peer, newKey string) error {
				sshKeysAdded = append(sshKeysAdded, newKey)
				return nil
			},
			RemoveAuthorizedKeyFunc: func(peer string) {
				sshPeersRemoved = append(sshPeersRemoved, peer)
			},
		}, nil
	}
	err = engine.Start()
	if err != nil {
		t.Fatal(err)
	}

	defer func() {
		err := engine.Stop()
		if err != nil {
			return
		}
	}()

	peerWithSSH := &mgmtProto.RemotePeerConfig{
		WgPubKey:   "MNHf3Ma6z6mdLbriAJbqhX7+nM/B71lgw2+91q3LfhU=",
		AllowedIps: []string{"100.64.0.21/24"},
		SshConfig: &mgmtProto.SSHConfig{
			SshPubKey: []byte("ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIFATYCqaQw/9id1Qkq3n16JYhDhXraI6Pc1fgB8ynEfQ"),
		},
	}

	// SSH server is not enabled so SSH config of a remote peer should be ignored
	networkMap := &mgmtProto.NetworkMap{
		Serial:             6,
		PeerConfig:         nil,
		RemotePeers:        []*mgmtProto.RemotePeerConfig{peerWithSSH},
		RemotePeersIsEmpty: false,
	}

	err = engine.updateNetworkMap(networkMap)
	if err != nil {
		t.Fatal(err)
	}

	assert.Nil(t, engine.sshServer)

	// SSH server is enabled, therefore SSH config should be applied
	networkMap = &mgmtProto.NetworkMap{
		Serial: 7,
		PeerConfig: &mgmtProto.PeerConfig{Address: "100.64.0.1/24",
			SshConfig: &mgmtProto.SSHConfig{SshEnabled: true}},
		RemotePeers:        []*mgmtProto.RemotePeerConfig{peerWithSSH},
		RemotePeersIsEmpty: false,
	}

	err = engine.updateNetworkMap(networkMap)
	if err != nil {
		t.Fatal(err)
	}

	time.Sleep(250 * time.Millisecond)
	assert.NotNil(t, engine.sshServer)
	assert.Contains(t, sshKeysAdded, "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIFATYCqaQw/9id1Qkq3n16JYhDhXraI6Pc1fgB8ynEfQ")

	// now remove peer
	networkMap = &mgmtProto.NetworkMap{
		Serial:             8,
		RemotePeers:        []*mgmtProto.RemotePeerConfig{},
		RemotePeersIsEmpty: false,
	}

	err = engine.updateNetworkMap(networkMap)
	if err != nil {
		t.Fatal(err)
	}

	//time.Sleep(250 * time.Millisecond)
	assert.NotNil(t, engine.sshServer)
	assert.Contains(t, sshPeersRemoved, "MNHf3Ma6z6mdLbriAJbqhX7+nM/B71lgw2+91q3LfhU=")

	// now disable SSH server
	networkMap = &mgmtProto.NetworkMap{
		Serial: 9,
		PeerConfig: &mgmtProto.PeerConfig{Address: "100.64.0.1/24",
			SshConfig: &mgmtProto.SSHConfig{SshEnabled: false}},
		RemotePeers:        []*mgmtProto.RemotePeerConfig{peerWithSSH},
		RemotePeersIsEmpty: false,
	}

	err = engine.updateNetworkMap(networkMap)
	if err != nil {
		t.Fatal(err)
	}

	assert.Nil(t, engine.sshServer)

}

func TestEngine_UpdateNetworkMap(t *testing.T) {
	// test setup
	key, err := wgtypes.GeneratePrivateKey()
	if err != nil {
		t.Fatal(err)
		return
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	engine := NewEngine(ctx, cancel, &signal.MockClient{}, &mgmt.MockClient{}, &EngineConfig{
		WgIfaceName:  "utun102",
		WgAddr:       "100.64.0.1/24",
		WgPrivateKey: key,
		WgPort:       33100,
	}, MobileDependency{}, peer.NewRecorder("https://mgm"))
	newNet, err := stdnet.NewNet()
	if err != nil {
		t.Fatal(err)
	}
	engine.wgInterface, err = iface.NewWGIFace("utun102", "100.64.0.1/24", iface.DefaultMTU, nil, newNet)
	if err != nil {
		t.Fatal(err)
	}
	engine.routeManager = routemanager.NewManager(ctx, key.PublicKey().String(), engine.wgInterface, engine.statusRecorder, nil)
	engine.dnsServer = &dns.MockServer{
		UpdateDNSServerFunc: func(serial uint64, update nbdns.Config) error { return nil },
	}
	conn, err := net.ListenUDP("udp4", nil)
	if err != nil {
		t.Fatal(err)
	}
	engine.udpMux = bind.NewUniversalUDPMuxDefault(bind.UniversalUDPMuxParams{UDPConn: conn})

	type testCase struct {
		name       string
		networkMap *mgmtProto.NetworkMap

		expectedLen    int
		expectedPeers  []*mgmtProto.RemotePeerConfig
		expectedSerial uint64
	}

	peer1 := &mgmtProto.RemotePeerConfig{
		WgPubKey:   "RRHf3Ma6z6mdLbriAJbqhX7+nM/B71lgw2+91q3LfhU=",
		AllowedIps: []string{"100.64.0.10/24"},
	}

	peer2 := &mgmtProto.RemotePeerConfig{
		WgPubKey:   "LLHf3Ma6z6mdLbriAJbqhX7+nM/B71lgw2+91q3LfhU=",
		AllowedIps: []string{"100.64.0.11/24"},
	}

	peer3 := &mgmtProto.RemotePeerConfig{
		WgPubKey:   "GGHf3Ma6z6mdLbriAJbqhX7+nM/B71lgw2+91q3LfhU=",
		AllowedIps: []string{"100.64.0.12/24"},
	}

	modifiedPeer3 := &mgmtProto.RemotePeerConfig{
		WgPubKey:   "GGHf3Ma6z6mdLbriAJbqhX7+nM/B71lgw2+91q3LfhU=",
		AllowedIps: []string{"100.64.0.20/24"},
	}

	case1 := testCase{
		name: "input with a new peer to add",
		networkMap: &mgmtProto.NetworkMap{
			Serial:     1,
			PeerConfig: nil,
			RemotePeers: []*mgmtProto.RemotePeerConfig{
				peer1,
			},
			RemotePeersIsEmpty: false,
		},
		expectedLen:    1,
		expectedPeers:  []*mgmtProto.RemotePeerConfig{peer1},
		expectedSerial: 1,
	}

	// 2nd case - one extra peer added and network map has CurrentSerial grater than local => apply the update
	case2 := testCase{
		name: "input with an old peer and a new peer to add",
		networkMap: &mgmtProto.NetworkMap{
			Serial:     2,
			PeerConfig: nil,
			RemotePeers: []*mgmtProto.RemotePeerConfig{
				peer1, peer2,
			},
			RemotePeersIsEmpty: false,
		},
		expectedLen:    2,
		expectedPeers:  []*mgmtProto.RemotePeerConfig{peer1, peer2},
		expectedSerial: 2,
	}

	case3 := testCase{
		name: "input with outdated (old) update to ignore",
		networkMap: &mgmtProto.NetworkMap{
			Serial:     0,
			PeerConfig: nil,
			RemotePeers: []*mgmtProto.RemotePeerConfig{
				peer1, peer2, peer3,
			},
			RemotePeersIsEmpty: false,
		},
		expectedLen:    2,
		expectedPeers:  []*mgmtProto.RemotePeerConfig{peer1, peer2},
		expectedSerial: 2,
	}

	case4 := testCase{
		name: "input with one peer to remove and one new to add",
		networkMap: &mgmtProto.NetworkMap{
			Serial:     4,
			PeerConfig: nil,
			RemotePeers: []*mgmtProto.RemotePeerConfig{
				peer2, peer3,
			},
			RemotePeersIsEmpty: false,
		},
		expectedLen:    2,
		expectedPeers:  []*mgmtProto.RemotePeerConfig{peer2, peer3},
		expectedSerial: 4,
	}

	case5 := testCase{
		name: "input with one peer to modify",
		networkMap: &mgmtProto.NetworkMap{
			Serial:     4,
			PeerConfig: nil,
			RemotePeers: []*mgmtProto.RemotePeerConfig{
				modifiedPeer3, peer2,
			},
			RemotePeersIsEmpty: false,
		},
		expectedLen:    2,
		expectedPeers:  []*mgmtProto.RemotePeerConfig{peer2, modifiedPeer3},
		expectedSerial: 4,
	}

	case6 := testCase{
		name: "input with all peers to remove",
		networkMap: &mgmtProto.NetworkMap{
			Serial:             5,
			PeerConfig:         nil,
			RemotePeers:        []*mgmtProto.RemotePeerConfig{},
			RemotePeersIsEmpty: true,
		},
		expectedLen:    0,
		expectedPeers:  nil,
		expectedSerial: 5,
	}

	for _, c := range []testCase{case1, case2, case3, case4, case5, case6} {
		t.Run(c.name, func(t *testing.T) {
			err = engine.updateNetworkMap(c.networkMap)
			if err != nil {
				t.Fatal(err)
				return
			}

			if len(engine.peerConns) != c.expectedLen {
				t.Errorf("expecting Engine.peerConns to be of size %d, got %d", c.expectedLen, len(engine.peerConns))
			}

			if engine.networkSerial != c.expectedSerial {
				t.Errorf("expecting Engine.networkSerial to be equal to %d, actual %d", c.expectedSerial, engine.networkSerial)
			}

			for _, p := range c.expectedPeers {
				conn, ok := engine.peerConns[p.GetWgPubKey()]
				if !ok {
					t.Errorf("expecting Engine.peerConns to contain peer %s", p)
				}
				expectedAllowedIPs := strings.Join(p.AllowedIps, ",")
				if conn.WgConfig().AllowedIps != expectedAllowedIPs {
					t.Errorf("expecting peer %s to have AllowedIPs= %s, got %s", p.GetWgPubKey(),
						expectedAllowedIPs, conn.WgConfig().AllowedIps)
				}
			}
		})
	}
}

func TestEngine_Sync(t *testing.T) {
	key, err := wgtypes.GeneratePrivateKey()
	if err != nil {
		t.Fatal(err)
		return
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// feed updates to Engine via mocked Management client
	updates := make(chan *mgmtProto.SyncResponse)
	defer close(updates)
	syncFunc := func(msgHandler func(msg *mgmtProto.SyncResponse) error) error {
		for msg := range updates {
			err := msgHandler(msg)
			if err != nil {
				t.Fatal(err)
			}
		}
		return nil
	}

	engine := NewEngine(ctx, cancel, &signal.MockClient{}, &mgmt.MockClient{SyncFunc: syncFunc}, &EngineConfig{
		WgIfaceName:  "utun103",
		WgAddr:       "100.64.0.1/24",
		WgPrivateKey: key,
		WgPort:       33100,
	}, MobileDependency{}, peer.NewRecorder("https://mgm"))

	engine.dnsServer = &dns.MockServer{
		UpdateDNSServerFunc: func(serial uint64, update nbdns.Config) error { return nil },
	}

	defer func() {
		err := engine.Stop()
		if err != nil {
			return
		}
	}()

	err = engine.Start()
	if err != nil {
		t.Fatal(err)
		return
	}

	peer1 := &mgmtProto.RemotePeerConfig{
		WgPubKey:   "RRHf3Ma6z6mdLbriAJbqhX7+nM/B71lgw2+91q3LfhU=",
		AllowedIps: []string{"100.64.0.10/24"},
	}
	peer2 := &mgmtProto.RemotePeerConfig{
		WgPubKey:   "LLHf3Ma6z6mdLbriAJbqhX9+nM/B71lgw2+91q3LlhU=",
		AllowedIps: []string{"100.64.0.11/24"},
	}
	peer3 := &mgmtProto.RemotePeerConfig{
		WgPubKey:   "GGHf3Ma6z6mdLbriAJbqhX9+nM/B71lgw2+91q3LlhU=",
		AllowedIps: []string{"100.64.0.12/24"},
	}
	// 1st update with just 1 peer and serial larger than the current serial of the engine => apply update
	updates <- &mgmtProto.SyncResponse{
		NetworkMap: &mgmtProto.NetworkMap{
			Serial:             10,
			PeerConfig:         nil,
			RemotePeers:        []*mgmtProto.RemotePeerConfig{peer1, peer2, peer3},
			RemotePeersIsEmpty: false,
		},
	}

	timeout := time.After(time.Second * 2)
	for {
		select {
		case <-timeout:
			t.Fatalf("timeout while waiting for test to finish")
			return
		default:
		}

		if getPeers(engine) == 3 && engine.networkSerial == 10 {
			break
		}
	}
}

func TestEngine_UpdateNetworkMapWithRoutes(t *testing.T) {
	testCases := []struct {
		name           string
		inputErr       error
		networkMap     *mgmtProto.NetworkMap
		expectedLen    int
		expectedRoutes []*route.Route
		expectedSerial uint64
	}{
		{
			name: "Routes Config Should Be Passed To Manager",
			networkMap: &mgmtProto.NetworkMap{
				Serial:             1,
				PeerConfig:         nil,
				RemotePeersIsEmpty: false,
				Routes: []*mgmtProto.Route{
					{
						ID:          "a",
						Network:     "192.168.0.0/24",
						NetID:       "n1",
						Peer:        "p1",
						NetworkType: 1,
						Masquerade:  false,
					},
					{
						ID:          "b",
						Network:     "192.168.1.0/24",
						NetID:       "n2",
						Peer:        "p1",
						NetworkType: 1,
						Masquerade:  false,
					},
				},
			},
			expectedLen: 2,
			expectedRoutes: []*route.Route{
				{
					ID:          "a",
					Network:     netip.MustParsePrefix("192.168.0.0/24"),
					NetID:       "n1",
					Peer:        "p1",
					NetworkType: 1,
					Masquerade:  false,
				},
				{
					ID:          "b",
					Network:     netip.MustParsePrefix("192.168.1.0/24"),
					NetID:       "n2",
					Peer:        "p1",
					NetworkType: 1,
					Masquerade:  false,
				},
			},
			expectedSerial: 1,
		},
		{
			name: "Empty Routes Config Should Be Passed",
			networkMap: &mgmtProto.NetworkMap{
				Serial:             1,
				PeerConfig:         nil,
				RemotePeersIsEmpty: false,
				Routes:             nil,
			},
			expectedLen:    0,
			expectedRoutes: []*route.Route{},
			expectedSerial: 1,
		},
		{
			name:     "Error Shouldn't Break Engine",
			inputErr: fmt.Errorf("mocking error"),
			networkMap: &mgmtProto.NetworkMap{
				Serial:             1,
				PeerConfig:         nil,
				RemotePeersIsEmpty: false,
				Routes:             nil,
			},
			expectedLen:    0,
			expectedRoutes: []*route.Route{},
			expectedSerial: 1,
		},
	}

	for n, testCase := range testCases {
		t.Run(testCase.name, func(t *testing.T) {
			// test setup
			key, err := wgtypes.GeneratePrivateKey()
			if err != nil {
				t.Fatal(err)
				return
			}

			ctx, cancel := context.WithCancel(context.Background())
			defer cancel()

			wgIfaceName := fmt.Sprintf("utun%d", 104+n)
			wgAddr := fmt.Sprintf("100.66.%d.1/24", n)

			engine := NewEngine(ctx, cancel, &signal.MockClient{}, &mgmt.MockClient{}, &EngineConfig{
				WgIfaceName:  wgIfaceName,
				WgAddr:       wgAddr,
				WgPrivateKey: key,
				WgPort:       33100,
			}, MobileDependency{}, peer.NewRecorder("https://mgm"))
			newNet, err := stdnet.NewNet()
			if err != nil {
				t.Fatal(err)
			}
			engine.wgInterface, err = iface.NewWGIFace(wgIfaceName, wgAddr, iface.DefaultMTU, nil, newNet)
			assert.NoError(t, err, "shouldn't return error")
			input := struct {
				inputSerial uint64
				inputRoutes []*route.Route
			}{}

			mockRouteManager := &routemanager.MockManager{
				UpdateRoutesFunc: func(updateSerial uint64, newRoutes []*route.Route) error {
					input.inputSerial = updateSerial
					input.inputRoutes = newRoutes
					return testCase.inputErr
				},
			}

			engine.routeManager = mockRouteManager
			engine.dnsServer = &dns.MockServer{}

			defer func() {
				exitErr := engine.Stop()
				if exitErr != nil {
					return
				}
			}()

			err = engine.updateNetworkMap(testCase.networkMap)
			assert.NoError(t, err, "shouldn't return error")
			assert.Equal(t, testCase.expectedSerial, input.inputSerial, "serial should match")
			assert.Len(t, input.inputRoutes, testCase.expectedLen, "routes len should match")
			assert.Equal(t, testCase.expectedRoutes, input.inputRoutes, "routes should match")
		})
	}
}

func TestEngine_UpdateNetworkMapWithDNSUpdate(t *testing.T) {
	testCases := []struct {
		name                string
		inputErr            error
		networkMap          *mgmtProto.NetworkMap
		expectedZonesLen    int
		expectedZones       []nbdns.CustomZone
		expectedNSGroupsLen int
		expectedNSGroups    []*nbdns.NameServerGroup
		expectedSerial      uint64
	}{
		{
			name: "DNS Config Should Be Passed To DNS Server",
			networkMap: &mgmtProto.NetworkMap{
				Serial:             1,
				PeerConfig:         nil,
				RemotePeersIsEmpty: false,
				Routes:             nil,
				DNSConfig: &mgmtProto.DNSConfig{
					ServiceEnable: true,
					CustomZones: []*mgmtProto.CustomZone{
						{
							Domain: "netbird.cloud.",
							Records: []*mgmtProto.SimpleRecord{
								{
									Name:  "peer-a.netbird.cloud.",
									Type:  1,
									Class: nbdns.DefaultClass,
									TTL:   300,
									RData: "100.64.0.1",
								},
							},
						},
					},
					NameServerGroups: []*mgmtProto.NameServerGroup{
						{
							Primary: true,
							NameServers: []*mgmtProto.NameServer{
								{
									IP:     "8.8.8.8",
									NSType: 1,
									Port:   53,
								},
							},
						},
					},
				},
			},
			expectedZonesLen: 1,
			expectedZones: []nbdns.CustomZone{
				{
					Domain: "netbird.cloud.",
					Records: []nbdns.SimpleRecord{
						{
							Name:  "peer-a.netbird.cloud.",
							Type:  1,
							Class: nbdns.DefaultClass,
							TTL:   300,
							RData: "100.64.0.1",
						},
					},
				},
			},
			expectedNSGroupsLen: 1,
			expectedNSGroups: []*nbdns.NameServerGroup{
				{
					Primary: true,
					NameServers: []nbdns.NameServer{
						{
							IP:     netip.MustParseAddr("8.8.8.8"),
							NSType: 1,
							Port:   53,
						},
					},
				},
			},
			expectedSerial: 1,
		},
		{
			name: "Empty DNS Config Should Be OK",
			networkMap: &mgmtProto.NetworkMap{
				Serial:             1,
				PeerConfig:         nil,
				RemotePeersIsEmpty: false,
				Routes:             nil,
				DNSConfig:          nil,
			},
			expectedZonesLen:    0,
			expectedZones:       []nbdns.CustomZone{},
			expectedNSGroupsLen: 0,
			expectedNSGroups:    []*nbdns.NameServerGroup{},
			expectedSerial:      1,
		},
		{
			name:     "Error Shouldn't Break Engine",
			inputErr: fmt.Errorf("mocking error"),
			networkMap: &mgmtProto.NetworkMap{
				Serial:             1,
				PeerConfig:         nil,
				RemotePeersIsEmpty: false,
				Routes:             nil,
			},
			expectedZonesLen:    0,
			expectedZones:       []nbdns.CustomZone{},
			expectedNSGroupsLen: 0,
			expectedNSGroups:    []*nbdns.NameServerGroup{},
			expectedSerial:      1,
		},
	}

	for n, testCase := range testCases {
		t.Run(testCase.name, func(t *testing.T) {
			// test setup
			key, err := wgtypes.GeneratePrivateKey()
			if err != nil {
				t.Fatal(err)
				return
			}

			ctx, cancel := context.WithCancel(context.Background())
			defer cancel()

			wgIfaceName := fmt.Sprintf("utun%d", 104+n)
			wgAddr := fmt.Sprintf("100.66.%d.1/24", n)

			engine := NewEngine(ctx, cancel, &signal.MockClient{}, &mgmt.MockClient{}, &EngineConfig{
				WgIfaceName:  wgIfaceName,
				WgAddr:       wgAddr,
				WgPrivateKey: key,
				WgPort:       33100,
			}, MobileDependency{}, peer.NewRecorder("https://mgm"))
			newNet, err := stdnet.NewNet()
			if err != nil {
				t.Fatal(err)
			}
			engine.wgInterface, err = iface.NewWGIFace(wgIfaceName, wgAddr, iface.DefaultMTU, nil, newNet)
			assert.NoError(t, err, "shouldn't return error")

			mockRouteManager := &routemanager.MockManager{
				UpdateRoutesFunc: func(updateSerial uint64, newRoutes []*route.Route) error {
					return nil
				},
			}

			engine.routeManager = mockRouteManager

			input := struct {
				inputSerial   uint64
				inputNSGroups []*nbdns.NameServerGroup
				inputZones    []nbdns.CustomZone
			}{}

			mockDNSServer := &dns.MockServer{
				UpdateDNSServerFunc: func(serial uint64, update nbdns.Config) error {
					input.inputSerial = serial
					input.inputZones = update.CustomZones
					input.inputNSGroups = update.NameServerGroups
					return testCase.inputErr
				},
			}

			engine.dnsServer = mockDNSServer

			defer func() {
				exitErr := engine.Stop()
				if exitErr != nil {
					return
				}
			}()

			err = engine.updateNetworkMap(testCase.networkMap)
			assert.NoError(t, err, "shouldn't return error")
			assert.Equal(t, testCase.expectedSerial, input.inputSerial, "serial should match")
			assert.Len(t, input.inputNSGroups, testCase.expectedZonesLen, "zones len should match")
			assert.Equal(t, testCase.expectedZones, input.inputZones, "custom zones should match")
			assert.Len(t, input.inputNSGroups, testCase.expectedNSGroupsLen, "ns groups len should match")
			assert.Equal(t, testCase.expectedNSGroups, input.inputNSGroups, "ns groups should match")
		})
	}
}

func TestEngine_MultiplePeers(t *testing.T) {
	// log.SetLevel(log.DebugLevel)

	dir := t.TempDir()

	err := util.CopyFileContents("../testdata/store.json", filepath.Join(dir, "store.json"))
	if err != nil {
		t.Fatal(err)
	}
	defer func() {
		err = os.Remove(filepath.Join(dir, "store.json")) //nolint
		if err != nil {
			t.Fatal(err)
			return
		}
	}()

	ctx, cancel := context.WithCancel(CtxInitState(context.Background()))
	defer cancel()

	sigServer, signalAddr, err := startSignal()
	if err != nil {
		t.Fatal(err)
		return
	}
	defer sigServer.Stop()
	mgmtServer, mgmtAddr, err := startManagement(dir)
	if err != nil {
		t.Fatal(err)
		return
	}
	defer mgmtServer.GracefulStop()

	setupKey := "A2C8E62B-38F5-4553-B31E-DD66C696CEBB"

	mu := sync.Mutex{}
	engines := []*Engine{}
	numPeers := 10
	wg := sync.WaitGroup{}
	wg.Add(numPeers)
	// create and start peers
	for i := 0; i < numPeers; i++ {
		j := i
		go func() {
			engine, err := createEngine(ctx, cancel, setupKey, j, mgmtAddr, signalAddr)
			if err != nil {
				wg.Done()
				t.Errorf("unable to create the engine for peer %d with error %v", j, err)
				return
			}
			engine.dnsServer = &dns.MockServer{}
			mu.Lock()
			defer mu.Unlock()
			err = engine.Start()
			if err != nil {
				t.Errorf("unable to start engine for peer %d with error %v", j, err)
				wg.Done()
				return
			}
			engines = append(engines, engine)
			wg.Done()
		}()
	}

	// wait until all have been created and started
	wg.Wait()
	if len(engines) != numPeers {
		t.Fatal("not all peers was started")
	}
	// check whether all the peer have expected peers connected

	expectedConnected := numPeers * (numPeers - 1)

	// adjust according to timeouts
	timeout := 50 * time.Second
	timeoutChan := time.After(timeout)
	ticker := time.NewTicker(time.Second)
	defer ticker.Stop()
loop:
	for {
		select {
		case <-timeoutChan:
			t.Fatalf("waiting for expected connections timeout after %s", timeout.String())
			break loop
		case <-ticker.C:
			totalConnected := 0
			for _, engine := range engines {
				totalConnected += getConnectedPeers(engine)
			}
			if totalConnected == expectedConnected {
				log.Infof("total connected=%d", totalConnected)
				break loop
			}
			log.Infof("total connected=%d", totalConnected)
		}
	}
	// cleanup test
	for n, peerEngine := range engines {
		t.Logf("stopping peer with interface %s from multipeer test, loopIndex %d", peerEngine.wgInterface.Name(), n)
		errStop := peerEngine.mgmClient.Close()
		if errStop != nil {
			log.Infoln("got error trying to close management clients from engine: ", errStop)
		}
		errStop = peerEngine.Stop()
		if errStop != nil {
			log.Infoln("got error trying to close testing peers engine: ", errStop)
		}
	}
}

func Test_ParseNATExternalIPMappings(t *testing.T) {
	ifaceList, err := net.Interfaces()
	if err != nil {
		t.Fatalf("could get the interface list, got error: %s", err)
	}

	var testingIP string
	var testingInterface string

	for _, iface := range ifaceList {
		addrList, err := iface.Addrs()
		if err != nil {
			t.Fatalf("could get the addr list, got error: %s", err)
		}
		for _, addr := range addrList {
			prefix := netip.MustParsePrefix(addr.String())
			if prefix.Addr().Is4() && !prefix.Addr().IsLoopback() {
				testingIP = prefix.Addr().String()
				testingInterface = iface.Name
			}
		}
	}

	testCases := []struct {
		name                    string
		inputMapList            []string
		inputBlacklistInterface []string
		expectedOutput          []string
	}{
		{
			name:                    "Parse Valid List Should Be OK",
			inputBlacklistInterface: defaultInterfaceBlacklist,
			inputMapList:            []string{"1.1.1.1", "8.8.8.8/" + testingInterface},
			expectedOutput:          []string{"1.1.1.1", "8.8.8.8/" + testingIP},
		},
		{
			name:                    "Only Interface name Should Return Nil",
			inputBlacklistInterface: defaultInterfaceBlacklist,
			inputMapList:            []string{testingInterface},
			expectedOutput:          nil,
		},
		{
			name:                    "Invalid IP Return Nil",
			inputBlacklistInterface: defaultInterfaceBlacklist,
			inputMapList:            []string{"1.1.1.1000"},
			expectedOutput:          nil,
		},
		{
			name:                    "Invalid Mapping Element Should return Nil",
			inputBlacklistInterface: defaultInterfaceBlacklist,
			inputMapList:            []string{"1.1.1.1/10.10.10.1/eth0"},
			expectedOutput:          nil,
		},
	}
	for _, testCase := range testCases {
		t.Run(testCase.name, func(t *testing.T) {
			engine := &Engine{
				config: &EngineConfig{
					IFaceBlackList: testCase.inputBlacklistInterface,
					NATExternalIPs: testCase.inputMapList,
				},
			}
			parsedList := engine.parseNATExternalIPMappings()
			require.ElementsMatchf(t, testCase.expectedOutput, parsedList, "elements of parsed list should match expected list")
		})
	}
}

func createEngine(ctx context.Context, cancel context.CancelFunc, setupKey string, i int, mgmtAddr string, signalAddr string) (*Engine, error) {
	key, err := wgtypes.GeneratePrivateKey()
	if err != nil {
		return nil, err
	}
	mgmtClient, err := mgmt.NewClient(ctx, mgmtAddr, key, false)
	if err != nil {
		return nil, err
	}
	signalClient, err := signal.NewClient(ctx, signalAddr, key, false)
	if err != nil {
		return nil, err
	}

	publicKey, err := mgmtClient.GetServerPublicKey()
	if err != nil {
		return nil, err
	}

	info := system.GetInfo(ctx)
	resp, err := mgmtClient.Register(*publicKey, setupKey, "", info, nil)
	if err != nil {
		return nil, err
	}

	var ifaceName string
	if runtime.GOOS == "darwin" {
		ifaceName = fmt.Sprintf("utun1%d", i)
	} else {
		ifaceName = fmt.Sprintf("wt%d", i)
	}

	wgPort := 33100 + i
	conf := &EngineConfig{
		WgIfaceName:  ifaceName,
		WgAddr:       resp.PeerConfig.Address,
		WgPrivateKey: key,
		WgPort:       wgPort,
	}

	return NewEngine(ctx, cancel, signalClient, mgmtClient, conf, MobileDependency{}, peer.NewRecorder("https://mgm")), nil
}

func startSignal() (*grpc.Server, string, error) {
	s := grpc.NewServer(grpc.KeepaliveEnforcementPolicy(kaep), grpc.KeepaliveParams(kasp))

	lis, err := net.Listen("tcp", "localhost:0")
	if err != nil {
		log.Fatalf("failed to listen: %v", err)
	}

	proto.RegisterSignalExchangeServer(s, signalServer.NewServer())

	go func() {
		if err = s.Serve(lis); err != nil {
			log.Fatalf("failed to serve: %v", err)
		}
	}()

	return s, lis.Addr().String(), nil
}

func startManagement(dataDir string) (*grpc.Server, string, error) {
	config := &server.Config{
		Stuns:      []*server.Host{},
		TURNConfig: &server.TURNConfig{},
		Signal: &server.Host{
			Proto: "http",
			URI:   "localhost:10000",
		},
		Datadir:    dataDir,
		HttpConfig: nil,
	}

	lis, err := net.Listen("tcp", "localhost:0")
	if err != nil {
		return nil, "", err
	}
	s := grpc.NewServer(grpc.KeepaliveEnforcementPolicy(kaep), grpc.KeepaliveParams(kasp))
	store, err := server.NewStoreFromJson(config.Datadir, nil)
	if err != nil {
		return nil, "", err
	}

	peersUpdateManager := server.NewPeersUpdateManager(nil)
	eventStore := &activity.InMemoryEventStore{}
	if err != nil {
		return nil, "", err
	}
	accountManager, err := server.BuildManager(store, peersUpdateManager, nil, "", "",
		eventStore, false)
	if err != nil {
		return nil, "", err
	}
	turnManager := server.NewTimeBasedAuthSecretsManager(peersUpdateManager, config.TURNConfig)
	mgmtServer, err := server.NewServer(config, accountManager, peersUpdateManager, turnManager, nil, nil)
	if err != nil {
		return nil, "", err
	}
	mgmtProto.RegisterManagementServiceServer(s, mgmtServer)
	go func() {
		if err = s.Serve(lis); err != nil {
			log.Fatalf("failed to serve: %v", err)
		}
	}()

	return s, lis.Addr().String(), nil
}

// getConnectedPeers returns a connection Status or nil if peer connection wasn't found
func getConnectedPeers(e *Engine) int {
	e.syncMsgMux.Lock()
	defer e.syncMsgMux.Unlock()
	i := 0
	for _, conn := range e.peerConns {
		if conn.Status() == peer.StatusConnected {
			i++
		}
	}
	return i
}

func getPeers(e *Engine) int {
	e.syncMsgMux.Lock()
	defer e.syncMsgMux.Unlock()

	return len(e.peerConns)
}