lightning-terminal/itest/litd_node.go

package itest

import (
	"bytes"
	"context"
	"crypto/rand"
	"encoding/base64"
	"encoding/hex"
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/btcsuite/btcd/btcutil"
	"github.com/btcsuite/btcd/chaincfg"
	"github.com/btcsuite/btcd/chaincfg/chainhash"
	"github.com/btcsuite/btcd/wire"
	"github.com/lightninglabs/faraday/frdrpc"
	terminal "github.com/lightninglabs/lightning-terminal"
	"github.com/lightninglabs/lightning-terminal/db"
	"github.com/lightninglabs/lightning-terminal/litrpc"
	"github.com/lightninglabs/lightning-terminal/subservers"
	"github.com/lightninglabs/loop/looprpc"
	"github.com/lightninglabs/pool/poolrpc"
	"github.com/lightninglabs/taproot-assets/taprpc"
	"github.com/lightningnetwork/lnd/lnrpc"
	"github.com/lightningnetwork/lnd/lnrpc/invoicesrpc"
	"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
	"github.com/lightningnetwork/lnd/lnrpc/signrpc"
	"github.com/lightningnetwork/lnd/lnrpc/walletrpc"
	"github.com/lightningnetwork/lnd/lnrpc/watchtowerrpc"
	"github.com/lightningnetwork/lnd/lnrpc/wtclientrpc"
	"github.com/lightningnetwork/lnd/lntest"
	"github.com/lightningnetwork/lnd/lntest/node"
	"github.com/lightningnetwork/lnd/lntest/port"
	"github.com/lightningnetwork/lnd/lntest/wait"
	"github.com/lightningnetwork/lnd/macaroons"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials"
	"gopkg.in/macaroon.v2"
)

const (
	// logPubKeyBytes is the number of bytes of the node's PubKey that will
	// be appended to the log file name. The whole PubKey is too long and
	// not really necessary to quickly identify what node produced which
	// log file.
	logPubKeyBytes = 4
)

var (
	// numActiveNodes is the number of active nodes within the test network.
	numActiveNodes    = 0
	numActiveNodesMtx sync.Mutex

	// litDBBackend is a command line flag for specifying the database
	// backend to use when starting a LiT daemon.
	litDBBackend = flag.String(
		"litdbbackend", terminal.DatabaseBackendBbolt, "Set the "+
			"database backend to use when starting a LiT daemon.",
	)

	// backwardCompatFlagOverride is a map of LiT versions to a map of
	// config file flags that need to be overwritten or added for the target
	// version to work. If a flag in the map is empty, it means it will be
	// removed from the config file of that version.
	backwardCompatFlagOverride = map[string]map[string]string{
		"v0.14.1-alpha": {
			"databasebackend":            "",
			"lnd.logging.no-commit-hash": "",
		},
	}

	// backwardCompatConfigOverride is a map of LiT versions to a map of
	// config file overriding functions.
	backwardCompatConfigOverride = map[string]func(*LitNodeConfig){
		"v0.14.1-alpha": func(cfg *LitNodeConfig) {
			cfg.OldChannelFormat = true
			cfg.SkipBalanceChecks = true
		},
	}
)

// Option is a function for updating a node's configuration.
type Option func(config *LitNodeConfig)

type LitNodeConfig struct {
	*node.BaseNodeConfig

	LitArgs    []string
	ActiveArgs *litArgs

	RemoteMode bool

	HasSeed bool

	FaradayMacPath string
	LoopMacPath    string
	PoolMacPath    string
	TapMacPath     string
	LitTLSCertPath string
	LitMacPath     string

	DBBackend      string
	PostgresConfig *db.PostgresConfig

	UIPassword string
	LitDir     string
	FaradayDir string
	LoopDir    string
	PoolDir    string
	TapdDir    string

	LitPort     int
	LitRESTPort int

	// OldChannelFormat is a flag for turning off certain checks for old
	// versions of litd during the backward compatibility test.
	OldChannelFormat bool

	// SkipBalanceChecks is a flag for turning off certain checks for old
	// versions of litd during the backward compatibility test.
	SkipBalanceChecks bool

	// backupDBDir is the path where a database backup is stored, if any.
	backupDBDir string
}

func (cfg *LitNodeConfig) LitAddr() string {
	return fmt.Sprintf(node.ListenerFormat, cfg.LitPort)
}

func (cfg *LitNodeConfig) LitRESTAddr() string {
	return fmt.Sprintf(node.ListenerFormat, cfg.LitRESTPort)
}

func (cfg *LitNodeConfig) GenerateListeningPorts() {
	cfg.BaseNodeConfig.GenerateListeningPorts()

	if cfg.LitPort == 0 {
		cfg.LitPort = port.NextAvailablePort()
	}
	if cfg.LitRESTPort == 0 {
		cfg.LitRESTPort = port.NextAvailablePort()
	}
}

// litArgs holds a key-value map of config option to config value. An empty
// string value means that the config option is a boolean.
type litArgs struct {
	args map[string]string

	mu sync.Mutex
}

// deleteArg deletes the argument with the given name from the set if it is
// present.
func (l *litArgs) deleteArg(argName string) {
	l.mu.Lock()
	defer l.mu.Unlock()

	delete(l.args, argName)
}

// addArg adds a new argument to the set. An empty value string will mean that
// the key will be added as a boolean flag.
func (l *litArgs) addArg(name, value string) {
	l.mu.Lock()
	defer l.mu.Unlock()

	l.args[name] = value
}

// getArg gets the arg with the given name from the set and returns the value.
// The boolean returned will be true if the argument is in the set. If the
// boolean is true but the string is empty, it means it is a boolean config
// flag.
func (l *litArgs) getArg(name string) (string, bool) {
	l.mu.Lock()
	defer l.mu.Unlock()

	value, ok := l.args[name]

	return value, ok
}

// toArgList converts the litArgs map to an arguments string slice.
func (l *litArgs) toArgList(nodeName string) []string {
	l.mu.Lock()
	defer l.mu.Unlock()

	args := make([]string, 0, len(l.args))
	for arg, setting := range l.args {
		if setting == "" {
			args = append(args, fmt.Sprintf("--%s", arg))
			continue
		}

		args = append(args, fmt.Sprintf("--%s=%s", arg, setting))
	}

	return append([]string{"--lnd.alias=" + nodeName}, args...)
}

// LitArgOption defines the signature of a functional option that can be used
// to tweak the default arguments of a Litd node.
type LitArgOption func(args *litArgs)

// WithoutLitArg can be used to delete a litd config option.
func WithoutLitArg(arg string) LitArgOption {
	return func(args *litArgs) {
		args.deleteArg(arg)
	}
}

// WithLitArg can be used to set a Litd config option. An empty value string
// will mean that the key will be added as a boolean flag.
func WithLitArg(key, value string) LitArgOption {
	return func(args *litArgs) {
		args.addArg(key, value)
	}
}

// GenArgs generates a slice of command line arguments from the lightning node
// config struct.
func (cfg *LitNodeConfig) GenArgs(opts ...LitArgOption) []string {
	args := cfg.defaultLitdArgs()

	for _, opt := range opts {
		opt(args)
	}

	cfg.ActiveArgs = args

	return args.toArgList(cfg.Name)
}

// defaultLitArgs generates the default arguments to be used with a Litd node.
func (cfg *LitNodeConfig) defaultLitdArgs() *litArgs {
	var (
		args = map[string]string{
			"httpslisten":            cfg.LitAddr(),
			"insecure-httplisten":    cfg.LitRESTAddr(),
			"lit-dir":                cfg.LitDir,
			"faraday.faradaydir":     cfg.FaradayDir,
			"loop.loopdir":           cfg.LoopDir,
			"pool.basedir":           cfg.PoolDir,
			"taproot-assets.tapddir": cfg.TapdDir,
			"taproot-assets-mode":    "integrated",
			"uipassword":             cfg.UIPassword,
			"enablerest":             "",
			"restcors":               "*",
			"lnd.debuglevel":         "trace,GRPC=error,PEER=info",
			"lndconnectinterval":     "200ms",
			"databasebackend":        cfg.DBBackend,
		}
	)

	if cfg.DBBackend == terminal.DatabaseBackendPostgres {
		args["postgres.host"] = cfg.PostgresConfig.Host
		args["postgres.port"] = fmt.Sprintf(
			"%d", cfg.PostgresConfig.Port,
		)
		args["postgres.user"] = cfg.PostgresConfig.User
		args["postgres.password"] = cfg.PostgresConfig.Password
		args["postgres.dbname"] = cfg.PostgresConfig.DBName
	}

	for _, arg := range cfg.LitArgs {
		parts := strings.Split(arg, "=")
		option := strings.TrimLeft(parts[0], "--")
		switch len(parts) {
		case 1:
			args[option] = ""
		case 2:
			args[option] = parts[1]
		}
	}

	switch cfg.NetParams {
	case &chaincfg.TestNet3Params:
		args["network"] = "testnet"
	case &chaincfg.TestNet4Params:
		args["network"] = "testnet4"
	case &chaincfg.SimNetParams:
		args["network"] = "simnet"
	case &chaincfg.RegressionNetParams:
		args["network"] = "regtest"
	case &chaincfg.SigNetParams:
		args["network"] = "signet"
	}

	// In remote mode, we don't need any lnd specific arguments other than
	// those we need to connect.
	if cfg.RemoteMode {
		args["lnd-mode"] = "remote"
		args["remote.lnd.rpcserver"] = cfg.RPCAddr()
		args["remote.lnd.tlscertpath"] = cfg.TLSCertPath
		args["remote.lnd.macaroonpath"] = cfg.AdminMacPath

		return &litArgs{args: args}
	}

	// All arguments so far were for lnd. Let's namespace them now so we can
	// add args for the other daemons and LiT itself afterwards.
	args["lnd-mode"] = "integrated"

	lndArgs := cfg.BaseNodeConfig.GenArgs()
	for idx := range lndArgs {
		arg := strings.ReplaceAll(lndArgs[idx], "--", "--lnd.")

		parts := strings.Split(arg, "=")
		option := strings.TrimLeft(parts[0], "--")
		switch len(parts) {
		case 1:
			args[option] = ""
		case 2:
			args[option] = parts[1]
		default:
			args[option] = strings.Join(parts[1:], "=")
		}
	}

	return &litArgs{args: args}
}

// policyUpdateMap defines a type to store channel policy updates. It has the
// format,
//
//	{
//	 "chanPoint1": {
//	      "advertisingNode1": [
//	             policy1, policy2, ...
//	      ],
//	      "advertisingNode2": [
//	             policy1, policy2, ...
//	      ]
//	 },
//	 "chanPoint2": ...
//	}
type policyUpdateMap map[string]map[string][]*lnrpc.RoutingPolicy

// HarnessNode represents an instance of lnd running within our test network
// harness. Each HarnessNode instance also fully embeds an RPC client in
// order to pragmatically drive the node.
type HarnessNode struct {
	Cfg *LitNodeConfig

	// NodeID is a unique identifier for the node within a NetworkHarness.
	NodeID int

	RemoteLnd *node.HarnessNode

	// PubKey is the serialized compressed identity public key of the node.
	// This field will only be populated once the node itself has been
	// started via the start() method.
	PubKey    [33]byte
	PubKeyStr string

	cmd     *exec.Cmd
	pidFile string
	logFile *os.File

	// processExit is a channel that's closed once it's detected that the
	// process this instance of HarnessNode is bound to has exited.
	processExit chan struct{}

	chanWatchRequests chan *chanWatchRequest

	// For each outpoint, we'll track an integer which denotes the number of
	// edges seen for that channel within the network. When this number
	// reaches 2, then it means that both edge advertisements has propagated
	// through the network.
	openChans        map[wire.OutPoint]int
	openChanWatchers map[wire.OutPoint][]chan struct{}

	closedChans       map[wire.OutPoint]struct{}
	closeChanWatchers map[wire.OutPoint][]chan struct{}

	// policyUpdates stores a slice of seen polices by each advertising
	// node and the outpoint.
	policyUpdates policyUpdateMap

	quit chan struct{}
	wg   sync.WaitGroup

	lnrpc.LightningClient

	lnrpc.WalletUnlockerClient

	invoicesrpc.InvoicesClient

	// SignerClient cannot be embedded because the name collisions of the
	// methods SignMessage and VerifyMessage.
	SignerClient signrpc.SignerClient

	// conn is the underlying connection to the lnd grpc endpoint of the
	// node.
	conn *grpc.ClientConn

	// litConn is the underlying connection to Lit's grpc endpoint.
	litConn *grpc.ClientConn

	// RouterClient, WalletKitClient, WatchtowerClient cannot be embedded,
	// because a name collision would occur with LightningClient.
	RouterClient     routerrpc.RouterClient
	WalletKitClient  walletrpc.WalletKitClient
	Watchtower       watchtowerrpc.WatchtowerClient
	WatchtowerClient wtclientrpc.WatchtowerClientClient
	StateClient      lnrpc.StateClient

	// backupDbDir is the path where a database backup is stored, if any.
	backupDbDir string
}

// Assert *HarnessNode implements the lnrpc.LightningClient interface.
var _ lnrpc.LightningClient = (*HarnessNode)(nil)
var _ lnrpc.WalletUnlockerClient = (*HarnessNode)(nil)
var _ invoicesrpc.InvoicesClient = (*HarnessNode)(nil)

// NewNode creates a new test lightning node instance from the passed config.
func NewNode(t *testing.T, cfg *LitNodeConfig,
	harness *lntest.HarnessTest) (*HarnessNode, error) {

	if cfg.BaseDir == "" {
		var err error
		cfg.BaseDir, err = os.MkdirTemp("", "litdtest-node")
		if err != nil {
			return nil, err
		}
	}
	cfg.DataDir = filepath.Join(cfg.BaseDir, "data")
	cfg.LogDir = filepath.Join(cfg.BaseDir, "log")
	cfg.LitDir = filepath.Join(cfg.BaseDir, "lit")
	cfg.FaradayDir = filepath.Join(cfg.LitDir, "faraday")
	cfg.LoopDir = filepath.Join(cfg.LitDir, "loop")
	cfg.PoolDir = filepath.Join(cfg.LitDir, "pool")
	cfg.TapdDir = filepath.Join(cfg.LitDir, "tapd")
	cfg.TLSCertPath = filepath.Join(cfg.BaseDir, "tls.cert")
	cfg.TLSKeyPath = filepath.Join(cfg.BaseDir, "tls.key")

	networkDir := filepath.Join(
		cfg.DataDir, "chain", "bitcoin", cfg.NetParams.Name,
	)
	cfg.AdminMacPath = filepath.Join(networkDir, "admin.macaroon")
	cfg.ReadMacPath = filepath.Join(networkDir, "readonly.macaroon")
	cfg.InvoiceMacPath = filepath.Join(networkDir, "invoice.macaroon")
	cfg.FaradayMacPath = filepath.Join(
		cfg.FaradayDir, cfg.NetParams.Name, "faraday.macaroon",
	)
	cfg.LoopMacPath = filepath.Join(
		cfg.LoopDir, cfg.NetParams.Name, "loop.macaroon",
	)
	cfg.PoolMacPath = filepath.Join(
		cfg.PoolDir, cfg.NetParams.Name, "pool.macaroon",
	)
	cfg.TapMacPath = filepath.Join(
		cfg.TapdDir, "data", cfg.NetParams.Name, "admin.macaroon",
	)
	cfg.LitMacPath = filepath.Join(
		cfg.LitDir, cfg.NetParams.Name, "lit.macaroon",
	)
	cfg.LitTLSCertPath = filepath.Join(cfg.LitDir, "tls.cert")
	cfg.GenerateListeningPorts()

	// Decide which DB backend to use.
	switch *litDBBackend {
	case terminal.DatabaseBackendSqlite:
		cfg.DBBackend = terminal.DatabaseBackendSqlite

	case terminal.DatabaseBackendPostgres:
		fixture := db.NewTestPgFixture(
			t, db.DefaultPostgresFixtureLifetime, true,
		)
		t.Cleanup(func() {
			fixture.TearDown(t)
		})

		cfg.DBBackend = terminal.DatabaseBackendPostgres
		cfg.PostgresConfig = fixture.GetConfig()

	default:
		cfg.DBBackend = terminal.DatabaseBackendBbolt
	}

	t.Logf("Using %v database backend", cfg.DBBackend)

	// Generate a random UI password by reading 16 random bytes and base64
	// encoding them.
	var randomBytes [16]byte
	_, _ = rand.Read(randomBytes[:])
	cfg.UIPassword = base64.URLEncoding.EncodeToString(randomBytes[:])

	numActiveNodesMtx.Lock()
	nodeNum := numActiveNodes
	numActiveNodes++
	numActiveNodesMtx.Unlock()

	var remoteNode *node.HarnessNode
	if cfg.RemoteMode {
		lndHarness := harness

		remoteNode = lndHarness.NewNode("bob-custom", cfg.ExtraArgs)
		tenBTC := btcutil.Amount(10 * btcutil.SatoshiPerBitcoin)
		lndHarness.FundCoins(tenBTC, remoteNode)

		cfg.RPCPort = remoteNode.Cfg.RPCPort
		cfg.P2PPort = remoteNode.Cfg.P2PPort
		cfg.TLSCertPath = remoteNode.Cfg.TLSCertPath
		cfg.AdminMacPath = remoteNode.Cfg.AdminMacPath
	}

	t.Logf("Created new node %s with p2p port %d", cfg.Name, cfg.P2PPort)

	return &HarnessNode{
		Cfg:               cfg,
		NodeID:            nodeNum,
		RemoteLnd:         remoteNode,
		chanWatchRequests: make(chan *chanWatchRequest),
		openChans:         make(map[wire.OutPoint]int),
		openChanWatchers:  make(map[wire.OutPoint][]chan struct{}),

		closedChans:       make(map[wire.OutPoint]struct{}),
		closeChanWatchers: make(map[wire.OutPoint][]chan struct{}),

		policyUpdates: policyUpdateMap{},
	}, nil
}

// String gives the internal state of the node which is useful for debugging.
func (hn *HarnessNode) String() string {
	type nodeCfg struct {
		LogFilenamePrefix string
		ExtraArgs         []string
		HasSeed           bool
		P2PPort           int
		RPCPort           int
		RESTPort          int
		ProfilePort       int
		AcceptKeySend     bool
		AcceptAMP         bool
		FeeURL            string
	}

	nodeState := struct {
		NodeID      int
		Name        string
		PubKey      string
		OpenChans   map[string]int
		ClosedChans map[string]struct{}
		NodeCfg     nodeCfg
	}{
		NodeID:      hn.NodeID,
		Name:        hn.Cfg.Name,
		PubKey:      hn.PubKeyStr,
		OpenChans:   make(map[string]int),
		ClosedChans: make(map[string]struct{}),
		NodeCfg: nodeCfg{
			LogFilenamePrefix: hn.Cfg.LogFilenamePrefix,
			ExtraArgs:         hn.Cfg.ExtraArgs,
			HasSeed:           hn.Cfg.HasSeed,
			P2PPort:           hn.Cfg.P2PPort,
			RPCPort:           hn.Cfg.RPCPort,
			RESTPort:          hn.Cfg.RESTPort,
			FeeURL:            hn.Cfg.FeeURL,
		},
	}

	for outpoint, count := range hn.openChans {
		nodeState.OpenChans[outpoint.String()] = count
	}
	for outpoint, count := range hn.closedChans {
		nodeState.ClosedChans[outpoint.String()] = count
	}

	b, err := json.MarshalIndent(nodeState, "", "\t")
	if err != nil {
		return fmt.Sprintf("\n encode node state with err: %v", err)
	}

	return fmt.Sprintf("\nnode state: %s", b)
}

// DBPath returns the filepath to the channeldb database file for this node.
func (hn *HarnessNode) DBPath() string {
	return hn.Cfg.DBPath()
}

// DBDir returns the path for the directory holding channeldb file(s).
func (hn *HarnessNode) DBDir() string {
	return hn.Cfg.DBDir()
}

// Name returns the name of this node set during initialization.
func (hn *HarnessNode) Name() string {
	return hn.Cfg.Name
}

// TLSCertStr returns the path where the TLS certificate is stored.
func (hn *HarnessNode) TLSCertStr() string {
	return hn.Cfg.TLSCertPath
}

// TLSKeyStr returns the path where the TLS key is stored.
func (hn *HarnessNode) TLSKeyStr() string {
	return hn.Cfg.TLSKeyPath
}

// ChanBackupPath returns the fielpath to the on-disk channel.backup file for
// this node.
func (hn *HarnessNode) ChanBackupPath() string {
	return hn.Cfg.ChanBackupPath()
}

// AdminMacPath returns the filepath to the admin.macaroon file for this node.
func (hn *HarnessNode) AdminMacPath() string {
	return hn.Cfg.AdminMacPath
}

// ReadMacPath returns the filepath to the readonly.macaroon file for this node.
func (hn *HarnessNode) ReadMacPath() string {
	return hn.Cfg.ReadMacPath
}

// InvoiceMacPath returns the filepath to the invoice.macaroon file for this
// node.
func (hn *HarnessNode) InvoiceMacPath() string {
	return hn.Cfg.InvoiceMacPath
}

// renameFile is a helper to rename (log) files created during integration
// tests.
func renameFile(fromFileName, toFileName string) {
	err := os.Rename(fromFileName, toFileName)
	if err != nil {
		fmt.Printf("could not rename %s to %s: %v\n",
			fromFileName, toFileName, err)
	}
}

// overrideFlagsAndBinary is a helper function that checks if the passed node
// name needs a version downgrade and if so, it will return the new binary
// name and the new arguments.
func (hn *HarnessNode) overrideFlagsAndBinary(backwardCompat map[string]string,
	binary string, args []LitArgOption) (string, []LitArgOption) {

	noopArg := WithLitArg("taproot-assets.channel.noop-htlcs", "")

	if _, ok := backwardCompat[hn.Name()]; !ok {
		args = append(args, noopArg)
		return binary, args
	}

	downgradeVersion, ok := backwardCompat[hn.Cfg.Name]
	if !ok {
		return binary, args
	}

	newBinary := fmt.Sprintf("%s-%s", binary, downgradeVersion)

	flagOverride, ok := backwardCompatFlagOverride[downgradeVersion]
	if !ok {
		return newBinary, args
	}

	for k, v := range flagOverride {
		if v == "" {
			args = append(args, WithoutLitArg(k))
		} else {
			args = append(args, WithLitArg(k, v))
		}
	}

	cfgOverride, ok := backwardCompatConfigOverride[downgradeVersion]
	if ok && cfgOverride != nil {
		cfgOverride(hn.Cfg)
	}

	return newBinary, args
}

// Start launches a new process running lnd. Additionally, the PID of the
// launched process is saved in order to possibly kill the process forcibly
// later.
//
// This may not clean up properly if an error is returned, so the caller should
// call shutdown() regardless of the return value.
func (hn *HarnessNode) Start(litdBinary string,
	backwardCompat map[string]string, litdError chan<- error,
	waitForStart bool, litArgOpts ...LitArgOption) error {

	hn.quit = make(chan struct{})

	litdBinary, litArgOpts = hn.overrideFlagsAndBinary(
		backwardCompat, litdBinary, litArgOpts,
	)

	args := hn.Cfg.GenArgs(litArgOpts...)
	hn.cmd = exec.Command(litdBinary, args...)

	// Redirect stderr output to buffer
	var errb bytes.Buffer
	hn.cmd.Stderr = &errb

	// Make sure the log file cleanup function is initialized, even
	// if no log file is created.
	var finalizeLogfile = func() {
		if hn.logFile != nil {
			_ = hn.logFile.Close()
		}
	}

	getFinalizedLogFilePrefix := func() string {
		pubKeyHex := hex.EncodeToString(hn.PubKey[:logPubKeyBytes])

		return fmt.Sprintf("%s/%d-%s-%s-%s", node.GetLogDir(),
			hn.NodeID, hn.Cfg.LogFilenamePrefix, hn.Cfg.Name,
			pubKeyHex)
	}

	// If the logoutput flag is passed, redirect output from the nodes to
	// log files.
	dir := node.GetLogDir()
	fileName := fmt.Sprintf("%s/%d-%s-%s-%s.log", dir, hn.NodeID,
		hn.Cfg.LogFilenamePrefix, hn.Cfg.Name,
		hex.EncodeToString(hn.PubKey[:logPubKeyBytes]))

	// If the node's PubKey is not yet initialized, create a
	// temporary file name. Later, after the PubKey has been
	// initialized, the file can be moved to its final name with
	// the PubKey included.
	if bytes.Equal(hn.PubKey[:4], []byte{0, 0, 0, 0}) {
		fileName = fmt.Sprintf("%s/%d-%s-%s-tmp__.log", dir,
			hn.NodeID, hn.Cfg.LogFilenamePrefix, hn.Cfg.Name)
	}

	// Once the node has done its work, the log file can be
	// renamed.
	finalizeLogfile = func() {
		if hn.logFile != nil {
			_ = hn.logFile.Close()

			newFileName := fmt.Sprintf("%v.log",
				getFinalizedLogFilePrefix(),
			)

			renameFile(fileName, newFileName)
		}
	}

	// Create file if not exists, otherwise append.
	file, err := os.OpenFile(fileName,
		os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0666,
	)
	if err != nil {
		return err
	}

	// Pass node's stderr to both errb and the file.
	w := io.MultiWriter(&errb, file)
	hn.cmd.Stderr = w

	// Pass the node's stdout only to the file.
	hn.cmd.Stdout = file

	// Let the node keep a reference to this file, such
	// that we can add to it if necessary.
	hn.logFile = file

	if err := hn.cmd.Start(); err != nil {
		return err
	}

	fmt.Printf("Starting node=%v, pid=%v\n", hn.Cfg.Name,
		hn.cmd.Process.Pid)

	// Launch a new goroutine which that bubbles up any potential fatal
	// process errors to the goroutine running the tests.
	hn.processExit = make(chan struct{})
	hn.wg.Add(1)
	go func() {
		defer hn.wg.Done()

		err := hn.cmd.Wait()
		if err != nil {
			litdError <- fmt.Errorf("%v\n%v\n", err, errb.String())
		}

		// Signal any onlookers that this process has exited.
		close(hn.processExit)

		// Make sure log file is closed and renamed if necessary.
		finalizeLogfile()
	}()

	// We may want to skip waiting for the node to come up (eg. the node
	// is waiting to become the leader).
	if !waitForStart {
		return nil
	}

	// Since Stop uses the LightningClient to stop the node, if we fail to
	// get a connected client, we have to kill the process.
	useMacaroons := !hn.Cfg.HasSeed
	conn, err := hn.ConnectRPC(useMacaroons)
	if err != nil {
		_ = hn.cmd.Process.Kill()
		return err
	}

	if err := hn.WaitUntilStarted(conn, lntest.DefaultTimeout); err != nil {
		return err
	}

	// If the node was created with a seed, we will need to perform an
	// additional step to unlock the wallet. The connection returned will
	// only use the TLS certs, and can only perform operations necessary to
	// unlock the daemon.
	if hn.Cfg.HasSeed {
		hn.WalletUnlockerClient = lnrpc.NewWalletUnlockerClient(conn)
		return nil
	}

	err = hn.initLightningClient(conn)
	if err != nil {
		return fmt.Errorf("could not init Lightning Client: %w", err)
	}

	// Also connect to Lit's RPC port for any Litd specific calls.
	litConn, err := connectLitRPC(
		context.Background(), hn.Cfg.LitAddr(), hn.Cfg.LitTLSCertPath,
		hn.Cfg.LitMacPath,
	)
	if err != nil {
		return fmt.Errorf("could not connect to Lit RPC: %w", err)
	}
	hn.litConn = litConn

	ctxt, cancel := context.WithTimeout(
		context.Background(), lntest.DefaultTimeout,
	)
	defer cancel()
	return wait.NoError(func() error {
		litConn := litrpc.NewProxyClient(hn.litConn)

		_, err = litConn.GetInfo(ctxt, &litrpc.GetInfoRequest{})
		return err
	}, lntest.DefaultTimeout)
}

// WaitForLNDWalletReady waits until the wallet state flips from
// "WAITING_TO_START".
func (hn *HarnessNode) WaitForLNDWalletReady() error {
	// First wait for Litd status server to show that LND has started.
	ctx := context.Background()
	rawConn, err := connectLitRPC(
		ctx, hn.Cfg.LitAddr(), hn.Cfg.LitTLSCertPath, "",
	)
	if err != nil {
		return err
	}

	litConn := litrpc.NewStatusClient(rawConn)

	return wait.NoError(func() error {
		states, err := litConn.SubServerStatus(
			ctx, &litrpc.SubServerStatusReq{},
		)
		if err != nil {
			return err
		}

		lndStatus, ok := states.SubServers[subservers.LND]
		if !ok {
			return fmt.Errorf("LND has not yet started")
		}

		if lndStatus.Running {
			return nil
		}

		if lndStatus.CustomStatus != "Wallet Ready" {
			return fmt.Errorf("LND has not yet started")
		}

		return nil
	}, defaultTimeout)
}

// WaitUntilStarted waits until the wallet state flips from "WAITING_TO_START"
// and waits for all LiT's active sub-servers to be ready.
func (hn *HarnessNode) WaitUntilStarted(conn grpc.ClientConnInterface,
	timeout time.Duration) error {

	// First wait for Litd status server to show that LND has started.
	ctx := context.Background()
	rawConn, err := connectLitRPC(
		ctx, hn.Cfg.LitAddr(), hn.Cfg.LitTLSCertPath, "",
	)
	if err != nil {
		return err
	}

	litConn := litrpc.NewStatusClient(rawConn)

	err = wait.NoError(func() error {
		states, err := litConn.SubServerStatus(
			ctx, &litrpc.SubServerStatusReq{},
		)
		if err != nil {
			return err
		}

		lndStatus, ok := states.SubServers[subservers.LND]
		if !ok || !lndStatus.Running {
			return fmt.Errorf("LND has not yet started")
		}

		return nil
	}, timeout)
	if err != nil {
		return err
	}

	err = hn.waitForState(conn, timeout, func(s lnrpc.WalletState) bool {
		return s >= lnrpc.WalletState_SERVER_ACTIVE
	})
	if err != nil {
		return err
	}

	faradayMode, _ := hn.Cfg.ActiveArgs.getArg("faraday-mode")
	loopMode, _ := hn.Cfg.ActiveArgs.getArg("loop-mode")
	poolMode, _ := hn.Cfg.ActiveArgs.getArg("pool-mode")
	tapMode, _ := hn.Cfg.ActiveArgs.getArg("taproot-assets-mode")

	ctxt, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()
	return wait.NoError(func() error {
		states, err := litConn.SubServerStatus(
			ctxt, &litrpc.SubServerStatusReq{},
		)
		if err != nil {
			return err
		}

		if faradayMode != terminal.ModeDisable {
			faraday, ok := states.SubServers[subservers.FARADAY]
			if !ok || !faraday.Running {
				return fmt.Errorf("faraday has not yet started")
			}
		}

		if loopMode != terminal.ModeDisable {
			loop, ok := states.SubServers[subservers.LOOP]
			if !ok || !loop.Running {
				return fmt.Errorf("loop has not yet started")
			}
		}

		if poolMode != terminal.ModeDisable {
			pool, ok := states.SubServers[subservers.POOL]
			if !ok || !pool.Running {
				return fmt.Errorf("pool has not yet started")
			}
		}

		if tapMode != terminal.ModeDisable {
			tap, ok := states.SubServers[subservers.TAP]
			if !ok || !tap.Running {
				return fmt.Errorf("tap has not yet started")
			}
		}

		return nil
	}, timeout)
}

func (hn *HarnessNode) faradayClient() (frdrpc.FaradayServerClient, error) {
	mac, err := hn.ReadMacaroon(
		hn.Cfg.FaradayMacPath, lntest.DefaultTimeout,
	)
	if err != nil {
		return nil, err
	}

	conn, err := hn.ConnectRPCWithMacaroon(mac)
	if err != nil {
		return nil, err
	}

	return frdrpc.NewFaradayServerClient(conn), nil
}

func (hn *HarnessNode) loopClient() (looprpc.SwapClientClient, error) {
	mac, err := hn.ReadMacaroon(hn.Cfg.LoopMacPath, lntest.DefaultTimeout)
	if err != nil {
		return nil, err
	}

	conn, err := hn.ConnectRPCWithMacaroon(mac)
	if err != nil {
		return nil, err
	}

	return looprpc.NewSwapClientClient(conn), nil
}

func (hn *HarnessNode) poolClient() (poolrpc.TraderClient, error) {
	mac, err := hn.ReadMacaroon(hn.Cfg.PoolMacPath, lntest.DefaultTimeout)
	if err != nil {
		return nil, err
	}

	conn, err := hn.ConnectRPCWithMacaroon(mac)
	if err != nil {
		return nil, err
	}

	return poolrpc.NewTraderClient(conn), nil
}

func (hn *HarnessNode) tapClient() (taprpc.TaprootAssetsClient, error) {
	mac, err := hn.ReadMacaroon(hn.Cfg.TapMacPath, lntest.DefaultTimeout)
	if err != nil {
		return nil, err
	}

	conn, err := hn.ConnectRPCWithMacaroon(mac)
	if err != nil {
		return nil, err
	}

	return taprpc.NewTaprootAssetsClient(conn), nil
}

// waitForState waits until the current node state fulfills the given
// predicate.
func (hn *HarnessNode) waitForState(conn grpc.ClientConnInterface,
	timeout time.Duration,
	predicate func(state lnrpc.WalletState) bool) error {

	stateClient := lnrpc.NewStateClient(conn)
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	var (
		stateStream lnrpc.State_SubscribeStateClient
		err         error
	)

	subscribeFunc := func() error {
		stateStream, err = stateClient.SubscribeState(
			ctx, &lnrpc.SubscribeStateRequest{},
		)

		return err
	}
	err = wait.NoError(subscribeFunc, lntest.DefaultTimeout)
	if err != nil {
		return err
	}

	errChan := make(chan error, 1)
	started := make(chan struct{})
	go func() {
		for {
			resp, err := stateStream.Recv()
			if err != nil {
				errChan <- err
				return
			}

			if predicate(resp.State) {
				close(started)
				return
			}
		}
	}()

	select {
	case <-started:
	case err = <-errChan:

	case <-time.After(timeout):
		return fmt.Errorf("WaitUntilLeader timed out")
	}

	return err
}

// initClientWhenReady waits until the main gRPC server is detected as active,
// then complete the normal HarnessNode gRPC connection creation. This can be
// used it a node has just been unlocked, or has its wallet state initialized.
func (hn *HarnessNode) initClientWhenReady(timeout time.Duration) error {
	var (
		conn    *grpc.ClientConn
		connErr error
	)
	if err := wait.NoError(func() error {
		conn, connErr = hn.ConnectRPC(true)
		return connErr
	}, timeout); err != nil {
		return err
	}

	return hn.initLightningClient(conn)
}

// Init initializes a harness node by passing the init request via rpc. After
// the request is submitted, this method will block until a
// macaroon-authenticated RPC connection can be established to the harness node.
// Once established, the new connection is used to initialize the
// LightningClient and subscribes the HarnessNode to topology changes.
func (hn *HarnessNode) Init(ctx context.Context,
	initReq *lnrpc.InitWalletRequest) (*lnrpc.InitWalletResponse, error) {

	ctxt, cancel := context.WithTimeout(ctx, lntest.DefaultTimeout)
	defer cancel()
	response, err := hn.InitWallet(ctxt, initReq)
	if err != nil {
		return nil, err
	}

	// Wait for the wallet to finish unlocking, such that we can connect to
	// it via a macaroon-authenticated rpc connection.
	var conn *grpc.ClientConn
	if err = wait.Predicate(func() bool {
		// If the node has been initialized stateless, we need to pass
		// the macaroon to the client.
		if initReq.StatelessInit {
			adminMac := &macaroon.Macaroon{}
			err := adminMac.UnmarshalBinary(response.AdminMacaroon)
			if err != nil {
				return false
			}
			conn, err = hn.ConnectRPCWithMacaroon(adminMac)
			return err == nil
		}

		// Normal initialization, we expect a macaroon to be in the
		// file system.
		conn, err = hn.ConnectRPC(true)
		return err == nil
	}, lntest.DefaultTimeout); err != nil {
		return nil, err
	}

	return response, hn.initLightningClient(conn)
}

// InitChangePassword initializes a harness node by passing the change password
// request via RPC. After the request is submitted, this method will block until
// a macaroon-authenticated RPC connection can be established to the harness
// node. Once established, the new connection is used to initialize the
// LightningClient and subscribes the HarnessNode to topology changes.
func (hn *HarnessNode) InitChangePassword(ctx context.Context,
	chngPwReq *lnrpc.ChangePasswordRequest) (*lnrpc.ChangePasswordResponse,
	error) {

	ctxt, cancel := context.WithTimeout(ctx, lntest.DefaultTimeout)
	defer cancel()
	response, err := hn.ChangePassword(ctxt, chngPwReq)
	if err != nil {
		return nil, err
	}

	// Wait for the wallet to finish unlocking, such that we can connect to
	// it via a macaroon-authenticated rpc connection.
	var conn *grpc.ClientConn
	if err = wait.Predicate(func() bool {
		// If the node has been initialized stateless, we need to pass
		// the macaroon to the client.
		if chngPwReq.StatelessInit {
			adminMac := &macaroon.Macaroon{}
			err := adminMac.UnmarshalBinary(response.AdminMacaroon)
			if err != nil {
				return false
			}
			conn, err = hn.ConnectRPCWithMacaroon(adminMac)
			return err == nil
		}

		// Normal initialization, we expect a macaroon to be in the
		// file system.
		conn, err = hn.ConnectRPC(true)
		return err == nil
	}, lntest.DefaultTimeout); err != nil {
		return nil, err
	}

	return response, hn.initLightningClient(conn)
}

// Unlock attempts to unlock the wallet of the target HarnessNode. This method
// should be called after the restart of a HarnessNode that was created with a
// seed+password. Once this method returns, the HarnessNode will be ready to
// accept normal gRPC requests and harness command.
func (hn *HarnessNode) Unlock(ctx context.Context,
	unlockReq *lnrpc.UnlockWalletRequest) error {

	ctxt, cancel := context.WithTimeout(ctx, lntest.DefaultTimeout)
	defer cancel()

	// Otherwise, we'll need to unlock the node before it's able to start
	// up properly.
	if _, err := hn.UnlockWallet(ctxt, unlockReq); err != nil {
		return err
	}

	// Now that the wallet has been unlocked, we'll wait for the RPC client
	// to be ready, then establish the normal gRPC connection.
	return hn.initClientWhenReady(lntest.DefaultTimeout)
}

// waitTillServerStarted makes a subscription to the server's state change and
// blocks until the server is in state ServerActive.
func (hn *HarnessNode) waitTillServerStarted() error {
	ctxb := context.Background()
	ctxt, cancel := context.WithTimeout(ctxb, wait.NodeStartTimeout)
	defer cancel()

	client, err := hn.StateClient.SubscribeState(
		ctxt, &lnrpc.SubscribeStateRequest{},
	)
	if err != nil {
		return fmt.Errorf("failed to subscribe to state: %w", err)
	}

	for {
		resp, err := client.Recv()
		if err != nil {
			return fmt.Errorf("failed to receive state "+
				"client stream: %w", err)
		}

		if resp.State == lnrpc.WalletState_SERVER_ACTIVE {
			return nil
		}
	}
}

// initLightningClient constructs the grpc LightningClient from the given client
// connection and subscribes the harness node to graph topology updates.
// This method also spawns a lightning network watcher for this node,
// which watches for topology changes.
func (hn *HarnessNode) initLightningClient(conn *grpc.ClientConn) error {
	// Construct the LightningClient that will allow us to use the
	// HarnessNode directly for normal rpc operations.
	hn.conn = conn
	hn.LightningClient = lnrpc.NewLightningClient(conn)
	hn.InvoicesClient = invoicesrpc.NewInvoicesClient(conn)
	hn.RouterClient = routerrpc.NewRouterClient(conn)
	hn.WalletKitClient = walletrpc.NewWalletKitClient(conn)
	hn.Watchtower = watchtowerrpc.NewWatchtowerClient(conn)
	hn.WatchtowerClient = wtclientrpc.NewWatchtowerClientClient(conn)
	hn.SignerClient = signrpc.NewSignerClient(conn)
	hn.StateClient = lnrpc.NewStateClient(conn)

	// Wait until the server is fully started.
	if err := hn.waitTillServerStarted(); err != nil {
		return err
	}

	// Set the harness node's pubkey to what the node claims in GetInfo.
	// Since the RPC might not be immediately active, we wrap the call in a
	// wait.NoError.
	err := wait.NoError(
		hn.FetchNodeInfo, lntest.DefaultTimeout,
	)
	if err != nil {
		return err
	}

	// Launch the watcher that will hook into graph related topology change
	// from the PoV of this node.
	hn.wg.Add(1)
	go hn.lightningNetworkWatcher()

	return nil
}

// FetchNodeInfo queries an unlocked node to retrieve its public key.
func (hn *HarnessNode) FetchNodeInfo() error {
	// Obtain the lnid of this node for quick identification purposes.
	ctxb := context.Background()
	info, err := hn.GetInfo(ctxb, &lnrpc.GetInfoRequest{})
	if err != nil {
		return err
	}

	hn.PubKeyStr = info.IdentityPubkey

	pubkey, err := hex.DecodeString(info.IdentityPubkey)
	if err != nil {
		return err
	}
	copy(hn.PubKey[:], pubkey)

	return nil
}

// AddToLog adds a line of choice to the node's logfile. This is useful
// to interleave test output with output from the node.
func (hn *HarnessNode) AddToLog(format string, a ...interface{}) {
	// If this node was not set up with a log file, just return early.
	if hn.logFile == nil {
		return
	}

	desc := fmt.Sprintf("itest: %s\n", fmt.Sprintf(format, a...))
	if _, err := hn.logFile.WriteString(desc); err != nil {
		hn.PrintErr("write to log err: %v", err)
	}
}

// ReadMacaroon waits a given duration for the macaroon file to be created. If
// the file is readable within the timeout, its content is de-serialized as a
// macaroon and returned.
func (hn *HarnessNode) ReadMacaroon(macPath string, timeout time.Duration) (
	*macaroon.Macaroon, error) {

	// Wait until macaroon file is created and has valid content before
	// using it.
	var mac *macaroon.Macaroon
	err := wait.NoError(func() error {
		macBytes, err := ioutil.ReadFile(macPath)
		if err != nil {
			return fmt.Errorf("error reading macaroon file: %v",
				err)
		}

		newMac := &macaroon.Macaroon{}
		if err = newMac.UnmarshalBinary(macBytes); err != nil {
			return fmt.Errorf("error unmarshalling macaroon "+
				"file: %v", err)
		}
		mac = newMac

		return nil
	}, timeout)

	return mac, err
}

// ConnectRPCWithMacaroon uses the TLS certificate and given macaroon to
// create a gRPC client connection.
func (hn *HarnessNode) ConnectRPCWithMacaroon(mac *macaroon.Macaroon) (
	*grpc.ClientConn, error) {

	var (
		certPath    = hn.Cfg.TLSCertPath
		connectAddr = hn.Cfg.RPCAddr()
	)
	if hn.Cfg.RemoteMode {
		certPath = hn.Cfg.LitTLSCertPath
		connectAddr = hn.Cfg.LitAddr()
	}

	// Wait until TLS certificate is created and has valid content before
	// using it, up to 30 sec.
	var tlsCreds credentials.TransportCredentials
	err := wait.NoError(func() error {
		var err error
		tlsCreds, err = credentials.NewClientTLSFromFile(certPath, "")
		return err
	}, lntest.DefaultTimeout)
	if err != nil {
		return nil, fmt.Errorf("error reading TLS cert: %v", err)
	}

	opts := []grpc.DialOption{
		grpc.WithBlock(),
		grpc.WithTransportCredentials(tlsCreds),
	}

	ctx, cancel := context.WithTimeout(
		context.Background(), lntest.DefaultTimeout,
	)
	defer cancel()

	if mac == nil {
		return grpc.DialContext(ctx, connectAddr, opts...)
	}
	macCred, err := macaroons.NewMacaroonCredential(mac)
	if err != nil {
		return nil, fmt.Errorf("error cloning mac: %v", err)
	}
	opts = append(opts, grpc.WithPerRPCCredentials(macCred))

	return grpc.DialContext(ctx, connectAddr, opts...)
}

// ConnectRPC uses the TLS certificate and admin macaroon files written by the
// lnd node to create a gRPC client connection.
func (hn *HarnessNode) ConnectRPC(useMacs bool) (*grpc.ClientConn, error) {
	// If we don't want to use macaroons, just pass nil, the next method
	// will handle it correctly.
	if !useMacs {
		return hn.ConnectRPCWithMacaroon(nil)
	}

	// If we should use a macaroon, always take the admin macaroon as a
	// default.
	mac, err := hn.ReadMacaroon(hn.Cfg.AdminMacPath, lntest.DefaultTimeout)
	if err != nil {
		return nil, err
	}
	return hn.ConnectRPCWithMacaroon(mac)
}

// SetExtraArgs assigns the ExtraArgs field for the node's configuration. The
// changes will take effect on restart.
func (hn *HarnessNode) SetExtraArgs(extraArgs []string) {
	hn.Cfg.ExtraArgs = extraArgs
}

// cleanup cleans up all the temporary files created by the node's process.
func (hn *HarnessNode) cleanup() error {
	if hn.Cfg.RemoteMode {
		err := hn.RemoteLnd.Shutdown()
		if err != nil {
			return fmt.Errorf("unable to shutdown remote lnd "+
				"dir: %v", err)
		}
	}

	if hn.backupDbDir != "" {
		err := os.RemoveAll(hn.backupDbDir)
		if err != nil {
			return fmt.Errorf("unable to remove backup dir: %v",
				err)
		}
	}

	return os.RemoveAll(hn.Cfg.BaseDir)
}

// Stop attempts to Stop the active litd process.
func (hn *HarnessNode) Stop() error {
	// Do nothing if the process is not running.
	if hn.processExit == nil {
		return nil
	}

	// If start() failed before creating a client, we will just wait for the
	// child process to die.
	if !hn.Cfg.RemoteMode && hn.LightningClient != nil {
		// Don't watch for error because sometimes the RPC connection
		// gets closed before a response is returned.
		req := lnrpc.StopRequest{}
		ctx := context.Background()

		err := wait.NoError(func() error {
			_, err := hn.LightningClient.StopDaemon(ctx, &req)
			switch {
			case err == nil:
				return nil

			// Try again if a recovery/rescan is in progress.
			case strings.Contains(
				err.Error(), "recovery in progress",
			):
				return err

			default:
				return nil
			}
		}, lntest.DefaultTimeout)
		if err != nil {
			return err
		}
	} else if hn.Cfg.RemoteMode {
		// If lit is running in remote mode, then calling LNDs
		// StopDaemon method will not shut down Lit, and so we need to
		// explicitly request lit to shut down.
		ctx, cancel := context.WithTimeout(
			context.Background(), lntest.DefaultTimeout,
		)
		litConn := litrpc.NewProxyClient(hn.litConn)
		_, err := litConn.StopDaemon(ctx, &litrpc.StopDaemonRequest{})
		cancel()
		if err != nil {
			return err
		}
	}

	// Wait for litd process and other goroutines to exit.
	select {
	case <-hn.processExit:
	case <-time.After(lntest.DefaultTimeout * 2):
		return fmt.Errorf("process did not exit")
	}

	close(hn.quit)
	hn.wg.Wait()

	hn.quit = nil
	hn.processExit = nil
	hn.LightningClient = nil
	hn.WalletUnlockerClient = nil
	hn.Watchtower = nil
	hn.WatchtowerClient = nil

	// Close any attempts at further grpc connections.
	if hn.conn != nil {
		err := hn.conn.Close()
		isConnClosingErr := strings.Contains(
			err.Error(), "connection is closing",
		)
		if err != nil && !isConnClosingErr {
			return fmt.Errorf("error attempting to stop grpc "+
				"client: %v", err)
		}
	}

	return nil
}

// shutdown stops the active lnd process and cleans up any temporary directories
// created along the way.
func (hn *HarnessNode) shutdown() error {
	if err := hn.Stop(); err != nil {
		return err
	}
	if err := hn.cleanup(); err != nil {
		return err
	}
	return nil
}

// kill kills the lnd process
func (hn *HarnessNode) kill() error {
	return hn.cmd.Process.Kill()
}

type chanWatchType uint8

const (
	// watchOpenChannel specifies that this is a request to watch an open
	// channel event.
	watchOpenChannel chanWatchType = iota

	// watchCloseChannel specifies that this is a request to watch a close
	// channel event.
	watchCloseChannel

	// watchPolicyUpdate specifies that this is a request to watch a policy
	// update event.
	watchPolicyUpdate
)

// closeChanWatchRequest is a request to the lightningNetworkWatcher to be
// notified once it's detected within the test Lightning Network, that a
// channel has either been added or closed.
type chanWatchRequest struct {
	chanPoint wire.OutPoint

	chanWatchType chanWatchType

	eventChan chan struct{}

	advertisingNode    string
	policy             *lnrpc.RoutingPolicy
	includeUnannounced bool
}

// getChanPointFundingTxid returns the given channel point's funding txid in
// raw bytes.
func getChanPointFundingTxid(chanPoint *lnrpc.ChannelPoint) ([]byte, error) {
	var txid []byte

	// A channel point's funding txid can be get/set as a byte slice or a
	// string. In the case it is a string, decode it.
	switch chanPoint.GetFundingTxid().(type) {
	case *lnrpc.ChannelPoint_FundingTxidBytes:
		txid = chanPoint.GetFundingTxidBytes()
	case *lnrpc.ChannelPoint_FundingTxidStr:
		s := chanPoint.GetFundingTxidStr()
		h, err := chainhash.NewHashFromStr(s)
		if err != nil {
			return nil, err
		}

		txid = h[:]
	}

	return txid, nil
}

func checkChanPointInGraph(ctx context.Context,
	node *HarnessNode, chanPoint wire.OutPoint) bool {

	ctxt, cancel := context.WithTimeout(ctx, lntest.DefaultTimeout)
	defer cancel()
	chanGraph, err := node.DescribeGraph(ctxt, &lnrpc.ChannelGraphRequest{})
	if err != nil {
		return false
	}

	targetChanPoint := chanPoint.String()
	for _, chanEdge := range chanGraph.Edges {
		candidateChanPoint := chanEdge.ChanPoint
		if targetChanPoint == candidateChanPoint {
			return true
		}
	}

	return false
}

// lightningNetworkWatcher is a goroutine which is able to dispatch
// notifications once it has been observed that a target channel has been
// closed or opened within the network. In order to dispatch these
// notifications, the GraphTopologySubscription client exposed as part of the
// gRPC interface is used.
func (hn *HarnessNode) lightningNetworkWatcher() {
	defer hn.wg.Done()

	graphUpdates := make(chan *lnrpc.GraphTopologyUpdate)

	// Start a goroutine to receive graph updates.
	hn.wg.Add(1)
	go func() {
		defer hn.wg.Done()
		err := hn.receiveTopologyClientStream(graphUpdates)
		if err != nil {
			hn.PrintErr("receive topology client stream "+
				"got err:%v", err)
		}
	}()

	for {
		select {
		// A new graph update has just been received, so we'll examine
		// the current set of registered clients to see if we can
		// dispatch any requests.
		case graphUpdate := <-graphUpdates:
			hn.handleChannelEdgeUpdates(graphUpdate.ChannelUpdates)
			hn.handleClosedChannelUpdate(graphUpdate.ClosedChans)
			// TODO(yy): handle node updates too

		// A new watch request, has just arrived. We'll either be able
		// to dispatch immediately, or need to add the client for
		// processing later.
		case watchRequest := <-hn.chanWatchRequests:
			switch watchRequest.chanWatchType {
			case watchOpenChannel:
				// TODO(roasbeef): add update type also, checks
				// for multiple of 2
				hn.handleOpenChannelWatchRequest(watchRequest)

			case watchCloseChannel:
				hn.handleCloseChannelWatchRequest(watchRequest)

			case watchPolicyUpdate:
				hn.handlePolicyUpdateWatchRequest(watchRequest)
			}

		case <-hn.quit:
			return
		}
	}
}

// WaitForNetworkChannelOpen will block until a channel with the target
// outpoint is seen as being fully advertised within the network. A channel is
// considered "fully advertised" once both of its directional edges has been
// advertised within the test Lightning Network.
func (hn *HarnessNode) WaitForNetworkChannelOpen(ctx context.Context,
	chanPoint *lnrpc.ChannelPoint) error {

	eventChan := make(chan struct{})

	op, err := MakeOutpoint(chanPoint)
	if err != nil {
		return fmt.Errorf("failed to create outpoint for %v "+
			"got err: %v", chanPoint, err)
	}

	hn.chanWatchRequests <- &chanWatchRequest{
		chanPoint:     op,
		eventChan:     eventChan,
		chanWatchType: watchOpenChannel,
	}

	select {
	case <-eventChan:
		return nil
	case <-ctx.Done():
		return fmt.Errorf("channel:%s not opened before timeout: %s",
			op, hn)
	}
}

// WaitForNetworkChannelClose will block until a channel with the target
// outpoint is seen as closed within the network. A channel is considered
// closed once a transaction spending the funding outpoint is seen within a
// confirmed block.
func (hn *HarnessNode) WaitForNetworkChannelClose(ctx context.Context,
	chanPoint *lnrpc.ChannelPoint) error {

	eventChan := make(chan struct{})

	op, err := MakeOutpoint(chanPoint)
	if err != nil {
		return fmt.Errorf("failed to create outpoint for %v "+
			"got err: %v", chanPoint, err)
	}

	hn.chanWatchRequests <- &chanWatchRequest{
		chanPoint:     op,
		eventChan:     eventChan,
		chanWatchType: watchCloseChannel,
	}

	select {
	case <-eventChan:
		return nil
	case <-ctx.Done():
		return fmt.Errorf("channel:%s not closed before timeout: "+
			"%s", op, hn)
	}
}

// WaitForChannelPolicyUpdate will block until a channel policy with the target
// outpoint and advertisingNode is seen within the network.
func (hn *HarnessNode) WaitForChannelPolicyUpdate(ctx context.Context,
	advertisingNode string, policy *lnrpc.RoutingPolicy,
	chanPoint *lnrpc.ChannelPoint, includeUnannounced bool) error {

	eventChan := make(chan struct{})

	op, err := MakeOutpoint(chanPoint)
	if err != nil {
		return fmt.Errorf("failed to create outpoint for %v"+
			"got err: %v", chanPoint, err)
	}

	ticker := time.NewTicker(wait.PollInterval)
	defer ticker.Stop()

	for {
		select {
		// Send a watch request every second.
		case <-ticker.C:
			// Did the event can close in the meantime? We want to
			// avoid a "close of closed channel" panic since we're
			// re-using the same event chan for multiple requests.
			select {
			case <-eventChan:
				return nil
			default:
			}

			hn.chanWatchRequests <- &chanWatchRequest{
				chanPoint:          op,
				eventChan:          eventChan,
				chanWatchType:      watchPolicyUpdate,
				policy:             policy,
				advertisingNode:    advertisingNode,
				includeUnannounced: includeUnannounced,
			}

		case <-eventChan:
			return nil

		case <-ctx.Done():
			return fmt.Errorf("channel:%s policy not updated "+
				"before timeout: [%s:%v] %s", op,
				advertisingNode, policy, hn.String())
		}
	}
}

// WaitForBlockchainSync waits for the target node to be fully synchronized with
// the blockchain. If the passed context object has a set timeout, it will
// continually poll until the timeout has elapsed. In the case that the chain
// isn't synced before the timeout is up, this function will return an error.
func (hn *HarnessNode) WaitForBlockchainSync(ctx context.Context) error {
	ticker := time.NewTicker(time.Millisecond * 100)
	defer ticker.Stop()

	for {
		resp, err := hn.GetInfo(ctx, &lnrpc.GetInfoRequest{})
		if err != nil {
			return err
		}
		if resp.SyncedToChain {
			return nil
		}

		select {
		case <-ctx.Done():
			return fmt.Errorf("timeout while waiting for " +
				"blockchain sync")
		case <-hn.quit:
			return nil
		case <-ticker.C:
		}
	}
}

// WaitForBalance waits until the node sees the expected confirmed/unconfirmed
// balance within their wallet.
func (hn *HarnessNode) WaitForBalance(expectedBalance btcutil.Amount,
	confirmed bool) error {

	ctx := context.Background()
	req := &lnrpc.WalletBalanceRequest{}

	var lastBalance btcutil.Amount
	doesBalanceMatch := func() bool {
		balance, err := hn.WalletBalance(ctx, req)
		if err != nil {
			return false
		}

		if confirmed {
			balanceAmt := btcutil.Amount(
				balance.ConfirmedBalance,
			)
			lastBalance = balanceAmt
			return balanceAmt == expectedBalance
		}

		balanceAmt := btcutil.Amount(balance.UnconfirmedBalance)
		lastBalance = balanceAmt
		return balanceAmt == expectedBalance
	}

	err := wait.Predicate(doesBalanceMatch, lntest.DefaultTimeout)
	if err != nil {
		return fmt.Errorf("balances not synced after deadline: "+
			"expected %v, only have %v", expectedBalance,
			lastBalance)
	}

	return nil
}

// PrintErr prints an error to the console.
func (hn *HarnessNode) PrintErr(format string, a ...interface{}) {
	fmt.Printf("itest error from [node:%s]: %s\n",
		hn.Cfg.Name, fmt.Sprintf(format, a...))
}

// MakeOutpoint returns the outpoint of the channel's funding transaction.
func MakeOutpoint(chanPoint *lnrpc.ChannelPoint) (wire.OutPoint, error) {
	fundingTxID, err := lnrpc.GetChanPointFundingTxid(chanPoint)
	if err != nil {
		return wire.OutPoint{}, err
	}

	return wire.OutPoint{
		Hash:  *fundingTxID,
		Index: chanPoint.OutputIndex,
	}, nil
}

// handleChannelEdgeUpdates takes a series of channel edge updates, extracts
// the outpoints, and saves them to harness node's internal state.
func (hn *HarnessNode) handleChannelEdgeUpdates(
	updates []*lnrpc.ChannelEdgeUpdate) {

	// For each new channel, we'll increment the number of
	// edges seen by one.
	for _, newChan := range updates {
		op, err := MakeOutpoint(newChan.ChanPoint)
		if err != nil {
			hn.PrintErr("failed to create outpoint for %v "+
				"got err: %v", newChan.ChanPoint, err)
			return
		}
		hn.openChans[op]++

		// For this new channel, if the number of edges seen is less
		// than two, then the channel hasn't been fully announced yet.
		if numEdges := hn.openChans[op]; numEdges < 2 {
			return
		}

		// Otherwise, we'll notify all the registered watchers and
		// remove the dispatched watchers.
		for _, eventChan := range hn.openChanWatchers[op] {
			close(eventChan)
		}
		delete(hn.openChanWatchers, op)

		// Check whether there's a routing policy update. If so, save
		// it to the node state.
		if newChan.RoutingPolicy == nil {
			continue
		}

		// Append the policy to the slice.
		node := newChan.AdvertisingNode
		policies := hn.policyUpdates[op.String()]

		// If the map[op] is nil, we need to initialize the map first.
		if policies == nil {
			policies = make(map[string][]*lnrpc.RoutingPolicy)
		}
		policies[node] = append(
			policies[node], newChan.RoutingPolicy,
		)
		hn.policyUpdates[op.String()] = policies
	}
}

// handleOpenChannelWatchRequest processes a watch open channel request by
// checking the number of the edges seen for a given channel point. If the
// number is no less than 2 then the channel is considered open. Otherwise, we
// will attempt to find it in its channel graph. If neither can be found, the
// request is added to a watch request list than will be handled by
// handleChannelEdgeUpdates.
func (hn *HarnessNode) handleOpenChannelWatchRequest(req *chanWatchRequest) {
	targetChan := req.chanPoint

	// If this is an open request, then it can be dispatched if the number
	// of edges seen for the channel is at least two.
	if numEdges := hn.openChans[targetChan]; numEdges >= 2 {
		close(req.eventChan)
		return
	}

	// Before we add the channel to our set of open clients, we'll check to
	// see if the channel is already in the channel graph of the target
	// node. This lets us handle the case where a node has already seen a
	// channel before a notification has been requested, causing us to miss
	// it.
	chanFound := checkChanPointInGraph(context.Background(), hn, targetChan)
	if chanFound {
		close(req.eventChan)
		return
	}

	// Otherwise, we'll add this to the list of open channel watchers for
	// this out point.
	hn.openChanWatchers[targetChan] = append(
		hn.openChanWatchers[targetChan],
		req.eventChan,
	)
}

// handleClosedChannelUpdate takes a series of closed channel updates, extracts
// the outpoints, saves them to harness node's internal state, and notifies all
// registered clients.
func (hn *HarnessNode) handleClosedChannelUpdate(
	updates []*lnrpc.ClosedChannelUpdate) {

	// For each channel closed, we'll mark that we've detected a channel
	// closure while lnd was pruning the channel graph.
	for _, closedChan := range updates {
		op, err := MakeOutpoint(closedChan.ChanPoint)
		if err != nil {
			hn.PrintErr("failed to create outpoint for %v "+
				"got err: %v", closedChan.ChanPoint, err)
			return
		}

		hn.closedChans[op] = struct{}{}

		// As the channel has been closed, we'll notify all register
		// watchers.
		for _, eventChan := range hn.closeChanWatchers[op] {
			close(eventChan)
		}
		delete(hn.closeChanWatchers, op)
	}
}

// handleCloseChannelWatchRequest processes a watch close channel request by
// checking whether the given channel point can be found in the node's internal
// state. If not, the request is added to a watch request list than will be
// handled by handleCloseChannelWatchRequest.
func (hn *HarnessNode) handleCloseChannelWatchRequest(req *chanWatchRequest) {
	targetChan := req.chanPoint

	// If this is a close request, then it can be immediately dispatched if
	// we've already seen a channel closure for this channel.
	if _, ok := hn.closedChans[targetChan]; ok {
		close(req.eventChan)
		return
	}

	// Otherwise, we'll add this to the list of close channel watchers for
	// this out point.
	hn.closeChanWatchers[targetChan] = append(
		hn.closeChanWatchers[targetChan],
		req.eventChan,
	)
}

type topologyClient lnrpc.Lightning_SubscribeChannelGraphClient

// newTopologyClient creates a topology client.
func (hn *HarnessNode) newTopologyClient(
	ctx context.Context) (topologyClient, error) {

	req := &lnrpc.GraphTopologySubscription{}
	client, err := hn.SubscribeChannelGraph(ctx, req)
	if err != nil {
		return nil, fmt.Errorf("%s(%d): unable to create topology "+
			"client: %v (%s)", hn.Name(), hn.NodeID, err,
			time.Now().String())
	}

	return client, nil
}

// receiveTopologyClientStream initializes a topologyClient to subscribe
// topology update events. Due to a race condition between the ChannelRouter
// starting and us making the subscription request, it's possible for our graph
// subscription to fail. In that case, we will retry the subscription until it
// succeeds or fail after 10 seconds.
//
// NOTE: must be run as a goroutine.
func (hn *HarnessNode) receiveTopologyClientStream(
	receiver chan *lnrpc.GraphTopologyUpdate) error {

	ctxb := context.Background()

	// Create a topology client to receive graph updates.
	client, err := hn.newTopologyClient(ctxb)
	if err != nil {
		return fmt.Errorf("create topologyClient failed: %v", err)
	}

	// We use the context to time out when retrying graph subscription.
	ctxt, cancel := context.WithTimeout(ctxb, lntest.DefaultTimeout)
	defer cancel()

	for {
		update, err := client.Recv()

		switch {
		case err == nil:
			// Good case. We will send the update to the receiver.

		case strings.Contains(err.Error(), "router not started"):
			// If the router hasn't been started, we will retry
			// every 200 ms until it has been started or fail
			// after the ctxt is timed out.
			select {
			case <-ctxt.Done():
				return fmt.Errorf("graph subscription: " +
					"router not started before timeout")
			case <-time.After(wait.PollInterval):
			case <-hn.quit:
				return nil
			}

			// Re-create the topology client.
			client, err = hn.newTopologyClient(ctxb)
			if err != nil {
				return fmt.Errorf("create topologyClient "+
					"failed: %v", err)
			}

			continue

		case strings.Contains(err.Error(), "EOF"):
			// End of subscription stream. Do nothing and quit.
			return nil

		default:
			// An expected error is returned, return and leave it
			// to be handled by the caller.
			return fmt.Errorf("graph subscription err: %v", err)
		}

		// Send the update or quit.
		select {
		case receiver <- update:
		case <-hn.quit:
			return nil
		}
	}
}

// CheckChannelPolicy checks that the policy matches the expected one.
func CheckChannelPolicy(policy, expectedPolicy *lnrpc.RoutingPolicy) error {
	if policy.FeeBaseMsat != expectedPolicy.FeeBaseMsat {
		return fmt.Errorf("expected base fee %v, got %v",
			expectedPolicy.FeeBaseMsat, policy.FeeBaseMsat)
	}
	if policy.FeeRateMilliMsat != expectedPolicy.FeeRateMilliMsat {
		return fmt.Errorf("expected fee rate %v, got %v",
			expectedPolicy.FeeRateMilliMsat,
			policy.FeeRateMilliMsat)
	}
	if policy.TimeLockDelta != expectedPolicy.TimeLockDelta {
		return fmt.Errorf("expected time lock delta %v, got %v",
			expectedPolicy.TimeLockDelta,
			policy.TimeLockDelta)
	}
	if policy.MinHtlc != expectedPolicy.MinHtlc {
		return fmt.Errorf("expected min htlc %v, got %v",
			expectedPolicy.MinHtlc, policy.MinHtlc)
	}
	if policy.MaxHtlcMsat != expectedPolicy.MaxHtlcMsat {
		return fmt.Errorf("expected max htlc %v, got %v",
			expectedPolicy.MaxHtlcMsat, policy.MaxHtlcMsat)
	}
	if policy.Disabled != expectedPolicy.Disabled {
		return errors.New("edge should be disabled but isn't")
	}

	return nil
}

// handlePolicyUpdateWatchRequest checks that if the expected policy can be
// found either in the node's interval state or describe graph response. If
// found, it will signal the request by closing the event channel. Otherwise it
// does nothing but returns nil.
func (hn *HarnessNode) handlePolicyUpdateWatchRequest(req *chanWatchRequest) {
	op := req.chanPoint

	// Get a list of known policies for this chanPoint+advertisingNode
	// combination. Start searching in the node state first.
	policies, ok := hn.policyUpdates[op.String()][req.advertisingNode]

	if !ok {
		// If it cannot be found in the node state, try searching it
		// from the node's DescribeGraph.
		policyMap := hn.getChannelPolicies(req.includeUnannounced)
		policies, ok = policyMap[op.String()][req.advertisingNode]
		if !ok {
			return
		}
	}

	// Check if there's a matched policy.
	for _, policy := range policies {
		if CheckChannelPolicy(policy, req.policy) == nil {
			close(req.eventChan)
			return
		}
	}
}

// getChannelPolicies queries the channel graph and formats the policies into
// the format defined in type policyUpdateMap.
func (hn *HarnessNode) getChannelPolicies(include bool) policyUpdateMap {
	ctxt, cancel := context.WithTimeout(
		context.Background(), lntest.DefaultTimeout,
	)
	defer cancel()

	graph, err := hn.DescribeGraph(ctxt, &lnrpc.ChannelGraphRequest{
		IncludeUnannounced: include,
	})
	if err != nil {
		hn.PrintErr("DescribeGraph got err: %v", err)
		return nil
	}

	policyUpdates := policyUpdateMap{}

	for _, e := range graph.Edges {
		policies := policyUpdates[e.ChanPoint]

		// If the map[op] is nil, we need to initialize the map first.
		if policies == nil {
			policies = make(map[string][]*lnrpc.RoutingPolicy)
		}

		if e.Node1Policy != nil {
			policies[e.Node1Pub] = append(
				policies[e.Node1Pub], e.Node1Policy,
			)
		}

		if e.Node2Policy != nil {
			policies[e.Node2Pub] = append(
				policies[e.Node2Pub], e.Node2Policy,
			)
		}

		policyUpdates[e.ChanPoint] = policies
	}

	return policyUpdates
}

// connectLitRPC can be used to connect to the lit rpc server.
func connectLitRPC(ctx context.Context, hostPort, tlsCertPath,
	macPath string) (*grpc.ClientConn, error) {

	tlsCreds, err := credentials.NewClientTLSFromFile(tlsCertPath, "")
	if err != nil {
		return nil, err
	}

	opts := []grpc.DialOption{
		grpc.WithBlock(),
		grpc.WithTransportCredentials(tlsCreds),
	}

	if macPath != "" {
		macBytes, err := ioutil.ReadFile(macPath)
		if err != nil {
			return nil, err
		}

		mac := &macaroon.Macaroon{}
		if err = mac.UnmarshalBinary(macBytes); err != nil {
			return nil, fmt.Errorf("error unmarshalling macaroon "+
				"file: %v", err)
		}

		macCred, err := macaroons.NewMacaroonCredential(mac)
		if err != nil {
			return nil, fmt.Errorf("error cloning mac: %v", err)
		}

		opts = append(opts, grpc.WithPerRPCCredentials(macCred))
	}

	return grpc.DialContext(ctx, hostPort, opts...)
}

// copyAll copies all files and directories from srcDir to dstDir recursively.
// Note that this function does not support links.
func copyAll(dstDir, srcDir string) error {
	entries, err := os.ReadDir(srcDir)
	if err != nil {
		return err
	}

	for _, entry := range entries {
		srcPath := filepath.Join(srcDir, entry.Name())
		dstPath := filepath.Join(dstDir, entry.Name())

		info, err := os.Stat(srcPath)
		if err != nil {
			return err
		}

		if info.IsDir() {
			err := os.Mkdir(dstPath, info.Mode())
			if err != nil && !os.IsExist(err) {
				return err
			}

			err = copyAll(dstPath, srcPath)
			if err != nil {
				return err
			}
		} else if err := CopyFile(dstPath, srcPath); err != nil {
			return err
		}
	}

	return nil
}