12235114561

Committed 09 Dec 2024 11:56AM UTC coverage: 49.773% (-9.0%) from 58.805%

Build # 12235114561

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push

github

Committed by

web-flow

Commit Message

Merge pull request #9330 from ProofOfKeags/update/fn2

multi: update to fn v2

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66.08

/lnrpc/walletrpc/walletkit_server.go

//go:build walletrpc
// +build walletrpc

package walletrpc

import (
        "bytes"
        "context"
        "encoding/base64"
        "encoding/binary"
        "errors"
        "fmt"
        "math"
        "os"
        "path/filepath"
        "sort"
        "time"

        "github.com/btcsuite/btcd/btcec/v2"
        "github.com/btcsuite/btcd/btcec/v2/ecdsa"
        "github.com/btcsuite/btcd/btcec/v2/schnorr"
        "github.com/btcsuite/btcd/btcutil"
        "github.com/btcsuite/btcd/btcutil/hdkeychain"
        "github.com/btcsuite/btcd/btcutil/psbt"
        "github.com/btcsuite/btcd/chaincfg/chainhash"
        "github.com/btcsuite/btcd/txscript"
        "github.com/btcsuite/btcd/wire"
        "github.com/btcsuite/btcwallet/waddrmgr"
        base "github.com/btcsuite/btcwallet/wallet"
        "github.com/btcsuite/btcwallet/wtxmgr"
        "github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
        "github.com/lightningnetwork/lnd/channeldb"
        "github.com/lightningnetwork/lnd/contractcourt"
        "github.com/lightningnetwork/lnd/fn/v2"
        "github.com/lightningnetwork/lnd/input"
        "github.com/lightningnetwork/lnd/keychain"
        "github.com/lightningnetwork/lnd/labels"
        "github.com/lightningnetwork/lnd/lnrpc"
        "github.com/lightningnetwork/lnd/lnrpc/signrpc"
        "github.com/lightningnetwork/lnd/lnwallet"
        "github.com/lightningnetwork/lnd/lnwallet/btcwallet"
        "github.com/lightningnetwork/lnd/lnwallet/chainfee"
        "github.com/lightningnetwork/lnd/lnwallet/chanfunding"
        "github.com/lightningnetwork/lnd/macaroons"
        "github.com/lightningnetwork/lnd/sweep"
        "golang.org/x/exp/maps"
        "google.golang.org/grpc"
        "gopkg.in/macaroon-bakery.v2/bakery"
)

var (
        // macaroonOps are the set of capabilities that our minted macaroon (if
        // it doesn't already exist) will have.
        macaroonOps = []bakery.Op{
                {
                        Entity: "address",
                        Action: "write",
                },
                {
                        Entity: "address",
                        Action: "read",
                },
                {
                        Entity: "onchain",
                        Action: "write",
                },
                {
                        Entity: "onchain",
                        Action: "read",
                },
        }

        // macPermissions maps RPC calls to the permissions they require.
        macPermissions = map[string][]bakery.Op{
                "/walletrpc.WalletKit/DeriveNextKey": {{
                        Entity: "address",
                        Action: "read",
                }},
                "/walletrpc.WalletKit/DeriveKey": {{
                        Entity: "address",
                        Action: "read",
                }},
                "/walletrpc.WalletKit/NextAddr": {{
                        Entity: "address",
                        Action: "read",
                }},
                "/walletrpc.WalletKit/GetTransaction": {{
                        Entity: "onchain",
                        Action: "read",
                }},
                "/walletrpc.WalletKit/PublishTransaction": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/SendOutputs": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/EstimateFee": {{
                        Entity: "onchain",
                        Action: "read",
                }},
                "/walletrpc.WalletKit/PendingSweeps": {{
                        Entity: "onchain",
                        Action: "read",
                }},
                "/walletrpc.WalletKit/BumpFee": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/BumpForceCloseFee": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/ListSweeps": {{
                        Entity: "onchain",
                        Action: "read",
                }},
                "/walletrpc.WalletKit/LabelTransaction": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/LeaseOutput": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/ReleaseOutput": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/ListLeases": {{
                        Entity: "onchain",
                        Action: "read",
                }},
                "/walletrpc.WalletKit/ListUnspent": {{
                        Entity: "onchain",
                        Action: "read",
                }},
                "/walletrpc.WalletKit/ListAddresses": {{
                        Entity: "onchain",
                        Action: "read",
                }},
                "/walletrpc.WalletKit/SignMessageWithAddr": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/VerifyMessageWithAddr": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/FundPsbt": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/SignPsbt": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/FinalizePsbt": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/ListAccounts": {{
                        Entity: "onchain",
                        Action: "read",
                }},
                "/walletrpc.WalletKit/RequiredReserve": {{
                        Entity: "onchain",
                        Action: "read",
                }},
                "/walletrpc.WalletKit/ImportAccount": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/ImportPublicKey": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/ImportTapscript": {{
                        Entity: "onchain",
                        Action: "write",
                }},
                "/walletrpc.WalletKit/RemoveTransaction": {{
                        Entity: "onchain",
                        Action: "write",
                }},
        }

        // DefaultWalletKitMacFilename is the default name of the wallet kit
        // macaroon that we expect to find via a file handle within the main
        // configuration file in this package.
        DefaultWalletKitMacFilename = "walletkit.macaroon"

        // allWitnessTypes is a mapping between the witness types defined in the
        // `input` package, and the witness types in the protobuf definition.
        // This map is necessary because the native enum and the protobuf enum
        // are numbered differently. The protobuf enum cannot be renumbered
        // because this would break backwards compatibility with older clients,
        // and the native enum cannot be renumbered because it is stored in the
        // watchtower and BreachArbitrator databases.
        //
        //nolint:ll
        allWitnessTypes = map[input.WitnessType]WitnessType{
                input.CommitmentTimeLock:                           WitnessType_COMMITMENT_TIME_LOCK,
                input.CommitmentNoDelay:                            WitnessType_COMMITMENT_NO_DELAY,
                input.CommitmentRevoke:                             WitnessType_COMMITMENT_REVOKE,
                input.HtlcOfferedRevoke:                            WitnessType_HTLC_OFFERED_REVOKE,
                input.HtlcAcceptedRevoke:                           WitnessType_HTLC_ACCEPTED_REVOKE,
                input.HtlcOfferedTimeoutSecondLevel:                WitnessType_HTLC_OFFERED_TIMEOUT_SECOND_LEVEL,
                input.HtlcAcceptedSuccessSecondLevel:               WitnessType_HTLC_ACCEPTED_SUCCESS_SECOND_LEVEL,
                input.HtlcOfferedRemoteTimeout:                     WitnessType_HTLC_OFFERED_REMOTE_TIMEOUT,
                input.HtlcAcceptedRemoteSuccess:                    WitnessType_HTLC_ACCEPTED_REMOTE_SUCCESS,
                input.HtlcSecondLevelRevoke:                        WitnessType_HTLC_SECOND_LEVEL_REVOKE,
                input.WitnessKeyHash:                               WitnessType_WITNESS_KEY_HASH,
                input.NestedWitnessKeyHash:                         WitnessType_NESTED_WITNESS_KEY_HASH,
                input.CommitmentAnchor:                             WitnessType_COMMITMENT_ANCHOR,
                input.HtlcOfferedTimeoutSecondLevelInputConfirmed:  WitnessType_HTLC_OFFERED_TIMEOUT_SECOND_LEVEL_INPUT_CONFIRMED,
                input.HtlcAcceptedSuccessSecondLevelInputConfirmed: WitnessType_HTLC_ACCEPTED_SUCCESS_SECOND_LEVEL_INPUT_CONFIRMED,
                input.CommitSpendNoDelayTweakless:                  WitnessType_COMMITMENT_NO_DELAY_TWEAKLESS,
                input.CommitmentToRemoteConfirmed:                  WitnessType_COMMITMENT_TO_REMOTE_CONFIRMED,
                input.LeaseCommitmentTimeLock:                      WitnessType_LEASE_COMMITMENT_TIME_LOCK,
                input.LeaseCommitmentToRemoteConfirmed:             WitnessType_LEASE_COMMITMENT_TO_REMOTE_CONFIRMED,
                input.LeaseHtlcOfferedTimeoutSecondLevel:           WitnessType_LEASE_HTLC_OFFERED_TIMEOUT_SECOND_LEVEL,
                input.LeaseHtlcAcceptedSuccessSecondLevel:          WitnessType_LEASE_HTLC_ACCEPTED_SUCCESS_SECOND_LEVEL,
                input.TaprootPubKeySpend:                           WitnessType_TAPROOT_PUB_KEY_SPEND,
                input.TaprootLocalCommitSpend:                      WitnessType_TAPROOT_LOCAL_COMMIT_SPEND,
                input.TaprootRemoteCommitSpend:                     WitnessType_TAPROOT_REMOTE_COMMIT_SPEND,
                input.TaprootAnchorSweepSpend:                      WitnessType_TAPROOT_ANCHOR_SWEEP_SPEND,
                input.TaprootHtlcOfferedTimeoutSecondLevel:         WitnessType_TAPROOT_HTLC_OFFERED_TIMEOUT_SECOND_LEVEL,
                input.TaprootHtlcAcceptedSuccessSecondLevel:        WitnessType_TAPROOT_HTLC_ACCEPTED_SUCCESS_SECOND_LEVEL,
                input.TaprootHtlcSecondLevelRevoke:                 WitnessType_TAPROOT_HTLC_SECOND_LEVEL_REVOKE,
                input.TaprootHtlcAcceptedRevoke:                    WitnessType_TAPROOT_HTLC_ACCEPTED_REVOKE,
                input.TaprootHtlcOfferedRevoke:                     WitnessType_TAPROOT_HTLC_OFFERED_REVOKE,
                input.TaprootHtlcOfferedRemoteTimeout:              WitnessType_TAPROOT_HTLC_OFFERED_REMOTE_TIMEOUT,
                input.TaprootHtlcLocalOfferedTimeout:               WitnessType_TAPROOT_HTLC_LOCAL_OFFERED_TIMEOUT,
                input.TaprootHtlcAcceptedRemoteSuccess:             WitnessType_TAPROOT_HTLC_ACCEPTED_REMOTE_SUCCESS,
                input.TaprootHtlcAcceptedLocalSuccess:              WitnessType_TAPROOT_HTLC_ACCEPTED_LOCAL_SUCCESS,
                input.TaprootCommitmentRevoke:                      WitnessType_TAPROOT_COMMITMENT_REVOKE,
        }
)

// ServerShell is a shell struct holding a reference to the actual sub-server.
// It is used to register the gRPC sub-server with the root server before we
// have the necessary dependencies to populate the actual sub-server.
type ServerShell struct {
        WalletKitServer
}

// WalletKit is a sub-RPC server that exposes a tool kit which allows clients
// to execute common wallet operations. This includes requesting new addresses,
// keys (for contracts!), and publishing transactions.
type WalletKit struct {
        // Required by the grpc-gateway/v2 library for forward compatibility.
        UnimplementedWalletKitServer

        cfg *Config
}

// A compile time check to ensure that WalletKit fully implements the
// WalletKitServer gRPC service.
var _ WalletKitServer = (*WalletKit)(nil)

// New creates a new instance of the WalletKit sub-RPC server.
func New(cfg *Config) (*WalletKit, lnrpc.MacaroonPerms, error) {
        // If the path of the wallet kit macaroon wasn't specified, then we'll
        // assume that it's found at the default network directory.
        if cfg.WalletKitMacPath == "" {
                cfg.WalletKitMacPath = filepath.Join(
                        cfg.NetworkDir, DefaultWalletKitMacFilename,
                )
        }

        // Now that we know the full path of the wallet kit macaroon, we can
        // check to see if we need to create it or not. If stateless_init is set
        // then we don't write the macaroons.
        macFilePath := cfg.WalletKitMacPath
        if cfg.MacService != nil && !cfg.MacService.StatelessInit &&
                !lnrpc.FileExists(macFilePath) {

                log.Infof("Baking macaroons for WalletKit RPC Server at: %v",
                        macFilePath)

                // At this point, we know that the wallet kit macaroon doesn't
                // yet, exist, so we need to create it with the help of the
                // main macaroon service.
                walletKitMac, err := cfg.MacService.NewMacaroon(
                        context.Background(), macaroons.DefaultRootKeyID,
                        macaroonOps...,
                )
                if err != nil {
                        return nil, nil, err
                }
                walletKitMacBytes, err := walletKitMac.M().MarshalBinary()
                if err != nil {
                        return nil, nil, err
                }
                err = os.WriteFile(macFilePath, walletKitMacBytes, 0644)
                if err != nil {
                        _ = os.Remove(macFilePath)
                        return nil, nil, err
                }
        }

        walletKit := &WalletKit{
                cfg: cfg,
        }

        return walletKit, macPermissions, nil
}

// Start launches any helper goroutines required for the sub-server to function.
//
// NOTE: This is part of the lnrpc.SubServer interface.
func (w *WalletKit) Start() error {
        return nil
}

// Stop signals any active goroutines for a graceful closure.
//
// NOTE: This is part of the lnrpc.SubServer interface.
func (w *WalletKit) Stop() error {
        return nil
}

// Name returns a unique string representation of the sub-server. This can be
// used to identify the sub-server and also de-duplicate them.
//
// NOTE: This is part of the lnrpc.SubServer interface.
func (w *WalletKit) Name() string {
        return SubServerName
}

// RegisterWithRootServer will be called by the root gRPC server to direct a
// sub RPC server to register itself with the main gRPC root server. Until this
// is called, each sub-server won't be able to have requests routed towards it.
//
// NOTE: This is part of the lnrpc.GrpcHandler interface.
func (r *ServerShell) RegisterWithRootServer(grpcServer *grpc.Server) error {
        // We make sure that we register it with the main gRPC server to ensure
        // all our methods are routed properly.
        RegisterWalletKitServer(grpcServer, r)

        log.Debugf("WalletKit RPC server successfully registered with " +
                "root gRPC server")

        return nil
}

// RegisterWithRestServer will be called by the root REST mux to direct a sub
// RPC server to register itself with the main REST mux server. Until this is
// called, each sub-server won't be able to have requests routed towards it.
//
// NOTE: This is part of the lnrpc.GrpcHandler interface.
func (r *ServerShell) RegisterWithRestServer(ctx context.Context,
        mux *runtime.ServeMux, dest string, opts []grpc.DialOption) error {

        // We make sure that we register it with the main REST server to ensure
        // all our methods are routed properly.
        err := RegisterWalletKitHandlerFromEndpoint(ctx, mux, dest, opts)
        if err != nil {
                log.Errorf("Could not register WalletKit REST server "+
                        "with root REST server: %v", err)
                return err
        }

        log.Debugf("WalletKit REST server successfully registered with " +
                "root REST server")
        return nil
}

// CreateSubServer populates the subserver's dependencies using the passed
// SubServerConfigDispatcher. This method should fully initialize the
// sub-server instance, making it ready for action. It returns the macaroon
// permissions that the sub-server wishes to pass on to the root server for all
// methods routed towards it.
//
// NOTE: This is part of the lnrpc.GrpcHandler interface.
func (r *ServerShell) CreateSubServer(configRegistry lnrpc.SubServerConfigDispatcher) (
        lnrpc.SubServer, lnrpc.MacaroonPerms, error) {

        subServer, macPermissions, err := createNewSubServer(configRegistry)
        if err != nil {
                return nil, nil, err
        }

        r.WalletKitServer = subServer
        return subServer, macPermissions, nil
}

// internalScope returns the internal key scope.
func (w *WalletKit) internalScope() waddrmgr.KeyScope {
        return waddrmgr.KeyScope{
                Purpose: keychain.BIP0043Purpose,
                Coin:    w.cfg.ChainParams.HDCoinType,
        }
}

// ListUnspent returns useful information about each unspent output owned by
// the wallet, as reported by the underlying `ListUnspentWitness`; the
// information returned is: outpoint, amount in satoshis, address, address
// type, scriptPubKey in hex and number of confirmations. The result is
// filtered to contain outputs whose number of confirmations is between a
// minimum and maximum number of confirmations specified by the user.
func (w *WalletKit) ListUnspent(ctx context.Context,
        req *ListUnspentRequest) (*ListUnspentResponse, error) {

        // Force min_confs and max_confs to be zero if unconfirmed_only is
        // true.
        if req.UnconfirmedOnly && (req.MinConfs != 0 || req.MaxConfs != 0) {
                return nil, fmt.Errorf("min_confs and max_confs must be zero " +
                        "if unconfirmed_only is true")
        }

        // When unconfirmed_only is inactive and max_confs is zero (default
        // values), we will override max_confs to be a MaxInt32, in order
        // to return all confirmed and unconfirmed utxos as a default response.
        if req.MaxConfs == 0 && !req.UnconfirmedOnly {
                req.MaxConfs = math.MaxInt32
        }

        // Validate the confirmation arguments.
        minConfs, maxConfs, err := lnrpc.ParseConfs(req.MinConfs, req.MaxConfs)
        if err != nil {
                return nil, err
        }

        // With our arguments validated, we'll query the internal wallet for
        // the set of UTXOs that match our query.
        //
        // We'll acquire the global coin selection lock to ensure there aren't
        // any other concurrent processes attempting to lock any UTXOs which may
        // be shown available to us.
        var utxos []*lnwallet.Utxo
        err = w.cfg.CoinSelectionLocker.WithCoinSelectLock(func() error {
                utxos, err = w.cfg.Wallet.ListUnspentWitness(
                        minConfs, maxConfs, req.Account,
                )

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

        rpcUtxos, err := lnrpc.MarshalUtxos(utxos, w.cfg.ChainParams)
        if err != nil {
                return nil, err
        }

        return &ListUnspentResponse{
                Utxos: rpcUtxos,
        }, nil
}

// LeaseOutput locks an output to the given ID, preventing it from being
// available for any future coin selection attempts. The absolute time of the
// lock's expiration is returned. The expiration of the lock can be extended by
// successive invocations of this call. Outputs can be unlocked before their
// expiration through `ReleaseOutput`.
//
// If the output is not known, wtxmgr.ErrUnknownOutput is returned. If the
// output has already been locked to a different ID, then
// wtxmgr.ErrOutputAlreadyLocked is returned.
func (w *WalletKit) LeaseOutput(ctx context.Context,
        req *LeaseOutputRequest) (*LeaseOutputResponse, error) {

        if len(req.Id) != 32 {
                return nil, errors.New("id must be 32 random bytes")
        }
        var lockID wtxmgr.LockID
        copy(lockID[:], req.Id)

        // Don't allow ID's of 32 bytes, but all zeros.
        if lockID == (wtxmgr.LockID{}) {
                return nil, errors.New("id must be 32 random bytes")
        }

        // Don't allow our internal ID to be used externally for locking. Only
        // unlocking is allowed.
        if lockID == chanfunding.LndInternalLockID {
                return nil, errors.New("reserved id cannot be used")
        }

        op, err := UnmarshallOutPoint(req.Outpoint)
        if err != nil {
                return nil, err
        }

        // Use the specified lock duration or fall back to the default.
        duration := chanfunding.DefaultLockDuration
        if req.ExpirationSeconds != 0 {
                duration = time.Duration(req.ExpirationSeconds) * time.Second
        }

        // Acquire the global coin selection lock to ensure there aren't any
        // other concurrent processes attempting to lease the same UTXO.
        var expiration time.Time
        err = w.cfg.CoinSelectionLocker.WithCoinSelectLock(func() error {
                expiration, err = w.cfg.Wallet.LeaseOutput(
                        lockID, *op, duration,
                )
                return err
        })
        if err != nil {
                return nil, err
        }

        return &LeaseOutputResponse{
                Expiration: uint64(expiration.Unix()),
        }, nil
}

// ReleaseOutput unlocks an output, allowing it to be available for coin
// selection if it remains unspent. The ID should match the one used to
// originally lock the output.
func (w *WalletKit) ReleaseOutput(ctx context.Context,
        req *ReleaseOutputRequest) (*ReleaseOutputResponse, error) {

        if len(req.Id) != 32 {
                return nil, errors.New("id must be 32 random bytes")
        }
        var lockID wtxmgr.LockID
        copy(lockID[:], req.Id)

        op, err := UnmarshallOutPoint(req.Outpoint)
        if err != nil {
                return nil, err
        }

        // Acquire the global coin selection lock to maintain consistency as
        // it's acquired when we initially leased the output.
        err = w.cfg.CoinSelectionLocker.WithCoinSelectLock(func() error {
                return w.cfg.Wallet.ReleaseOutput(lockID, *op)
        })
        if err != nil {
                return nil, err
        }

        return &ReleaseOutputResponse{
                Status: fmt.Sprintf("output %v released", op.String()),
        }, nil
}

// ListLeases returns a list of all currently locked utxos.
func (w *WalletKit) ListLeases(ctx context.Context,
        req *ListLeasesRequest) (*ListLeasesResponse, error) {

        leases, err := w.cfg.Wallet.ListLeasedOutputs()
        if err != nil {
                return nil, err
        }

        return &ListLeasesResponse{
                LockedUtxos: marshallLeases(leases),
        }, nil
}

// DeriveNextKey attempts to derive the *next* key within the key family
// (account in BIP43) specified. This method should return the next external
// child within this branch.
func (w *WalletKit) DeriveNextKey(ctx context.Context,
        req *KeyReq) (*signrpc.KeyDescriptor, error) {

        nextKeyDesc, err := w.cfg.KeyRing.DeriveNextKey(
                keychain.KeyFamily(req.KeyFamily),
        )
        if err != nil {
                return nil, err
        }

        return &signrpc.KeyDescriptor{
                KeyLoc: &signrpc.KeyLocator{
                        KeyFamily: int32(nextKeyDesc.Family),
                        KeyIndex:  int32(nextKeyDesc.Index),
                },
                RawKeyBytes: nextKeyDesc.PubKey.SerializeCompressed(),
        }, nil
}

// DeriveKey attempts to derive an arbitrary key specified by the passed
// KeyLocator.
func (w *WalletKit) DeriveKey(ctx context.Context,
        req *signrpc.KeyLocator) (*signrpc.KeyDescriptor, error) {

        keyDesc, err := w.cfg.KeyRing.DeriveKey(keychain.KeyLocator{
                Family: keychain.KeyFamily(req.KeyFamily),
                Index:  uint32(req.KeyIndex),
        })
        if err != nil {
                return nil, err
        }

        return &signrpc.KeyDescriptor{
                KeyLoc: &signrpc.KeyLocator{
                        KeyFamily: int32(keyDesc.Family),
                        KeyIndex:  int32(keyDesc.Index),
                },
                RawKeyBytes: keyDesc.PubKey.SerializeCompressed(),
        }, nil
}

// NextAddr returns the next unused address within the wallet.
func (w *WalletKit) NextAddr(ctx context.Context,
        req *AddrRequest) (*AddrResponse, error) {

        account := lnwallet.DefaultAccountName
        if req.Account != "" {
                account = req.Account
        }

        addrType := lnwallet.WitnessPubKey
        switch req.Type {
        case AddressType_NESTED_WITNESS_PUBKEY_HASH:
                addrType = lnwallet.NestedWitnessPubKey

        case AddressType_HYBRID_NESTED_WITNESS_PUBKEY_HASH:
                return nil, fmt.Errorf("invalid address type for next "+
                        "address: %v", req.Type)

        case AddressType_TAPROOT_PUBKEY:
                addrType = lnwallet.TaprootPubkey
        }

        addr, err := w.cfg.Wallet.NewAddress(addrType, req.Change, account)
        if err != nil {
                return nil, err
        }

        return &AddrResponse{
                Addr: addr.String(),
        }, nil
}

// GetTransaction returns a transaction from the wallet given its hash.
func (w *WalletKit) GetTransaction(_ context.Context,
        req *GetTransactionRequest) (*lnrpc.Transaction, error) {

        // If the client doesn't specify a hash, then there's nothing to
        // return.
        if req.Txid == "" {
                return nil, fmt.Errorf("must provide a transaction hash")
        }

        txHash, err := chainhash.NewHashFromStr(req.Txid)
        if err != nil {
                return nil, err
        }

        res, err := w.cfg.Wallet.GetTransactionDetails(txHash)
        if err != nil {
                return nil, err
        }

        return lnrpc.RPCTransaction(res), nil
}

// Attempts to publish the passed transaction to the network. Once this returns
// without an error, the wallet will continually attempt to re-broadcast the
// transaction on start up, until it enters the chain.
func (w *WalletKit) PublishTransaction(ctx context.Context,
        req *Transaction) (*PublishResponse, error) {

        switch {
        // If the client doesn't specify a transaction, then there's nothing to
        // publish.
        case len(req.TxHex) == 0:
                return nil, fmt.Errorf("must provide a transaction to " +
                        "publish")
        }

        tx := &wire.MsgTx{}
        txReader := bytes.NewReader(req.TxHex)
        if err := tx.Deserialize(txReader); err != nil {
                return nil, err
        }

        label, err := labels.ValidateAPI(req.Label)
        if err != nil {
                return nil, err
        }

        err = w.cfg.Wallet.PublishTransaction(tx, label)
        if err != nil {
                return nil, err
        }

        return &PublishResponse{}, nil
}

// RemoveTransaction attempts to remove the transaction and all of its
// descendants resulting from further spends of the outputs of the provided
// transaction id.
// NOTE: We do not remove the transaction from the rebroadcaster which might
// run in the background rebroadcasting not yet confirmed transactions. We do
// not have access to the rebroadcaster here nor should we. This command is not
// a way to remove transactions from the network. It is a way to shortcircuit
// wallet utxo housekeeping while transactions are still unconfirmed and we know
// that a transaction will never confirm because a replacement already pays
// higher fees.
func (w *WalletKit) RemoveTransaction(_ context.Context,
        req *GetTransactionRequest) (*RemoveTransactionResponse, error) {

        // If the client doesn't specify a hash, then there's nothing to
        // return.
        if req.Txid == "" {
                return nil, fmt.Errorf("must provide a transaction hash")
        }

        txHash, err := chainhash.NewHashFromStr(req.Txid)
        if err != nil {
                return nil, err
        }

        // Query the tx store of our internal wallet for the specified
        // transaction.
        res, err := w.cfg.Wallet.GetTransactionDetails(txHash)
        if err != nil {
                return nil, fmt.Errorf("transaction with txid=%v not found "+
                        "in the internal wallet store", txHash)
        }

        // Only allow unconfirmed transactions to be removed because as soon
        // as a transaction is confirmed it will be evaluated by the wallet
        // again and the wallet state would be updated in case the user had
        // removed the transaction accidentally.
        if res.NumConfirmations > 0 {
                return nil, fmt.Errorf("transaction with txid=%v is already "+
                        "confirmed (numConfs=%d) cannot be removed", txHash,
                        res.NumConfirmations)
        }

        tx := &wire.MsgTx{}
        txReader := bytes.NewReader(res.RawTx)
        if err := tx.Deserialize(txReader); err != nil {
                return nil, err
        }

        err = w.cfg.Wallet.RemoveDescendants(tx)
        if err != nil {
                return nil, err
        }

        return &RemoveTransactionResponse{
                Status: "Successfully removed transaction",
        }, nil
}

// SendOutputs is similar to the existing sendmany call in Bitcoind, and allows
// the caller to create a transaction that sends to several outputs at once.
// This is ideal when wanting to batch create a set of transactions.
func (w *WalletKit) SendOutputs(ctx context.Context,
        req *SendOutputsRequest) (*SendOutputsResponse, error) {

        switch {
        // If the client didn't specify any outputs to create, then  we can't
        // proceed .
        case len(req.Outputs) == 0:
                return nil, fmt.Errorf("must specify at least one output " +
                        "to create")
        }

        // Before we can request this transaction to be created, we'll need to
        // amp the protos back into the format that the internal wallet will
        // recognize.
        var totalOutputValue int64
        outputsToCreate := make([]*wire.TxOut, 0, len(req.Outputs))
        for _, output := range req.Outputs {
                outputsToCreate = append(outputsToCreate, &wire.TxOut{
                        Value:    output.Value,
                        PkScript: output.PkScript,
                })
                totalOutputValue += output.Value
        }

        // Then, we'll extract the minimum number of confirmations that each
        // output we use to fund the transaction should satisfy.
        minConfs, err := lnrpc.ExtractMinConfs(
                req.MinConfs, req.SpendUnconfirmed,
        )
        if err != nil {
                return nil, err
        }

        // Before sending out funds we need to ensure that the remainder of our
        // wallet funds would cover for the anchor reserve requirement. We'll
        // also take unconfirmed funds into account.
        walletBalance, err := w.cfg.Wallet.ConfirmedBalance(
                0, lnwallet.DefaultAccountName,
        )
        if err != nil {
                return nil, err
        }

        // We'll get the currently required reserve amount.
        reserve, err := w.RequiredReserve(ctx, &RequiredReserveRequest{})
        if err != nil {
                return nil, err
        }

        // Then we check if our current wallet balance undershoots the required
        // reserve if we'd send out the outputs specified in the request.
        if int64(walletBalance)-totalOutputValue < reserve.RequiredReserve {
                return nil, ErrInsufficientReserve
        }

        label, err := labels.ValidateAPI(req.Label)
        if err != nil {
                return nil, err
        }

        coinSelectionStrategy, err := lnrpc.UnmarshallCoinSelectionStrategy(
                req.CoinSelectionStrategy, w.cfg.CoinSelectionStrategy,
        )
        if err != nil {
                return nil, err
        }

        // Now that we have the outputs mapped and checked for the reserve
        // requirement, we can request that the wallet attempts to create this
        // transaction.
        tx, err := w.cfg.Wallet.SendOutputs(
                nil, outputsToCreate, chainfee.SatPerKWeight(req.SatPerKw),
                minConfs, label, coinSelectionStrategy,
        )
        if err != nil {
                return nil, err
        }

        var b bytes.Buffer
        if err := tx.Serialize(&b); err != nil {
                return nil, err
        }

        return &SendOutputsResponse{
                RawTx: b.Bytes(),
        }, nil
}

// EstimateFee attempts to query the internal fee estimator of the wallet to
// determine the fee (in sat/kw) to attach to a transaction in order to achieve
// the confirmation target.
func (w *WalletKit) EstimateFee(ctx context.Context,
        req *EstimateFeeRequest) (*EstimateFeeResponse, error) {

        switch {
        // A confirmation target of zero doesn't make any sense. Similarly, we
        // reject confirmation targets of 1 as they're unreasonable.
        case req.ConfTarget == 0 || req.ConfTarget == 1:
                return nil, fmt.Errorf("confirmation target must be greater " +
                        "than 1")
        }

        satPerKw, err := w.cfg.FeeEstimator.EstimateFeePerKW(
                uint32(req.ConfTarget),
        )
        if err != nil {
                return nil, err
        }

        relayFeePerKw := w.cfg.FeeEstimator.RelayFeePerKW()

        return &EstimateFeeResponse{
                SatPerKw:            int64(satPerKw),
                MinRelayFeeSatPerKw: int64(relayFeePerKw),
        }, nil
}

// PendingSweeps returns lists of on-chain outputs that lnd is currently
// attempting to sweep within its central batching engine. Outputs with similar
// fee rates are batched together in order to sweep them within a single
// transaction. The fee rate of each sweeping transaction is determined by
// taking the average fee rate of all the outputs it's trying to sweep.
func (w *WalletKit) PendingSweeps(ctx context.Context,
        in *PendingSweepsRequest) (*PendingSweepsResponse, error) {

        // Retrieve all of the outputs the UtxoSweeper is currently trying to
        // sweep.
        inputsMap, err := w.cfg.Sweeper.PendingInputs()
        if err != nil {
                return nil, err
        }

        // Convert them into their respective RPC format.
        rpcPendingSweeps := make([]*PendingSweep, 0, len(inputsMap))
        for _, inp := range inputsMap {
                witnessType, ok := allWitnessTypes[inp.WitnessType]
                if !ok {
                        return nil, fmt.Errorf("unhandled witness type %v for "+
                                "input %v", inp.WitnessType, inp.OutPoint)
                }

                op := lnrpc.MarshalOutPoint(&inp.OutPoint)
                amountSat := uint32(inp.Amount)
                satPerVbyte := uint64(inp.LastFeeRate.FeePerVByte())
                broadcastAttempts := uint32(inp.BroadcastAttempts)

                // Get the requested starting fee rate, if set.
                startingFeeRate := fn.MapOptionZ(
                        inp.Params.StartingFeeRate,
                        func(feeRate chainfee.SatPerKWeight) uint64 {
                                return uint64(feeRate.FeePerVByte())
                        })

                ps := &PendingSweep{
                        Outpoint:             op,
                        WitnessType:          witnessType,
                        AmountSat:            amountSat,
                        SatPerVbyte:          satPerVbyte,
                        BroadcastAttempts:    broadcastAttempts,
                        Immediate:            inp.Params.Immediate,
                        Budget:               uint64(inp.Params.Budget),
                        DeadlineHeight:       inp.DeadlineHeight,
                        RequestedSatPerVbyte: startingFeeRate,
                }
                rpcPendingSweeps = append(rpcPendingSweeps, ps)
        }

        return &PendingSweepsResponse{
                PendingSweeps: rpcPendingSweeps,
        }, nil
}

// UnmarshallOutPoint converts an outpoint from its lnrpc type to its canonical
// type.
func UnmarshallOutPoint(op *lnrpc.OutPoint) (*wire.OutPoint, error) {
        if op == nil {
                return nil, fmt.Errorf("empty outpoint provided")
        }

        var hash chainhash.Hash
        switch {
        // Return an error if both txid fields are unpopulated.
        case len(op.TxidBytes) == 0 && len(op.TxidStr) == 0:
                return nil, fmt.Errorf("TxidBytes and TxidStr are both " +
                        "unspecified")

        // The hash was provided as raw bytes.
        case len(op.TxidBytes) != 0:
                copy(hash[:], op.TxidBytes)

        // The hash was provided as a hex-encoded string.
        case len(op.TxidStr) != 0:
                h, err := chainhash.NewHashFromStr(op.TxidStr)
                if err != nil {
                        return nil, err
                }
                hash = *h
        }

        return &wire.OutPoint{
                Hash:  hash,
                Index: op.OutputIndex,
        }, nil
}

// validateBumpFeeRequest makes sure the deprecated fields are not used when
// the new fields are set.
func validateBumpFeeRequest(in *BumpFeeRequest) (
        fn.Option[chainfee.SatPerKWeight], bool, error) {

        // Get the specified fee rate if set.
        satPerKwOpt := fn.None[chainfee.SatPerKWeight]()

        // We only allow using either the deprecated field or the new field.
        switch {
        case in.SatPerByte != 0 && in.SatPerVbyte != 0:
                return satPerKwOpt, false, fmt.Errorf("either SatPerByte or " +
                        "SatPerVbyte should be set, but not both")

        case in.SatPerByte != 0:
                satPerKw := chainfee.SatPerVByte(
                        in.SatPerByte,
                ).FeePerKWeight()
                satPerKwOpt = fn.Some(satPerKw)

        case in.SatPerVbyte != 0:
                satPerKw := chainfee.SatPerVByte(
                        in.SatPerVbyte,
                ).FeePerKWeight()
                satPerKwOpt = fn.Some(satPerKw)
        }

        var immediate bool
        switch {
        case in.Force && in.Immediate:
                return satPerKwOpt, false, fmt.Errorf("either Force or " +
                        "Immediate should be set, but not both")

        case in.Force:
                immediate = in.Force

        case in.Immediate:
                immediate = in.Immediate
        }

        return satPerKwOpt, immediate, nil
}

// prepareSweepParams creates the sweep params to be used for the sweeper. It
// returns the new params and a bool indicating whether this is an existing
// input.
func (w *WalletKit) prepareSweepParams(in *BumpFeeRequest,
        op wire.OutPoint, currentHeight int32) (sweep.Params, bool, error) {

        // Return an error if both deprecated and new fields are used.
        feerate, immediate, err := validateBumpFeeRequest(in)
        if err != nil {
                return sweep.Params{}, false, err
        }

        // Get the current pending inputs.
        inputMap, err := w.cfg.Sweeper.PendingInputs()
        if err != nil {
                return sweep.Params{}, false, fmt.Errorf("unable to get "+
                        "pending inputs: %w", err)
        }

        // Find the pending input.
        //
        // TODO(yy): act differently based on the state of the input?
        inp, ok := inputMap[op]

        if !ok {
                // NOTE: if this input doesn't exist and the new budget is not
                // specified, the params would have a zero budget.
                params := sweep.Params{
                        Immediate:       immediate,
                        StartingFeeRate: feerate,
                        Budget:          btcutil.Amount(in.Budget),
                }
                if in.TargetConf != 0 {
                        params.DeadlineHeight = fn.Some(
                                int32(in.TargetConf) + currentHeight,
                        )
                }

                return params, ok, nil
        }

        // Find the existing budget used for this input. Note that this value
        // must be greater than zero.
        budget := inp.Params.Budget

        // Set the new budget if specified.
        if in.Budget != 0 {
                budget = btcutil.Amount(in.Budget)
        }

        // For an existing input, we assign it first, then overwrite it if
        // a deadline is requested.
        deadline := inp.Params.DeadlineHeight

        // Set the deadline if target conf is specified.
        //
        // TODO(yy): upgrade `falafel` so we can make this field optional. Atm
        // we cannot distinguish between user's not setting the field and
        // setting it to 0.
        if in.TargetConf != 0 {
                deadline = fn.Some(int32(in.TargetConf) + currentHeight)
        }

        // Prepare the new sweep params.
        //
        // NOTE: if this input doesn't exist and the new budget is not
        // specified, the params would have a zero budget.
        params := sweep.Params{
                Immediate:       immediate,
                StartingFeeRate: feerate,
                DeadlineHeight:  deadline,
                Budget:          budget,
        }

        if ok {
                log.Infof("[BumpFee]: bumping fee for existing input=%v, old "+
                        "params=%v, new params=%v", op, inp.Params, params)
        }

        return params, ok, nil
}

// BumpFee allows bumping the fee rate of an arbitrary input. A fee preference
// can be expressed either as a specific fee rate or a delta of blocks in which
// the output should be swept on-chain within. If a fee preference is not
// explicitly specified, then an error is returned. The status of the input
// sweep can be checked through the PendingSweeps RPC.
func (w *WalletKit) BumpFee(ctx context.Context,
        in *BumpFeeRequest) (*BumpFeeResponse, error) {

        // Parse the outpoint from the request.
        op, err := UnmarshallOutPoint(in.Outpoint)
        if err != nil {
                return nil, err
        }

        // Get the current height so we can calculate the deadline height.
        _, currentHeight, err := w.cfg.Chain.GetBestBlock()
        if err != nil {
                return nil, fmt.Errorf("unable to retrieve current height: %w",
                        err)
        }

        // We now create a new sweeping params and update it in the sweeper.
        // This will complicate the RBF conditions if this input has already
        // been offered to sweeper before and it has already been included in a
        // tx with other inputs. If this is the case, two results are possible:
        // - either this input successfully RBFed the existing tx, or,
        // - the budget of this input was not enough to RBF the existing tx.
        params, existing, err := w.prepareSweepParams(in, *op, currentHeight)
        if err != nil {
                return nil, err
        }

        // If this input exists, we will update its params.
        if existing {
                _, err = w.cfg.Sweeper.UpdateParams(*op, params)
                if err != nil {
                        return nil, err
                }

                return &BumpFeeResponse{
                        Status: "Successfully registered rbf-tx with sweeper",
                }, nil
        }

        // Otherwise, create a new sweeping request for this input.
        err = w.sweepNewInput(op, uint32(currentHeight), params)
        if err != nil {
                return nil, err
        }

        return &BumpFeeResponse{
                Status: "Successfully registered CPFP-tx with the sweeper",
        }, nil
}

// getWaitingCloseChannel returns the waiting close channel in case it does
// exist in the underlying channel state database.
func (w *WalletKit) getWaitingCloseChannel(
        chanPoint wire.OutPoint) (*channeldb.OpenChannel, error) {

        // Fetch all channels, which still have their commitment transaction not
        // confirmed (waiting close channels).
        chans, err := w.cfg.ChanStateDB.FetchWaitingCloseChannels()
        if err != nil {
                return nil, err
        }

        channel := fn.Find(chans, func(c *channeldb.OpenChannel) bool {
                return c.FundingOutpoint == chanPoint
        })

        return channel.UnwrapOrErr(errors.New("channel not found"))
}

// BumpForceCloseFee bumps the fee rate of an unconfirmed anchor channel. It
// updates the new fee rate parameters with the sweeper subsystem. Additionally
// it will try to create anchor cpfp transactions for all possible commitment
// transactions (local, remote, remote-dangling) so depending on which
// commitment is in the local mempool only one of them will succeed in being
// broadcasted.
func (w *WalletKit) BumpForceCloseFee(_ context.Context,
        in *BumpForceCloseFeeRequest) (*BumpForceCloseFeeResponse, error) {

        if in.ChanPoint == nil {
                return nil, fmt.Errorf("no chan_point provided")
        }

        lnrpcOutpoint, err := lnrpc.GetChannelOutPoint(in.ChanPoint)
        if err != nil {
                return nil, err
        }

        outPoint, err := UnmarshallOutPoint(lnrpcOutpoint)
        if err != nil {
                return nil, err
        }

        // Get the relevant channel if it is in the waiting close state.
        channel, err := w.getWaitingCloseChannel(*outPoint)
        if err != nil {
                return nil, err
        }

        if !channel.ChanType.HasAnchors() {
                return nil, fmt.Errorf("not able to bump the fee of a " +
                        "non-anchor channel")
        }

        // Match pending sweeps with commitments of the channel for which a bump
        // is requested. Depending on the commitment state when force closing
        // the channel we might have up to 3 commitments to consider when
        // bumping the fee.
        commitSet := fn.NewSet[chainhash.Hash]()

        if channel.LocalCommitment.CommitTx != nil {
                localTxID := channel.LocalCommitment.CommitTx.TxHash()
                commitSet.Add(localTxID)
        }

        if channel.RemoteCommitment.CommitTx != nil {
                remoteTxID := channel.RemoteCommitment.CommitTx.TxHash()
                commitSet.Add(remoteTxID)
        }

        // Check whether there was a dangling commitment at the time the channel
        // was force closed.
        remoteCommitDiff, err := channel.RemoteCommitChainTip()
        if err != nil && !errors.Is(err, channeldb.ErrNoPendingCommit) {
                return nil, err
        }

        if remoteCommitDiff != nil {
                hash := remoteCommitDiff.Commitment.CommitTx.TxHash()
                commitSet.Add(hash)
        }

        // Retrieve all of the outputs the UtxoSweeper is currently trying to
        // sweep.
        inputsMap, err := w.cfg.Sweeper.PendingInputs()
        if err != nil {
                return nil, err
        }

        // Get the current height so we can calculate the deadline height.
        _, currentHeight, err := w.cfg.Chain.GetBestBlock()
        if err != nil {
                return nil, fmt.Errorf("unable to retrieve current height: %w",
                        err)
        }

        pendingSweeps := maps.Values(inputsMap)

        // Discard everything except for the anchor sweeps.
        anchors := fn.Filter(
                pendingSweeps,
                func(sweep *sweep.PendingInputResponse) bool {
                        // Only filter for anchor inputs because these are the
                        // only inputs which can be used to bump a closed
                        // unconfirmed commitment transaction.
                        isCommitAnchor := sweep.WitnessType ==
                                input.CommitmentAnchor
                        isTaprootSweepSpend := sweep.WitnessType ==
                                input.TaprootAnchorSweepSpend
                        if !isCommitAnchor && !isTaprootSweepSpend {
                                return false
                        }

                        return commitSet.Contains(sweep.OutPoint.Hash)
                },
        )

        if len(anchors) == 0 {
                return nil, fmt.Errorf("unable to find pending anchor outputs")
        }

        // Filter all relevant anchor sweeps and update the sweep request.
        for _, anchor := range anchors {
                // Anchor cpfp bump request are predictable because they are
                // swept separately hence not batched with other sweeps (they
                // are marked with the exclusive group flag). Bumping the fee
                // rate does not create any conflicting fee bump conditions.
                // Either the rbf requirements are met or the bump is rejected
                // by the mempool rules.
                params, existing, err := w.prepareSweepParams(
                        &BumpFeeRequest{
                                Outpoint:    lnrpcOutpoint,
                                TargetConf:  in.DeadlineDelta,
                                SatPerVbyte: in.StartingFeerate,
                                Immediate:   in.Immediate,
                                Budget:      in.Budget,
                        }, anchor.OutPoint, currentHeight,
                )
                if err != nil {
                        return nil, err
                }

                // There might be the case when an anchor sweep is confirmed
                // between fetching the pending sweeps and preparing the sweep
                // params. We log this case and proceed.
                if !existing {
                        log.Errorf("Sweep anchor input(%v) not known to the " +
                                "sweeper subsystem")
                        continue
                }

                _, err = w.cfg.Sweeper.UpdateParams(anchor.OutPoint, params)
                if err != nil {
                        return nil, err
                }
        }

        return &BumpForceCloseFeeResponse{
                Status: "Successfully registered anchor-cpfp transaction to" +
                        "bump channel force close transaction",
        }, nil
}

// sweepNewInput handles the case where an input is seen the first time by the
// sweeper. It will fetch the output from the wallet and construct an input and
// offer it to the sweeper.
//
// NOTE: if the budget is not set, the default budget ratio is used.
func (w *WalletKit) sweepNewInput(op *wire.OutPoint, currentHeight uint32,
        params sweep.Params) error {

        log.Debugf("Attempting to sweep outpoint %s", op)

        // Since the sweeper is not aware of the input, we'll assume the user
        // is attempting to bump an unconfirmed transaction's fee rate by
        // sweeping an output within it under control of the wallet with a
        // higher fee rate. In this case, this will be a CPFP.
        //
        // We'll gather all of the information required by the UtxoSweeper in
        // order to sweep the output.
        utxo, err := w.cfg.Wallet.FetchOutpointInfo(op)
        if err != nil {
                return err
        }

        // We're only able to bump the fee of unconfirmed transactions.
        if utxo.Confirmations > 0 {
                return errors.New("unable to bump fee of a confirmed " +
                        "transaction")
        }

        // If there's no budget set, use the default value.
        if params.Budget == 0 {
                params.Budget = utxo.Value.MulF64(
                        contractcourt.DefaultBudgetRatio,
                )
        }

        signDesc := &input.SignDescriptor{
                Output: &wire.TxOut{
                        PkScript: utxo.PkScript,
                        Value:    int64(utxo.Value),
                },
                HashType: txscript.SigHashAll,
        }

        var witnessType input.WitnessType
        switch utxo.AddressType {
        case lnwallet.WitnessPubKey:
                witnessType = input.WitnessKeyHash
        case lnwallet.NestedWitnessPubKey:
                witnessType = input.NestedWitnessKeyHash
        case lnwallet.TaprootPubkey:
                witnessType = input.TaprootPubKeySpend
                signDesc.HashType = txscript.SigHashDefault
        default:
                return fmt.Errorf("unknown input witness %v", op)
        }

        log.Infof("[BumpFee]: bumping fee for new input=%v, params=%v", op,
                params)

        inp := input.NewBaseInput(op, witnessType, signDesc, currentHeight)
        if _, err = w.cfg.Sweeper.SweepInput(inp, params); err != nil {
                return err
        }

        return nil
}

// ListSweeps returns a list of the sweeps that our node has published.
func (w *WalletKit) ListSweeps(ctx context.Context,
        in *ListSweepsRequest) (*ListSweepsResponse, error) {

        sweeps, err := w.cfg.Sweeper.ListSweeps()
        if err != nil {
                return nil, err
        }

        sweepTxns := make(map[string]bool)
        for _, sweep := range sweeps {
                sweepTxns[sweep.String()] = true
        }

        // Some of our sweeps could have been replaced by fee, or dropped out
        // of the mempool. Here, we lookup our wallet transactions so that we
        // can match our list of sweeps against the list of transactions that
        // the wallet is still tracking. Sweeps are currently always swept to
        // the default wallet account.
        txns, firstIdx, lastIdx, err := w.cfg.Wallet.ListTransactionDetails(
                in.StartHeight, btcwallet.UnconfirmedHeight,
                lnwallet.DefaultAccountName, 0, 0,
        )
        if err != nil {
                return nil, err
        }

        var (
                txids     []string
                txDetails []*lnwallet.TransactionDetail
        )

        for _, tx := range txns {
                _, ok := sweepTxns[tx.Hash.String()]
                if !ok {
                        continue
                }

                // Add the txid or full tx details depending on whether we want
                // verbose output or not.
                if in.Verbose {
                        txDetails = append(txDetails, tx)
                } else {
                        txids = append(txids, tx.Hash.String())
                }
        }

        if in.Verbose {
                return &ListSweepsResponse{
                        Sweeps: &ListSweepsResponse_TransactionDetails{
                                TransactionDetails: lnrpc.RPCTransactionDetails(
                                        txDetails, firstIdx, lastIdx,
                                ),
                        },
                }, nil
        }

        return &ListSweepsResponse{
                Sweeps: &ListSweepsResponse_TransactionIds{
                        TransactionIds: &ListSweepsResponse_TransactionIDs{
                                TransactionIds: txids,
                        },
                },
        }, nil
}

// LabelTransaction adds a label to a transaction.
func (w *WalletKit) LabelTransaction(ctx context.Context,
        req *LabelTransactionRequest) (*LabelTransactionResponse, error) {

        // Check that the label provided in non-zero.
        if len(req.Label) == 0 {
                return nil, ErrZeroLabel
        }

        // Validate the length of the non-zero label. We do not need to use the
        // label returned here, because the original is non-zero so will not
        // be replaced.
        if _, err := labels.ValidateAPI(req.Label); err != nil {
                return nil, err
        }

        hash, err := chainhash.NewHash(req.Txid)
        if err != nil {
                return nil, err
        }

        err = w.cfg.Wallet.LabelTransaction(*hash, req.Label, req.Overwrite)

        return &LabelTransactionResponse{
                Status: fmt.Sprintf("transaction label '%s' added", req.Label),
        }, err
}

// FundPsbt creates a fully populated PSBT that contains enough inputs to fund
// the outputs specified in the template. There are three ways a user can
// specify what we call the template (a list of inputs and outputs to use in the
// PSBT): Either as a PSBT packet directly with no coin selection (using the
// legacy "psbt" field), a PSBT with advanced coin selection support (using the
// new "coin_select" field) or as a raw RPC message (using the "raw" field).
// The legacy "psbt" and "raw" modes, the following restrictions apply:
//  1. If there are no inputs specified in the template, coin selection is
//     performed automatically.
//  2. If the template does contain any inputs, it is assumed that full coin
//     selection happened externally and no additional inputs are added. If the
//     specified inputs aren't enough to fund the outputs with the given fee
//     rate, an error is returned.
//
// The new "coin_select" mode does not have these restrictions and allows the
// user to specify a PSBT with inputs and outputs and still perform coin
// selection on top of that.
// For all modes this RPC requires any inputs that are specified to be locked by
// the user (if they belong to this node in the first place).
// After either selecting or verifying the inputs, all input UTXOs are locked
// with an internal app ID. A custom address type for change can be specified
// for default accounts and single imported public keys (only P2TR for now).
// Otherwise, P2WPKH will be used by default. No custom address type should be
// provided for custom accounts as we will always generate the change address
// using the coin selection key scope.
//
// NOTE: If this method returns without an error, it is the caller's
// responsibility to either spend the locked UTXOs (by finalizing and then
// publishing the transaction) or to unlock/release the locked UTXOs in case of
// an error on the caller's side.
func (w *WalletKit) FundPsbt(_ context.Context,
        req *FundPsbtRequest) (*FundPsbtResponse, error) {

        coinSelectionStrategy, err := lnrpc.UnmarshallCoinSelectionStrategy(
                req.CoinSelectionStrategy, w.cfg.CoinSelectionStrategy,
        )
        if err != nil {
                return nil, err
        }

        // Determine the desired transaction fee.
        var feeSatPerKW chainfee.SatPerKWeight
        switch {
        // Estimate the fee by the target number of blocks to confirmation.
        case req.GetTargetConf() != 0:
                targetConf := req.GetTargetConf()
                if targetConf < 2 {
                        return nil, fmt.Errorf("confirmation target must be " +
                                "greater than 1")
                }

                feeSatPerKW, err = w.cfg.FeeEstimator.EstimateFeePerKW(
                        targetConf,
                )
                if err != nil {
                        return nil, fmt.Errorf("could not estimate fee: %w",
                                err)
                }

        // Convert the fee to sat/kW from the specified sat/vByte.
        case req.GetSatPerVbyte() != 0:
                feeSatPerKW = chainfee.SatPerKVByte(
                        req.GetSatPerVbyte() * 1000,
                ).FeePerKWeight()

        case req.GetSatPerKw() != 0:
                feeSatPerKW = chainfee.SatPerKWeight(req.GetSatPerKw())

        default:
                return nil, fmt.Errorf("fee definition missing, need to " +
                        "specify either target_conf, sat_per_vbyte or " +
                        "sat_per_kw")
        }

        // Then, we'll extract the minimum number of confirmations that each
        // output we use to fund the transaction should satisfy.
        minConfs, err := lnrpc.ExtractMinConfs(
                req.GetMinConfs(), req.GetSpendUnconfirmed(),
        )
        if err != nil {
                return nil, err
        }

        // We'll assume the PSBT will be funded by the default account unless
        // otherwise specified.
        account := lnwallet.DefaultAccountName
        if req.Account != "" {
                account = req.Account
        }

        // There are three ways a user can specify what we call the template (a
        // list of inputs and outputs to use in the PSBT): Either as a PSBT
        // packet directly with no coin selection, a PSBT with coin selection or
        // as a special RPC message. Find out which one the user wants to use,
        // they are mutually exclusive.
        switch {
        // The template is specified as a PSBT. All we have to do is parse it.
        case req.GetPsbt() != nil:
                r := bytes.NewReader(req.GetPsbt())
                packet, err := psbt.NewFromRawBytes(r, false)
                if err != nil {
                        return nil, fmt.Errorf("could not parse PSBT: %w", err)
                }

                // Run the actual funding process now, using the internal
                // wallet.
                return w.fundPsbtInternalWallet(
                        account, keyScopeFromChangeAddressType(req.ChangeType),
                        packet, minConfs, feeSatPerKW, coinSelectionStrategy,
                )

        // The template is specified as a PSBT with the intention to perform
        // coin selection even if inputs are already present.
        case req.GetCoinSelect() != nil:
                coinSelectRequest := req.GetCoinSelect()
                r := bytes.NewReader(coinSelectRequest.Psbt)
                packet, err := psbt.NewFromRawBytes(r, false)
                if err != nil {
                        return nil, fmt.Errorf("could not parse PSBT: %w", err)
                }

                numOutputs := int32(len(packet.UnsignedTx.TxOut))
                if numOutputs == 0 {
                        return nil, fmt.Errorf("no outputs specified in " +
                                "template")
                }

                outputSum := int64(0)
                for _, txOut := range packet.UnsignedTx.TxOut {
                        outputSum += txOut.Value
                }
                if outputSum <= 0 {
                        return nil, fmt.Errorf("output sum must be positive")
                }

                var (
                        changeIndex int32 = -1
                        changeType  chanfunding.ChangeAddressType
                )
                switch t := coinSelectRequest.ChangeOutput.(type) {
                // The user wants to use an existing output as change output.
                case *PsbtCoinSelect_ExistingOutputIndex:
                        if t.ExistingOutputIndex < 0 ||
                                t.ExistingOutputIndex >= numOutputs {

                                return nil, fmt.Errorf("change output index "+
                                        "out of range: %d",
                                        t.ExistingOutputIndex)
                        }

                        changeIndex = t.ExistingOutputIndex

                        changeOut := packet.UnsignedTx.TxOut[changeIndex]
                        _, err := txscript.ParsePkScript(changeOut.PkScript)
                        if err != nil {
                                return nil, fmt.Errorf("error parsing change "+
                                        "script: %w", err)
                        }

                        changeType = chanfunding.ExistingChangeAddress

                // The user wants to use a new output as change output.
                case *PsbtCoinSelect_Add:
                        // We already set the change index to -1 above to
                        // indicate no change output should be used if possible
                        // or a new one should be created if needed. So we only
                        // need to parse the type of change output we want to
                        // create.
                        switch req.ChangeType {
                        case ChangeAddressType_CHANGE_ADDRESS_TYPE_P2TR:
                                changeType = chanfunding.P2TRChangeAddress

                        default:
                                changeType = chanfunding.P2WKHChangeAddress
                        }

                default:
                        return nil, fmt.Errorf("unknown change output type")
                }

                maxFeeRatio := chanfunding.DefaultMaxFeeRatio

                if req.MaxFeeRatio != 0 {
                        maxFeeRatio = req.MaxFeeRatio
                }

                // Run the actual funding process now, using the channel funding
                // coin selection algorithm.
                return w.fundPsbtCoinSelect(
                        account, changeIndex, packet, minConfs, changeType,
                        feeSatPerKW, coinSelectionStrategy, maxFeeRatio,
                )

        // The template is specified as a RPC message. We need to create a new
        // PSBT and copy the RPC information over.
        case req.GetRaw() != nil:
                tpl := req.GetRaw()

                txOut := make([]*wire.TxOut, 0, len(tpl.Outputs))
                for addrStr, amt := range tpl.Outputs {
                        addr, err := btcutil.DecodeAddress(
                                addrStr, w.cfg.ChainParams,
                        )
                        if err != nil {
                                return nil, fmt.Errorf("error parsing address "+
                                        "%s for network %s: %v", addrStr,
                                        w.cfg.ChainParams.Name, err)
                        }

                        if !addr.IsForNet(w.cfg.ChainParams) {
                                return nil, fmt.Errorf("address is not for %s",
                                        w.cfg.ChainParams.Name)
                        }

                        pkScript, err := txscript.PayToAddrScript(addr)
                        if err != nil {
                                return nil, fmt.Errorf("error getting pk "+
                                        "script for address %s: %w", addrStr,
                                        err)
                        }

                        txOut = append(txOut, &wire.TxOut{
                                Value:    int64(amt),
                                PkScript: pkScript,
                        })
                }

                txIn := make([]*wire.OutPoint, len(tpl.Inputs))
                for idx, in := range tpl.Inputs {
                        op, err := UnmarshallOutPoint(in)
                        if err != nil {
                                return nil, fmt.Errorf("error parsing "+
                                        "outpoint: %w", err)
                        }
                        txIn[idx] = op
                }

                sequences := make([]uint32, len(txIn))
                packet, err := psbt.New(txIn, txOut, 2, 0, sequences)
                if err != nil {
                        return nil, fmt.Errorf("could not create PSBT: %w", err)
                }

                // Run the actual funding process now, using the internal
                // wallet.
                return w.fundPsbtInternalWallet(
                        account, keyScopeFromChangeAddressType(req.ChangeType),
                        packet, minConfs, feeSatPerKW, coinSelectionStrategy,
                )

        default:
                return nil, fmt.Errorf("transaction template missing, need " +
                        "to specify either PSBT or raw TX template")
        }
}

// fundPsbtInternalWallet uses the "old" PSBT funding method of the internal
// wallet that does not allow specifying custom inputs while selecting coins.
func (w *WalletKit) fundPsbtInternalWallet(account string,
        keyScope *waddrmgr.KeyScope, packet *psbt.Packet, minConfs int32,
        feeSatPerKW chainfee.SatPerKWeight,
        strategy base.CoinSelectionStrategy) (*FundPsbtResponse, error) {

        // The RPC parsing part is now over. Several of the following operations
        // require us to hold the global coin selection lock, so we do the rest
        // of the tasks while holding the lock. The result is a list of locked
        // UTXOs.
        var response *FundPsbtResponse
        err := w.cfg.CoinSelectionLocker.WithCoinSelectLock(func() error {
                // In case the user did specify inputs, we need to make sure
                // they are known to us, still unspent and not yet locked.
                if len(packet.UnsignedTx.TxIn) > 0 {
                        // Get a list of all unspent witness outputs.
                        utxos, err := w.cfg.Wallet.ListUnspentWitness(
                                minConfs, defaultMaxConf, account,
                        )
                        if err != nil {
                                return err
                        }

                        // filterFn makes sure utxos which are unconfirmed and
                        // still used by the sweeper are not used.
                        filterFn := func(u *lnwallet.Utxo) bool {
                                // Confirmed utxos are always allowed.
                                if u.Confirmations > 0 {
                                        return true
                                }

                                // Unconfirmed utxos in use by the sweeper are
                                // not stable to use because they can be
                                // replaced.
                                if w.cfg.Sweeper.IsSweeperOutpoint(u.OutPoint) {
                                        log.Warnf("Cannot use unconfirmed "+
                                                "utxo=%v because it is "+
                                                "unstable and could be "+
                                                "replaced", u.OutPoint)

                                        return false
                                }

                                return true
                        }

                        eligibleUtxos := fn.Filter(utxos, filterFn)

                        // Validate all inputs against our known list of UTXOs
                        // now.
                        err = verifyInputsUnspent(
                                packet.UnsignedTx.TxIn, eligibleUtxos,
                        )
                        if err != nil {
                                return err
                        }
                }

                // currentHeight is needed to determine whether the internal
                // wallet utxo is still unconfirmed.
                _, currentHeight, err := w.cfg.Chain.GetBestBlock()
                if err != nil {
                        return fmt.Errorf("unable to retrieve current "+
                                "height: %v", err)
                }

                // restrictUnstableUtxos is a filter function which disallows
                // the usage of unconfirmed outputs published (still in use) by
                // the sweeper.
                restrictUnstableUtxos := func(utxo wtxmgr.Credit) bool {
                        // Wallet utxos which are unmined have a height
                        // of -1.
                        if utxo.Height != -1 && utxo.Height <= currentHeight {
                                // Confirmed utxos are always allowed.
                                return true
                        }

                        // Utxos used by the sweeper are not used for
                        // channel openings.
                        allowed := !w.cfg.Sweeper.IsSweeperOutpoint(
                                utxo.OutPoint,
                        )
                        if !allowed {
                                log.Warnf("Cannot use unconfirmed "+
                                        "utxo=%v because it is "+
                                        "unstable and could be "+
                                        "replaced", utxo.OutPoint)
                        }

                        return allowed
                }

                // We made sure the input from the user is as sane as possible.
                // We can now ask the wallet to fund the TX. This will not yet
                // lock any coins but might still change the wallet DB by
                // generating a new change address.
                changeIndex, err := w.cfg.Wallet.FundPsbt(
                        packet, minConfs, feeSatPerKW, account, keyScope,
                        strategy, restrictUnstableUtxos,
                )
                if err != nil {
                        return fmt.Errorf("wallet couldn't fund PSBT: %w", err)
                }

                // Now we have obtained a set of coins that can be used to fund
                // the TX. Let's lock them to be sure they aren't spent by the
                // time the PSBT is published. This is the action we do here
                // that could cause an error. Therefore, if some of the UTXOs
                // cannot be locked, the rollback of the other's locks also
                // happens in this function. If we ever need to do more after
                // this function, we need to extract the rollback needs to be
                // extracted into a defer.
                outpoints := make([]wire.OutPoint, len(packet.UnsignedTx.TxIn))
                for i, txIn := range packet.UnsignedTx.TxIn {
                        outpoints[i] = txIn.PreviousOutPoint
                }

                response, err = w.lockAndCreateFundingResponse(
                        packet, outpoints, changeIndex,
                )

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

        return response, nil
}

// fundPsbtCoinSelect uses the "new" PSBT funding method using the channel
// funding coin selection algorithm that allows specifying custom inputs while
// selecting coins.
func (w *WalletKit) fundPsbtCoinSelect(account string, changeIndex int32,
        packet *psbt.Packet, minConfs int32,
        changeType chanfunding.ChangeAddressType,
        feeRate chainfee.SatPerKWeight, strategy base.CoinSelectionStrategy,
        maxFeeRatio float64) (*FundPsbtResponse, error) {

        // We want to make sure we don't select any inputs that are already
        // specified in the template. To do that, we require those inputs to
        // either not belong to this lnd at all or to be already locked through
        // a manual lock call by the user. Either way, they should not appear in
        // the list of unspent outputs.
        err := w.assertNotAvailable(packet.UnsignedTx.TxIn, minConfs, account)
        if err != nil {
                return nil, err
        }

        // In case the user just specified the input outpoints of UTXOs we own,
        // the fee estimation below will error out because the UTXO information
        // is missing. We need to fetch the UTXO information from the wallet
        // and add it to the PSBT. We ignore inputs we don't actually know as
        // they could belong to another wallet.
        err = w.cfg.Wallet.DecorateInputs(packet, false)
        if err != nil {
                return nil, fmt.Errorf("error decorating inputs: %w", err)
        }

        // Before we select anything, we need to calculate the input, output and
        // current weight amounts. While doing that we also ensure the PSBT has
        // all the required information we require at this step.
        var (
                inputSum, outputSum btcutil.Amount
                estimator           input.TxWeightEstimator
        )
        for i := range packet.Inputs {
                in := packet.Inputs[i]

                err := btcwallet.EstimateInputWeight(&in, &estimator)
                if err != nil {
                        return nil, fmt.Errorf("error estimating input "+
                                "weight: %w", err)
                }

                inputSum += btcutil.Amount(in.WitnessUtxo.Value)
        }
        for i := range packet.UnsignedTx.TxOut {
                out := packet.UnsignedTx.TxOut[i]

                estimator.AddOutput(out.PkScript)
                outputSum += btcutil.Amount(out.Value)
        }

        // The amount we want to fund is the total output sum plus the current
        // fee estimate, minus the sum of any already specified inputs. Since we
        // pass the estimator of the current transaction into the coin selection
        // algorithm, we don't need to subtract the fees here.
        fundingAmount := outputSum - inputSum

        var changeDustLimit btcutil.Amount
        switch changeType {
        case chanfunding.P2TRChangeAddress:
                changeDustLimit = lnwallet.DustLimitForSize(input.P2TRSize)

        case chanfunding.P2WKHChangeAddress:
                changeDustLimit = lnwallet.DustLimitForSize(input.P2WPKHSize)

        case chanfunding.ExistingChangeAddress:
                changeOut := packet.UnsignedTx.TxOut[changeIndex]
                changeDustLimit = lnwallet.DustLimitForSize(
                        len(changeOut.PkScript),
                )
        }

        // Do we already have enough inputs specified to pay for the TX as it
        // is? In that case we only need to allocate any change, if there is
        // any.
        packetFeeNoChange := feeRate.FeeForWeight(estimator.Weight())
        if inputSum >= outputSum+packetFeeNoChange {
                // Calculate the packet's fee with a change output so, so we can
                // let the coin selection algorithm decide whether to use a
                // change output or not.
                switch changeType {
                case chanfunding.P2TRChangeAddress:
                        estimator.AddP2TROutput()

                case chanfunding.P2WKHChangeAddress:
                        estimator.AddP2WKHOutput()
                }
                packetFeeWithChange := feeRate.FeeForWeight(estimator.Weight())

                changeAmt, needMore, err := chanfunding.CalculateChangeAmount(
                        inputSum, outputSum, packetFeeNoChange,
                        packetFeeWithChange, changeDustLimit, changeType,
                        maxFeeRatio,
                )
                if err != nil {
                        return nil, fmt.Errorf("error calculating change "+
                                "amount: %w", err)
                }

                // We shouldn't get into this branch if the input sum isn't
                // enough to pay for the current package without a change
                // output. So this should never be non-zero.
                if needMore != 0 {
                        return nil, fmt.Errorf("internal error with change " +
                                "amount calculation")
                }

                if changeAmt > 0 {
                        changeIndex, err = w.handleChange(
                                packet, changeIndex, int64(changeAmt),
                                changeType, account,
                        )
                        if err != nil {
                                return nil, fmt.Errorf("error handling change "+
                                        "amount: %w", err)
                        }
                }

                // We're done. Let's serialize and return the updated package.
                return w.lockAndCreateFundingResponse(packet, nil, changeIndex)
        }

        // The RPC parsing part is now over. Several of the following operations
        // require us to hold the global coin selection lock, so we do the rest
        // of the tasks while holding the lock. The result is a list of locked
        // UTXOs.
        var response *FundPsbtResponse
        err = w.cfg.CoinSelectionLocker.WithCoinSelectLock(func() error {
                // Get a list of all unspent witness outputs.
                utxos, err := w.cfg.Wallet.ListUnspentWitness(
                        minConfs, defaultMaxConf, account,
                )
                if err != nil {
                        return err
                }

                coins := make([]base.Coin, len(utxos))
                for i, utxo := range utxos {
                        coins[i] = base.Coin{
                                TxOut: wire.TxOut{
                                        Value:    int64(utxo.Value),
                                        PkScript: utxo.PkScript,
                                },
                                OutPoint: utxo.OutPoint,
                        }
                }

                selectedCoins, changeAmount, err := chanfunding.CoinSelect(
                        feeRate, fundingAmount, changeDustLimit, coins,
                        strategy, estimator, changeType, maxFeeRatio,
                )
                if err != nil {
                        return fmt.Errorf("error selecting coins: %w", err)
                }

                if changeAmount > 0 {
                        changeIndex, err = w.handleChange(
                                packet, changeIndex, int64(changeAmount),
                                changeType, account,
                        )
                        if err != nil {
                                return fmt.Errorf("error handling change "+
                                        "amount: %w", err)
                        }
                }

                addedOutpoints := make([]wire.OutPoint, len(selectedCoins))
                for i := range selectedCoins {
                        coin := selectedCoins[i]
                        addedOutpoints[i] = coin.OutPoint

                        packet.UnsignedTx.TxIn = append(
                                packet.UnsignedTx.TxIn, &wire.TxIn{
                                        PreviousOutPoint: coin.OutPoint,
                                },
                        )
                        packet.Inputs = append(packet.Inputs, psbt.PInput{
                                WitnessUtxo: &coin.TxOut,
                        })
                }

                // Now that we've added the bare TX inputs, we also need to add
                // the more verbose input information to the packet, so a future
                // signer doesn't need to do any lookups. We skip any inputs
                // that our wallet doesn't own.
                err = w.cfg.Wallet.DecorateInputs(packet, false)
                if err != nil {
                        return fmt.Errorf("error decorating inputs: %w", err)
                }

                response, err = w.lockAndCreateFundingResponse(
                        packet, addedOutpoints, changeIndex,
                )

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

        return response, nil
}

// assertNotAvailable makes sure the specified inputs either don't belong to
// this node or are already locked by the user.
func (w *WalletKit) assertNotAvailable(inputs []*wire.TxIn, minConfs int32,
        account string) error {

        return w.cfg.CoinSelectionLocker.WithCoinSelectLock(func() error {
                // Get a list of all unspent witness outputs.
                utxos, err := w.cfg.Wallet.ListUnspentWitness(
                        minConfs, defaultMaxConf, account,
                )
                if err != nil {
                        return fmt.Errorf("error fetching UTXOs: %w", err)
                }

                // We'll now check that none of the inputs specified in the
                // template are available to us. That means they either don't
                // belong to us or are already locked by the user.
                for _, txIn := range inputs {
                        for _, utxo := range utxos {
                                if txIn.PreviousOutPoint == utxo.OutPoint {
                                        return fmt.Errorf("input %v is not "+
                                                "locked", txIn.PreviousOutPoint)
                                }
                        }
                }

                return nil
        })
}

// lockAndCreateFundingResponse locks the given outpoints and creates a funding
// response with the serialized PSBT, the change index and the locked UTXOs.
func (w *WalletKit) lockAndCreateFundingResponse(packet *psbt.Packet,
        newOutpoints []wire.OutPoint, changeIndex int32) (*FundPsbtResponse,
        error) {

        // Make sure we can properly serialize the packet. If this goes wrong
        // then something isn't right with the inputs, and we probably shouldn't
        // try to lock any of them.
        var buf bytes.Buffer
        err := packet.Serialize(&buf)
        if err != nil {
                return nil, fmt.Errorf("error serializing funded PSBT: %w", err)
        }

        locks, err := lockInputs(w.cfg.Wallet, newOutpoints)
        if err != nil {
                return nil, fmt.Errorf("could not lock inputs: %w", err)
        }

        // Convert the lock leases to the RPC format.
        rpcLocks := marshallLeases(locks)

        return &FundPsbtResponse{
                FundedPsbt:        buf.Bytes(),
                ChangeOutputIndex: changeIndex,
                LockedUtxos:       rpcLocks,
        }, nil
}

// handleChange is a closure that either adds the non-zero change amount to an
// existing output or creates a change output. The function returns the new
// change output index if a new change output was added.
func (w *WalletKit) handleChange(packet *psbt.Packet, changeIndex int32,
        changeAmount int64, changeType chanfunding.ChangeAddressType,
        changeAccount string) (int32, error) {

        // Does an existing output get the change?
        if changeIndex >= 0 {
                changeOut := packet.UnsignedTx.TxOut[changeIndex]
                changeOut.Value += changeAmount

                return changeIndex, nil
        }

        // The user requested a new change output.
        addrType := addrTypeFromChangeAddressType(changeType)
        changeAddr, err := w.cfg.Wallet.NewAddress(
                addrType, true, changeAccount,
        )
        if err != nil {
                return 0, fmt.Errorf("could not derive change address: %w", err)
        }

        changeScript, err := txscript.PayToAddrScript(changeAddr)
        if err != nil {
                return 0, fmt.Errorf("could not derive change script: %w", err)
        }

        // We need to add the derivation info for the change address in case it
        // is a P2TR address. This is mostly to prove it's a bare BIP-0086
        // address, which is required for some protocols (such as Taproot
        // Assets).
        pOut := psbt.POutput{}
        _, isTaprootChangeAddr := changeAddr.(*btcutil.AddressTaproot)
        if isTaprootChangeAddr {
                changeAddrInfo, err := w.cfg.Wallet.AddressInfo(changeAddr)
                if err != nil {
                        return 0, fmt.Errorf("could not get address info: %w",
                                err)
                }

                deriv, trDeriv, _, err := btcwallet.Bip32DerivationFromAddress(
                        changeAddrInfo,
                )
                if err != nil {
                        return 0, fmt.Errorf("could not get derivation info: "+
                                "%w", err)
                }

                pOut.TaprootInternalKey = trDeriv.XOnlyPubKey
                pOut.Bip32Derivation = []*psbt.Bip32Derivation{deriv}
                pOut.TaprootBip32Derivation = []*psbt.TaprootBip32Derivation{
                        trDeriv,
                }
        }

        newChangeIndex := int32(len(packet.Outputs))
        packet.UnsignedTx.TxOut = append(
                packet.UnsignedTx.TxOut, &wire.TxOut{
                        Value:    changeAmount,
                        PkScript: changeScript,
                },
        )
        packet.Outputs = append(packet.Outputs, pOut)

        return newChangeIndex, nil
}

// marshallLeases converts the lock leases to the RPC format.
func marshallLeases(locks []*base.ListLeasedOutputResult) []*UtxoLease {
        rpcLocks := make([]*UtxoLease, len(locks))
        for idx, lock := range locks {
                lock := lock

                rpcLocks[idx] = &UtxoLease{
                        Id:         lock.LockID[:],
                        Outpoint:   lnrpc.MarshalOutPoint(&lock.Outpoint),
                        Expiration: uint64(lock.Expiration.Unix()),
                        PkScript:   lock.PkScript,
                        Value:      uint64(lock.Value),
                }
        }

        return rpcLocks
}

// keyScopeFromChangeAddressType maps a ChangeAddressType from protobuf to a
// KeyScope. If the type is ChangeAddressType_CHANGE_ADDRESS_TYPE_UNSPECIFIED,
// it returns nil.
func keyScopeFromChangeAddressType(
        changeAddressType ChangeAddressType) *waddrmgr.KeyScope {

        switch changeAddressType {
        case ChangeAddressType_CHANGE_ADDRESS_TYPE_P2TR:
                return &waddrmgr.KeyScopeBIP0086

        default:
                return nil
        }
}

// addrTypeFromChangeAddressType maps a chanfunding.ChangeAddressType to the
// lnwallet.AddressType.
func addrTypeFromChangeAddressType(
        changeAddressType chanfunding.ChangeAddressType) lnwallet.AddressType {

        switch changeAddressType {
        case chanfunding.P2TRChangeAddress:
                return lnwallet.TaprootPubkey

        default:
                return lnwallet.WitnessPubKey
        }
}

// SignPsbt expects a partial transaction with all inputs and outputs fully
// declared and tries to sign all unsigned inputs that have all required fields
// (UTXO information, BIP32 derivation information, witness or sig scripts)
// set.
// If no error is returned, the PSBT is ready to be given to the next signer or
// to be finalized if lnd was the last signer.
//
// NOTE: This RPC only signs inputs (and only those it can sign), it does not
// perform any other tasks (such as coin selection, UTXO locking or
// input/output/fee value validation, PSBT finalization). Any input that is
// incomplete will be skipped.
func (w *WalletKit) SignPsbt(_ context.Context, req *SignPsbtRequest) (
        *SignPsbtResponse, error) {

        packet, err := psbt.NewFromRawBytes(
                bytes.NewReader(req.FundedPsbt), false,
        )
        if err != nil {
                log.Debugf("Error parsing PSBT: %v, raw input: %x", err,
                        req.FundedPsbt)
                return nil, fmt.Errorf("error parsing PSBT: %w", err)
        }

        // Before we attempt to sign the packet, ensure that every input either
        // has a witness UTXO, or a non witness UTXO.
        for idx := range packet.UnsignedTx.TxIn {
                in := packet.Inputs[idx]

                // Doesn't have either a witness or non witness UTXO so we need
                // to exit here as otherwise signing will fail.
                if in.WitnessUtxo == nil && in.NonWitnessUtxo == nil {
                        return nil, fmt.Errorf("input (index=%v) doesn't "+
                                "specify any UTXO info", idx)
                }
        }

        // Let the wallet do the heavy lifting. This will sign all inputs that
        // we have the UTXO for. If some inputs can't be signed and don't have
        // witness data attached, they will just be skipped.
        signedInputs, err := w.cfg.Wallet.SignPsbt(packet)
        if err != nil {
                return nil, fmt.Errorf("error signing PSBT: %w", err)
        }

        // Serialize the signed PSBT in both the packet and wire format.
        var signedPsbtBytes bytes.Buffer
        err = packet.Serialize(&signedPsbtBytes)
        if err != nil {
                return nil, fmt.Errorf("error serializing PSBT: %w", err)
        }

        return &SignPsbtResponse{
                SignedPsbt:   signedPsbtBytes.Bytes(),
                SignedInputs: signedInputs,
        }, nil
}

// FinalizePsbt expects a partial transaction with all inputs and outputs fully
// declared and tries to sign all inputs that belong to the wallet. Lnd must be
// the last signer of the transaction. That means, if there are any unsigned
// non-witness inputs or inputs without UTXO information attached or inputs
// without witness data that do not belong to lnd's wallet, this method will
// fail. If no error is returned, the PSBT is ready to be extracted and the
// final TX within to be broadcast.
//
// NOTE: This method does NOT publish the transaction once finalized. It is the
// caller's responsibility to either publish the transaction on success or
// unlock/release any locked UTXOs in case of an error in this method.
func (w *WalletKit) FinalizePsbt(_ context.Context,
        req *FinalizePsbtRequest) (*FinalizePsbtResponse, error) {

        // We'll assume the PSBT was funded by the default account unless
        // otherwise specified.
        account := lnwallet.DefaultAccountName
        if req.Account != "" {
                account = req.Account
        }

        // Parse the funded PSBT.
        packet, err := psbt.NewFromRawBytes(
                bytes.NewReader(req.FundedPsbt), false,
        )
        if err != nil {
                return nil, fmt.Errorf("error parsing PSBT: %w", err)
        }

        // The only check done at this level is to validate that the PSBT is
        // not complete. The wallet performs all other checks.
        if packet.IsComplete() {
                return nil, fmt.Errorf("PSBT is already fully signed")
        }

        // Let the wallet do the heavy lifting. This will sign all inputs that
        // we have the UTXO for. If some inputs can't be signed and don't have
        // witness data attached, this will fail.
        err = w.cfg.Wallet.FinalizePsbt(packet, account)
        if err != nil {
                return nil, fmt.Errorf("error finalizing PSBT: %w", err)
        }

        var (
                finalPsbtBytes bytes.Buffer
                finalTxBytes   bytes.Buffer
        )

        // Serialize the finalized PSBT in both the packet and wire format.
        err = packet.Serialize(&finalPsbtBytes)
        if err != nil {
                return nil, fmt.Errorf("error serializing PSBT: %w", err)
        }
        finalTx, err := psbt.Extract(packet)
        if err != nil {
                return nil, fmt.Errorf("unable to extract final TX: %w", err)
        }
        err = finalTx.Serialize(&finalTxBytes)
        if err != nil {
                return nil, fmt.Errorf("error serializing final TX: %w", err)
        }

        return &FinalizePsbtResponse{
                SignedPsbt: finalPsbtBytes.Bytes(),
                RawFinalTx: finalTxBytes.Bytes(),
        }, nil
}

// marshalWalletAccount converts the properties of an account into its RPC
// representation.
func marshalWalletAccount(internalScope waddrmgr.KeyScope,
        account *waddrmgr.AccountProperties) (*Account, error) {

        var addrType AddressType
        switch account.KeyScope {
        case waddrmgr.KeyScopeBIP0049Plus:
                // No address schema present represents the traditional BIP-0049
                // address derivation scheme.
                if account.AddrSchema == nil {
                        addrType = AddressType_HYBRID_NESTED_WITNESS_PUBKEY_HASH
                        break
                }

                switch *account.AddrSchema {
                case waddrmgr.KeyScopeBIP0049AddrSchema:
                        addrType = AddressType_NESTED_WITNESS_PUBKEY_HASH

                case waddrmgr.ScopeAddrMap[waddrmgr.KeyScopeBIP0049Plus]:
                        addrType = AddressType_HYBRID_NESTED_WITNESS_PUBKEY_HASH

                default:
                        return nil, fmt.Errorf("unsupported address schema %v",
                                *account.AddrSchema)
                }

        case waddrmgr.KeyScopeBIP0084:
                addrType = AddressType_WITNESS_PUBKEY_HASH

        case waddrmgr.KeyScopeBIP0086:
                addrType = AddressType_TAPROOT_PUBKEY

        case internalScope:
                addrType = AddressType_WITNESS_PUBKEY_HASH

        default:
                return nil, fmt.Errorf("account %v has unsupported "+
                        "key scope %v", account.AccountName, account.KeyScope)
        }

        rpcAccount := &Account{
                Name:             account.AccountName,
                AddressType:      addrType,
                ExternalKeyCount: account.ExternalKeyCount,
                InternalKeyCount: account.InternalKeyCount,
                WatchOnly:        account.IsWatchOnly,
        }

        // The remaining fields can only be done on accounts other than the
        // default imported one existing within each key scope.
        if account.AccountName != waddrmgr.ImportedAddrAccountName {
                nonHardenedIndex := account.AccountPubKey.ChildIndex() -
                        hdkeychain.HardenedKeyStart
                rpcAccount.ExtendedPublicKey = account.AccountPubKey.String()
                if account.MasterKeyFingerprint != 0 {
                        var mkfp [4]byte
                        binary.BigEndian.PutUint32(
                                mkfp[:], account.MasterKeyFingerprint,
                        )
                        rpcAccount.MasterKeyFingerprint = mkfp[:]
                }
                rpcAccount.DerivationPath = fmt.Sprintf("%v/%v'",
                        account.KeyScope, nonHardenedIndex)
        }

        return rpcAccount, nil
}

// marshalWalletAddressList converts the list of address into its RPC
// representation.
func marshalWalletAddressList(w *WalletKit, account *waddrmgr.AccountProperties,
        addressList []lnwallet.AddressProperty) (*AccountWithAddresses, error) {

        // Get the RPC representation of account.
        rpcAccount, err := marshalWalletAccount(
                w.internalScope(), account,
        )
        if err != nil {
                return nil, err
        }

        addresses := make([]*AddressProperty, len(addressList))
        for idx, addr := range addressList {
                var pubKeyBytes []byte
                if addr.PublicKey != nil {
                        pubKeyBytes = addr.PublicKey.SerializeCompressed()
                }
                addresses[idx] = &AddressProperty{
                        Address:        addr.Address,
                        IsInternal:     addr.Internal,
                        Balance:        int64(addr.Balance),
                        DerivationPath: addr.DerivationPath,
                        PublicKey:      pubKeyBytes,
                }
        }

        rpcAddressList := &AccountWithAddresses{
                Name:           rpcAccount.Name,
                AddressType:    rpcAccount.AddressType,
                DerivationPath: rpcAccount.DerivationPath,
                Addresses:      addresses,
        }

        return rpcAddressList, nil
}

// ListAccounts retrieves all accounts belonging to the wallet by default. A
// name and key scope filter can be provided to filter through all of the wallet
// accounts and return only those matching.
func (w *WalletKit) ListAccounts(ctx context.Context,
        req *ListAccountsRequest) (*ListAccountsResponse, error) {

        // Map the supported address types into their corresponding key scope.
        var keyScopeFilter *waddrmgr.KeyScope
        switch req.AddressType {
        case AddressType_UNKNOWN:
                break

        case AddressType_WITNESS_PUBKEY_HASH:
                keyScope := waddrmgr.KeyScopeBIP0084
                keyScopeFilter = &keyScope

        case AddressType_NESTED_WITNESS_PUBKEY_HASH,
                AddressType_HYBRID_NESTED_WITNESS_PUBKEY_HASH:

                keyScope := waddrmgr.KeyScopeBIP0049Plus
                keyScopeFilter = &keyScope

        case AddressType_TAPROOT_PUBKEY:
                keyScope := waddrmgr.KeyScopeBIP0086
                keyScopeFilter = &keyScope

        default:
                return nil, fmt.Errorf("unhandled address type %v",
                        req.AddressType)
        }

        accounts, err := w.cfg.Wallet.ListAccounts(req.Name, keyScopeFilter)
        if err != nil {
                return nil, err
        }

        rpcAccounts := make([]*Account, 0, len(accounts))
        for _, account := range accounts {
                // Don't include the default imported accounts created by the
                // wallet in the response if they don't have any keys imported.
                if account.AccountName == waddrmgr.ImportedAddrAccountName &&
                        account.ImportedKeyCount == 0 {

                        continue
                }

                rpcAccount, err := marshalWalletAccount(
                        w.internalScope(), account,
                )
                if err != nil {
                        return nil, err
                }
                rpcAccounts = append(rpcAccounts, rpcAccount)
        }

        return &ListAccountsResponse{Accounts: rpcAccounts}, nil
}

// RequiredReserve returns the minimum amount of satoshis that should be
// kept in the wallet in order to fee bump anchor channels if necessary.
// The value scales with the number of public anchor channels but is
// capped at a maximum.
func (w *WalletKit) RequiredReserve(ctx context.Context,
        req *RequiredReserveRequest) (*RequiredReserveResponse, error) {

        numAnchorChans, err := w.cfg.CurrentNumAnchorChans()
        if err != nil {
                return nil, err
        }

        additionalChans := req.AdditionalPublicChannels
        totalChans := uint32(numAnchorChans) + additionalChans
        reserved := w.cfg.Wallet.RequiredReserve(totalChans)

        return &RequiredReserveResponse{
                RequiredReserve: int64(reserved),
        }, nil
}

// ListAddresses retrieves all the addresses along with their balance. An
// account name filter can be provided to filter through all of the
// wallet accounts and return the addresses of only those matching.
func (w *WalletKit) ListAddresses(ctx context.Context,
        req *ListAddressesRequest) (*ListAddressesResponse, error) {

        addressLists, err := w.cfg.Wallet.ListAddresses(
                req.AccountName,
                req.ShowCustomAccounts,
        )
        if err != nil {
                return nil, err
        }

        // Create a slice of accounts from addressLists map.
        accounts := make([]*waddrmgr.AccountProperties, 0, len(addressLists))
        for account := range addressLists {
                accounts = append(accounts, account)
        }

        // Sort the accounts by derivation path.
        sort.Slice(accounts, func(i, j int) bool {
                scopeI := accounts[i].KeyScope
                scopeJ := accounts[j].KeyScope
                if scopeI.Purpose == scopeJ.Purpose {
                        if scopeI.Coin == scopeJ.Coin {
                                acntNumI := accounts[i].AccountNumber
                                acntNumJ := accounts[j].AccountNumber
                                return acntNumI < acntNumJ
                        }

                        return scopeI.Coin < scopeJ.Coin
                }

                return scopeI.Purpose < scopeJ.Purpose
        })

        rpcAddressLists := make([]*AccountWithAddresses, 0, len(addressLists))
        for _, account := range accounts {
                addressList := addressLists[account]
                rpcAddressList, err := marshalWalletAddressList(
                        w, account, addressList,
                )
                if err != nil {
                        return nil, err
                }

                rpcAddressLists = append(rpcAddressLists, rpcAddressList)
        }

        return &ListAddressesResponse{
                AccountWithAddresses: rpcAddressLists,
        }, nil
}

// parseAddrType parses an address type from its RPC representation to a
// *waddrmgr.AddressType.
func parseAddrType(addrType AddressType,
        required bool) (*waddrmgr.AddressType, error) {

        switch addrType {
        case AddressType_UNKNOWN:
                if required {
                        return nil, fmt.Errorf("an address type must be " +
                                "specified")
                }
                return nil, nil

        case AddressType_WITNESS_PUBKEY_HASH:
                addrTyp := waddrmgr.WitnessPubKey
                return &addrTyp, nil

        case AddressType_NESTED_WITNESS_PUBKEY_HASH:
                addrTyp := waddrmgr.NestedWitnessPubKey
                return &addrTyp, nil

        case AddressType_HYBRID_NESTED_WITNESS_PUBKEY_HASH:
                addrTyp := waddrmgr.WitnessPubKey
                return &addrTyp, nil

        case AddressType_TAPROOT_PUBKEY:
                addrTyp := waddrmgr.TaprootPubKey
                return &addrTyp, nil

        default:
                return nil, fmt.Errorf("unhandled address type %v", addrType)
        }
}

// msgSignaturePrefix is a prefix used to prevent inadvertently signing a
// transaction or a signature. It is prepended in front of the message and
// follows the same standard as bitcoin core and btcd.
const msgSignaturePrefix = "Bitcoin Signed Message:\n"

// SignMessageWithAddr signs a message with the private key of the provided
// address. The address needs to belong to the lnd wallet.
func (w *WalletKit) SignMessageWithAddr(_ context.Context,
        req *SignMessageWithAddrRequest) (*SignMessageWithAddrResponse, error) {

        addr, err := btcutil.DecodeAddress(req.Addr, w.cfg.ChainParams)
        if err != nil {
                return nil, fmt.Errorf("unable to decode address: %w", err)
        }

        if !addr.IsForNet(w.cfg.ChainParams) {
                return nil, fmt.Errorf("encoded address is for "+
                        "the wrong network %s", req.Addr)
        }

        // Fetch address infos from own wallet and check whether it belongs
        // to the lnd wallet.
        managedAddr, err := w.cfg.Wallet.AddressInfo(addr)
        if err != nil {
                return nil, fmt.Errorf("address could not be found in the "+
                        "wallet database: %w", err)
        }

        // Verifying by checking the interface type that the wallet knows about
        // the public and private keys so it can sign the message with the
        // private key of this address.
        pubKey, ok := managedAddr.(waddrmgr.ManagedPubKeyAddress)
        if !ok {
                return nil, fmt.Errorf("private key to address is unknown")
        }

        digest, err := doubleHashMessage(msgSignaturePrefix, string(req.Msg))
        if err != nil {
                return nil, err
        }

        // For all address types (P2WKH, NP2WKH,P2TR) the ECDSA compact signing
        // algorithm is used. For P2TR addresses this represents a special case.
        // ECDSA is used to create a compact signature which makes the public
        // key of the signature recoverable. For Schnorr no known compact
        // signing algorithm exists yet.
        privKey, err := pubKey.PrivKey()
        if err != nil {
                return nil, fmt.Errorf("no private key could be "+
                        "fetched from wallet database: %w", err)
        }

        sigBytes := ecdsa.SignCompact(privKey, digest, pubKey.Compressed())

        // Bitcoin signatures are base64 encoded (being compatible with
        // bitcoin-core and btcd).
        sig := base64.StdEncoding.EncodeToString(sigBytes)

        return &SignMessageWithAddrResponse{
                Signature: sig,
        }, nil
}

// VerifyMessageWithAddr verifies a signature on a message with a provided
// address, it checks both the validity of the signature itself and then
// verifies whether the signature corresponds to the public key of the
// provided address. There is no dependence on the private key of the address
// therefore also external addresses are allowed to verify signatures.
// Supported address types are P2PKH, P2WKH, NP2WKH, P2TR.
func (w *WalletKit) VerifyMessageWithAddr(_ context.Context,
        req *VerifyMessageWithAddrRequest) (*VerifyMessageWithAddrResponse,
        error) {

        sig, err := base64.StdEncoding.DecodeString(req.Signature)
        if err != nil {
                return nil, fmt.Errorf("malformed base64 encoding of "+
                        "the signature: %w", err)
        }

        digest, err := doubleHashMessage(msgSignaturePrefix, string(req.Msg))
        if err != nil {
                return nil, err
        }

        pk, wasCompressed, err := ecdsa.RecoverCompact(sig, digest)
        if err != nil {
                return nil, fmt.Errorf("unable to recover public key "+
                        "from compact signature: %w", err)
        }

        var serializedPubkey []byte
        if wasCompressed {
                serializedPubkey = pk.SerializeCompressed()
        } else {
                serializedPubkey = pk.SerializeUncompressed()
        }

        addr, err := btcutil.DecodeAddress(req.Addr, w.cfg.ChainParams)
        if err != nil {
                return nil, fmt.Errorf("unable to decode address: %w", err)
        }

        if !addr.IsForNet(w.cfg.ChainParams) {
                return nil, fmt.Errorf("encoded address is for"+
                        "the wrong network %s", req.Addr)
        }

        var (
                address    btcutil.Address
                pubKeyHash = btcutil.Hash160(serializedPubkey)
        )

        // Ensure the address is one of the supported types.
        switch addr.(type) {
        case *btcutil.AddressPubKeyHash:
                address, err = btcutil.NewAddressPubKeyHash(
                        pubKeyHash, w.cfg.ChainParams,
                )
                if err != nil {
                        return nil, err
                }

        case *btcutil.AddressWitnessPubKeyHash:
                address, err = btcutil.NewAddressWitnessPubKeyHash(
                        pubKeyHash, w.cfg.ChainParams,
                )
                if err != nil {
                        return nil, err
                }

        case *btcutil.AddressScriptHash:
                // Check if address is a Nested P2WKH (NP2WKH).
                address, err = btcutil.NewAddressWitnessPubKeyHash(
                        pubKeyHash, w.cfg.ChainParams,
                )
                if err != nil {
                        return nil, err
                }

                witnessScript, err := txscript.PayToAddrScript(address)
                if err != nil {
                        return nil, err
                }

                address, err = btcutil.NewAddressScriptHashFromHash(
                        btcutil.Hash160(witnessScript), w.cfg.ChainParams,
                )
                if err != nil {
                        return nil, err
                }

        case *btcutil.AddressTaproot:
                // Only addresses without a tapscript are allowed because
                // the verification is using the internal key.
                tapKey := txscript.ComputeTaprootKeyNoScript(pk)
                address, err = btcutil.NewAddressTaproot(
                        schnorr.SerializePubKey(tapKey),
                        w.cfg.ChainParams,
                )
                if err != nil {
                        return nil, err
                }

        default:
                return nil, fmt.Errorf("unsupported address type")
        }

        return &VerifyMessageWithAddrResponse{
                Valid:  req.Addr == address.EncodeAddress(),
                Pubkey: serializedPubkey,
        }, nil
}

// ImportAccount imports an account backed by an account extended public key.
// The master key fingerprint denotes the fingerprint of the root key
// corresponding to the account public key (also known as the key with
// derivation path m/). This may be required by some hardware wallets for proper
// identification and signing.
//
// The address type can usually be inferred from the key's version, but may be
// required for certain keys to map them into the proper scope.
//
// For BIP-0044 keys, an address type must be specified as we intend to not
// support importing BIP-0044 keys into the wallet using the legacy
// pay-to-pubkey-hash (P2PKH) scheme. A nested witness address type will force
// the standard BIP-0049 derivation scheme, while a witness address type will
// force the standard BIP-0084 derivation scheme.
//
// For BIP-0049 keys, an address type must also be specified to make a
// distinction between the standard BIP-0049 address schema (nested witness
// pubkeys everywhere) and our own BIP-0049Plus address schema (nested pubkeys
// externally, witness pubkeys internally).
func (w *WalletKit) ImportAccount(_ context.Context,
        req *ImportAccountRequest) (*ImportAccountResponse, error) {

        accountPubKey, err := hdkeychain.NewKeyFromString(req.ExtendedPublicKey)
        if err != nil {
                return nil, err
        }

        var mkfp uint32
        switch len(req.MasterKeyFingerprint) {
        // No master key fingerprint provided, which is fine as it's not
        // required.
        case 0:
        // Expected length.
        case 4:
                mkfp = binary.BigEndian.Uint32(req.MasterKeyFingerprint)
        default:
                return nil, errors.New("invalid length for master key " +
                        "fingerprint, expected 4 bytes in big-endian")
        }

        addrType, err := parseAddrType(req.AddressType, false)
        if err != nil {
                return nil, err
        }

        accountProps, extAddrs, intAddrs, err := w.cfg.Wallet.ImportAccount(
                req.Name, accountPubKey, mkfp, addrType, req.DryRun,
        )
        if err != nil {
                return nil, err
        }

        rpcAccount, err := marshalWalletAccount(w.internalScope(), accountProps)
        if err != nil {
                return nil, err
        }

        resp := &ImportAccountResponse{Account: rpcAccount}
        if !req.DryRun {
                return resp, nil
        }

        resp.DryRunExternalAddrs = make([]string, len(extAddrs))
        for i := 0; i < len(extAddrs); i++ {
                resp.DryRunExternalAddrs[i] = extAddrs[i].String()
        }
        resp.DryRunInternalAddrs = make([]string, len(intAddrs))
        for i := 0; i < len(intAddrs); i++ {
                resp.DryRunInternalAddrs[i] = intAddrs[i].String()
        }

        return resp, nil
}

// ImportPublicKey imports a single derived public key into the wallet. The
// address type can usually be inferred from the key's version, but in the case
// of legacy versions (xpub, tpub), an address type must be specified as we
// intend to not support importing BIP-44 keys into the wallet using the legacy
// pay-to-pubkey-hash (P2PKH) scheme. For Taproot keys, this will only watch
// the BIP-0086 style output script. Use ImportTapscript for more advanced key
// spend or script spend outputs.
func (w *WalletKit) ImportPublicKey(_ context.Context,
        req *ImportPublicKeyRequest) (*ImportPublicKeyResponse, error) {

        var (
                pubKey *btcec.PublicKey
                err    error
        )
        switch req.AddressType {
        case AddressType_TAPROOT_PUBKEY:
                pubKey, err = schnorr.ParsePubKey(req.PublicKey)

        default:
                pubKey, err = btcec.ParsePubKey(req.PublicKey)
        }
        if err != nil {
                return nil, err
        }

        addrType, err := parseAddrType(req.AddressType, true)
        if err != nil {
                return nil, err
        }

        if err := w.cfg.Wallet.ImportPublicKey(pubKey, *addrType); err != nil {
                return nil, err
        }

        return &ImportPublicKeyResponse{
                Status: fmt.Sprintf("public key %x imported",
                        pubKey.SerializeCompressed()),
        }, nil
}

// ImportTapscript imports a Taproot script and internal key and adds the
// resulting Taproot output key as a watch-only output script into the wallet.
// For BIP-0086 style Taproot keys (no root hash commitment and no script spend
// path) use ImportPublicKey.
//
// NOTE: Taproot keys imported through this RPC currently _cannot_ be used for
// funding PSBTs. Only tracking the balance and UTXOs is currently supported.
func (w *WalletKit) ImportTapscript(_ context.Context,
        req *ImportTapscriptRequest) (*ImportTapscriptResponse, error) {

        internalKey, err := schnorr.ParsePubKey(req.InternalPublicKey)
        if err != nil {
                return nil, fmt.Errorf("error parsing internal key: %w", err)
        }

        var tapscript *waddrmgr.Tapscript
        switch {
        case req.GetFullTree() != nil:
                tree := req.GetFullTree()
                leaves := make([]txscript.TapLeaf, len(tree.AllLeaves))
                for idx, leaf := range tree.AllLeaves {
                        leaves[idx] = txscript.TapLeaf{
                                LeafVersion: txscript.TapscriptLeafVersion(
                                        leaf.LeafVersion,
                                ),
                                Script: leaf.Script,
                        }
                }

                tapscript = input.TapscriptFullTree(internalKey, leaves...)

        case req.GetPartialReveal() != nil:
                partialReveal := req.GetPartialReveal()
                if partialReveal.RevealedLeaf == nil {
                        return nil, fmt.Errorf("missing revealed leaf")
                }

                revealedLeaf := txscript.TapLeaf{
                        LeafVersion: txscript.TapscriptLeafVersion(
                                partialReveal.RevealedLeaf.LeafVersion,
                        ),
                        Script: partialReveal.RevealedLeaf.Script,
                }
                if len(partialReveal.FullInclusionProof)%32 != 0 {
                        return nil, fmt.Errorf("invalid inclusion proof "+
                                "length, expected multiple of 32, got %d",
                                len(partialReveal.FullInclusionProof)%32)
                }

                tapscript = input.TapscriptPartialReveal(
                        internalKey, revealedLeaf,
                        partialReveal.FullInclusionProof,
                )

        case req.GetRootHashOnly() != nil:
                rootHash := req.GetRootHashOnly()
                if len(rootHash) == 0 {
                        return nil, fmt.Errorf("missing root hash")
                }

                tapscript = input.TapscriptRootHashOnly(internalKey, rootHash)

        case req.GetFullKeyOnly():
                tapscript = input.TapscriptFullKeyOnly(internalKey)

        default:
                return nil, fmt.Errorf("invalid script")
        }

        taprootScope := waddrmgr.KeyScopeBIP0086
        addr, err := w.cfg.Wallet.ImportTaprootScript(taprootScope, tapscript)
        if err != nil {
                return nil, fmt.Errorf("error importing script into wallet: %w",
                        err)
        }

        return &ImportTapscriptResponse{
                P2TrAddress: addr.Address().String(),
        }, nil
}

lightningnetwork / lnd / 12235114561

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