lnwallet+peer: move internalKeyForAddr to lnwallet package

This way we can re-use it. We also make it slightly more generalized.

server.go

@@ -18,6 +18,7 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcec/v2/ecdsa"
 	"github.com/btcsuite/btcd/btcutil"
+	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/connmgr"
 	"github.com/btcsuite/btcd/txscript"
@@ -520,6 +521,8 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 	var serializedPubKey [33]byte
 	copy(serializedPubKey[:], nodeKeyDesc.PubKey.SerializeCompressed())
 
+	netParams := cfg.ActiveNetParams.Params
+
 	// Initialize the sphinx router.
 	replayLog := htlcswitch.NewDecayedLog(
 		dbs.DecayedLogDB, cc.ChainNotifier,
@@ -1123,8 +1126,10 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 	})
 
 	s.sweeper = sweep.New(&sweep.UtxoSweeperConfig{
-		FeeEstimator:         cc.FeeEstimator,
-		GenSweepScript:       newSweepPkScriptGen(cc.Wallet),
+		FeeEstimator: cc.FeeEstimator,
+		GenSweepScript: newSweepPkScriptGen(
+			cc.Wallet, s.cfg.ActiveNetParams.Params,
+		),
 		Signer:               cc.Wallet.Cfg.Signer,
 		Wallet:               newSweeperWallet(cc.Wallet),
 		Mempool:              cc.MempoolNotifier,
@@ -1167,10 +1172,19 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 
 	s.breachArbitrator = contractcourt.NewBreachArbitrator(
 		&contractcourt.BreachConfig{
-			CloseLink:          closeLink,
-			DB:                 s.chanStateDB,
-			Estimator:          s.cc.FeeEstimator,
-			GenSweepScript:     newSweepPkScriptGen(cc.Wallet),
+			CloseLink: closeLink,
+			DB:        s.chanStateDB,
+			Estimator: s.cc.FeeEstimator,
+			GenSweepScript: func() ([]byte, error) {
+				addr, err := newSweepPkScriptGen(
+					cc.Wallet, netParams,
+				)().Unpack()
+				if err != nil {
+					return nil, err
+				}
+
+				return addr.DeliveryAddress, nil
+			},
 			Notifier:           cc.ChainNotifier,
 			PublishTransaction: cc.Wallet.PublishTransaction,
 			ContractBreaches:   contractBreaches,
@@ -1186,8 +1200,17 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 		ChainHash:              *s.cfg.ActiveNetParams.GenesisHash,
 		IncomingBroadcastDelta: lncfg.DefaultIncomingBroadcastDelta,
 		OutgoingBroadcastDelta: lncfg.DefaultOutgoingBroadcastDelta,
-		NewSweepAddr:           newSweepPkScriptGen(cc.Wallet),
-		PublishTx:              cc.Wallet.PublishTransaction,
+		NewSweepAddr: func() ([]byte, error) {
+			addr, err := newSweepPkScriptGen(
+				cc.Wallet, netParams,
+			)().Unpack()
+			if err != nil {
+				return nil, err
+			}
+
+			return addr.DeliveryAddress, nil
+		},
+		PublishTx: cc.Wallet.PublishTransaction,
 		DeliverResolutionMsg: func(msgs ...contractcourt.ResolutionMsg) error {
 			for _, msg := range msgs {
 				err := s.htlcSwitch.ProcessContractResolution(msg)
@@ -1665,8 +1688,17 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 				return s.channelNotifier.
 					SubscribeChannelEvents()
 			},
-			Signer:             cc.Wallet.Cfg.Signer,
-			NewAddress:         newSweepPkScriptGen(cc.Wallet),
+			Signer: cc.Wallet.Cfg.Signer,
+			NewAddress: func() ([]byte, error) {
+				addr, err := newSweepPkScriptGen(
+					cc.Wallet, netParams,
+				)().Unpack()
+				if err != nil {
+					return nil, err
+				}
+
+				return addr.DeliveryAddress, nil
+			},
 			SecretKeyRing:      s.cc.KeyRing,
 			Dial:               cfg.net.Dial,
 			AuthDial:           authDial,
@@ -4935,18 +4967,39 @@ func (s *server) SendCustomMessage(peerPub [33]byte, msgType lnwire.MessageType,
 // Specifically, the script generated is a version 0, pay-to-witness-pubkey-hash
 // (p2wkh) output.
 func newSweepPkScriptGen(
-	wallet lnwallet.WalletController) func() ([]byte, error) {
+	wallet lnwallet.WalletController,
+	netParams *chaincfg.Params) func() fn.Result[lnwallet.AddrWithKey] {
 
-	return func() ([]byte, error) {
+	return func() fn.Result[lnwallet.AddrWithKey] {
 		sweepAddr, err := wallet.NewAddress(
 			lnwallet.TaprootPubkey, false,
 			lnwallet.DefaultAccountName,
 		)
 		if err != nil {
-			return nil, err
+			return fn.Err[lnwallet.AddrWithKey](err)
 		}
 
-		return txscript.PayToAddrScript(sweepAddr)
+		addr, err := txscript.PayToAddrScript(sweepAddr)
+		if err != nil {
+			return fn.Err[lnwallet.AddrWithKey](err)
+		}
+
+		internalKeyDesc, err := lnwallet.InternalKeyForAddr(
+			wallet, netParams, addr,
+		)
+		if err != nil {
+			return fn.Err[lnwallet.AddrWithKey](err)
+		}
+
+		return fn.Ok(lnwallet.AddrWithKey{
+			DeliveryAddress: addr,
+			InternalKey: fn.MapOption(func(
+				desc keychain.KeyDescriptor) btcec.PublicKey {
+
+				return *desc.PubKey
+			},
+			)(internalKeyDesc),
+		})
 	}
 }