package main import ( "bytes" "encoding/hex" "github.com/btcsuite/btcd/chaincfg/chainhash" "github.com/btcsuite/btcd/txscript" "github.com/btcsuite/btcd/wire" "github.com/btcsuite/btcutil" "github.com/muun/libwallet" "github.com/muun/recovery/scanner" ) func buildSweepTx(utxos []*scanner.Utxo, sweepAddress btcutil.Address, fee int64) ([]byte, error) { tx := wire.NewMsgTx(2) value := int64(0) for _, utxo := range utxos { chainHash, err := chainhash.NewHashFromStr(utxo.TxID) if err != nil { return nil, err } outpoint := wire.OutPoint{ Hash: *chainHash, Index: uint32(utxo.OutputIndex), } tx.AddTxIn(wire.NewTxIn(&outpoint, []byte{}, [][]byte{})) value += utxo.Amount } value -= fee script, err := txscript.PayToAddrScript(sweepAddress) if err != nil { return nil, err } tx.AddTxOut(wire.NewTxOut(value, script)) writer := &bytes.Buffer{} err = tx.Serialize(writer) if err != nil { return nil, err } if fee != 0 { readConfirmation(value, fee, sweepAddress.String()) } return writer.Bytes(), nil } func buildSignedTx(utxos []*scanner.Utxo, sweepTx []byte, userKey *libwallet.HDPrivateKey, muunKey *libwallet.HDPrivateKey) (*wire.MsgTx, error) { inputList := &libwallet.InputList{} for _, utxo := range utxos { inputList.Add(&input{ utxo, []byte{}, }) } pstx, err := libwallet.NewPartiallySignedTransaction(inputList, sweepTx) if err != nil { return nil, err } signedTx, err := pstx.FullySign(userKey, muunKey) if err != nil { return nil, err } wireTx := wire.NewMsgTx(0) wireTx.BtcDecode(bytes.NewReader(signedTx.Bytes), 0, wire.WitnessEncoding) return wireTx, nil } // input is a minimal type that implements libwallet.Input type input struct { utxo *scanner.Utxo muunSignature []byte } func (i *input) OutPoint() libwallet.Outpoint { return &outpoint{utxo: i.utxo} } func (i *input) Address() libwallet.MuunAddress { return i.utxo.Address } func (i *input) UserSignature() []byte { return []byte{} } func (i *input) MuunSignature() []byte { return i.muunSignature } func (i *input) SubmarineSwapV1() libwallet.InputSubmarineSwapV1 { return nil } func (i *input) SubmarineSwapV2() libwallet.InputSubmarineSwapV2 { return nil } func (i *input) IncomingSwap() libwallet.InputIncomingSwap { return nil } // outpoint is a minimal type that implements libwallet.Outpoint type outpoint struct { utxo *scanner.Utxo } func (o *outpoint) TxId() []byte { raw, err := hex.DecodeString(o.utxo.TxID) if err != nil { panic(err) // we wrote this hex value ourselves, no input from anywhere else } return raw } func (o *outpoint) Index() int { return o.utxo.OutputIndex } func (o *outpoint) Amount() int64 { return o.utxo.Amount }