Update project structure and build process

libwallet/segwit.go

@@ -0,0 +1,64 @@
+package libwallet
+
+import (
+	"crypto/sha256"
+	"fmt"
+
+	"github.com/btcsuite/btcd/txscript"
+	"github.com/btcsuite/btcd/wire"
+	"github.com/btcsuite/btcutil"
+)
+
+func signNativeSegwitInput(index int, tx *wire.MsgTx, privateKey *HDPrivateKey, witnessScript []byte, amount btcutil.Amount) ([]byte, error) {
+
+	privKey, err := privateKey.key.ECPrivKey()
+	if err != nil {
+		return nil, fmt.Errorf("failed to produce EC priv key for signing: %w", err)
+	}
+
+	sigHashes := txscript.NewTxSigHashes(tx)
+	sig, err := txscript.RawTxInWitnessSignature(tx, sigHashes, index, int64(amount), witnessScript, txscript.SigHashAll, privKey)
+	if err != nil {
+		return nil, fmt.Errorf("failed to sign V4 input: %w", err)
+	}
+
+	return sig, nil
+}
+
+func createNonNativeSegwitRedeemScript(witnessScript []byte) ([]byte, error) {
+	witnessScriptHash := sha256.Sum256(witnessScript)
+
+	builder := txscript.NewScriptBuilder()
+	builder.AddInt64(0)
+	builder.AddData(witnessScriptHash[:])
+
+	return builder.Script()
+}
+
+func signNonNativeSegwitInput(index int, tx *wire.MsgTx, privateKey *HDPrivateKey,
+	redeemScript, witnessScript []byte, amount btcutil.Amount) ([]byte, error) {
+
+	txInput := tx.TxIn[index]
+
+	builder := txscript.NewScriptBuilder()
+	builder.AddData(redeemScript)
+	script, err := builder.Script()
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate signing script: %w", err)
+	}
+	txInput.SignatureScript = script
+
+	privKey, err := privateKey.key.ECPrivKey()
+	if err != nil {
+		return nil, fmt.Errorf("failed to produce EC priv key for signing: %w", err)
+	}
+
+	sigHashes := txscript.NewTxSigHashes(tx)
+	sig, err := txscript.RawTxInWitnessSignature(
+		tx, sigHashes, index, int64(amount), witnessScript, txscript.SigHashAll, privKey)
+	if err != nil {
+		return nil, fmt.Errorf("failed to sign V3 input: %w", err)
+	}
+
+	return sig, nil
+}