ark/server/internal/infrastructure/tx-builder/covenant/utils.go

package txbuilder

import (
	"encoding/hex"
	"fmt"

	"github.com/ark-network/ark/internal/core/domain"
	"github.com/ark-network/ark/internal/core/ports"
	"github.com/btcsuite/btcd/btcec/v2/schnorr"
	"github.com/btcsuite/btcd/txscript"
	"github.com/decred/dcrd/dcrec/secp256k1/v4"
	"github.com/vulpemventures/go-elements/address"
	"github.com/vulpemventures/go-elements/elementsutil"
	"github.com/vulpemventures/go-elements/network"
	"github.com/vulpemventures/go-elements/payment"
	"github.com/vulpemventures/go-elements/psetv2"
	"github.com/vulpemventures/go-elements/taproot"
	"github.com/vulpemventures/go-elements/transaction"
)

func p2wpkhScript(publicKey *secp256k1.PublicKey, net *network.Network) ([]byte, error) {
	payment := payment.FromPublicKey(publicKey, net, nil)
	addr, err := payment.WitnessPubKeyHash()
	if err != nil {
		return nil, err
	}

	return address.ToOutputScript(addr)
}

func getTxid(txStr string) (string, error) {
	pset, err := psetv2.NewPsetFromBase64(txStr)
	if err != nil {
		return "", err
	}

	return getPsetId(pset)
}

func getPsetId(pset *psetv2.Pset) (string, error) {
	utx, err := pset.UnsignedTx()
	if err != nil {
		return "", err
	}

	return utx.TxHash().String(), nil
}

func getOnchainReceivers(
	payments []domain.Payment,
) []domain.Receiver {
	receivers := make([]domain.Receiver, 0)
	for _, payment := range payments {
		for _, receiver := range payment.Receivers {
			if receiver.IsOnchain() {
				receivers = append(receivers, receiver)
			}
		}
	}
	return receivers
}

func getOffchainReceivers(
	payments []domain.Payment,
) []domain.Receiver {
	receivers := make([]domain.Receiver, 0)
	for _, payment := range payments {
		for _, receiver := range payment.Receivers {
			if !receiver.IsOnchain() {
				receivers = append(receivers, receiver)
			}
		}
	}
	return receivers
}

func toWitnessUtxo(in ports.TxInput) (*transaction.TxOutput, error) {
	valueBytes, err := elementsutil.ValueToBytes(in.GetValue())
	if err != nil {
		return nil, fmt.Errorf("failed to convert value to bytes: %s", err)
	}

	assetBytes, err := elementsutil.AssetHashToBytes(in.GetAsset())
	if err != nil {
		return nil, fmt.Errorf("failed to convert asset to bytes: %s", err)
	}

	scriptBytes, err := hex.DecodeString(in.GetScript())
	if err != nil {
		return nil, fmt.Errorf("failed to decode script: %s", err)
	}

	return transaction.NewTxOutput(assetBytes, valueBytes, scriptBytes), nil
}

func countSpentVtxos(payments []domain.Payment) uint64 {
	var sum uint64
	for _, payment := range payments {
		sum += uint64(len(payment.Inputs))
	}
	return sum
}

func addInputs(
	updater *psetv2.Updater,
	inputs []ports.TxInput,
) error {
	for _, in := range inputs {
		inputArg := psetv2.InputArgs{
			Txid:    in.GetTxid(),
			TxIndex: in.GetIndex(),
		}

		witnessUtxo, err := toWitnessUtxo(in)
		if err != nil {
			return err
		}

		if err := updater.AddInputs([]psetv2.InputArgs{inputArg}); err != nil {
			return err
		}

		index := int(updater.Pset.Global.InputCount) - 1
		if err := updater.AddInWitnessUtxo(index, witnessUtxo); err != nil {
			return err
		}

		if err := updater.AddInSighashType(index, txscript.SigHashAll); err != nil {
			return err
		}
	}

	return nil
}

// wrapper of updater methods adding a taproot input to the pset with all the necessary data to spend it via any taproot script
func addTaprootInput(
	updater *psetv2.Updater,
	input psetv2.InputArgs,
	internalTaprootKey *secp256k1.PublicKey,
	taprootTree *taproot.IndexedElementsTapScriptTree,
) error {
	if err := updater.AddInputs([]psetv2.InputArgs{input}); err != nil {
		return err
	}

	if err := updater.AddInTapInternalKey(0, schnorr.SerializePubKey(internalTaprootKey)); err != nil {
		return err
	}

	for _, proof := range taprootTree.LeafMerkleProofs {
		controlBlock := proof.ToControlBlock(internalTaprootKey)

		if err := updater.AddInTapLeafScript(0, psetv2.TapLeafScript{
			TapElementsLeaf: taproot.NewBaseTapElementsLeaf(proof.Script),
			ControlBlock:    controlBlock,
		}); err != nil {
			return err
		}
	}

	return nil
}

func taprootOutputScript(taprootKey *secp256k1.PublicKey) ([]byte, error) {
	return txscript.NewScriptBuilder().AddOp(txscript.OP_1).AddData(schnorr.SerializePubKey(taprootKey)).Script()
}