Files
atomic-swap/protocol/xmrtaker/min_balance.go
2023-05-30 21:49:22 -05:00

103 lines
3.2 KiB
Go

package xmrtaker
import (
"context"
"math/big"
"github.com/cockroachdb/apd/v3"
"github.com/athanorlabs/atomic-swap/coins"
"github.com/athanorlabs/atomic-swap/common/types"
contracts "github.com/athanorlabs/atomic-swap/ethereum"
"github.com/athanorlabs/atomic-swap/ethereum/extethclient"
)
// validateMinBalance validates that the Taker has sufficient funds to take an
// offer
func validateMinBalance(
ctx context.Context,
ec extethclient.EthClient,
providesAmt *apd.Decimal,
asset types.EthAsset,
) error {
gasPrice, err := ec.SuggestGasPrice(ctx)
if err != nil {
return err
}
weiBalance, err := ec.Balance(ctx)
if err != nil {
return err
}
if asset.IsETH() {
return validateMinBalForETHSwap(weiBalance, providesAmt, gasPrice)
}
tokenBalance, err := ec.ERC20Balance(ctx, asset.Address())
if err != nil {
return err
}
return validateMinBalForTokenSwap(weiBalance, tokenBalance, providesAmt, gasPrice)
}
// validateMinBalForETHSwap validates that the Taker has sufficient funds to take an
// offer of XMR for ETH
func validateMinBalForETHSwap(weiBalance *coins.WeiAmount, providesAmt *apd.Decimal, gasPriceWei *big.Int) error {
providedAmtWei := coins.EtherToWei(providesAmt).BigInt()
neededGas := big.NewInt(contracts.MaxNewSwapETHGas + contracts.MaxSetReadyGas + contracts.MaxRefundETHGas)
neededWeiForGas := new(big.Int).Mul(neededGas, gasPriceWei)
neededBalanceWei := new(big.Int).Add(providedAmtWei, neededWeiForGas)
if weiBalance.BigInt().Cmp(neededBalanceWei) < 0 {
log.Warnf("Ethereum account needs additional funds, balance=%s ETH, required=%s ETH",
weiBalance.AsEtherString(), coins.NewWeiAmount(neededBalanceWei).AsEtherString())
return errETHBalanceTooLow{
currentBalanceETH: weiBalance.AsEther(),
requiredBalanceETH: coins.NewWeiAmount(neededBalanceWei).AsEther(),
}
}
return nil
}
// validateMinBalForTokenSwap validates that the Taker has sufficient tokens for
// to take an XMR->Token swap, and sufficient ETH funds to pay for the gas of
// the swap.
func validateMinBalForTokenSwap(
weiBalance *coins.WeiAmount,
tokenBalance *coins.ERC20TokenAmount,
providesAmt *apd.Decimal, // standard units
gasPriceWei *big.Int,
) error {
if tokenBalance.AsStd().Cmp(providesAmt) < 0 {
return errTokenBalanceTooLow{
providedAmount: providesAmt,
tokenBalance: tokenBalance.AsStd(),
symbol: tokenBalance.StdSymbol(),
}
}
// For a token swap, we only need an ETH balance to pay for gas. While we
// hopefully won't need gas to call refund, we don't want to start the swap
// if we don't have enough ETH to call it.
neededGas := big.NewInt(contracts.MaxTokenApproveGas +
contracts.MaxNewSwapTokenGas +
contracts.MaxSetReadyGas +
contracts.MaxRefundTokenGas,
)
neededWeiForGas := new(big.Int).Mul(neededGas, gasPriceWei)
if weiBalance.BigInt().Cmp(neededWeiForGas) < 0 {
log.Warnf("Ethereum account has infufficient balance to pay for gas, balance=%s ETH, required=%s ETH",
weiBalance.AsEtherString(), coins.NewWeiAmount(neededWeiForGas).AsEtherString())
return errETHBalanceTooLow{
currentBalanceETH: weiBalance.AsEther(),
requiredBalanceETH: coins.NewWeiAmount(neededWeiForGas).AsEther(),
}
}
return nil
}