eth/client: Redeem

client/asset/eth/eth.go

@@ -168,6 +168,7 @@ type ethFetcher interface {
 	unlock(ctx context.Context, pw string, acct *accounts.Account) error
 	signData(addr common.Address, data []byte) ([]byte, error)
 	suggestGasTipCap(ctx context.Context) (*big.Int, error)
+	suggestGasPrice(ctx context.Context) (*big.Int, error)
 }
 
 // Check that ExchangeWallet satisfies the asset.Wallet interface.
@@ -737,20 +738,9 @@ func (eth *ExchangeWallet) Swap(swaps *asset.Swaps) ([]asset.Receipt, asset.Coin
 		return fail(fmt.Errorf("Swap: coin inputs value %d < required %d", totalInputValue, totalUsedValue))
 	}
 
-	suggestedGasTipCap, err := eth.node.suggestGasTipCap(eth.ctx)
+	gasTipCap, err := eth.gasTipCapToUse()
 	if err != nil {
-		return fail(fmt.Errorf("Swap: failed to get suggested gas tip cap %w", err))
-	}
-
-	var gasTipCap *big.Int
-	suggestedGasTipCapGwei, err := srveth.ToGwei(suggestedGasTipCap)
-	if err != nil {
-		return fail(fmt.Errorf("Swap: failed to convert to gwei: %w", err))
-	}
-	if suggestedGasTipCapGwei > MinGasTipCap {
-		gasTipCap = suggestedGasTipCap
-	} else {
-		gasTipCap = big.NewInt(MinGasTipCap * srveth.GweiFactor)
+		return fail(fmt.Errorf("Swap: unable to determine gas tip cap to use: %w", err))
 	}
 
 	opts := bind.TransactOpts{
@@ -796,10 +786,102 @@ func (eth *ExchangeWallet) Swap(swaps *asset.Swaps) ([]asset.Receipt, asset.Coin
 	return receipts, change, maxPossibleFee, nil
 }
 
+// gasTipCapToUse return the maximum of the gas tip cap suggested by
+// the eth client and MinGasTipCap.
+func (eth *ExchangeWallet) gasTipCapToUse() (*big.Int, error) {
+	suggestedGasTipCap, err := eth.node.suggestGasTipCap(eth.ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	minGasTipCapWei := srveth.ToWei(MinGasTipCap)
+
+	if suggestedGasTipCap.Cmp(minGasTipCapWei) > 0 {
+		return suggestedGasTipCap, nil
+	} else {
+		return minGasTipCapWei, nil
+	}
+}
+
 // Redeem sends the redemption transaction, which may contain more than one
 // redemption.
-func (*ExchangeWallet) Redeem(form *asset.RedeemForm) ([]dex.Bytes, asset.Coin, uint64, error) {
-	return nil, nil, 0, asset.ErrNotImplemented
+func (eth *ExchangeWallet) Redeem(form *asset.RedeemForm) ([]dex.Bytes, asset.Coin, uint64, error) {
+	fail := func(err error) ([]dex.Bytes, asset.Coin, uint64, error) {
+		return nil, nil, 0, err
+	}
+
+	if len(form.Redemptions) == 0 {
+		return fail(errors.New("Redeem: must be called with at least 1 redemption"))
+	}
+
+	inputs := make([]dex.Bytes, 0, len(form.Redemptions))
+	redemptions := make([]dexeth.ETHSwapRedemption, 0, len(form.Redemptions))
+	var redeemedValue uint64
+	for _, redemption := range form.Redemptions {
+		coinID := redemption.Spends.Coin.ID()
+		inputs = append(inputs, coinID)
+
+		decodedID, err := srveth.DecodeCoinID(coinID)
+		if err != nil {
+			return fail(err)
+		}
+		swapCoinID, ok := decodedID.(*srveth.SwapCoinID)
+		if !ok {
+			return fail(
+				fmt.Errorf("Redeem: coin id in redemption should be swap coin id, but got %T",
+					swapCoinID))
+		}
+		swap, err := eth.node.swap(eth.ctx, eth.acct, swapCoinID.SecretHash)
+		if err != nil {
+			return fail(fmt.Errorf("Redeem: unable to retrieve swap: %w", err))
+		}
+		swapValue, err := srveth.ToGwei(swap.Value)
+		if err != nil {
+			return fail(fmt.Errorf("Redeem: unable to convert value to gwei: %w", err))
+		}
+		redeemedValue += swapValue
+
+		var secret [32]byte
+		var secretHash [32]byte
+		copy(secret[:], redemption.Secret)
+		copy(secretHash[:], redemption.Spends.SecretHash)
+		redemptions = append(redemptions,
+			dexeth.ETHSwapRedemption{
+				Secret:     secret,
+				SecretHash: secretHash,
+			})
+	}
+
+	gasTipCap, err := eth.gasTipCapToUse()
+	if err != nil {
+		return fail(fmt.Errorf("Swap: unable to determine gas tip cap to use: %w", err))
+	}
+
+	// TODO: make sure the amount we locked for redemption is enough to cover the gas
+	// fees.
+	gasFeeCap := srveth.ToWei(form.FeeSuggestion)
+	suggestedFeeRate, err := eth.node.suggestGasPrice(eth.ctx)
+	if err != nil {
+		return fail(fmt.Errorf("Swap: unable to retrieve suggested gas price: %w", err))
+	}
+	if suggestedFeeRate.Cmp(gasFeeCap) > 0 {
+		gasFeeCap = suggestedFeeRate
+	}
+
+	opts := bind.TransactOpts{
+		From:      eth.acct.Address,
+		GasFeeCap: gasFeeCap,
+		GasTipCap: gasTipCap,
+		Context:   eth.ctx,
+	}
+	_, err = eth.node.redeem(&opts, eth.networkID, redemptions)
+	if err != nil {
+		return fail(fmt.Errorf("Redeem: redeem error: %w", err))
+	}
+
+	outputCoin := eth.createAmountCoin(redeemedValue)
+	gasRequired := srveth.GasToRedeemSwaps(uint64(len(redemptions)))
+	return inputs, outputCoin, gasRequired * form.FeeSuggestion, nil
 }
 
 // SignMessage signs the message with the private key associated with the