+gas estimation

api/chain/gateway/internal/service/gateway/commands/transfer/destination.go

@@ -0,0 +1,50 @@
+package transfer
+
+import (
+	"context"
+	"strings"
+
+	"github.com/tech/sendico/chain/gateway/storage/model"
+	"github.com/tech/sendico/pkg/merrors"
+	gatewayv1 "github.com/tech/sendico/pkg/proto/chain/gateway/v1"
+	"go.uber.org/zap"
+)
+
+func resolveDestination(ctx context.Context, deps Deps, dest *gatewayv1.TransferDestination, source *model.ManagedWallet) (model.TransferDestination, error) {
+	if dest == nil {
+		return model.TransferDestination{}, merrors.InvalidArgument("destination is required")
+	}
+	managedRef := strings.TrimSpace(dest.GetManagedWalletRef())
+	external := strings.TrimSpace(dest.GetExternalAddress())
+	if managedRef != "" && external != "" {
+		deps.Logger.Warn("both managed and external destination provided")
+		return model.TransferDestination{}, merrors.InvalidArgument("destination must be managed_wallet_ref or external_address")
+	}
+	if managedRef != "" {
+		wallet, err := deps.Storage.Wallets().Get(ctx, managedRef)
+		if err != nil {
+			deps.Logger.Warn("destination wallet lookup failed", zap.Error(err), zap.String("managed_wallet_ref", managedRef))
+			return model.TransferDestination{}, err
+		}
+		if !strings.EqualFold(wallet.Network, source.Network) {
+			deps.Logger.Warn("destination wallet network mismatch", zap.String("source_network", source.Network), zap.String("dest_network", wallet.Network))
+			return model.TransferDestination{}, merrors.InvalidArgument("destination wallet network mismatch")
+		}
+		if strings.TrimSpace(wallet.DepositAddress) == "" {
+			deps.Logger.Warn("destination wallet missing deposit address", zap.String("managed_wallet_ref", managedRef))
+			return model.TransferDestination{}, merrors.InvalidArgument("destination wallet missing deposit address")
+		}
+		return model.TransferDestination{
+			ManagedWalletRef: wallet.WalletRef,
+			Memo:             strings.TrimSpace(dest.GetMemo()),
+		}, nil
+	}
+	if external == "" {
+		deps.Logger.Warn("destination external address missing")
+		return model.TransferDestination{}, merrors.InvalidArgument("destination is required")
+	}
+	return model.TransferDestination{
+		ExternalAddress: strings.ToLower(external),
+		Memo:            strings.TrimSpace(dest.GetMemo()),
+	}, nil
+}

api/chain/gateway/internal/service/gateway/commands/transfer/destination_address.go

@@ -0,0 +1,26 @@
+package transfer
+
+import (
+	"context"
+	"strings"
+
+	"github.com/tech/sendico/chain/gateway/storage/model"
+	"github.com/tech/sendico/pkg/merrors"
+)
+
+func destinationAddress(ctx context.Context, deps Deps, dest model.TransferDestination) (string, error) {
+	if ref := strings.TrimSpace(dest.ManagedWalletRef); ref != "" {
+		wallet, err := deps.Storage.Wallets().Get(ctx, ref)
+		if err != nil {
+			return "", err
+		}
+		if strings.TrimSpace(wallet.DepositAddress) == "" {
+			return "", merrors.Internal("destination wallet missing deposit address")
+		}
+		return wallet.DepositAddress, nil
+	}
+	if addr := strings.TrimSpace(dest.ExternalAddress); addr != "" {
+		return strings.ToLower(addr), nil
+	}
+	return "", merrors.InvalidArgument("transfer destination address not resolved")
+}

api/chain/gateway/internal/service/gateway/commands/transfer/fee.go

@@ -2,9 +2,21 @@ package transfer
 
 import (
 	"context"
+	"errors"
+	"math/big"
+	"strings"
+	"time"
 
+	"github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/accounts/abi"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/shopspring/decimal"
+	"github.com/tech/sendico/chain/gateway/internal/service/gateway/shared"
+	"github.com/tech/sendico/chain/gateway/storage/model"
 	"github.com/tech/sendico/pkg/api/routers/gsresponse"
 	"github.com/tech/sendico/pkg/merrors"
+	"github.com/tech/sendico/pkg/mlogger"
 	"github.com/tech/sendico/pkg/mservice"
 	gatewayv1 "github.com/tech/sendico/pkg/proto/chain/gateway/v1"
 	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
@@ -24,18 +36,213 @@ func (c *estimateTransferFeeCommand) Execute(ctx context.Context, req *gatewayv1
 		c.deps.Logger.Warn("repository unavailable", zap.Error(err))
 		return gsresponse.Unavailable[gatewayv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, err)
 	}
-	if req == nil || req.GetAmount() == nil {
-		c.deps.Logger.Warn("amount missing")
+	if req == nil {
+		c.deps.Logger.Warn("nil request")
+		return gsresponse.InvalidArgument[gatewayv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("request is required"))
+	}
+
+	sourceWalletRef := strings.TrimSpace(req.GetSourceWalletRef())
+	if sourceWalletRef == "" {
+		c.deps.Logger.Warn("source wallet ref missing")
+		return gsresponse.InvalidArgument[gatewayv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("source_wallet_ref is required"))
+	}
+	amount := req.GetAmount()
+	if amount == nil || strings.TrimSpace(amount.GetAmount()) == "" || strings.TrimSpace(amount.GetCurrency()) == "" {
+		c.deps.Logger.Warn("amount missing or incomplete")
 		return gsresponse.InvalidArgument[gatewayv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("amount is required"))
 	}
-	currency := req.GetAmount().GetCurrency()
-	fee := &moneyv1.Money{
-		Currency: currency,
-		Amount:   "0",
+
+	sourceWallet, err := c.deps.Storage.Wallets().Get(ctx, sourceWalletRef)
+	if err != nil {
+		if errors.Is(err, merrors.ErrNoData) {
+			c.deps.Logger.Warn("source wallet not found", zap.String("source_wallet_ref", sourceWalletRef))
+			return gsresponse.NotFound[gatewayv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, err)
+		}
+		c.deps.Logger.Warn("storage get wallet failed", zap.Error(err), zap.String("source_wallet_ref", sourceWalletRef))
+		return gsresponse.Auto[gatewayv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, err)
 	}
+
+	networkKey := strings.ToLower(strings.TrimSpace(sourceWallet.Network))
+	networkCfg, ok := c.deps.Networks[networkKey]
+	if !ok {
+		c.deps.Logger.Warn("unsupported chain", zap.String("network", networkKey))
+		return gsresponse.InvalidArgument[gatewayv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("unsupported chain for wallet"))
+	}
+
+	dest, err := resolveDestination(ctx, c.deps, req.GetDestination(), sourceWallet)
+	if err != nil {
+		if errors.Is(err, merrors.ErrNoData) {
+			c.deps.Logger.Warn("destination not found", zap.String("destination_wallet_ref", req.GetDestination().GetManagedWalletRef()))
+			return gsresponse.NotFound[gatewayv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, err)
+		}
+		c.deps.Logger.Warn("invalid destination", zap.Error(err))
+		return gsresponse.InvalidArgument[gatewayv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, err)
+	}
+
+	destinationAddress, err := destinationAddress(ctx, c.deps, dest)
+	if err != nil {
+		c.deps.Logger.Warn("failed to resolve destination address", zap.Error(err))
+		return gsresponse.InvalidArgument[gatewayv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, err)
+	}
+
+	feeMoney, err := estimateNetworkFee(ctx, c.deps.Logger, networkCfg, sourceWallet, destinationAddress, amount)
+	if err != nil {
+		c.deps.Logger.Warn("fee estimation failed", zap.Error(err))
+		return gsresponse.Auto[gatewayv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, err)
+	}
+
 	resp := &gatewayv1.EstimateTransferFeeResponse{
-		NetworkFee:        fee,
-		EstimationContext: "not_implemented",
+		NetworkFee:        feeMoney,
+		EstimationContext: "erc20_transfer",
 	}
 	return gsresponse.Success(resp)
 }
+
+func estimateNetworkFee(ctx context.Context, logger mlogger.Logger, network shared.Network, wallet *model.ManagedWallet, destination string, amount *moneyv1.Money) (*moneyv1.Money, error) {
+	rpcURL := strings.TrimSpace(network.RPCURL)
+	if rpcURL == "" {
+		return nil, merrors.InvalidArgument("network rpc url not configured")
+	}
+	if strings.TrimSpace(wallet.ContractAddress) == "" {
+		return nil, merrors.NotImplemented("native token transfers not supported")
+	}
+	if !common.IsHexAddress(wallet.ContractAddress) {
+		return nil, merrors.InvalidArgument("invalid token contract address")
+	}
+	if !common.IsHexAddress(wallet.DepositAddress) {
+		return nil, merrors.InvalidArgument("invalid source wallet address")
+	}
+	if !common.IsHexAddress(destination) {
+		return nil, merrors.InvalidArgument("invalid destination address")
+	}
+
+	client, err := ethclient.DialContext(ctx, rpcURL)
+	if err != nil {
+		return nil, merrors.Internal("failed to connect to rpc: " + err.Error())
+	}
+	defer client.Close()
+
+	timeoutCtx, cancel := context.WithTimeout(ctx, 15*time.Second)
+	defer cancel()
+
+	tokenABI, err := abi.JSON(strings.NewReader(erc20TransferABI))
+	if err != nil {
+		return nil, merrors.Internal("failed to parse erc20 abi: " + err.Error())
+	}
+	tokenAddr := common.HexToAddress(wallet.ContractAddress)
+	toAddr := common.HexToAddress(destination)
+	fromAddr := common.HexToAddress(wallet.DepositAddress)
+
+	decimals, err := erc20Decimals(timeoutCtx, client, tokenABI, tokenAddr)
+	if err != nil {
+		logger.Warn("failed to read token decimals", zap.Error(err))
+		return nil, err
+	}
+
+	amountBase, err := toBaseUnits(strings.TrimSpace(amount.GetAmount()), decimals)
+	if err != nil {
+		return nil, err
+	}
+
+	input, err := tokenABI.Pack("transfer", toAddr, amountBase)
+	if err != nil {
+		return nil, merrors.Internal("failed to encode transfer call: " + err.Error())
+	}
+
+	gasPrice, err := client.SuggestGasPrice(timeoutCtx)
+	if err != nil {
+		return nil, merrors.Internal("failed to suggest gas price: " + err.Error())
+	}
+
+	callMsg := ethereum.CallMsg{
+		From:     fromAddr,
+		To:       &tokenAddr,
+		GasPrice: gasPrice,
+		Data:     input,
+	}
+	gasLimit, err := client.EstimateGas(timeoutCtx, callMsg)
+	if err != nil {
+		return nil, merrors.Internal("failed to estimate gas: " + err.Error())
+	}
+
+	fee := new(big.Int).Mul(gasPrice, new(big.Int).SetUint64(gasLimit))
+	feeDec := decimal.NewFromBigInt(fee, 0)
+
+	currency := strings.ToUpper(strings.TrimSpace(network.NativeToken))
+	if currency == "" {
+		currency = strings.ToUpper(network.Name)
+	}
+
+	return &moneyv1.Money{
+		Currency: currency,
+		Amount:   feeDec.String(),
+	}, nil
+}
+
+func erc20Decimals(ctx context.Context, client *ethclient.Client, tokenABI abi.ABI, token common.Address) (uint8, error) {
+	callData, err := tokenABI.Pack("decimals")
+	if err != nil {
+		return 0, merrors.Internal("failed to encode decimals call: " + err.Error())
+	}
+	msg := ethereum.CallMsg{
+		To:   &token,
+		Data: callData,
+	}
+	output, err := client.CallContract(ctx, msg, nil)
+	if err != nil {
+		return 0, merrors.Internal("decimals call failed: " + err.Error())
+	}
+	values, err := tokenABI.Unpack("decimals", output)
+	if err != nil {
+		return 0, merrors.Internal("failed to unpack decimals: " + err.Error())
+	}
+	if len(values) == 0 {
+		return 0, merrors.Internal("decimals call returned no data")
+	}
+	decimals, ok := values[0].(uint8)
+	if !ok {
+		return 0, merrors.Internal("decimals call returned unexpected type")
+	}
+	return decimals, nil
+}
+
+func toBaseUnits(amount string, decimals uint8) (*big.Int, error) {
+	value, err := decimal.NewFromString(strings.TrimSpace(amount))
+	if err != nil {
+		return nil, merrors.InvalidArgument("invalid amount " + amount + ": " + err.Error())
+	}
+	if value.IsNegative() {
+		return nil, merrors.InvalidArgument("amount must be positive")
+	}
+	multiplier := decimal.NewFromInt(1).Shift(int32(decimals))
+	scaled := value.Mul(multiplier)
+	if !scaled.Equal(scaled.Truncate(0)) {
+		return nil, merrors.InvalidArgument("amount " + amount + " exceeds token precision")
+	}
+	return scaled.BigInt(), nil
+}
+
+const erc20TransferABI = `
+[
+	{
+		"constant": true,
+		"inputs": [],
+		"name": "decimals",
+		"outputs": [{ "name": "", "type": "uint8" }],
+		"payable": false,
+		"stateMutability": "view",
+        "type": "function"
+	},
+	{
+		"constant": false,
+		"inputs": [
+			{ "name": "_to", "type": "address" },
+			{ "name": "_value", "type": "uint256" }
+		],
+		"name": "transfer",
+		"outputs": [{ "name": "", "type": "bool" }],
+		"payable": false,
+		"stateMutability": "nonpayable",
+		"type": "function"
+	}
+]`

api/chain/gateway/internal/service/gateway/commands/transfer/submit.go

@@ -84,7 +84,7 @@ func (c *submitTransferCommand) Execute(ctx context.Context, req *gatewayv1.Subm
 		return gsresponse.InvalidArgument[gatewayv1.SubmitTransferResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("unsupported chain for wallet"))
 	}
 
-	destination, err := c.resolveDestination(ctx, req.GetDestination(), sourceWallet)
+	destination, err := resolveDestination(ctx, c.deps, req.GetDestination(), sourceWallet)
 	if err != nil {
 		if errors.Is(err, merrors.ErrNoData) {
 			c.deps.Logger.Warn("destination not found", zap.String("destination_wallet_ref", req.GetDestination().GetManagedWalletRef()))
@@ -146,43 +146,3 @@ func (c *submitTransferCommand) Execute(ctx context.Context, req *gatewayv1.Subm
 
 	return gsresponse.Success(&gatewayv1.SubmitTransferResponse{Transfer: toProtoTransfer(saved)})
 }
-
-func (c *submitTransferCommand) resolveDestination(ctx context.Context, dest *gatewayv1.TransferDestination, source *model.ManagedWallet) (model.TransferDestination, error) {
-	if dest == nil {
-		c.deps.Logger.Warn("destination missing")
-		return model.TransferDestination{}, merrors.InvalidArgument("destination is required")
-	}
-	managedRef := strings.TrimSpace(dest.GetManagedWalletRef())
-	external := strings.TrimSpace(dest.GetExternalAddress())
-	if managedRef != "" && external != "" {
-		c.deps.Logger.Warn("both managed and external destination provided")
-		return model.TransferDestination{}, merrors.InvalidArgument("destination must be managed_wallet_ref or external_address")
-	}
-	if managedRef != "" {
-		wallet, err := c.deps.Storage.Wallets().Get(ctx, managedRef)
-		if err != nil {
-			c.deps.Logger.Warn("destination wallet lookup failed", zap.Error(err), zap.String("managed_wallet_ref", managedRef))
-			return model.TransferDestination{}, err
-		}
-		if !strings.EqualFold(wallet.Network, source.Network) {
-			c.deps.Logger.Warn("destination network mismatch", zap.String("source_network", source.Network), zap.String("dest_network", wallet.Network))
-			return model.TransferDestination{}, merrors.InvalidArgument("destination wallet network mismatch")
-		}
-		if strings.TrimSpace(wallet.DepositAddress) == "" {
-			c.deps.Logger.Warn("destination wallet missing deposit address", zap.String("managed_wallet_ref", managedRef))
-			return model.TransferDestination{}, merrors.InvalidArgument("destination wallet missing deposit address")
-		}
-		return model.TransferDestination{
-			ManagedWalletRef: wallet.WalletRef,
-			Memo:             strings.TrimSpace(dest.GetMemo()),
-		}, nil
-	}
-	if external == "" {
-		c.deps.Logger.Warn("destination external address missing")
-		return model.TransferDestination{}, merrors.InvalidArgument("destination is required")
-	}
-	return model.TransferDestination{
-		ExternalAddress: strings.ToLower(external),
-		Memo:            strings.TrimSpace(dest.GetMemo()),
-	}, nil
-}