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Swap feature implementation
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@wirew0lf
wirew0lf committed Jun 13, 2024
1 parent 38246ff commit 0e6349f
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237 changes: 137 additions & 100 deletions AxelarHandler/src/AxelarHandler.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -7,19 +7,17 @@ import {IAxelarGasService} from "lib/axelar-gmp-sdk-solidity/contracts/interface
import {AxelarExecutableUpgradeable} from "./AxelarExecutableUpgradeable.sol";

import {IERC20Upgradeable} from "lib/openzeppelin-contracts-upgradeable/contracts/token/ERC20/IERC20Upgradeable.sol";
import {SafeERC20Upgradeable} from "lib/openzeppelin-contracts-upgradeable/contracts/token/ERC20/utils/SafeERC20Upgradeable.sol";
import {Ownable2StepUpgradeable} from "lib/openzeppelin-contracts-upgradeable/contracts/access/Ownable2StepUpgradeable.sol";
import {SafeERC20Upgradeable} from
"lib/openzeppelin-contracts-upgradeable/contracts/token/ERC20/utils/SafeERC20Upgradeable.sol";
import {Ownable2StepUpgradeable} from
"lib/openzeppelin-contracts-upgradeable/contracts/access/Ownable2StepUpgradeable.sol";
import {UUPSUpgradeable} from "lib/openzeppelin-contracts-upgradeable/contracts/proxy/utils/UUPSUpgradeable.sol";
import {Initializable} from "lib/openzeppelin-contracts-upgradeable/contracts/proxy/utils/Initializable.sol";

/// @title AxelarHandler
/// @notice allows to send and receive tokens to/from other chains through axelar gateway while wrapping the native tokens.
/// @author Skip Protocol.
contract AxelarHandler is
AxelarExecutableUpgradeable,
Ownable2StepUpgradeable,
UUPSUpgradeable
{
contract AxelarHandler is AxelarExecutableUpgradeable, Ownable2StepUpgradeable, UUPSUpgradeable {
using SafeERC20Upgradeable for IERC20Upgradeable;

error EmptySymbol();
Expand All @@ -32,6 +30,10 @@ contract AxelarHandler is
error NonNativeCannotBeUnwrapped();
error NativePaymentFailed();
error WrappingNotEnabled();
error SwapFailed();
error InsufficientSwapOutput();
error InsufficientNativeToken();
error ETHSendFailed();

bytes32 private _wETHSymbolHash;

Expand All @@ -40,18 +42,15 @@ contract AxelarHandler is

mapping(address => bool) public approved;

bytes32 public constant DISABLED_SYMBOL =
keccak256(abi.encodePacked("DISABLED"));
bytes32 public constant DISABLED_SYMBOL = keccak256(abi.encodePacked("DISABLED"));

address public swapRouter;

constructor() {
_disableInitializers();
}

function initialize(
address axGateway,
address axGasService,
string memory wethSymbol
) external initializer {
function initialize(address axGateway, address axGasService, string memory wethSymbol) external initializer {
if (axGasService == address(0)) revert ZeroAddress();
if (bytes(wethSymbol).length == 0) revert EmptySymbol();

Expand All @@ -64,20 +63,23 @@ contract AxelarHandler is
_wETHSymbolHash = keccak256(abi.encodePacked(wethSymbol));
}

function setWETHSybol(string memory wethSymbol) external {
function setWETHSybol(string memory wethSymbol) external onlyOwner {
if (bytes(wethSymbol).length == 0) revert EmptySymbol();

wETHSymbol = wethSymbol;
_wETHSymbolHash = keccak256(abi.encodePacked(wethSymbol));
}

function setSwapRouter(address _swapRouter) external onlyOwner {
if (_swapRouter == address(0)) revert ZeroAddress();

swapRouter = _swapRouter;
}

/// @notice Sends native currency to other chains through the axelar gateway.
/// @param destinationChain name of the destination chain.
/// @param destinationAddress address of the destination wallet in string form.
function sendNativeToken(
string memory destinationChain,
string memory destinationAddress
) external payable {
function sendNativeToken(string memory destinationChain, string memory destinationAddress) external payable {
if (_wETHSymbolHash == DISABLED_SYMBOL) revert WrappingNotEnabled();
if (msg.value == 0) revert ZeroNativeSent();

Expand All @@ -88,12 +90,7 @@ contract AxelarHandler is
IWETH(token).deposit{value: msg.value}();

// Call Axelar Gateway to transfer the WETH.
gateway.sendToken(
destinationChain,
destinationAddress,
wETHSymbol,
msg.value
);
gateway.sendToken(destinationChain, destinationAddress, wETHSymbol, msg.value);
}

/// @notice Sends a ERC20 token to other chains through the axelar gateway.
Expand Down Expand Up @@ -134,31 +131,18 @@ contract AxelarHandler is
if (_wETHSymbolHash == DISABLED_SYMBOL) revert WrappingNotEnabled();
if (amount == 0) revert ZeroAmount();
if (gasPaymentAmount == 0) revert ZeroGasAmount();
if (msg.value != amount + gasPaymentAmount)
if (msg.value != amount + gasPaymentAmount) {
revert NativeSentDoesNotMatchAmounts();
}

// Wrap the ether to be sent into the gateway.
IWETH(_getTokenAddress(wETHSymbol)).deposit{value: amount}();

gasService.payNativeGasForContractCallWithToken{
value: gasPaymentAmount
}(
address(this),
destinationChain,
contractAddress,
payload,
wETHSymbol,
amount,
msg.sender
gasService.payNativeGasForContractCallWithToken{value: gasPaymentAmount}(
address(this), destinationChain, contractAddress, payload, wETHSymbol, amount, msg.sender
);

gateway.callContractWithToken(
destinationChain,
contractAddress,
payload,
wETHSymbol,
amount
);
gateway.callContractWithToken(destinationChain, contractAddress, payload, wETHSymbol, amount);
}

/// @notice Sends ERC20 to other chain while calling a contract in the destination chain and paying gas with native token.
Expand All @@ -176,11 +160,12 @@ contract AxelarHandler is
string memory symbol, // argument passed to both child contract calls
uint256 amount, // argument passed to both child contract calls
uint256 gasPaymentAmount // amount to send with gas payment call
) external payable {
) public payable {
if (amount == 0) revert ZeroAmount();
if (gasPaymentAmount == 0) revert ZeroGasAmount();
if (msg.value != gasPaymentAmount)
if (msg.value != gasPaymentAmount) {
revert NativeSentDoesNotMatchAmounts();
}
if (bytes(symbol).length == 0) revert EmptySymbol();

// Get the token address.
Expand All @@ -189,27 +174,107 @@ contract AxelarHandler is
// Transfer the amount from the msg.sender.
token.safeTransferFrom(msg.sender, address(this), amount);

gasService.payNativeGasForContractCallWithToken{
value: gasPaymentAmount
}(
address(this),
destinationChain,
contractAddress,
payload,
symbol,
amount,
msg.sender
gasService.payNativeGasForContractCallWithToken{value: gasPaymentAmount}(
address(this), destinationChain, contractAddress, payload, symbol, amount, msg.sender
);

require(token.balanceOf(address(this)) >= amount, "NOT ENOUGH BALANCE");

gateway.callContractWithToken(
destinationChain,
contractAddress,
payload,
symbol,
amount
gateway.callContractWithToken(destinationChain, contractAddress, payload, symbol, amount);
}

/// @notice Swap the input token to a axelar supported token before doing a GMP Transfer.
/// @param inputToken address of the ERC20 token to be swapped.
/// @param amount the amount of either input tokens or native currency to be swapped.
/// @param destinationChain name of the destination chain.
/// @param contractAddress address of the contract that will be called in the destination chain.
/// @param payload the payload that will be sent to the contract in the destination chain.
/// @param symbol the symbol of the ERC20 token to be sent.
/// @param gasPaymentAmount the amount of native currency that will be used for paying gas.
/// @dev The amount of native currency sent (msg.value) must be equal to gasPaymentAmount.
function swapAndGmpTransferERC20Token(
address inputToken,
uint256 amount,
bytes memory swapCalldata,
string memory destinationChain,
string memory contractAddress,
bytes memory payload,
string memory symbol,
uint256 gasPaymentAmount
) external payable {
if (amount == 0) revert ZeroAmount();
if (gasPaymentAmount == 0) revert ZeroGasAmount();
if (bytes(symbol).length == 0) revert EmptySymbol();

// Get the address of the output token based on the symbol provided
IERC20Upgradeable outputToken = IERC20Upgradeable(_getTokenAddress(symbol));

uint256 outputAmount;
if (inputToken == address(0)) {
// Native Token
if (amount + gasPaymentAmount != msg.value) revert InsufficientNativeToken();

// Get the contract's balances previous to the swap
uint256 preInputBalance = address(this).balance;
uint256 preOutputBalance = outputToken.balanceOf(address(this));

// Call the swap router and perform the swap
(bool success,) = swapRouter.call{value: amount}(swapCalldata);
if (!success) revert SwapFailed();

// Get the contract's balances after the swap
uint256 postInputBalance = address(this).balance;
uint256 postOutputBalance = outputToken.balanceOf(address(this));

// Check that the contract's native token balance has increased
outputAmount = postOutputBalance - preOutputBalance;

// Refund the remaining ETH
uint256 dust = postInputBalance + amount - preInputBalance;
if (dust != 0) {
(bool ethSuccess,) = msg.sender.call{value: dust}("");
if (!ethSuccess) revert ETHSendFailed();
}
} else {
// ERC20 Token
if (gasPaymentAmount != msg.value) revert();

// Transfer input ERC20 tokens to the contract
IERC20Upgradeable token = IERC20Upgradeable(inputToken);
token.safeTransferFrom(msg.sender, address(this), amount);

// Approve the swap router to spend the input tokens
token.safeApprove(swapRouter, amount);

// Get the contract's balances previous to the swap
uint256 preInputBalance = token.balanceOf(address(this));
uint256 preOutputBalance = outputToken.balanceOf(address(this));

// Call the swap router and perform the swap
(bool success,) = swapRouter.call(swapCalldata);
if (!success) revert SwapFailed();

// Get the contract's balances after the swap
uint256 dust = token.balanceOf(address(this)) + amount - preInputBalance;
uint256 postOutputBalance = outputToken.balanceOf(address(this));

// Check that the contract's output token balance has increased
if (preOutputBalance >= postOutputBalance) revert InsufficientSwapOutput();
outputAmount = postOutputBalance - preOutputBalance;

// Refund the remaining amount
if (dust != 0) {
token.transfer(msg.sender, dust);
}
}

// Pay the gas for the GMP transfer
gasService.payNativeGasForContractCallWithToken{value: gasPaymentAmount}(
address(this), destinationChain, contractAddress, payload, symbol, outputAmount, msg.sender
);

// Perform the GMP transfer
gateway.callContractWithToken(destinationChain, contractAddress, payload, symbol, outputAmount);
}

/// @notice Sends ERC20 to other chain while calling a contract in the destination chain and paying gas with destination token.
Expand All @@ -236,11 +301,7 @@ contract AxelarHandler is
IERC20Upgradeable token = IERC20Upgradeable(_getTokenAddress(symbol));

// Transfer the amount and gas payment amount from the msg.sender.
token.safeTransferFrom(
msg.sender,
address(this),
amount + gasPaymentAmount
);
token.safeTransferFrom(msg.sender, address(this), amount + gasPaymentAmount);

gasService.payGasForContractCallWithToken(
address(this),
Expand All @@ -254,13 +315,7 @@ contract AxelarHandler is
msg.sender
);

gateway.callContractWithToken(
destinationChain,
contractAddress,
payload,
symbol,
amount
);
gateway.callContractWithToken(destinationChain, contractAddress, payload, symbol, amount);
}

receive() external payable {}
Expand All @@ -269,21 +324,13 @@ contract AxelarHandler is

/// @notice Ensures a token is supported by the axelar gateway, and returns it's address.
/// @param symbol the symbol of the ERC20 token to be checked.
function _getTokenAddress(
string memory symbol
) internal returns (address token) {
function _getTokenAddress(string memory symbol) internal returns (address token) {
token = gateway.tokenAddresses(symbol);
if (token == address(0)) revert TokenNotSupported();

if (!approved[token]) {
IERC20Upgradeable(token).safeApprove(
address(gateway),
type(uint256).max
);
IERC20Upgradeable(token).safeApprove(
address(gasService),
type(uint256).max
);
IERC20Upgradeable(token).safeApprove(address(gateway), type(uint256).max);
IERC20Upgradeable(token).safeApprove(address(gasService), type(uint256).max);
approved[token] = true;
}
}
Expand All @@ -302,26 +349,18 @@ contract AxelarHandler is
string calldata tokenSymbol,
uint256 amount
) internal override {
(bool unwrap, address destination) = abi.decode(
payload,
(bool, address)
);
IERC20Upgradeable token = IERC20Upgradeable(
_getTokenAddress(tokenSymbol)
);
(bool unwrap, address destination) = abi.decode(payload, (bool, address));
IERC20Upgradeable token = IERC20Upgradeable(_getTokenAddress(tokenSymbol));

// If unwrap is set and the token can be unwrapped.
if (
unwrap &&
_wETHSymbolHash != DISABLED_SYMBOL &&
keccak256(abi.encodePacked(tokenSymbol)) == _wETHSymbolHash
) {
if (unwrap && _wETHSymbolHash != DISABLED_SYMBOL && keccak256(abi.encodePacked(tokenSymbol)) == _wETHSymbolHash)
{
// Unwrap native token.
IWETH weth = IWETH(address(token));
weth.withdraw(amount);

// Send it unwrapped to the destination
(bool success, ) = destination.call{value: amount}("");
(bool success,) = destination.call{value: amount}("");

if (!success) {
revert NativePaymentFailed();
Expand All @@ -333,7 +372,5 @@ contract AxelarHandler is
}
}

function _authorizeUpgrade(
address newImplementation
) internal override onlyOwner {}
function _authorizeUpgrade(address newImplementation) internal override onlyOwner {}
}
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