liquid-funding/contracts/SwapProxy.sol

89 lines
3.8 KiB
Solidity

pragma solidity ^0.4.18;
import "./LiquidPledging.sol";
// On mainnet extract the values from here: https://developer.kyber.network/docs/Environments-Mainnet/
// On ropsten extract the values from here: https://developer.kyber.network/docs/Environments-Ropsten/
contract KyberNetworkProxy {
function getExpectedRate(address src, address dest, uint srcQty) public pure returns(uint expectedRate, uint slippageRate);
function trade(address src, uint srcAmount, address dest, address destAddress, uint maxDestAmount, uint minConversionRate, address walletId) public payable returns(uint);
function swapTokenToToken(address src, uint srcAmount, address dest, uint minConversionRate) public pure;
function swapEtherToToken(address token, uint minConversionRate) public payable returns(uint);
}
interface ERC20Token {
function transfer(address _to, uint256 _value) external returns (bool success);
function approve(address _spender, uint256 _value) external returns (bool success);
function transferFrom(address _from, address _to, uint256 _value) external returns (bool success);
function balanceOf(address _owner) external view returns (uint256 balance);
function allowance(address _owner, address _spender) external view returns (uint256 remaining);
function totalSupply() external view returns (uint256 supply);
event Transfer(address indexed _from, address indexed _to, uint256 _value);
event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}
contract SwapProxy {
address public ETH;
KyberNetworkProxy public kyberProxy;
LiquidPledging public liquidPledging;
address public vault;
/**
* @param _liquidPledging LiquidPledging contract address
* @param _kyberProxy Kyber Network Proxy address
* @param _ETH Kyber ETH address
* @param _vault address that receives swap fees
*/
constructor(address _liquidPledging, address _kyberProxy, address _ETH, address _vault) public {
if (_vault == address(0)){
_vault = address(this);
}
liquidPledging = LiquidPledging(_liquidPledging);
kyberProxy = KyberNetworkProxy(_kyberProxy);
ETH = _ETH;
vault = _vault;
}
/**
* @notice Gets the conversion rate for the destToken given the srcQty.
* @param srcToken source token contract address
* @param srcQty amount of source tokens
* @param destToken destination token contract address
* @return exchange rate
*/
function getConversionRates(address srcToken, uint srcQty, address destToken) public view returns (uint exchangeRate)
{
if(srcToken == address(0)){
srcToken = ETH;
}
uint minConversionRate;
(minConversionRate, ) = kyberProxy.getExpectedRate(srcToken, destToken, srcQty);
return minConversionRate;
}
/**
* @notice Funds a project in desired token using ETH
* @dev Requires a msg.value
* @param idReceiver receiver of donation
* @param token token to convert from ETH
*/
function fundWithETH(uint64 idReceiver, address token) public payable {
require(msg.value > 0, "Not enough ETH");
(uint expectedRate, uint slippageRate) = kyberProxy.getExpectedRate(ETH, token, msg.value);
require(expectedRate > 0, "expected rate can not be 0");
uint slippagePercent = (slippageRate * 100) / expectedRate;
require(slippagePercent < 15, "slippage exceeds 15%, try a smaller amount");
uint maxDestinationAmount = (slippageRate / (10**18)) * msg.value;
uint amount = kyberProxy.trade.value(msg.value)(ETH, msg.value, token, address(this), maxDestinationAmount, slippageRate, vault);
require(amount > 0, "Not enough tokens for funding");
ERC20Token(token).approve(address(LiquidPledging), sntBalance);
liquidPledging.addGiverAndDonate(idReceiver, token, amount);
}
}