Hi there, currently learning and developing on Cronos testnet blockchain.
I'm trying to get a staking contract to work. You stake CoinA, receive CoinB
So I deployed two simple ERC20 tokens, one for each coin, and minted plenty of each into their respective owner wallets.
I then made a 3rd wallet, transferred the reward token (CoinB) into it's balance, then deployed it.
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;
import "./IERC20.sol";
contract StakingRewards {
IERC20 public immutable stakingToken;
IERC20 public immutable rewardsToken;
address public owner;
// Duration of rewards to be paid out (in seconds)
uint256 public duration;
// Timestamp of when the rewards finish
uint256 public finishAt;
// Minimum of last updated time and reward finish time
uint256 public updatedAt;
// Reward to be paid out per second
uint256 public rewardRate;
// Sum of (reward rate * dt * 1e18 / total supply)
uint256 public rewardPerTokenStored;
// User address => rewardPerTokenStored
mapping(address => uint256) public userRewardPerTokenPaid;
// User address => rewards to be claimed
mapping(address => uint256) public rewards;
// Total staked
uint256 public totalSupply;
// User address => staked amount
mapping(address => uint256) public balanceOf;
constructor(address _stakingToken, address _rewardToken) {
owner = msg.sender;
stakingToken = IERC20(_stakingToken);
rewardsToken = IERC20(_rewardToken);
}
modifier onlyOwner() {
require(msg.sender == owner, "not authorized");
_;
}
modifier updateReward(address _account) {
rewardPerTokenStored = rewardPerToken();
updatedAt = lastTimeRewardApplicable();
if (_account != address(0)) {
rewards[_account] = earned(_account);
userRewardPerTokenPaid[_account] = rewardPerTokenStored;
}
_;
}
function lastTimeRewardApplicable() public view returns (uint256) {
return _min(finishAt, block.timestamp);
}
function rewardPerToken() public view returns (uint256) {
if (totalSupply == 0) {
return rewardPerTokenStored;
}
return rewardPerTokenStored
+ (rewardRate * (lastTimeRewardApplicable() - updatedAt) * 1e18)
/ totalSupply;
}
function stake(uint256 _amount) external updateReward(msg.sender) {
require(_amount > 0, "amount = 0");
stakingToken.transferFrom(msg.sender, address(this), _amount);
balanceOf[msg.sender] += _amount;
totalSupply += _amount;
}
function withdraw(uint256 _amount) external updateReward(msg.sender) {
require(_amount > 0, "amount = 0");
balanceOf[msg.sender] -= _amount;
totalSupply -= _amount;
stakingToken.transfer(msg.sender, _amount);
}
function earned(address _account) public view returns (uint256) {
return (
(
balanceOf[_account]
* (rewardPerToken() - userRewardPerTokenPaid[_account])
) / 1e18
) + rewards[_account];
}
function getReward() external updateReward(msg.sender) {
uint256 reward = rewards[msg.sender];
if (reward > 0) {
rewards[msg.sender] = 0;
rewardsToken.transfer(msg.sender, reward);
}
}
function setRewardsDuration(uint256 _duration) external onlyOwner {
require(finishAt < block.timestamp, "reward duration not finished");
duration = _duration;
}
function notifyRewardAmount(uint256 _amount)
external
onlyOwner
updateReward(address(0))
{
if (block.timestamp >= finishAt) {
rewardRate = _amount / duration;
} else {
uint256 remainingRewards = (finishAt - block.timestamp) * rewardRate;
rewardRate = (_amount + remainingRewards) / duration;
}
require(rewardRate > 0, "reward rate = 0");
require(
rewardRate * duration <= rewardsToken.balanceOf(address(this)),
"reward amount > balance"
);
finishAt = block.timestamp + duration;
updatedAt = block.timestamp;
}
function _min(uint256 x, uint256 y) private pure returns (uint256) {
return x <= y ? x : y;
}
}
PROBLEM: When I am currently on metamask for CoinA, when I attempt to stake on the StakingRewards contract (with a large supply of CoinA), I get this error regardless of the amount I attempt to stake