infrastructure-upgrade/lib/torn-token/contracts/Vesting.sol
T-Hax 735546619e
init
Signed-off-by: T-Hax <>
2023-04-08 18:46:18 +00:00

106 lines
3.3 KiB
Solidity

// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "@openzeppelin/contracts/math/Math.sol";
import "@openzeppelin/contracts/math/SafeMath.sol";
import "./ENS.sol";
/**
* @title Vesting
* @dev A token holder contract that can release its token balance gradually like a
* typical vesting scheme, with a cliff and vesting period. Optionally revocable by the
* owner.
*/
contract Vesting is EnsResolve {
using SafeERC20 for IERC20;
using SafeMath for uint256;
uint256 public constant SECONDS_PER_MONTH = 30 days;
event Released(uint256 amount);
// beneficiary of tokens after they are released
address public immutable beneficiary;
IERC20 public immutable token;
uint256 public immutable cliffInMonths;
uint256 public immutable startTimestamp;
uint256 public immutable durationInMonths;
uint256 public released;
/**
* @dev Creates a vesting contract that vests its balance of any ERC20 token to the
* _beneficiary, monthly in a linear fashion until duration has passed. By then all
* of the balance will have vested.
* @param _beneficiary address of the beneficiary to whom vested tokens are transferred
* @param _cliffInMonths duration in months of the cliff in which tokens will begin to vest
* @param _durationInMonths duration in months of the period in which the tokens will vest
*/
constructor(
bytes32 _token,
address _beneficiary,
uint256 _startTimestamp,
uint256 _cliffInMonths,
uint256 _durationInMonths
) public {
require(_beneficiary != address(0), "Beneficiary cannot be empty");
require(_cliffInMonths <= _durationInMonths, "Cliff is greater than duration");
token = IERC20(resolve(_token));
beneficiary = _beneficiary;
durationInMonths = _durationInMonths;
cliffInMonths = _cliffInMonths;
startTimestamp = _startTimestamp == 0 ? blockTimestamp() : _startTimestamp;
}
/**
* @notice Transfers vested tokens to beneficiary.
*/
function release() external {
uint256 vested = vestedAmount();
require(vested > 0, "No tokens to release");
released = released.add(vested);
token.safeTransfer(beneficiary, vested);
emit Released(vested);
}
/**
* @dev Calculates the amount that has already vested but hasn't been released yet.
*/
function vestedAmount() public view returns (uint256) {
if (blockTimestamp() < startTimestamp) {
return 0;
}
uint256 elapsedTime = blockTimestamp().sub(startTimestamp);
uint256 elapsedMonths = elapsedTime.div(SECONDS_PER_MONTH);
if (elapsedMonths < cliffInMonths) {
return 0;
}
// If over vesting duration, all tokens vested
if (elapsedMonths >= durationInMonths) {
return token.balanceOf(address(this));
} else {
uint256 currentBalance = token.balanceOf(address(this));
uint256 totalBalance = currentBalance.add(released);
uint256 vested = totalBalance.mul(elapsedMonths).div(durationInMonths);
uint256 unreleased = vested.sub(released);
// currentBalance can be 0 in case of vesting being revoked earlier.
return Math.min(currentBalance, unreleased);
}
}
function blockTimestamp() public view virtual returns (uint256) {
return block.timestamp;
}
}