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wKLC_Vesting_Contracts/contracts/TokenVesting.sol

351 lines
12 KiB

// contracts/TokenVesting.sol
// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.8.11;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/math/Math.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";
/**
* @title TokenVesting
*/
contract TokenVesting is Ownable, ReentrancyGuard{
using SafeMath for uint256;
using SafeERC20 for IERC20;
struct VestingSchedule{
bool initialized;
// beneficiary of tokens after they are released
address beneficiary;
// cliff period in seconds
uint256 cliff;
// start time of the vesting period
uint256 start;
// duration of the vesting period in seconds
uint256 duration;
// duration of a slice period for the vesting in seconds
uint256 slicePeriodSeconds;
// whether or not the vesting is revocable
bool revocable;
// total amount of tokens to be released at the end of the vesting
uint256 amountTotal;
// amount of tokens released
uint256 released;
// whether or not the vesting has been revoked
bool revoked;
}
// address of the ERC20 token
IERC20 immutable private _token;
bytes32[] private vestingSchedulesIds;
mapping(bytes32 => VestingSchedule) private vestingSchedules;
uint256 private vestingSchedulesTotalAmount;
mapping(address => uint256) private holdersVestingCount;
event Released(uint256 amount);
event Revoked();
/**
* @dev Reverts if no vesting schedule matches the passed identifier.
*/
modifier onlyIfVestingScheduleExists(bytes32 vestingScheduleId) {
require(vestingSchedules[vestingScheduleId].initialized == true);
_;
}
/**
* @dev Reverts if the vesting schedule does not exist or has been revoked.
*/
modifier onlyIfVestingScheduleNotRevoked(bytes32 vestingScheduleId) {
require(vestingSchedules[vestingScheduleId].initialized == true);
require(vestingSchedules[vestingScheduleId].revoked == false);
_;
}
/**
* @dev Creates a vesting contract.
* @param token_ address of the ERC20 token contract
*/
constructor(address token_) {
require(token_ != address(0x0));
_token = IERC20(token_);
}
receive() external payable {}
fallback() external payable {}
/**
* @dev Returns the number of vesting schedules associated to a beneficiary.
* @return the number of vesting schedules
*/
function getVestingSchedulesCountByBeneficiary(address _beneficiary)
external
view
returns(uint256){
return holdersVestingCount[_beneficiary];
}
/**
* @dev Returns the vesting schedule id at the given index.
* @return the vesting id
*/
function getVestingIdAtIndex(uint256 index)
external
view
returns(bytes32){
require(index < getVestingSchedulesCount(), "TokenVesting: index out of bounds");
return vestingSchedulesIds[index];
}
/**
* @notice Returns the vesting schedule information for a given holder and index.
* @return the vesting schedule structure information
*/
function getVestingScheduleByAddressAndIndex(address holder, uint256 index)
external
view
returns(VestingSchedule memory){
return getVestingSchedule(computeVestingScheduleIdForAddressAndIndex(holder, index));
}
/**
* @notice Returns the total amount of vesting schedules.
* @return the total amount of vesting schedules
*/
function getVestingSchedulesTotalAmount()
external
view
returns(uint256){
return vestingSchedulesTotalAmount;
}
/**
* @dev Returns the address of the ERC20 token managed by the vesting contract.
*/
function getToken()
external
view
returns(address){
return address(_token);
}
/**
* @notice Creates a new vesting schedule for a beneficiary.
* @param _beneficiary address of the beneficiary to whom vested tokens are transferred
* @param _start start time of the vesting period
* @param _cliff duration in seconds of the cliff in which tokens will begin to vest
* @param _duration duration in seconds of the period in which the tokens will vest
* @param _slicePeriodSeconds duration of a slice period for the vesting in seconds
* @param _revocable whether the vesting is revocable or not
* @param _amount total amount of tokens to be released at the end of the vesting
*/
function createVestingSchedule(
address _beneficiary,
uint256 _start,
uint256 _cliff,
uint256 _duration,
uint256 _slicePeriodSeconds,
bool _revocable,
uint256 _amount
)
public
onlyOwner{
require(
this.getWithdrawableAmount() >= _amount,
"TokenVesting: cannot create vesting schedule because not sufficient tokens"
);
require(_duration > 0, "TokenVesting: duration must be > 0");
require(_amount > 0, "TokenVesting: amount must be > 0");
require(_slicePeriodSeconds >= 1, "TokenVesting: slicePeriodSeconds must be >= 1");
bytes32 vestingScheduleId = this.computeNextVestingScheduleIdForHolder(_beneficiary);
uint256 cliff = _start.add(_cliff);
vestingSchedules[vestingScheduleId] = VestingSchedule(
true,
_beneficiary,
cliff,
_start,
_duration,
_slicePeriodSeconds,
_revocable,
_amount,
0,
false
);
vestingSchedulesTotalAmount = vestingSchedulesTotalAmount.add(_amount);
vestingSchedulesIds.push(vestingScheduleId);
uint256 currentVestingCount = holdersVestingCount[_beneficiary];
holdersVestingCount[_beneficiary] = currentVestingCount.add(1);
}
/**
* @notice Revokes the vesting schedule for given identifier.
* @param vestingScheduleId the vesting schedule identifier
*/
function revoke(bytes32 vestingScheduleId)
public
onlyOwner
onlyIfVestingScheduleNotRevoked(vestingScheduleId){
VestingSchedule storage vestingSchedule = vestingSchedules[vestingScheduleId];
require(vestingSchedule.revocable == true, "TokenVesting: vesting is not revocable");
uint256 vestedAmount = _computeReleasableAmount(vestingSchedule);
if(vestedAmount > 0){
release(vestingScheduleId, vestedAmount);
}
uint256 unreleased = vestingSchedule.amountTotal.sub(vestingSchedule.released);
vestingSchedulesTotalAmount = vestingSchedulesTotalAmount.sub(unreleased);
vestingSchedule.revoked = true;
}
/**
* @notice Withdraw the specified amount if possible.
* @param amount the amount to withdraw
*/
function withdraw(uint256 amount)
public
nonReentrant
onlyOwner{
require(this.getWithdrawableAmount() >= amount, "TokenVesting: not enough withdrawable funds");
_token.safeTransfer(owner(), amount);
}
/**
* @notice Release vested amount of tokens.
* @param vestingScheduleId the vesting schedule identifier
* @param amount the amount to release
*/
function release(
bytes32 vestingScheduleId,
uint256 amount
)
public
nonReentrant
onlyIfVestingScheduleNotRevoked(vestingScheduleId){
VestingSchedule storage vestingSchedule = vestingSchedules[vestingScheduleId];
bool isBeneficiary = msg.sender == vestingSchedule.beneficiary;
bool isOwner = msg.sender == owner();
require(
isBeneficiary || isOwner,
"TokenVesting: only beneficiary and owner can release vested tokens"
);
uint256 vestedAmount = _computeReleasableAmount(vestingSchedule);
require(vestedAmount >= amount, "TokenVesting: cannot release tokens, not enough vested tokens");
vestingSchedule.released = vestingSchedule.released.add(amount);
address payable beneficiaryPayable = payable(vestingSchedule.beneficiary);
vestingSchedulesTotalAmount = vestingSchedulesTotalAmount.sub(amount);
_token.safeTransfer(beneficiaryPayable, amount);
}
/**
* @dev Returns the number of vesting schedules managed by this contract.
* @return the number of vesting schedules
*/
function getVestingSchedulesCount()
public
view
returns(uint256){
return vestingSchedulesIds.length;
}
/**
* @notice Computes the vested amount of tokens for the given vesting schedule identifier.
* @return the vested amount
*/
function computeReleasableAmount(bytes32 vestingScheduleId)
public
onlyIfVestingScheduleNotRevoked(vestingScheduleId)
view
returns(uint256){
VestingSchedule storage vestingSchedule = vestingSchedules[vestingScheduleId];
return _computeReleasableAmount(vestingSchedule);
}
/**
* @notice Returns the vesting schedule information for a given identifier.
* @return the vesting schedule structure information
*/
function getVestingSchedule(bytes32 vestingScheduleId)
public
view
returns(VestingSchedule memory){
return vestingSchedules[vestingScheduleId];
}
/**
* @dev Returns the amount of tokens that can be withdrawn by the owner.
* @return the amount of tokens
*/
function getWithdrawableAmount()
public
view
returns(uint256){
return _token.balanceOf(address(this)).sub(vestingSchedulesTotalAmount);
}
/**
* @dev Computes the next vesting schedule identifier for a given holder address.
*/
function computeNextVestingScheduleIdForHolder(address holder)
public
view
returns(bytes32){
return computeVestingScheduleIdForAddressAndIndex(holder, holdersVestingCount[holder]);
}
/**
* @dev Returns the last vesting schedule for a given holder address.
*/
function getLastVestingScheduleForHolder(address holder)
public
view
returns(VestingSchedule memory){
return vestingSchedules[computeVestingScheduleIdForAddressAndIndex(holder, holdersVestingCount[holder] - 1)];
}
/**
* @dev Computes the vesting schedule identifier for an address and an index.
*/
function computeVestingScheduleIdForAddressAndIndex(address holder, uint256 index)
public
pure
returns(bytes32){
return keccak256(abi.encodePacked(holder, index));
}
/**
* @dev Computes the releasable amount of tokens for a vesting schedule.
* @return the amount of releasable tokens
*/
function _computeReleasableAmount(VestingSchedule memory vestingSchedule)
internal
view
returns(uint256){
uint256 currentTime = getCurrentTime();
if ((currentTime < vestingSchedule.cliff) || vestingSchedule.revoked == true) {
return 0;
} else if (currentTime >= vestingSchedule.start.add(vestingSchedule.duration)) {
return vestingSchedule.amountTotal.sub(vestingSchedule.released);
} else {
uint256 timeFromStart = currentTime.sub(vestingSchedule.start);
uint secondsPerSlice = vestingSchedule.slicePeriodSeconds;
uint256 vestedSlicePeriods = timeFromStart.div(secondsPerSlice);
uint256 vestedSeconds = vestedSlicePeriods.mul(secondsPerSlice);
uint256 vestedAmount = vestingSchedule.amountTotal.mul(vestedSeconds).div(vestingSchedule.duration);
vestedAmount = vestedAmount.sub(vestingSchedule.released);
return vestedAmount;
}
}
function getCurrentTime()
internal
virtual
view
returns(uint256){
return block.timestamp;
}
}