Contract Source Code:
File 1 of 1 : TokensFarm
// Sources flattened with hardhat v2.1.2 https://hardhat.org
// File @openzeppelin/contracts/token/ERC20/[email protected]
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address recipient, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
}
// File @openzeppelin/contracts/math/[email protected]
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
*
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
*/
library SafeMath {
/**
* @dev Returns the addition of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
uint256 c = a + b;
if (c < a) return (false, 0);
return (true, c);
}
/**
* @dev Returns the substraction of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b > a) return (false, 0);
return (true, a - b);
}
/**
* @dev Returns the multiplication of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
if (a == 0) return (true, 0);
uint256 c = a * b;
if (c / a != b) return (false, 0);
return (true, c);
}
/**
* @dev Returns the division of two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b == 0) return (false, 0);
return (true, a / b);
}
/**
* @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b == 0) return (false, 0);
return (true, a % b);
}
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
*
* - Addition cannot overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
require(b <= a, "SafeMath: subtraction overflow");
return a - b;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
*
* - Multiplication cannot overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
if (a == 0) return 0;
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
require(b > 0, "SafeMath: division by zero");
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
require(b > 0, "SafeMath: modulo by zero");
return a % b;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {trySub}.
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b <= a, errorMessage);
return a - b;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting with custom message on
* division by zero. The result is rounded towards zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryDiv}.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b > 0, errorMessage);
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting with custom message when dividing by zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryMod}.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b > 0, errorMessage);
return a % b;
}
}
// File @openzeppelin/contracts/utils/[email protected]
pragma solidity >=0.6.2 <0.8.0;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint256 size;
// solhint-disable-next-line no-inline-assembly
assembly { size := extcodesize(account) }
return size > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
(bool success, ) = recipient.call{ value: amount }("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain`call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.call{ value: value }(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.staticcall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.delegatecall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
// solhint-disable-next-line no-inline-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
// File @openzeppelin/contracts/token/ERC20/[email protected]
pragma solidity >=0.6.0 <0.8.0;
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
using SafeMath for uint256;
using Address for address;
function safeTransfer(IERC20 token, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
/**
* @dev Deprecated. This function has issues similar to the ones found in
* {IERC20-approve}, and its usage is discouraged.
*
* Whenever possible, use {safeIncreaseAllowance} and
* {safeDecreaseAllowance} instead.
*/
function safeApprove(IERC20 token, address spender, uint256 value) internal {
// safeApprove should only be called when setting an initial allowance,
// or when resetting it to zero. To increase and decrease it, use
// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
// solhint-disable-next-line max-line-length
require((value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 newAllowance = token.allowance(address(this), spender).add(value);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/
function _callOptionalReturn(IERC20 token, bytes memory data) private {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
// the target address contains contract code and also asserts for success in the low-level call.
bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length > 0) { // Return data is optional
// solhint-disable-next-line max-line-length
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
// File @openzeppelin/contracts/utils/[email protected]
pragma solidity >=0.6.0 <0.8.0;
/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with GSN meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address payable) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
// File @openzeppelin/contracts/access/[email protected]
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
abstract contract Ownable is Context {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor () internal {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(owner() == _msgSender(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public virtual onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
// File @openzeppelin/contracts/utils/[email protected]
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Contract module that helps prevent reentrant calls to a function.
*
* Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
* available, which can be applied to functions to make sure there are no nested
* (reentrant) calls to them.
*
* Note that because there is a single `nonReentrant` guard, functions marked as
* `nonReentrant` may not call one another. This can be worked around by making
* those functions `private`, and then adding `external` `nonReentrant` entry
* points to them.
*
* TIP: If you would like to learn more about reentrancy and alternative ways
* to protect against it, check out our blog post
* https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
*/
abstract contract ReentrancyGuard {
// Booleans are more expensive than uint256 or any type that takes up a full
// word because each write operation emits an extra SLOAD to first read the
// slot's contents, replace the bits taken up by the boolean, and then write
// back. This is the compiler's defense against contract upgrades and
// pointer aliasing, and it cannot be disabled.
// The values being non-zero value makes deployment a bit more expensive,
// but in exchange the refund on every call to nonReentrant will be lower in
// amount. Since refunds are capped to a percentage of the total
// transaction's gas, it is best to keep them low in cases like this one, to
// increase the likelihood of the full refund coming into effect.
uint256 private constant _NOT_ENTERED = 1;
uint256 private constant _ENTERED = 2;
uint256 private _status;
constructor () internal {
_status = _NOT_ENTERED;
}
/**
* @dev Prevents a contract from calling itself, directly or indirectly.
* Calling a `nonReentrant` function from another `nonReentrant`
* function is not supported. It is possible to prevent this from happening
* by making the `nonReentrant` function external, and make it call a
* `private` function that does the actual work.
*/
modifier nonReentrant() {
// On the first call to nonReentrant, _notEntered will be true
require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
// Any calls to nonReentrant after this point will fail
_status = _ENTERED;
_;
// By storing the original value once again, a refund is triggered (see
// https://eips.ethereum.org/EIPS/eip-2200)
_status = _NOT_ENTERED;
}
}
// File contracts/TokensFarm.sol
pragma solidity 0.6.12;
contract TokensFarm is Ownable, ReentrancyGuard {
using SafeMath for uint256;
using SafeERC20 for IERC20;
enum EarlyWithdrawPenalty {
NO_PENALTY,
BURN_REWARDS,
REDISTRIBUTE_REWARDS
}
// Info of each user.
struct StakeInfo {
uint256 amount; // How many tokens the user has provided.
uint256 rewardDebt; // Reward debt. See explanation below.
uint256 depositTime; // Time when user deposited.
}
IERC20 public tokenStaked; // Address of ERC20 token contract.
uint256 public lastRewardTime; // Last time number that ERC20s distribution occurs.
uint256 public accERC20PerShare; // Accumulated ERC20s per share, times 1e18.
uint256 public totalDeposits; // Total tokens deposited in the farm.
// If contractor allows early withdraw on stakes
bool public isEarlyWithdrawAllowed;
// Minimal period of time to stake
uint256 public minTimeToStake;
// Address of the ERC20 Token contract.
IERC20 public erc20;
// The total amount of ERC20 that's paid out as reward.
uint256 public paidOut;
// ERC20 tokens rewarded per second.
uint256 public rewardPerSecond;
// Total rewards added to farm
uint256 public totalRewards;
// Info of each user that stakes ERC20 tokens.
mapping(address => StakeInfo[]) public stakeInfo;
// The time when farming starts.
uint256 public startTime;
// The time when farming ends.
uint256 public endTime;
// Early withdraw penalty
EarlyWithdrawPenalty public penalty;
// Counter for funding
uint256 fundCounter;
// Congress address
address public congressAddress;
// Stake fee percent
uint256 public stakeFeePercent;
// Reward fee percent
uint256 public rewardFeePercent;
// Fee collector address
address payable public feeCollector;
// Flat fee amount
uint256 public flatFeeAmount;
// Fee option
bool public isFlatFeeAllowed;
// Events
event Deposit(address indexed user, uint256 stakeId, uint256 amount);
event Withdraw(address indexed user, uint256 stakeId, uint256 amount);
event EmergencyWithdraw(
address indexed user,
uint256 stakeId,
uint256 amount
);
event EarlyWithdrawPenaltyChange(EarlyWithdrawPenalty penalty);
modifier validateStakeByStakeId(address _user, uint256 stakeId) {
require(stakeId < stakeInfo[_user].length, "Stake does not exist");
_;
}
constructor(
IERC20 _erc20,
uint256 _rewardPerSecond,
uint256 _startTime,
uint256 _minTimeToStake,
bool _isEarlyWithdrawAllowed,
EarlyWithdrawPenalty _penalty,
IERC20 _tokenStaked,
address _congressAddress,
uint256 _stakeFeePercent,
uint256 _rewardFeePercent,
uint256 _flatFeeAmount,
address payable _feeCollector,
bool _isFlatFeeAllowed
) public {
require(address(_erc20) != address(0x0), "Wrong token address.");
require(_rewardPerSecond > 0, "Rewards per second must be > 0.");
require(
_startTime >= block.timestamp,
"Start timne can not be in the past."
);
require(_stakeFeePercent < 100, "Stake fee must be < 100.");
require(_rewardFeePercent < 100, "Reward fee must be < 100.");
require(_feeCollector != address(0x0), "Wrong fee collector address.");
require(
_congressAddress != address(0x0),
"Congress address can not be 0."
);
erc20 = _erc20;
rewardPerSecond = _rewardPerSecond;
startTime = _startTime;
endTime = _startTime;
minTimeToStake = _minTimeToStake;
isEarlyWithdrawAllowed = _isEarlyWithdrawAllowed;
congressAddress = _congressAddress;
stakeFeePercent = _stakeFeePercent;
rewardFeePercent = _rewardFeePercent;
flatFeeAmount = _flatFeeAmount;
feeCollector = _feeCollector;
isFlatFeeAllowed = _isFlatFeeAllowed;
_setEarlyWithdrawPenalty(_penalty);
_addPool(_tokenStaked);
}
// Set minimun time to stake
function setMinTimeToStake(uint256 _minTimeToStake) external onlyOwner {
minTimeToStake = _minTimeToStake;
}
// Set fee collector address
function setFeeCollector(address payable _feeCollector) external onlyOwner {
require(_feeCollector != address(0x0), "Wrong fee collector address.");
feeCollector = _feeCollector;
}
// Set early withdrawal penalty, if applicable
function _setEarlyWithdrawPenalty(EarlyWithdrawPenalty _penalty) internal {
penalty = _penalty;
emit EarlyWithdrawPenaltyChange(penalty);
}
// Fund the farm, increase the end time
function fund(uint256 _amount) external {
fundCounter = fundCounter.add(1);
_fundInternal(_amount);
erc20.safeTransferFrom(address(msg.sender), address(this), _amount);
if (fundCounter == 2) {
transferOwnership(congressAddress);
}
}
// Internally fund the farm by adding farmed rewards by user to the end
function _fundInternal(uint256 _amount) internal {
require(
block.timestamp < endTime,
"fund: too late, the farm is closed"
);
require(_amount > 0, "Amount must be greater than 0.");
// Compute new end time
endTime += _amount.div(rewardPerSecond);
// Increase farm total rewards
totalRewards = totalRewards.add(_amount);
}
// Add a new ERC20 token to the pool. Can only be called by the owner.
function _addPool(IERC20 _tokenStaked) internal {
require(
address(_tokenStaked) != address(0x0),
"Must input valid address."
);
require(
address(tokenStaked) == address(0x0),
"Pool can be set only once."
);
uint256 _lastRewardTime = block.timestamp > startTime
? block.timestamp
: startTime;
tokenStaked = _tokenStaked;
lastRewardTime = _lastRewardTime;
accERC20PerShare = 0;
totalDeposits = 0;
}
// View function to see deposited ERC20 token for a user.
function deposited(address _user, uint256 stakeId)
public
view
validateStakeByStakeId(_user, stakeId)
returns (uint256)
{
StakeInfo storage stake = stakeInfo[_user][stakeId];
return stake.amount;
}
// View function to see pending ERC20s for a user.
function pending(address _user, uint256 stakeId)
public
view
validateStakeByStakeId(_user, stakeId)
returns (uint256)
{
StakeInfo storage stake = stakeInfo[_user][stakeId];
if (stake.amount == 0) {
return 0;
}
uint256 _accERC20PerShare = accERC20PerShare;
uint256 tokenSupply = totalDeposits;
if (block.timestamp > lastRewardTime && tokenSupply != 0) {
uint256 lastTime = block.timestamp < endTime
? block.timestamp
: endTime;
uint256 timeToCompare = lastRewardTime < endTime
? lastRewardTime
: endTime;
uint256 nrOfSeconds = lastTime.sub(timeToCompare);
uint256 erc20Reward = nrOfSeconds.mul(rewardPerSecond);
_accERC20PerShare = _accERC20PerShare.add(
erc20Reward.mul(1e18).div(tokenSupply)
);
}
return
stake.amount.mul(_accERC20PerShare).div(1e18).sub(stake.rewardDebt);
}
// View function to see deposit timestamp for a user.
function depositTimestamp(address _user, uint256 stakeId)
public
view
validateStakeByStakeId(_user, stakeId)
returns (uint256)
{
StakeInfo storage stake = stakeInfo[_user][stakeId];
return stake.depositTime;
}
// View function for total reward the farm has yet to pay out.
function totalPending() external view returns (uint256) {
if (block.timestamp <= startTime) {
return 0;
}
uint256 lastTime = block.timestamp < endTime
? block.timestamp
: endTime;
return rewardPerSecond.mul(lastTime - startTime).sub(paidOut);
}
// Update reward variables of the given pool to be up-to-date.
function updatePool() public {
uint256 lastTime = block.timestamp < endTime
? block.timestamp
: endTime;
if (lastTime <= lastRewardTime) {
return;
}
uint256 tokenSupply = totalDeposits;
if (tokenSupply == 0) {
lastRewardTime = lastTime;
return;
}
uint256 nrOfSeconds = lastTime.sub(lastRewardTime);
uint256 erc20Reward = nrOfSeconds.mul(rewardPerSecond);
accERC20PerShare = accERC20PerShare.add(
erc20Reward.mul(1e18).div(tokenSupply)
);
lastRewardTime = block.timestamp;
}
// Deposit ERC20 tokens to Farm for ERC20 allocation.
function deposit(uint256 _amount) external payable {
StakeInfo memory stake;
// Update pool
updatePool();
// Take token and transfer to contract
tokenStaked.safeTransferFrom(
address(msg.sender),
address(this),
_amount
);
uint256 stakedAmount = _amount;
if (isFlatFeeAllowed) {
// Collect flat fee
require(
msg.value >= flatFeeAmount,
"Payable amount is less than fee amount."
);
(bool sent, ) = payable(feeCollector).call{value: msg.value}("");
require(sent, "Failed to send flat fee");
} else if (stakeFeePercent > 0) { // Handle this case only if flat fee is not allowed, and stakeFeePercent > 0
// Compute the fee
uint256 feeAmount = _amount.mul(stakeFeePercent).div(100);
// Compute stake amount
stakedAmount = _amount.sub(feeAmount);
// Transfer fee to Fee Collector
tokenStaked.safeTransfer(feeCollector, feeAmount);
}
// Increase total deposits
totalDeposits = totalDeposits.add(stakedAmount);
// Update user accounting
stake.amount = stakedAmount;
stake.rewardDebt = stake.amount.mul(accERC20PerShare).div(1e18);
stake.depositTime = block.timestamp;
// Compute stake id
uint256 stakeId = stakeInfo[msg.sender].length;
// Push new stake to array of stakes for user
stakeInfo[msg.sender].push(stake);
// Emit deposit event
emit Deposit(msg.sender, stakeId, stakedAmount);
}
// Withdraw ERC20 tokens from Farm.
function withdraw(uint256 _amount, uint256 stakeId)
external
payable
nonReentrant
validateStakeByStakeId(msg.sender, stakeId)
{
bool minimalTimeStakeRespected;
StakeInfo storage stake = stakeInfo[msg.sender][stakeId];
require(
stake.amount >= _amount,
"withdraw: can't withdraw more than deposit"
);
updatePool();
minimalTimeStakeRespected = stake.depositTime.add(minTimeToStake) <= block.timestamp;
// if early withdraw is not allowed, user can't withdraw funds before
if (!isEarlyWithdrawAllowed) {
// Check if user has respected minimal time to stake, require it.
require(
minimalTimeStakeRespected,
"User can not withdraw funds yet."
);
}
// Compute pending rewards amount of user rewards
uint256 pendingAmount = stake
.amount
.mul(accERC20PerShare)
.div(1e18)
.sub(stake.rewardDebt);
// Penalties in case user didn't stake enough time
if (pendingAmount > 0) {
if (
penalty == EarlyWithdrawPenalty.BURN_REWARDS &&
!minimalTimeStakeRespected
) {
// Burn to address (1)
_erc20Transfer(address(1), pendingAmount);
} else if (
penalty == EarlyWithdrawPenalty.REDISTRIBUTE_REWARDS &&
!minimalTimeStakeRespected
) {
if (block.timestamp >= endTime) {
// Burn rewards because farm can not be funded anymore since it ended
_erc20Transfer(address(1), pendingAmount);
} else {
// Re-fund the farm
_fundInternal(pendingAmount);
}
} else {
// In case either there's no penalty
_erc20Transfer(msg.sender, pendingAmount);
}
}
stake.amount = stake.amount.sub(_amount);
stake.rewardDebt = stake.amount.mul(accERC20PerShare).div(1e18);
tokenStaked.safeTransfer(address(msg.sender), _amount);
totalDeposits = totalDeposits.sub(_amount);
// Emit Withdraw event
emit Withdraw(msg.sender, stakeId, _amount);
}
// Withdraw without caring about rewards. EMERGENCY ONLY.
function emergencyWithdraw(uint256 stakeId)
external
nonReentrant
validateStakeByStakeId(msg.sender, stakeId)
{
StakeInfo storage stake = stakeInfo[msg.sender][stakeId];
// if early withdraw is not allowed, user can't withdraw funds before
if (!isEarlyWithdrawAllowed) {
bool minimalTimeStakeRespected = stake.depositTime.add(
minTimeToStake
) <= block.timestamp;
// Check if user has respected minimal time to stake, require it.
require(
minimalTimeStakeRespected,
"User can not withdraw funds yet."
);
}
tokenStaked.safeTransfer(address(msg.sender), stake.amount);
totalDeposits = totalDeposits.sub(stake.amount);
emit EmergencyWithdraw(msg.sender, stakeId, stake.amount);
stake.amount = 0;
stake.rewardDebt = 0;
}
// Get number of stakes user has
function getNumberOfUserStakes(address user)
external
view
returns (uint256)
{
return stakeInfo[user].length;
}
// Get user pending amounts, stakes and deposit time
function getUserStakesAndPendingAmounts(address user)
external
view
returns (
uint256[] memory,
uint256[] memory,
uint256[] memory
)
{
uint256 numberOfStakes = stakeInfo[user].length;
uint256[] memory deposits = new uint256[](numberOfStakes);
uint256[] memory pendingAmounts = new uint256[](numberOfStakes);
uint256[] memory depositTime = new uint256[](numberOfStakes);
for (uint256 i = 0; i < numberOfStakes; i++) {
deposits[i] = deposited(user, i);
pendingAmounts[i] = pending(user, i);
depositTime[i] = depositTimestamp(user, i);
}
return (deposits, pendingAmounts, depositTime);
}
// Get total rewards locked/unlocked
function getTotalRewardsLockedUnlocked()
external
view
returns (uint256, uint256)
{
uint256 totalRewardsLocked;
uint256 totalRewardsUnlocked;
if (block.timestamp <= startTime) {
totalRewardsUnlocked = 0;
totalRewardsLocked = totalRewards;
} else {
uint256 lastTime = block.timestamp < endTime
? block.timestamp
: endTime;
totalRewardsUnlocked = rewardPerSecond.mul(lastTime - startTime);
totalRewardsLocked = totalRewards - totalRewardsUnlocked;
}
return (totalRewardsUnlocked, totalRewardsLocked);
}
// Transfer ERC20 and update the required ERC20 to payout all rewards
function _erc20Transfer(address _to, uint256 _amount) internal {
if (isFlatFeeAllowed) {
// Collect flat fee
require(
msg.value >= flatFeeAmount,
"Payable amount is less than fee amount."
);
(bool sent, ) = payable(feeCollector).call{value: msg.value}("");
require(sent, "Failed to end flat fee");
// send reward
erc20.transfer(_to, _amount);
paidOut += _amount;
} else if (stakeFeePercent > 0) {
// Collect reward fee
uint256 feeAmount = _amount.mul(rewardFeePercent).div(100);
uint256 rewardAmount = _amount.sub(feeAmount);
erc20.transfer(feeCollector, feeAmount);
// send reward
erc20.transfer(_to, rewardAmount);
paidOut += _amount;
} else {
erc20.transfer(_to, _amount);
paidOut += _amount;
}
}
}