/**
 *Submitted for verification at Etherscan.io on 2021-01-13
*/

// SPDX-License-Identifier: MIT
pragma solidity ^0.6.12;


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;
    }
}

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 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;
    }
}


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);
}

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");
        }
    }
}

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);
    }

    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);
            }
        }
    }
}

library SafeMath {
    /**
     * @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) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * 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);
        uint256 c = a - b;

        return c;
    }

    /**
     * @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) {
        // 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 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts 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) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts 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) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;

        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping (bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) { // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.

            bytes32 lastvalue = set._values[lastIndex];

            // Move the last value to the index where the value to delete is
            set._values[toDeleteIndex] = lastvalue;
            // Update the index for the moved value
            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        require(set._values.length > index, "EnumerableSet: index out of bounds");
        return set._values[index];
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint256(_at(set._inner, index)));
    }


    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
}

library Math {
    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow, so we distribute
        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
    }
}

abstract contract AccessControl is Context {
    using EnumerableSet for EnumerableSet.AddressSet;
    using Address for address;

    struct RoleData {
        EnumerableSet.AddressSet members;
        bytes32 adminRole;
    }

    mapping (bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);

    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view returns (bool) {
        return _roles[role].members.contains(account);
    }

    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) public view returns (uint256) {
        return _roles[role].members.length();
    }

    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) public view returns (address) {
        return _roles[role].members.at(index);
    }

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view returns (bytes32) {
        return _roles[role].adminRole;
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to grant");

        _grantRole(role, account);
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to revoke");

        _revokeRole(role, account);
    }

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) public virtual {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");

        _revokeRole(role, account);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }

    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        emit RoleAdminChanged(role, _roles[role].adminRole, adminRole);
        _roles[role].adminRole = adminRole;
    }

    function _grantRole(bytes32 role, address account) private {
        if (_roles[role].members.add(account)) {
            emit RoleGranted(role, account, _msgSender());
        }
    }

    function _revokeRole(bytes32 role, address account) private {
        if (_roles[role].members.remove(account)) {
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}






contract ContractGuard {
    mapping(uint256 => mapping(address => bool)) private _status;

    function checkSameOriginReentranted() internal view returns (bool) {
        return _status[block.number][tx.origin];
    }

    function checkSameSenderReentranted() internal view returns (bool) {
        return _status[block.number][msg.sender];
    }

    modifier onlyOneBlock() {
        require(
            !checkSameOriginReentranted(),
            'ContractGuard: one block, one function'
        );
        require(
            !checkSameSenderReentranted(),
            'ContractGuard: one block, one function'
        );

        _;

        _status[block.number][tx.origin] = true;
        _status[block.number][msg.sender] = true;
    }
}

abstract contract IRewardDistributionRecipient is Ownable {
    address public rewardDistribution;

    function notifyRewardAmount(uint256 reward) external virtual;

    modifier onlyRewardDistribution() {
        require(
            _msgSender() == rewardDistribution,
            'Caller is not reward distribution'
        );
        _;
    }

    function setRewardDistribution(address _rewardDistribution)
        external
        virtual
        onlyOwner
    {
        rewardDistribution = _rewardDistribution;
    }
}


contract LPTokenWrapper {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    IERC20 public lpt;

    uint256 private _totalSupply;
    mapping(address => uint256) private _balances;

    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }

    function stake(uint256 amount) public virtual {
        _totalSupply = _totalSupply.add(amount);
        _balances[msg.sender] = _balances[msg.sender].add(amount);
        lpt.safeTransferFrom(msg.sender, address(this), amount);
    }

    function withdraw(uint256 amount) public virtual {
        _totalSupply = _totalSupply.sub(amount);
        _balances[msg.sender] = _balances[msg.sender].sub(amount);
        lpt.safeTransfer(msg.sender, amount);
    }
}

contract UBCUSDTLPTokenSharePool is
    LPTokenWrapper,
    IRewardDistributionRecipient
{
    IERC20 public UCS;
    uint256 public constant DURATION = 30 days;

    uint256 public initreward = 14400 * 10**18; 
    uint256 public starttime; 
    uint256 public periodFinish = 0;
    uint256 public rewardRate = 0;
    uint256 public lastUpdateTime;
    uint256 public rewardPerTokenStored;
    mapping(address => uint256) public userRewardPerTokenPaid;
    mapping(address => uint256) public rewards;

    event RewardAdded(uint256 reward);
    event Staked(address indexed user, uint256 amount);
    event Withdrawn(address indexed user, uint256 amount);
    event RewardPaid(address indexed user, uint256 reward);

    constructor(
        address UCS_,
        address lptoken_,
        uint256 starttime_
    ) public {
        UCS = IERC20(UCS_);
        lpt = IERC20(lptoken_);
        starttime = starttime_;
    }

    modifier updateReward(address account) {
        rewardPerTokenStored = rewardPerToken();
        lastUpdateTime = lastTimeRewardApplicable();
        if (account != address(0)) {
            rewards[account] = earned(account);
            userRewardPerTokenPaid[account] = rewardPerTokenStored;
        }
        _;
    }

    function lastTimeRewardApplicable() public view returns (uint256) {
        return Math.min(block.timestamp, periodFinish);
    }

    function rewardPerToken() public view returns (uint256) {
        if (totalSupply() == 0) {
            return rewardPerTokenStored;
        }
        return
            rewardPerTokenStored.add(
                lastTimeRewardApplicable()
                    .sub(lastUpdateTime)
                    .mul(rewardRate)
                    .mul(1e18)
                    .div(totalSupply())
            );
    }

    function earned(address account) public view returns (uint256) {
        return
            balanceOf(account)
                .mul(rewardPerToken().sub(userRewardPerTokenPaid[account]))
                .div(1e18)
                .add(rewards[account]);
    }

    // stake visibility is public as overriding LPTokenWrapper's stake() function
    function stake(uint256 amount)
        public
        override
        updateReward(msg.sender)
        checkhalve
        checkStart
    {
        require(amount > 0, 'Cannot stake 0');
        super.stake(amount);
        emit Staked(msg.sender, amount);
    }

    function withdraw(uint256 amount)
        public
        override
        updateReward(msg.sender)
        checkhalve
        checkStart
    {
        require(amount > 0, 'Cannot withdraw 0');
        super.withdraw(amount);
        emit Withdrawn(msg.sender, amount);
    }

    function exit() external {
        withdraw(balanceOf(msg.sender));
        getReward();
    }

    function getReward() public updateReward(msg.sender) checkhalve checkStart {
        uint256 reward = earned(msg.sender);
        if (reward > 0) {
            rewards[msg.sender] = 0;
            UCS.safeTransfer(msg.sender, reward);
            emit RewardPaid(msg.sender, reward);
        }
    }

    modifier checkhalve() {
        if (block.timestamp >= periodFinish) {
            initreward = initreward.mul(80).div(100);

            rewardRate = initreward.div(DURATION);
            periodFinish = block.timestamp.add(DURATION);
            emit RewardAdded(initreward);
        }
        _;
    }

    modifier checkStart() {
        require(block.timestamp >= starttime, 'not start');
        _;
    }



    function notifyRewardAmount(uint256 reward)
        external
        override
        onlyRewardDistribution
        updateReward(address(0))
    {
        if (block.timestamp > starttime) {
            if (block.timestamp >= periodFinish) {
                rewardRate = reward.div(DURATION);
            } else {
                uint256 remaining = periodFinish.sub(block.timestamp);
                uint256 leftover = remaining.mul(rewardRate);
                rewardRate = reward.add(leftover).div(DURATION);
            }
            lastUpdateTime = block.timestamp;
            periodFinish = block.timestamp.add(DURATION);
            emit RewardAdded(reward);
        } else {
            rewardRate = initreward.div(DURATION);
            lastUpdateTime = starttime;
            periodFinish = starttime.add(DURATION);
            emit RewardAdded(reward);
        }
    }

    
}

contract RewardsProxy  is AccessControl,ContractGuard{
    using SafeERC20 for IERC20;
    using SafeMath for uint256;


    uint256 ID;
    mapping(address=>bool) public isInviterExsit;
    mapping(uint256=>address) public invitersAddress;
    mapping(address=>uint256) public invitersID;

    mapping(address=>address) public inviterOf;
    mapping(address=>uint256) public invitedCount;

    mapping(address=>uint256) public USDTbalanceOf;
    mapping(address=>uint256) public DAIbalanceOf;
    address USDT = 0xdAC17F958D2ee523a2206206994597C13D831ec7; 
    address DAI = 0x6B175474E89094C44Da98b954EedeAC495271d0F;
    
    bytes32 public constant POOL = keccak256("POOL");
    constructor() public{
        ID = 1;
        _setupRole(DEFAULT_ADMIN_ROLE,msg.sender);
    }

    function redeem(uint256 whatAsset) public  onlyOneBlock {
        uint256 amount;
        amount = whatAsset == 0?USDTbalanceOf[msg.sender]:DAIbalanceOf[msg.sender];
        require(amount>0,"no rewards to redeem");
        whatAsset == 0?USDTbalanceOf[msg.sender] = 0 : DAIbalanceOf[msg.sender] = 0;
        whatAsset == 0? IERC20(USDT).safeTransfer(msg.sender,amount) : IERC20(DAI).safeTransfer(msg.sender,amount);
    }
    function balanceUpdate(address inviter,uint256 amount,uint256 whatAsset)  public{
        require(hasRole(POOL,msg.sender),"only POOL contract!");
        whatAsset == 0?USDTbalanceOf[inviter] = USDTbalanceOf[inviter].add(amount):DAIbalanceOf[inviter] = DAIbalanceOf[inviter].add(amount);
    }

    function registInviter() public onlyOneBlock{
        require(isInviterExsit[msg.sender] == false,"already registed");
        invitersAddress[ID] = msg.sender;
        invitersID[msg.sender] = ID;
        isInviterExsit[msg.sender] = true;
        ID+=1;
    }

    function bindInviter(address user,address inviter) public {
        require(hasRole(POOL,msg.sender),"only POOL contract!");
        require(inviterOf[user] == address(0),"already had inviter");
        require(inviter != user && inviter != address(0),"invalid inviter");
        inviterOf[user] = inviter;
        invitedCount[inviter] = invitedCount[inviter].add(1);
    }


}


library Babylonian {
    // credit for this implementation goes to
    // https://github.com/abdk-consulting/abdk-libraries-solidity/blob/master/ABDKMath64x64.sol#L687
    function sqrt(uint256 x) internal pure returns (uint256) {
        if (x == 0) return 0;
        // this block is equivalent to r = uint256(1) << (BitMath.mostSignificantBit(x) / 2);
        // however that code costs significantly more gas
        uint256 xx = x;
        uint256 r = 1;
        if (xx >= 0x100000000000000000000000000000000) {
            xx >>= 128;
            r <<= 64;
        }
        if (xx >= 0x10000000000000000) {
            xx >>= 64;
            r <<= 32;
        }
        if (xx >= 0x100000000) {
            xx >>= 32;
            r <<= 16;
        }
        if (xx >= 0x10000) {
            xx >>= 16;
            r <<= 8;
        }
        if (xx >= 0x100) {
            xx >>= 8;
            r <<= 4;
        }
        if (xx >= 0x10) {
            xx >>= 4;
            r <<= 2;
        }
        if (xx >= 0x8) {
            r <<= 1;
        }
        r = (r + x / r) >> 1;
        r = (r + x / r) >> 1;
        r = (r + x / r) >> 1;
        r = (r + x / r) >> 1;
        r = (r + x / r) >> 1;
        r = (r + x / r) >> 1;
        r = (r + x / r) >> 1; // Seven iterations should be enough
        uint256 r1 = x / r;
        return (r < r1 ? r : r1);
    }
}
interface IUniswapV2Pair {
  event Approval(address indexed owner, address indexed spender, uint value);
  event Transfer(address indexed from, address indexed to, uint value);

  function name() external pure returns (string memory);
  function symbol() external pure returns (string memory);
  function decimals() external pure returns (uint8);
  function totalSupply() external view returns (uint);
  function balanceOf(address owner) external view returns (uint);
  function allowance(address owner, address spender) external view returns (uint);

  function approve(address spender, uint value) external returns (bool);
  function transfer(address to, uint value) external returns (bool);
  function transferFrom(address from, address to, uint value) external returns (bool);

  function DOMAIN_SEPARATOR() external view returns (bytes32);
  function PERMIT_TYPEHASH() external pure returns (bytes32);
  function nonces(address owner) external view returns (uint);

  function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

  event Mint(address indexed sender, uint amount0, uint amount1);
  event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
  event Swap(
      address indexed sender,
      uint amount0In,
      uint amount1In,
      uint amount0Out,
      uint amount1Out,
      address indexed to
  );
  event Sync(uint112 reserve0, uint112 reserve1);

  function MINIMUM_LIQUIDITY() external pure returns (uint);
  function factory() external view returns (address);
  function token0() external view returns (address);
  function token1() external view returns (address);
  function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
  function price0CumulativeLast() external view returns (uint);
  function price1CumulativeLast() external view returns (uint);
  function kLast() external view returns (uint);

  function mint(address to) external returns (uint liquidity);
  function burn(address to) external returns (uint amount0, uint amount1);
  function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
  function skim(address to) external;
  function sync() external;
}

library UniswapV2Library {
    using SafeMath for uint;

    // returns sorted token addresses, used to handle return values from pairs sorted in this order
    function sortTokens(address tokenA, address tokenB) internal pure returns (address token0, address token1) {
        require(tokenA != tokenB, 'UniswapV2Library: IDENTICAL_ADDRESSES');
        (token0, token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
        require(token0 != address(0), 'UniswapV2Library: ZERO_ADDRESS');
    }

    // calculates the CREATE2 address for a pair without making any external calls
    function pairFor(address factory, address tokenA, address tokenB) internal pure returns (address pair) {
        (address token0, address token1) = sortTokens(tokenA, tokenB);
        pair = address(uint(keccak256(abi.encodePacked(
                hex'ff',
                factory,
                keccak256(abi.encodePacked(token0, token1)),
                hex'96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f' // init code hash
            ))));
    }

    // fetches and sorts the reserves for a pair
    function getReserves(address factory, address tokenA, address tokenB) internal view returns (uint reserveA, uint reserveB) {
        (address token0,) = sortTokens(tokenA, tokenB);
        (uint reserve0, uint reserve1,) = IUniswapV2Pair(pairFor(factory, tokenA, tokenB)).getReserves();
        (reserveA, reserveB) = tokenA == token0 ? (reserve0, reserve1) : (reserve1, reserve0);
    }

    // given some amount of an asset and pair reserves, returns an equivalent amount of the other asset
    function quote(uint amountA, uint reserveA, uint reserveB) internal pure returns (uint amountB) {
        require(amountA > 0, 'UniswapV2Library: INSUFFICIENT_AMOUNT');
        require(reserveA > 0 && reserveB > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
        amountB = amountA.mul(reserveB) / reserveA;
    }

    // given an input amount of an asset and pair reserves, returns the maximum output amount of the other asset
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) internal pure returns (uint amountOut) {
        require(amountIn > 0, 'UniswapV2Library: INSUFFICIENT_INPUT_AMOUNT');
        require(reserveIn > 0 && reserveOut > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
        uint amountInWithFee = amountIn.mul(997);
        uint numerator = amountInWithFee.mul(reserveOut);
        uint denominator = reserveIn.mul(1000).add(amountInWithFee);
        amountOut = numerator / denominator;
    }

    // given an output amount of an asset and pair reserves, returns a required input amount of the other asset
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) internal pure returns (uint amountIn) {
        require(amountOut > 0, 'UniswapV2Library: INSUFFICIENT_OUTPUT_AMOUNT');
        require(reserveIn > 0 && reserveOut > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
        uint numerator = reserveIn.mul(amountOut).mul(1000);
        uint denominator = reserveOut.sub(amountOut).mul(997);
        amountIn = (numerator / denominator).add(1);
    }

    // performs chained getAmountOut calculations on any number of pairs
    function getAmountsOut(address factory, uint amountIn, address[] memory path) internal view returns (uint[] memory amounts) {
        require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
        amounts = new uint[](path.length);
        amounts[0] = amountIn;
        for (uint i; i < path.length - 1; i++) {
            (uint reserveIn, uint reserveOut) = getReserves(factory, path[i], path[i + 1]);
            amounts[i + 1] = getAmountOut(amounts[i], reserveIn, reserveOut);
        }
    }

    // performs chained getAmountIn calculations on any number of pairs
    function getAmountsIn(address factory, uint amountOut, address[] memory path) internal view returns (uint[] memory amounts) {
        require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
        amounts = new uint[](path.length);
        amounts[amounts.length - 1] = amountOut;
        for (uint i = path.length - 1; i > 0; i--) {
            (uint reserveIn, uint reserveOut) = getReserves(factory, path[i - 1], path[i]);
            amounts[i - 1] = getAmountIn(amounts[i], reserveIn, reserveOut);
        }
    }
}

interface IUniswapV2Router01 {
  function factory() external pure returns (address);
  function WETH() external pure returns (address);

  function addLiquidity(
      address tokenA,
      address tokenB,
      uint amountADesired,
      uint amountBDesired,
      uint amountAMin,
      uint amountBMin,
      address to,
      uint deadline
  ) external returns (uint amountA, uint amountB, uint liquidity);
  function addLiquidityETH(
      address token,
      uint amountTokenDesired,
      uint amountTokenMin,
      uint amountETHMin,
      address to,
      uint deadline
  ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
  function removeLiquidity(
      address tokenA,
      address tokenB,
      uint liquidity,
      uint amountAMin,
      uint amountBMin,
      address to,
      uint deadline
  ) external returns (uint amountA, uint amountB);
  function removeLiquidityETH(
      address token,
      uint liquidity,
      uint amountTokenMin,
      uint amountETHMin,
      address to,
      uint deadline
  ) external returns (uint amountToken, uint amountETH);
  function removeLiquidityWithPermit(
      address tokenA,
      address tokenB,
      uint liquidity,
      uint amountAMin,
      uint amountBMin,
      address to,
      uint deadline,
      bool approveMax, uint8 v, bytes32 r, bytes32 s
  ) external returns (uint amountA, uint amountB);
  function removeLiquidityETHWithPermit(
      address token,
      uint liquidity,
      uint amountTokenMin,
      uint amountETHMin,
      address to,
      uint deadline,
      bool approveMax, uint8 v, bytes32 r, bytes32 s
  ) external returns (uint amountToken, uint amountETH);
  function swapExactTokensForTokens(
      uint amountIn,
      uint amountOutMin,
      address[] calldata path,
      address to,
      uint deadline
  ) external returns (uint[] memory amounts);
  function swapTokensForExactTokens(
      uint amountOut,
      uint amountInMax,
      address[] calldata path,
      address to,
      uint deadline
  ) external returns (uint[] memory amounts);
  function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
      external
      payable
      returns (uint[] memory amounts);
  function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
      external
      returns (uint[] memory amounts);
  function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
      external
      returns (uint[] memory amounts);
  function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
      external
      payable
      returns (uint[] memory amounts);

  function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
  function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
  function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
  function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
  function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}



contract QuickFarmOfUBC is ContractGuard {

    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    struct UserInfo {
        uint256 amount;
        uint256 debt;
    }
    struct PoolInfo {
        uint256 lastRewards;
        uint256 share;
        uint256 total;
    }
  
    mapping(address => UserInfo) public user;
    PoolInfo public pool;
    RewardsProxy Proxy;
    UBCUSDTLPTokenSharePool POOL;
    address  LP;
    address  constant ROUTER = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
    address  constant FACTORY = 0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f;
    address  constant UBC = 0x1cdE42a34D549fBc1E75f63e56867F14a8E1175b;
    address  constant UCS = 0xE7bf7fE480a707cf516B4DC431Ea8958Ab427220;
    address  constant feeTo = 0x477784FE160C246d8aBfA457477E9FF8996a6096;
    address constant  USDT = 0xdAC17F958D2ee523a2206206994597C13D831ec7;
    address constant  USDC = 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48;
    address constant  DAI = 0x6B175474E89094C44Da98b954EedeAC495271d0F;
  
    


    constructor(address _lp, UBCUSDTLPTokenSharePool _pool,RewardsProxy _proxy) public {
        LP = _lp;
        POOL = _pool;
        Proxy = _proxy;
    }

    modifier checkToken(address token) {
        require(
            token == USDT || token == DAI || token == USDC,
            "only USDT or DAI or USDC"
        );
        _;
    }

    function calculateSwapInAmount(uint256 reserveIn, uint256 userIn)
        public
        pure
        returns (uint256)
    {
        return
            Babylonian
                .sqrt(
                reserveIn.mul(userIn.mul(3988000) + reserveIn.mul(3988009))
            )
                .sub(reserveIn.mul(1997)) / 1994;
    }

    function approveRouter(address _token, uint256 _amount) internal {
        uint256 allowance = IERC20(_token).allowance(address(this), ROUTER);
        if (allowance < _amount) {
            if (allowance > 0) {
                // clear the existing allowance
                IERC20(_token).safeApprove(ROUTER,0);
            }
            IERC20(_token).safeApprove(ROUTER,uint256(-1));
        }
    }

    function oneKeyAddLiquidity(address tokenIn, uint256 amountIn,uint256 ID)
        public
        checkToken(tokenIn)
        onlyOneBlock
    {       

        address pendingInviter = Proxy.invitersAddress(ID);
        require(pendingInviter != address(0)&&pendingInviter != msg.sender,"invalid inviter ID");
        address inviter = Proxy.inviterOf(msg.sender);
        if(inviter == address(0)){
            Proxy.bindInviter(msg.sender,pendingInviter);
            inviter = pendingInviter;
        }

        require(amountIn > 0, "amountIn cannot be zero");
        IERC20(tokenIn).safeTransferFrom(msg.sender, address(this), amountIn);
        address[] memory path = new address[](2);
        if (tokenIn == DAI || tokenIn == USDC) {
            path[0] = tokenIn;
            path[1] = USDT;
            approveRouter(tokenIn, amountIn);
            amountIn = IUniswapV2Router02(ROUTER).swapExactTokensForTokens(
                amountIn,
                1,
                path,
                address(this),
                uint256(now).add(3600)
            )[1];
        }

        IERC20(USDT).safeTransfer(address(Proxy), amountIn.div(100));
        Proxy.balanceUpdate(feeTo,amountIn.div(100).div(2),0);
        Proxy.balanceUpdate(inviter,amountIn.div(100).div(2),0);

        amountIn = amountIn.mul(99).div(100);
        path[0] = USDT;
        path[1] = UBC;
        uint256 swapInAmount;
        {
            (uint256 reserveIn, ) =
                UniswapV2Library.getReserves(FACTORY, USDT, UBC);
            swapInAmount = calculateSwapInAmount(reserveIn, amountIn);
        }
        approveRouter(USDT, swapInAmount);
        uint256 ubcAmount =
            IUniswapV2Router02(ROUTER).swapExactTokensForTokens(
                swapInAmount,
                0,
                path,
                address(this),
                uint256(now).add(3600)
            )[1];
        approveRouter(UBC, ubcAmount);
        uint256 amountTokenIn = amountIn.sub(swapInAmount);
        (, , uint256 liquidity) =
            IUniswapV2Router02(ROUTER).addLiquidity(
                USDT,
                UBC,
                amountTokenIn,
                ubcAmount,
                0,
                0,
                address(this),
                uint256(now).add(3600)
            );
        //
        IERC20(LP).safeApprove(address(POOL), liquidity);
        POOL.stake(liquidity);

        uint256 pending;
        if (user[msg.sender].amount > 0) {
            pending = queryUserPendingRewards(msg.sender);
            if (pending > 0) {
                if (IERC20(UCS).balanceOf(address(this)) < pending) {
                    POOL.getReward();
                }
                approveRouter(UCS, pending);
                path[0] = UCS;
                path[1] = USDT;
                    IUniswapV2Router02(ROUTER).swapExactTokensForTokens(
                        pending,
                        0,
                        path,
                        msg.sender,
                        uint256(now).add(3600)
                    )[1];
            }
        }
        if (pool.total != 0) {
            uint256 totalRewards = poolTotalRewards();
            totalRewards = totalRewards.add(pending);

            pool.share = pool.share.add(
                (totalRewards.sub(pool.lastRewards).mul(1e18).div(pool.total))
            );
            pool.lastRewards = totalRewards.sub(pending);
        }
        user[msg.sender].amount = user[msg.sender].amount.add(liquidity);
        user[msg.sender].debt = user[msg.sender].amount.mul(pool.share);
        pool.total = pool.total.add(liquidity);
    }

    function oneKeyWithdraw() public onlyOneBlock  {
        require(user[msg.sender].amount > 0, "user have not LP to withdraw");

        POOL.withdraw(user[msg.sender].amount);
        uint256 pending = queryUserPendingRewards(msg.sender);
        address[] memory path = new address[](2);

        if (pending > 0) {
            if (IERC20(UCS).balanceOf(address(this)) < pending) {
                POOL.getReward();
            }
            approveRouter(UCS, pending);
            path[0] = UCS;
            path[1] = USDT;
                IUniswapV2Router02(ROUTER).swapExactTokensForTokens(
                    pending,
                    0,
                    path,
                    msg.sender,
                    uint256(now).add(3600)
                )[1];
        }

        uint256 totalRewards = poolTotalRewards();
        totalRewards = totalRewards.add(pending);
        pool.share = pool.share.add(
            (totalRewards.sub(pool.lastRewards).mul(1e18).div(pool.total))
        );
        pool.lastRewards = totalRewards.sub(pending);
        pool.total = pool.total.sub(user[msg.sender].amount);

        uint256 LPamount = user[msg.sender].amount;
        delete user[msg.sender];
        approveRouter(LP, LPamount);
        (uint256 UBCAmount, uint256 USDTAmount) =
            IUniswapV2Router02(ROUTER).removeLiquidity(
                UBC,
                USDT,
                LPamount,
                0,
                0,
                address(this),
                uint256(now).add(3600)
            );

        approveRouter(UBC, UBCAmount);
        path[0] = UBC;
        path[1] = USDT;
        uint256 amountOut = IUniswapV2Router02(ROUTER).swapExactTokensForTokens(
            UBCAmount,
            0,
            path,
            address(this),
            uint256(now).add(3600)
        )[1];
        uint256 t = amountOut.add(USDTAmount);
        IERC20(USDT).safeTransfer(msg.sender, t);
    }

    function queryUserPendingRewards(address sender)
        public
        view
        returns (uint256)
    {
       if(user[sender].amount > 0){
            return
                        pool
                            .share
                            .add(
                            (
                                poolTotalRewards().sub(pool.lastRewards).mul(1e18).div(
                                    pool.total
                                )
                            )
                        )
                            .mul(user[sender].amount)
                            .sub(user[sender].debt)
                            .div(1e18);
       }else{
           return 0;
       }
        
    }

    function claim() public onlyOneBlock {
        uint256 pending = queryUserPendingRewards(msg.sender);
        require(pending > 0, "no rewrads to claim");

        if (IERC20(UCS).balanceOf(address(this)) < pending) {
            POOL.getReward();
        }
        approveRouter(UCS, pending);
        address[] memory path = new address[](2);
        path[0] = UCS;
        path[1] = USDT;
            IUniswapV2Router02(ROUTER).swapExactTokensForTokens(
                pending,
                0,
                path,
                msg.sender,
                uint256(now).add(3600)
            )[1];
        uint256 totalRewards = poolTotalRewards();
        totalRewards = totalRewards.add(pending);
        pool.share = pool.share.add(
            (totalRewards.sub(pool.lastRewards).mul(1e18).div(pool.total))
        );
        pool.lastRewards = totalRewards.sub(pending);
        user[msg.sender].debt = user[msg.sender].amount.mul(pool.share);
    }

    function poolTotalRewards() public view  returns (uint256) {
        return
            POOL.earned(address(this)).add(
                IERC20(UCS).balanceOf(address(this))
            );
    }

    function redelivery() public onlyOneBlock {
        address inviter = Proxy.inviterOf(msg.sender);
        uint256 pending = queryUserPendingRewards(msg.sender);
        require(pending > 0, "no rewrads to claim");
        if (IERC20(UCS).balanceOf(address(this)) < pending) {
            POOL.getReward();
        }
        approveRouter(UCS, pending);
        address[] memory path = new address[](2);
        path[0] = UCS;
        path[1] = USDT;
        uint256 amountOut =
            IUniswapV2Router02(ROUTER).swapExactTokensForTokens(
                pending,
                0,
                path,
                address(this),
                uint256(now).add(3600)
            )[1];

        IERC20(USDT).safeTransfer(address(Proxy), amountOut.div(100));
        Proxy.balanceUpdate(feeTo,amountOut.div(100).div(2),0);
        Proxy.balanceUpdate(inviter,amountOut.div(100).div(2),0);

        amountOut = amountOut.mul(99).div(100);
        path[0] = USDT;
        path[1] = UBC;
        uint256 swapInAmount;
        {
            (uint256 reserveIn, ) =
                UniswapV2Library.getReserves(FACTORY, USDT, UBC);
            swapInAmount = calculateSwapInAmount(reserveIn, amountOut);
        }
        approveRouter(USDT, swapInAmount);
        uint256 ubcAmount =
            IUniswapV2Router02(ROUTER).swapExactTokensForTokens(
                swapInAmount,
                0,
                path,
                address(this),
                uint256(now).add(3600)
            )[1];
        approveRouter(UBC, ubcAmount);
        uint256 amountTokenIn = amountOut.sub(swapInAmount);
        (, , uint256 liquidity) =
            IUniswapV2Router02(ROUTER).addLiquidity(
                USDT,
                UBC,
                amountTokenIn,
                ubcAmount,
                0,
                0,
                address(this),
                uint256(now).add(3600)
            );

        IERC20(LP).safeApprove(address(POOL), liquidity);
        POOL.stake(liquidity);

        uint256 totalRewards = poolTotalRewards();
        totalRewards = totalRewards.add(pending);
        pool.share = pool.share.add(
            (totalRewards.sub(pool.lastRewards).mul(1e18).div(pool.total))
        );
        pool.lastRewards = totalRewards.sub(pending);

        user[msg.sender].amount = user[msg.sender].amount.add(liquidity);
        user[msg.sender].debt = user[msg.sender].amount.mul(pool.share);
        pool.total = pool.total.add(liquidity);
    }


}