pragma solidity ^0.6.0;


/**
 * @dev Standard math utilities missing in the Solidity language.
 */
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);
    }
}

/**
 * @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, 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.
     *
     * _Available since v2.4.0._
     */
    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.
     *
     * _Available since v2.4.0._
     */
    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        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.
     *
     * _Available since v2.4.0._
     */
    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

/*
 * @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.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor() internal {}

    // solhint-disable-previous-line no-empty-blocks

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view returns (bytes memory) {
        this;
        // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

/**
 * @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.
 *
 * 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.
 */
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 {
        _owner = _msgSender();
        emit OwnershipTransferred(address(0), _owner);
    }

    /**
     * @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(isOwner(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Returns true if the caller is the current owner.
     */
    function isOwner() public view returns (bool) {
        return _msgSender() == _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 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 onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     */
    function _transferOwnership(address newOwner) internal {
        require(
            newOwner != address(0),
            "Ownable: new owner is the zero address"
        );
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
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);

    function mint(address account, uint256 amount) external;

    /**
     * @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
    );
}

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * This test is non-exhaustive, and there may be false-negatives: during the
     * execution of a contract's constructor, its address will be reported as
     * not containing 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.
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies in extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;


            bytes32 accountHash
         = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            codehash := extcodehash(account)
        }
        return (codehash != 0x0 && codehash != accountHash);
    }

    /**
     * @dev Converts an `address` into `address payable`. Note that this is
     * simply a type cast: the actual underlying value is not changed.
     *
     * _Available since v2.4.0._
     */
    function toPayable(address account)
        internal
        pure
        returns (address payable)
    {
        return address(uint160(account));
    }

    /**
     * @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].
     *
     * _Available since v2.4.0._
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(
            address(this).balance >= amount,
            "Address: insufficient balance"
        );

        (bool success, ) = recipient.call{value: amount}("");
        require(
            success,
            "Address: unable to send value, recipient may have reverted"
        );
    }
}

/**
 * @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 ERC20;` 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)
        );
    }

    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.

        // A Solidity high level call has three parts:
        //  1. The target address is checked to verify it contains contract code
        //  2. The call itself is made, and success asserted
        //  3. The return value is decoded, which in turn checks the size of the returned data.
        // solhint-disable-next-line max-line-length
        require(address(token).isContract(), "SafeERC20: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "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"
            );
        }
    }
}

contract BankManagerAddress is Ownable {
    address BankAddress;

    modifier onlyBankAddress() {
        require(
            _msgSender() == BankAddress,
            "Caller is not reward distribution"
        );
        _;
    }

    function setBankAddress(address _bankAddress) external onlyOwner {
        BankAddress = _bankAddress;
    }
}

contract Bank is Ownable {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    IERC20 public HoldToken;
    IERC20 public InterestToken;

    uint256 private _totalSupply;
    uint256 private _bankBudget;
    mapping(address => uint256) private _balances;

    constructor(address _holdToken, address _interestToken) public {
        HoldToken = IERC20(_holdToken);
        InterestToken = IERC20(_interestToken);
    }

    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    function bankBudget() public view returns (uint256) {
        return _bankBudget;
    }

    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }

    function backBank(uint256 amount) public virtual {
        _bankBudget = _bankBudget.sub(amount);
        InterestToken.safeTransfer(_msgSender(), amount);
    }

    function disbursement(uint256 amount) public virtual {
        _bankBudget = _bankBudget.add(amount);
        InterestToken.safeTransferFrom(_msgSender(), address(this), amount);
    }

    function getInterest(uint256 amount) public virtual {
        _bankBudget = _bankBudget.sub(amount);
        InterestToken.safeTransfer(_msgSender(), amount);
    }

    function saving(uint256 amount) public virtual {
        _totalSupply = _totalSupply.add(amount);
        _balances[_msgSender()] = _balances[_msgSender()].add(amount);
        HoldToken.safeTransferFrom(_msgSender(), address(this), amount);
    }

    function withdraw(uint256 amount) public virtual {
        _totalSupply = _totalSupply.sub(amount);
        _balances[_msgSender()] = _balances[_msgSender()].sub(amount);
        HoldToken.safeTransfer(_msgSender(), amount);
    }
}

contract yVaultWETH is
    Bank(
        0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2, // HoldToken: user save to bank
        0x90D702f071d2af33032943137AD0aB4280705817 // InterestToken: bank pay to user
    ),
    BankManagerAddress
{
    // uint256 public constant DURATION = 10 days;
    // uint256 public constant INTEREST_RATE = 5; // 5%: 100 vault token -> period time -> 5 bank token

    uint256 public DURATION = 10 days;
    uint256 public INTEREST_RATE = 16;
    uint256 public MAX_SAVING = 2000 * 10**18;

    uint256 public nonce = 0;

    uint256 public startTime = 0;
    bool public isBankOpened = true;

    event BankDisbursement(uint256 reward);
    event OpenBank(uint256 time);
    event CloseBanking(uint256 time);
    event Saving(address indexed user, uint256 amount);
    event Withdrawn(address indexed user, uint256 amount);
    event InterestPaid(address indexed user, uint256 amount);
    event UpdateVualtConfig(uint256 duration, uint256 interest_rate);
    event ChangeMaxSaving(uint256 amount);

    struct SavingInfo {
        uint256 savingTime;
        uint256 amount;
        uint256 duration;
        uint256 interest_rate;
        bool status;
        uint256 updateTime;
    }

    mapping(address => SavingInfo[]) private usersPackages;
    mapping(address => uint256) public userNonce;

    modifier requireBankOpened() {
        require(isBankOpened, "Bank is closed.");
        _;
    }

    function isEndOfPeriod(uint256 savingTime, uint256 duration)
        private
        view
        returns (bool)
    {
        return block.timestamp > savingTime.add(duration);
    }

    constructor() public {
        BankAddress = _msgSender();
    }

    function changeMaxSaving(uint256 _maxSaving) public onlyBankAddress {
        require(_maxSaving > 0, "Cannot change to 0");
        MAX_SAVING = _maxSaving;
        emit ChangeMaxSaving(_maxSaving);
    }

    function close() public onlyBankAddress {
        require(isBankOpened, "Bank is closed.");
        isBankOpened = false;
        emit CloseBanking(block.timestamp);
    }

    function open() public onlyBankAddress {
        require(!isBankOpened, "Bank is opened.");
        isBankOpened = true;
        startTime = block.timestamp;
        emit OpenBank(block.timestamp);
    }

    function updateVaultConfig(uint256 _duration, uint256 _rate) public {
        require(_duration > 0, "Invalid duration.");
        DURATION = _duration;
        INTEREST_RATE = _rate;
        emit UpdateVualtConfig(_duration, _rate);
    }

    function backBank(uint256 amount) public override onlyBankAddress {
        require(amount > 0, "Cannot back 0");
        super.backBank(amount);
        emit BankDisbursement(amount);
    }

    function disbursement(uint256 amount) public override onlyBankAddress {
        require(amount > 0, "Cannot disbursement 0");
        super.disbursement(amount);
        emit BankDisbursement(amount);
    }

    function saving(uint256 amount) public override requireBankOpened {
        require(amount > 0, "Cannot saving 0");
        require(amount <= MAX_SAVING, "Cannot saving over max");
        super.saving(amount);
        usersPackages[_msgSender()].push(
            SavingInfo({
                savingTime: block.timestamp,
                updateTime: block.timestamp,
                amount: amount,
                duration: DURATION,
                interest_rate: INTEREST_RATE,
                status: true
            })
        );
        nonce++;
        userNonce[_msgSender()]++;
        emit Saving(_msgSender(), amount);
    }

    function getSavingPackage(address sender, uint256 pIndex)
        public
        view
        returns (
            uint256 savingTime,
            uint256 amount,
            uint256 duration,
            uint256 interest_rate,
            bool status
        )
    {
        SavingInfo storage savingInfo = usersPackages[sender][pIndex];
        savingTime = savingInfo.savingTime;
        amount = savingInfo.amount;
        duration = savingInfo.duration;
        interest_rate = savingInfo.interest_rate;
        status = savingInfo.status;
    }

    function userInformation(address sender)
        public
        view
        returns (
            uint256 available,
            uint256 wish,
            uint256 done,
            uint256 pending
        )
    {
        if (userNonce[sender] == 0) {
            return (0, 0, 0, 0);
        }
        for (uint8 index = 0; index < userNonce[sender]; index++) {
            (
                uint256 savingTime,
                uint256 amount,
                uint256 duration,
                uint256 interest_rate,
                bool status
            ) = getSavingPackage(sender, index);
            if (status) {
                if (isEndOfPeriod(savingTime, duration)) {
                    available = available.add(
                        amount.mul(interest_rate).div(100)
                    );
                }
                wish = wish.add(amount.mul(interest_rate).div(100));
                pending++;
            } else {
                done++;
            }
        }
    }

    function withdraw(uint256 pIndex) public override {
        require(pIndex < userNonce[_msgSender()], "Package is not available.");

        (
            uint256 savingTime,
            uint256 amount,
            uint256 duration,
            uint256 interest_rate,
            bool status
        ) = getSavingPackage(_msgSender(), pIndex);

        require(status, "Package is end.");

        usersPackages[_msgSender()][pIndex].status = false;
        usersPackages[_msgSender()][pIndex].updateTime = block.timestamp;
        if (isEndOfPeriod(savingTime, duration)) {
            super.getInterest(amount.mul(interest_rate).div(100));
        }

        super.withdraw(amount);
        emit Withdrawn(_msgSender(), amount);
    }

    function withdrawAll() public {
        for (
            uint8 index = 0;
            index < usersPackages[_msgSender()].length;
            index++
        ) {
            if (usersPackages[_msgSender()][index].status) {
                withdraw(index);
            }
        }
    }

    function savingInfo(address sender, uint256 pIndex)
        public
        view
        returns (uint256 interest, uint256 countdownTime)
    {
        if (userNonce[sender] <= 0 || pIndex >= userNonce[sender]) {
            return (0, 0);
        }
        (
            uint256 savingTime,
            uint256 amount,
            uint256 duration,
            uint256 interest_rate,
            bool status
        ) = getSavingPackage(sender, pIndex);
        if (status) {
            interest = amount.mul(interest_rate).div(100);
            if (!isEndOfPeriod(savingTime, duration)) {
                countdownTime = savingTime.add(duration).sub(block.timestamp);
            }
        }
    }

    function getInterest(uint256) public override {
        (uint256 available, , , ) = userInformation(_msgSender());
        require(available > 0, "No Interest.");
        require(available < bankBudget(), "Contact bank manager for detail.");
        for (
            uint8 index = 0;
            index < usersPackages[_msgSender()].length;
            index++
        ) {
            (
                uint256 savingTime,
                uint256 amount,
                uint256 duration,
                ,
                bool status
            ) = getSavingPackage(_msgSender(), index);
            if (status && isEndOfPeriod(savingTime, duration)) {
                usersPackages[_msgSender()][index].status = false;
                super.withdraw(amount);
                usersPackages[_msgSender()][index].updateTime = block.timestamp;
            }
        }

        super.getInterest(available);
        emit InterestPaid(_msgSender(), available);
    }
}