// File: @openzeppelin/contracts/GSN/Context.sol

pragma solidity ^0.5.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
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;
    }
}

// File: @openzeppelin/contracts/ownership/Ownable.sol

pragma solidity ^0.5.0;

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * 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 {
        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(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;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol

pragma solidity ^0.5.0;

/**
 * @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);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: @openzeppelin/contracts/math/SafeMath.sol

pragma solidity ^0.5.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, 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;
    }
}

// File: @openzeppelin/contracts/utils/Address.sol

pragma solidity ^0.5.5;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following 
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // 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 != accountHash && codehash != 0x0);
    }

    /**
     * @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");

        // solhint-disable-next-line avoid-call-value
        (bool success, ) = recipient.call.value(amount)("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}

// File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol

pragma solidity ^0.5.0;




/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for 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");
        }
    }
}

// File: @openzeppelin/contracts/utils/ReentrancyGuard.sol

pragma solidity ^0.5.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 *
 * _Since v2.5.0:_ this module is now much more gas efficient, given net gas
 * metering changes introduced in the Istanbul hardfork.
 */
contract ReentrancyGuard {
    bool private _notEntered;

    constructor () internal {
        // Storing an initial non-zero value makes deployment a bit more
        // expensive, but in exchange the refund on every call to nonReentrant
        // will be lower in amount. Since refunds are capped to a percetange of
        // the total transaction's gas, it is best to keep them low in cases
        // like this one, to increase the likelihood of the full refund coming
        // into effect.
        _notEntered = true;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_notEntered, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _notEntered = false;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _notEntered = true;
    }
}

// File: @openzeppelin/contracts/crowdsale/Crowdsale.sol

pragma solidity ^0.5.0;






/**
 * @title Crowdsale
 * @dev Crowdsale is a base contract for managing a token crowdsale,
 * allowing investors to purchase tokens with ether. This contract implements
 * such functionality in its most fundamental form and can be extended to provide additional
 * functionality and/or custom behavior.
 * The external interface represents the basic interface for purchasing tokens, and conforms
 * the base architecture for crowdsales. It is *not* intended to be modified / overridden.
 * The internal interface conforms the extensible and modifiable surface of crowdsales. Override
 * the methods to add functionality. Consider using 'super' where appropriate to concatenate
 * behavior.
 */
contract Crowdsale is Context, ReentrancyGuard {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    // The token being sold
    IERC20 private _token;

    // Address where funds are collected
    address payable private _wallet;

    // How many token units a buyer gets per wei.
    // The rate is the conversion between wei and the smallest and indivisible token unit.
    // So, if you are using a rate of 1 with a ERC20Detailed token with 3 decimals called TOK
    // 1 wei will give you 1 unit, or 0.001 TOK.
    uint256 private _rate;

    // Amount of wei raised
    uint256 private _weiRaised;

    /**
     * Event for token purchase logging
     * @param purchaser who paid for the tokens
     * @param beneficiary who got the tokens
     * @param value weis paid for purchase
     * @param amount amount of tokens purchased
     */
    event TokensPurchased(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount);

    /**
     * @param rate Number of token units a buyer gets per wei
     * @dev The rate is the conversion between wei and the smallest and indivisible
     * token unit. So, if you are using a rate of 1 with a ERC20Detailed token
     * with 3 decimals called TOK, 1 wei will give you 1 unit, or 0.001 TOK.
     * @param wallet Address where collected funds will be forwarded to
     * @param token Address of the token being sold
     */
    constructor (uint256 rate, address payable wallet, IERC20 token) public {
        require(rate > 0, "Crowdsale: rate is 0");
        require(wallet != address(0), "Crowdsale: wallet is the zero address");
        require(address(token) != address(0), "Crowdsale: token is the zero address");

        _rate = rate;
        _wallet = wallet;
        _token = token;
    }

    /**
     * @dev fallback function ***DO NOT OVERRIDE***
     * Note that other contracts will transfer funds with a base gas stipend
     * of 2300, which is not enough to call buyTokens. Consider calling
     * buyTokens directly when purchasing tokens from a contract.
     */
    function () external payable {
        buyTokens(_msgSender());
    }

    /**
     * @return the token being sold.
     */
    function token() public view returns (IERC20) {
        return _token;
    }

    /**
     * @return the address where funds are collected.
     */
    function wallet() public view returns (address payable) {
        return _wallet;
    }

    /**
     * @return the number of token units a buyer gets per wei.
     */
    function rate() public view returns (uint256) {
        return _rate;
    }

    /**
     * @return the amount of wei raised.
     */
    function weiRaised() public view returns (uint256) {
        return _weiRaised;
    }

    /**
     * @dev low level token purchase ***DO NOT OVERRIDE***
     * This function has a non-reentrancy guard, so it shouldn't be called by
     * another `nonReentrant` function.
     * @param beneficiary Recipient of the token purchase
     */
    function buyTokens(address beneficiary) public nonReentrant payable {
        uint256 weiAmount = msg.value;
        _preValidatePurchase(beneficiary, weiAmount);

        // calculate token amount to be created
        uint256 tokens = _getTokenAmount(weiAmount);

        // update state
        _weiRaised = _weiRaised.add(weiAmount);

        _processPurchase(beneficiary, tokens);
        emit TokensPurchased(_msgSender(), beneficiary, weiAmount, tokens);

        _updatePurchasingState(beneficiary, weiAmount);

        _forwardFunds();
        _postValidatePurchase(beneficiary, weiAmount);
    }

    /**
     * @dev Validation of an incoming purchase. Use require statements to revert state when conditions are not met.
     * Use `super` in contracts that inherit from Crowdsale to extend their validations.
     * Example from CappedCrowdsale.sol's _preValidatePurchase method:
     *     super._preValidatePurchase(beneficiary, weiAmount);
     *     require(weiRaised().add(weiAmount) <= cap);
     * @param beneficiary Address performing the token purchase
     * @param weiAmount Value in wei involved in the purchase
     */
    function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
        require(beneficiary != address(0), "Crowdsale: beneficiary is the zero address");
        require(weiAmount != 0, "Crowdsale: weiAmount is 0");
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
    }

    /**
     * @dev Validation of an executed purchase. Observe state and use revert statements to undo rollback when valid
     * conditions are not met.
     * @param beneficiary Address performing the token purchase
     * @param weiAmount Value in wei involved in the purchase
     */
    function _postValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
        // solhint-disable-previous-line no-empty-blocks
    }

    /**
     * @dev Source of tokens. Override this method to modify the way in which the crowdsale ultimately gets and sends
     * its tokens.
     * @param beneficiary Address performing the token purchase
     * @param tokenAmount Number of tokens to be emitted
     */
    function _deliverTokens(address beneficiary, uint256 tokenAmount) internal {
        _token.safeTransfer(beneficiary, tokenAmount);
    }

    /**
     * @dev Executed when a purchase has been validated and is ready to be executed. Doesn't necessarily emit/send
     * tokens.
     * @param beneficiary Address receiving the tokens
     * @param tokenAmount Number of tokens to be purchased
     */
    function _processPurchase(address beneficiary, uint256 tokenAmount) internal {
        _deliverTokens(beneficiary, tokenAmount);
    }

    /**
     * @dev Override for extensions that require an internal state to check for validity (current user contributions,
     * etc.)
     * @param beneficiary Address receiving the tokens
     * @param weiAmount Value in wei involved in the purchase
     */
    function _updatePurchasingState(address beneficiary, uint256 weiAmount) internal {
        // solhint-disable-previous-line no-empty-blocks
    }

    /**
     * @dev Override to extend the way in which ether is converted to tokens.
     * @param weiAmount Value in wei to be converted into tokens
     * @return Number of tokens that can be purchased with the specified _weiAmount
     */
    function _getTokenAmount(uint256 weiAmount) internal view returns (uint256) {
        return weiAmount.mul(_rate);
    }

    /**
     * @dev Determines how ETH is stored/forwarded on purchases.
     */
    function _forwardFunds() internal {
        _wallet.transfer(msg.value);
    }
}

// File: @openzeppelin/contracts/math/Math.sol

pragma solidity ^0.5.0;

/**
 * @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);
    }
}

// File: @openzeppelin/contracts/crowdsale/emission/AllowanceCrowdsale.sol

pragma solidity ^0.5.0;






/**
 * @title AllowanceCrowdsale
 * @dev Extension of Crowdsale where tokens are held by a wallet, which approves an allowance to the crowdsale.
 */
contract AllowanceCrowdsale is Crowdsale {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    address private _tokenWallet;

    /**
     * @dev Constructor, takes token wallet address.
     * @param tokenWallet Address holding the tokens, which has approved allowance to the crowdsale.
     */
    constructor (address tokenWallet) public {
        require(tokenWallet != address(0), "AllowanceCrowdsale: token wallet is the zero address");
        _tokenWallet = tokenWallet;
    }

    /**
     * @return the address of the wallet that will hold the tokens.
     */
    function tokenWallet() public view returns (address) {
        return _tokenWallet;
    }

    /**
     * @dev Checks the amount of tokens left in the allowance.
     * @return Amount of tokens left in the allowance
     */
    function remainingTokens() public view returns (uint256) {
        return Math.min(token().balanceOf(_tokenWallet), token().allowance(_tokenWallet, address(this)));
    }

    /**
     * @dev Overrides parent behavior by transferring tokens from wallet.
     * @param beneficiary Token purchaser
     * @param tokenAmount Amount of tokens purchased
     */
    function _deliverTokens(address beneficiary, uint256 tokenAmount) internal {
        token().safeTransferFrom(_tokenWallet, beneficiary, tokenAmount);
    }
}

// File: @openzeppelin/contracts/crowdsale/validation/TimedCrowdsale.sol

pragma solidity ^0.5.0;



/**
 * @title TimedCrowdsale
 * @dev Crowdsale accepting contributions only within a time frame.
 */
contract TimedCrowdsale is Crowdsale {
    using SafeMath for uint256;

    uint256 private _openingTime;
    uint256 private _closingTime;

    /**
     * Event for crowdsale extending
     * @param newClosingTime new closing time
     * @param prevClosingTime old closing time
     */
    event TimedCrowdsaleExtended(uint256 prevClosingTime, uint256 newClosingTime);

    /**
     * @dev Reverts if not in crowdsale time range.
     */
    modifier onlyWhileOpen {
        require(isOpen(), "TimedCrowdsale: not open");
        _;
    }

    /**
     * @dev Constructor, takes crowdsale opening and closing times.
     * @param openingTime Crowdsale opening time
     * @param closingTime Crowdsale closing time
     */
    constructor (uint256 openingTime, uint256 closingTime) public {
        // solhint-disable-next-line not-rely-on-time
        require(openingTime >= block.timestamp, "TimedCrowdsale: opening time is before current time");
        // solhint-disable-next-line max-line-length
        require(closingTime > openingTime, "TimedCrowdsale: opening time is not before closing time");

        _openingTime = openingTime;
        _closingTime = closingTime;
    }

    /**
     * @return the crowdsale opening time.
     */
    function openingTime() public view returns (uint256) {
        return _openingTime;
    }

    /**
     * @return the crowdsale closing time.
     */
    function closingTime() public view returns (uint256) {
        return _closingTime;
    }

    /**
     * @return true if the crowdsale is open, false otherwise.
     */
    function isOpen() public view returns (bool) {
        // solhint-disable-next-line not-rely-on-time
        return block.timestamp >= _openingTime && block.timestamp <= _closingTime;
    }

    /**
     * @dev Checks whether the period in which the crowdsale is open has already elapsed.
     * @return Whether crowdsale period has elapsed
     */
    function hasClosed() public view returns (bool) {
        // solhint-disable-next-line not-rely-on-time
        return block.timestamp > _closingTime;
    }

    /**
     * @dev Extend parent behavior requiring to be within contributing period.
     * @param beneficiary Token purchaser
     * @param weiAmount Amount of wei contributed
     */
    function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal onlyWhileOpen view {
        super._preValidatePurchase(beneficiary, weiAmount);
    }

    /**
     * @dev Extend crowdsale.
     * @param newClosingTime Crowdsale closing time
     */
    function _extendTime(uint256 newClosingTime) internal {
        require(!hasClosed(), "TimedCrowdsale: already closed");
        // solhint-disable-next-line max-line-length
        require(newClosingTime > _closingTime, "TimedCrowdsale: new closing time is before current closing time");

        emit TimedCrowdsaleExtended(_closingTime, newClosingTime);
        _closingTime = newClosingTime;
    }
}

// File: @openzeppelin/contracts/crowdsale/distribution/FinalizableCrowdsale.sol

pragma solidity ^0.5.0;



/**
 * @title FinalizableCrowdsale
 * @dev Extension of TimedCrowdsale with a one-off finalization action, where one
 * can do extra work after finishing.
 */
contract FinalizableCrowdsale is TimedCrowdsale {
    using SafeMath for uint256;

    bool private _finalized;

    event CrowdsaleFinalized();

    constructor () internal {
        _finalized = false;
    }

    /**
     * @return true if the crowdsale is finalized, false otherwise.
     */
    function finalized() public view returns (bool) {
        return _finalized;
    }

    /**
     * @dev Must be called after crowdsale ends, to do some extra finalization
     * work. Calls the contract's finalization function.
     */
    function finalize() public {
        require(!_finalized, "FinalizableCrowdsale: already finalized");
        require(hasClosed(), "FinalizableCrowdsale: not closed");

        _finalized = true;

        _finalization();
        emit CrowdsaleFinalized();
    }

    /**
     * @dev Can be overridden to add finalization logic. The overriding function
     * should call super._finalization() to ensure the chain of finalization is
     * executed entirely.
     */
    function _finalization() internal {
        // solhint-disable-previous-line no-empty-blocks
    }
}

// File: @openzeppelin/contracts/ownership/Secondary.sol

pragma solidity ^0.5.0;

/**
 * @dev A Secondary contract can only be used by its primary account (the one that created it).
 */
contract Secondary is Context {
    address private _primary;

    /**
     * @dev Emitted when the primary contract changes.
     */
    event PrimaryTransferred(
        address recipient
    );

    /**
     * @dev Sets the primary account to the one that is creating the Secondary contract.
     */
    constructor () internal {
        address msgSender = _msgSender();
        _primary = msgSender;
        emit PrimaryTransferred(msgSender);
    }

    /**
     * @dev Reverts if called from any account other than the primary.
     */
    modifier onlyPrimary() {
        require(_msgSender() == _primary, "Secondary: caller is not the primary account");
        _;
    }

    /**
     * @return the address of the primary.
     */
    function primary() public view returns (address) {
        return _primary;
    }

    /**
     * @dev Transfers contract to a new primary.
     * @param recipient The address of new primary.
     */
    function transferPrimary(address recipient) public onlyPrimary {
        require(recipient != address(0), "Secondary: new primary is the zero address");
        _primary = recipient;
        emit PrimaryTransferred(recipient);
    }
}

// File: @openzeppelin/contracts/payment/escrow/Escrow.sol

pragma solidity ^0.5.0;




 /**
  * @title Escrow
  * @dev Base escrow contract, holds funds designated for a payee until they
  * withdraw them.
  *
  * Intended usage: This contract (and derived escrow contracts) should be a
  * standalone contract, that only interacts with the contract that instantiated
  * it. That way, it is guaranteed that all Ether will be handled according to
  * the `Escrow` rules, and there is no need to check for payable functions or
  * transfers in the inheritance tree. The contract that uses the escrow as its
  * payment method should be its primary, and provide public methods redirecting
  * to the escrow's deposit and withdraw.
  */
contract Escrow is Secondary {
    using SafeMath for uint256;
    using Address for address payable;

    event Deposited(address indexed payee, uint256 weiAmount);
    event Withdrawn(address indexed payee, uint256 weiAmount);

    mapping(address => uint256) private _deposits;

    function depositsOf(address payee) public view returns (uint256) {
        return _deposits[payee];
    }

    /**
     * @dev Stores the sent amount as credit to be withdrawn.
     * @param payee The destination address of the funds.
     */
    function deposit(address payee) public onlyPrimary payable {
        uint256 amount = msg.value;
        _deposits[payee] = _deposits[payee].add(amount);

        emit Deposited(payee, amount);
    }

    /**
     * @dev Withdraw accumulated balance for a payee, forwarding 2300 gas (a
     * Solidity `transfer`).
     *
     * NOTE: This function has been deprecated, use {withdrawWithGas} instead.
     * Calling contracts with fixed-gas limits is an anti-pattern and may break
     * contract interactions in network upgrades (hardforks).
     * https://diligence.consensys.net/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more.]
     *
     * @param payee The address whose funds will be withdrawn and transferred to.
     */
    function withdraw(address payable payee) public onlyPrimary {
        uint256 payment = _deposits[payee];

        _deposits[payee] = 0;

        payee.transfer(payment);

        emit Withdrawn(payee, payment);
    }

    /**
     * @dev Same as {withdraw}, but forwarding all gas to the recipient.
     *
     * WARNING: Forwarding all gas opens the door to reentrancy vulnerabilities.
     * Make sure you trust the recipient, or are either following the
     * checks-effects-interactions pattern or using {ReentrancyGuard}.
     *
     * _Available since v2.4.0._
     */
    function withdrawWithGas(address payable payee) public onlyPrimary {
        uint256 payment = _deposits[payee];

        _deposits[payee] = 0;

        payee.sendValue(payment);

        emit Withdrawn(payee, payment);
    }
}

// File: @openzeppelin/contracts/payment/escrow/ConditionalEscrow.sol

pragma solidity ^0.5.0;


/**
 * @title ConditionalEscrow
 * @dev Base abstract escrow to only allow withdrawal if a condition is met.
 * @dev Intended usage: See {Escrow}. Same usage guidelines apply here.
 */
contract ConditionalEscrow is Escrow {
    /**
     * @dev Returns whether an address is allowed to withdraw their funds. To be
     * implemented by derived contracts.
     * @param payee The destination address of the funds.
     */
    function withdrawalAllowed(address payee) public view returns (bool);

    function withdraw(address payable payee) public {
        require(withdrawalAllowed(payee), "ConditionalEscrow: payee is not allowed to withdraw");
        super.withdraw(payee);
    }
}

// File: @openzeppelin/contracts/payment/escrow/RefundEscrow.sol

pragma solidity ^0.5.0;


/**
 * @title RefundEscrow
 * @dev Escrow that holds funds for a beneficiary, deposited from multiple
 * parties.
 * @dev Intended usage: See {Escrow}. Same usage guidelines apply here.
 * @dev The primary account (that is, the contract that instantiates this
 * contract) may deposit, close the deposit period, and allow for either
 * withdrawal by the beneficiary, or refunds to the depositors. All interactions
 * with `RefundEscrow` will be made through the primary contract. See the
 * `RefundableCrowdsale` contract for an example of `RefundEscrow`’s use.
 */
contract RefundEscrow is ConditionalEscrow {
    enum State { Active, Refunding, Closed }

    event RefundsClosed();
    event RefundsEnabled();

    State private _state;
    address payable private _beneficiary;

    /**
     * @dev Constructor.
     * @param beneficiary The beneficiary of the deposits.
     */
    constructor (address payable beneficiary) public {
        require(beneficiary != address(0), "RefundEscrow: beneficiary is the zero address");
        _beneficiary = beneficiary;
        _state = State.Active;
    }

    /**
     * @return The current state of the escrow.
     */
    function state() public view returns (State) {
        return _state;
    }

    /**
     * @return The beneficiary of the escrow.
     */
    function beneficiary() public view returns (address) {
        return _beneficiary;
    }

    /**
     * @dev Stores funds that may later be refunded.
     * @param refundee The address funds will be sent to if a refund occurs.
     */
    function deposit(address refundee) public payable {
        require(_state == State.Active, "RefundEscrow: can only deposit while active");
        super.deposit(refundee);
    }

    /**
     * @dev Allows for the beneficiary to withdraw their funds, rejecting
     * further deposits.
     */
    function close() public onlyPrimary {
        require(_state == State.Active, "RefundEscrow: can only close while active");
        _state = State.Closed;
        emit RefundsClosed();
    }

    /**
     * @dev Allows for refunds to take place, rejecting further deposits.
     */
    function enableRefunds() public onlyPrimary {
        require(_state == State.Active, "RefundEscrow: can only enable refunds while active");
        _state = State.Refunding;
        emit RefundsEnabled();
    }

    /**
     * @dev Withdraws the beneficiary's funds.
     */
    function beneficiaryWithdraw() public {
        require(_state == State.Closed, "RefundEscrow: beneficiary can only withdraw while closed");
        _beneficiary.transfer(address(this).balance);
    }

    /**
     * @dev Returns whether refundees can withdraw their deposits (be refunded). The overridden function receives a
     * 'payee' argument, but we ignore it here since the condition is global, not per-payee.
     */
    function withdrawalAllowed(address) public view returns (bool) {
        return _state == State.Refunding;
    }
}

// File: @openzeppelin/contracts/crowdsale/distribution/RefundableCrowdsale.sol

pragma solidity ^0.5.0;





/**
 * @title RefundableCrowdsale
 * @dev Extension of `FinalizableCrowdsale` contract that adds a funding goal, and the possibility of users
 * getting a refund if goal is not met.
 *
 * Deprecated, use `RefundablePostDeliveryCrowdsale` instead. Note that if you allow tokens to be traded before the goal
 * is met, then an attack is possible in which the attacker purchases tokens from the crowdsale and when they sees that
 * the goal is unlikely to be met, they sell their tokens (possibly at a discount). The attacker will be refunded when
 * the crowdsale is finalized, and the users that purchased from them will be left with worthless tokens.
 */
contract RefundableCrowdsale is Context, FinalizableCrowdsale {
    using SafeMath for uint256;

    // minimum amount of funds to be raised in weis
    uint256 private _goal;

    // refund escrow used to hold funds while crowdsale is running
    RefundEscrow private _escrow;

    /**
     * @dev Constructor, creates RefundEscrow.
     * @param goal Funding goal
     */
    constructor (uint256 goal) public {
        require(goal > 0, "RefundableCrowdsale: goal is 0");
        _escrow = new RefundEscrow(wallet());
        _goal = goal;
    }

    /**
     * @return minimum amount of funds to be raised in wei.
     */
    function goal() public view returns (uint256) {
        return _goal;
    }

    /**
     * @dev Investors can claim refunds here if crowdsale is unsuccessful.
     * @param refundee Whose refund will be claimed.
     */
    function claimRefund(address payable refundee) public {
        require(finalized(), "RefundableCrowdsale: not finalized");
        require(!goalReached(), "RefundableCrowdsale: goal reached");

        _escrow.withdraw(refundee);
    }

    /**
     * @dev Checks whether funding goal was reached.
     * @return Whether funding goal was reached
     */
    function goalReached() public view returns (bool) {
        return weiRaised() >= _goal;
    }

    /**
     * @dev Escrow finalization task, called when finalize() is called.
     */
    function _finalization() internal {
        if (goalReached()) {
            _escrow.close();
            _escrow.beneficiaryWithdraw();
        } else {
            _escrow.enableRefunds();
        }

        super._finalization();
    }

    /**
     * @dev Overrides Crowdsale fund forwarding, sending funds to escrow.
     */
    function _forwardFunds() internal {
        _escrow.deposit.value(msg.value)(_msgSender());
    }
}

// File: contracts/lib/ds-hub.sol

pragma solidity ^0.5.17;

interface DSAuthority {
  function canCall(
    address src,
    address dst,
    bytes4 sig
  ) external view returns (bool);
}

contract DSAuthEvents {
  event LogSetAuthority(address indexed authority);
  event LogSetOwner(address indexed owner);
}

contract DSAuth is DSAuthEvents {
  DSAuthority public authority;
  address public owner;

  constructor() public {
    owner = msg.sender;
    emit LogSetOwner(msg.sender);
  }

  function setOwner(address owner_) public auth {
    owner = owner_;
    emit LogSetOwner(owner);
  }

  function setAuthority(DSAuthority authority_) public auth {
    authority = authority_;
    emit LogSetAuthority(address(authority));
  }

  modifier auth {
    require(isAuthorized(msg.sender, msg.sig), "ds-auth-unauthorized");
    _;
  }

  function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
    if (src == address(this)) {
      return true;
    } else if (src == owner) {
      return true;
    } else if (authority == DSAuthority(0)) {
      return false;
    } else {
      return authority.canCall(src, address(this), sig);
    }
  }
}

contract DSNote {
  event LogNote(bytes4 indexed sig, address indexed guy, bytes32 indexed foo, bytes32 indexed bar, uint256 wad, bytes fax) anonymous;

  modifier note {
    bytes32 foo;
    bytes32 bar;
    uint256 wad;

    assembly {
      foo := calldataload(4)
      bar := calldataload(36)
      wad := callvalue()
    }

    _;

    emit LogNote(msg.sig, msg.sender, foo, bar, wad, msg.data);
  }
}

contract DSMath {
  function add(uint256 x, uint256 y) internal pure returns (uint256 z) {
    require((z = x + y) >= x, "ds-math-add-overflow");
  }

  function sub(uint256 x, uint256 y) internal pure returns (uint256 z) {
    require((z = x - y) <= x, "ds-math-sub-underflow");
  }

  function mul(uint256 x, uint256 y) internal pure returns (uint256 z) {
    require(y == 0 || (z = x * y) / y == x, "ds-math-mul-overflow");
  }

  function min(uint256 x, uint256 y) internal pure returns (uint256 z) {
    return x <= y ? x : y;
  }

  function max(uint256 x, uint256 y) internal pure returns (uint256 z) {
    return x >= y ? x : y;
  }

  function imin(int256 x, int256 y) internal pure returns (int256 z) {
    return x <= y ? x : y;
  }

  function imax(int256 x, int256 y) internal pure returns (int256 z) {
    return x >= y ? x : y;
  }

  uint256 constant WAD = 10**18;
  uint256 constant RAY = 10**27;

  //rounds to zero if x*y < WAD / 2
  function wmul(uint256 x, uint256 y) internal pure returns (uint256 z) {
    z = add(mul(x, y), WAD / 2) / WAD;
  }

  //rounds to zero if x*y < WAD / 2
  function rmul(uint256 x, uint256 y) internal pure returns (uint256 z) {
    z = add(mul(x, y), RAY / 2) / RAY;
  }

  //rounds to zero if x*y < WAD / 2
  function wdiv(uint256 x, uint256 y) internal pure returns (uint256 z) {
    z = add(mul(x, WAD), y / 2) / y;
  }

  //rounds to zero if x*y < RAY / 2
  function rdiv(uint256 x, uint256 y) internal pure returns (uint256 z) {
    z = add(mul(x, RAY), y / 2) / y;
  }

  // This famous algorithm is called "exponentiation by squaring"
  // and calculates x^n with x as fixed-point and n as regular unsigned.
  //
  // It's O(log n), instead of O(n) for naive repeated multiplication.
  //
  // These facts are why it works:
  //
  //  If n is even, then x^n = (x^2)^(n/2).
  //  If n is odd,  then x^n = x * x^(n-1),
  //   and applying the equation for even x gives
  //    x^n = x * (x^2)^((n-1) / 2).
  //
  //  Also, EVM division is flooring and
  //    floor[(n-1) / 2] = floor[n / 2].
  //
  function rpow(uint256 x, uint256 n) internal pure returns (uint256 z) {
    z = n % 2 != 0 ? x : RAY;

    for (n /= 2; n != 0; n /= 2) {
      x = rmul(x, x);

      if (n % 2 != 0) {
        z = rmul(z, x);
      }
    }
  }
}

contract DSThing is DSAuth, DSNote, DSMath {
  function S(string memory s) internal pure returns (bytes4) {
    return bytes4(keccak256(abi.encodePacked(s)));
  }
}

contract DSValue is DSThing {
  bool has;
  bytes32 val;

  function peek() public view returns (bytes32, bool) {
    return (val, has);
  }

  function read() public view returns (bytes32) {
    bytes32 wut;
    bool haz;
    (wut, haz) = peek();
    require(haz, "haz-not");
    return wut;
  }

  function poke(bytes32 wut) public note auth {
    val = wut;
    has = true;
  }

  function void() public note auth {
    // unset the value
    has = false;
  }
}

// File: contracts/lib/IUniswapV2Pair.sol

pragma solidity >=0.5.10;

interface IUniswapV2Pair {
  event Approval(address indexed owner, address indexed spender, uint256 value);
  event Transfer(address indexed from, address indexed to, uint256 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 (uint256);

  function balanceOf(address owner) external view returns (uint256);

  function allowance(address owner, address spender) external view returns (uint256);

  function approve(address spender, uint256 value) external returns (bool);

  function transfer(address to, uint256 value) external returns (bool);

  function transferFrom(
    address from,
    address to,
    uint256 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 (uint256);

  function permit(
    address owner,
    address spender,
    uint256 value,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;

  event Mint(address indexed sender, uint256 amount0, uint256 amount1);
  event Burn(address indexed sender, uint256 amount0, uint256 amount1, address indexed to);
  event Swap(address indexed sender, uint256 amount0In, uint256 amount1In, uint256 amount0Out, uint256 amount1Out, address indexed to);
  event Sync(uint112 reserve0, uint112 reserve1);

  function MINIMUM_LIQUIDITY() external pure returns (uint256);

  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);

  function price0CumulativeLast() external view returns (uint256);

  function price1CumulativeLast() external view returns (uint256);

  function kLast() external view returns (uint256);

  function mint(address to) external returns (uint256 liquidity);

  function burn(address to) external returns (uint256 amount0, uint256 amount1);

  function swap(
    uint256 amount0Out,
    uint256 amount1Out,
    address to,
    bytes calldata data
  ) external;

  function skim(address to) external;

  function sync() external;

  function initialize(address, address) external;
}

// File: contracts/sale/PricePicker.sol

pragma solidity ^0.5.17;





// calc eth price in usd
contract PricePicker is DSMath, Ownable {
  function src() public pure returns (address) {
    return 0xA478c2975Ab1Ea89e8196811F51A7B7Ade33eB11;
  }

  function getPrice() public view returns (uint256) {
    (uint112 reserve0, uint112 reserve1) = IUniswapV2Pair(src()).getReserves();
    return wdiv(uint256(reserve0), uint256(reserve1));
  }
}

// File: contracts/sale/RoundCrowdsale.sol

pragma solidity ^0.5.17;




contract RoundCrowdsale is DSMath, Crowdsale {
  using SafeMath for uint256;

  bool private _initialized;

  uint256 private _startTime;

  uint256 private _nRound;

  // array of block time stamps
  uint256[] private _roundEndTime;

  // array of rates of tokens per wei in WAD unit.
  uint256[] private _rates;

  uint256 private _roundTokenCap;

  mapping(uint256 => uint256) private _roundSoldToken;

  function initialize(
    uint256 roundTokenCap,
    uint256 startTime,
    uint256[] memory roundEndTime,
    uint256[] memory rates
  ) public {
    require(_initialized == false);
    require(roundEndTime.length == rates.length, "RoundCrowdsale: invalid input length");
    require(startTime < roundEndTime[0], "RoundCrowdsale: invalid start time");

    uint256 n = roundEndTime.length;

    for (uint256 i = 1; i < n; i++) {
      require(roundEndTime[i - 1] < roundEndTime[i], "RoundCrowdsale: time not sorted");
    }
    _startTime = startTime;
    _nRound = n;

    _roundEndTime = roundEndTime;
    _rates = rates;

    _roundTokenCap = roundTokenCap;

    _initialized = true;
  }

  function nRound() public view returns (uint256) {
    return _nRound;
  }

  function startTime() public view returns (uint256) {
    return _startTime;
  }

  function roundEndTimes(uint256 i) public view returns (uint256) {
    return _roundEndTime[i];
  }

  function roundSoldToken(uint256 i) public view returns (uint256) {
    return _roundSoldToken[i];
  }

  function roundTokenCap() public view returns (uint256) {
    return _roundTokenCap;
  }

  function rates(uint256 i) external view returns (uint256) {
    return _rates[i];
  }

  function isOpen() public view returns (bool) {
    // solhint-disable-next-line not-rely-on-time
    return block.timestamp >= _startTime && block.timestamp <= _roundEndTime[_roundEndTime.length - 1];
  }

  /**
   * The base rate function is overridden to revert, since this crowdsale doesn't use it, and
   * all calls to it are a mistake.
   */
  function rate() public view returns (uint256) {
    revert("RoundCrowdsale: rate() called");
  }

  function getCurrentRound() public view returns (uint256) {
    require(isOpen());

    uint256 index;
    for (; index < _rates.length; index++) {
      if (block.timestamp <= _roundEndTime[index]) break;
    }

    return index;
  }

  /**
   * @dev Returns the rate of tokens per wei at the present time.
   * Note that, as price _increases_ with time, the rate _decreases_.
   * @return The number of tokens a buyer gets per wei at a given time
   */
  function getCurrentRate() public view returns (uint256) {
    if (!isOpen()) {
      return 0;
    }

    return _rates[getCurrentRound()];
  }

  /**
   * @dev Override Crowdsale#_processPurchase
   * @param beneficiary Address receiving the tokens
   * @param tokenAmount Number of tokens to be purchased
   */
  function _processPurchase(address beneficiary, uint256 tokenAmount) internal {
    uint256 index = getCurrentRound();

    require(_roundSoldToken[index].add(tokenAmount) < _roundTokenCap, "RoundCrowdsale: over payment");

    _roundSoldToken[index] = _roundSoldToken[index].add(tokenAmount);
    super._processPurchase(beneficiary, tokenAmount);
  }

  /**
   * @dev Overrides parent method taking into account variable rate.
   * @param weiAmount The value in wei to be converted into tokens
   * @return The number of tokens _weiAmount wei will buy at present time
   */
  function _getTokenAmount(uint256 weiAmount) internal view returns (uint256) {
    uint256 currentRate = getCurrentRate();
    return wmul(currentRate, weiAmount);
  }

  /**
   * @dev Overrides Crowdsale._preValidatePurchase
   * @param beneficiary Address performing the token purchase
   * @param weiAmount Value in wei involved in the purchase
   */
  function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
    super._preValidatePurchase(beneficiary, weiAmount);
    require(isOpen(), "RoundCrowdsale: not open yet");
    this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
  }
}

// File: contracts/lib/MerkleProof.sol

// https://github.com/ameensol/merkle-tree-solidity/blob/master/src/MerkleProof.sol

pragma solidity >=0.4.22 <0.8.0;

contract MerkleProof {
  function checkProof(
    bytes memory proof,
    bytes32 root,
    bytes32 hash
  ) public pure returns (bool) {
    bytes32 el;
    bytes32 h = hash;

    for (uint256 i = 32; i <= proof.length; i += 32) {
      assembly {
        el := mload(add(proof, i))
      }

      if (h < el) {
        h = keccak256(abi.encodePacked(h, el));
      } else {
        h = keccak256(abi.encodePacked(el, h));
      }
    }

    return h == root;
  }

  // from StorJ -- https://github.com/nginnever/storj-audit-verifier/blob/master/contracts/MerkleVerifyv3.sol
  function checkProofOrdered(
    bytes memory proof,
    bytes32 root,
    bytes32 hash,
    uint256 index
  ) public pure returns (bool) {
    // use the index to determine the node ordering
    // index ranges 1 to n

    bytes32 el;
    bytes32 h = hash;
    uint256 remaining;

    for (uint256 j = 32; j <= proof.length; j += 32) {
      assembly {
        el := mload(add(proof, j))
      }

      // calculate remaining elements in proof
      remaining = (proof.length - j + 32) / 32;

      // we don't assume that the tree is padded to a power of 2
      // if the index is odd then the proof will start with a hash at a higher
      // layer, so we have to adjust the index to be the index at that layer
      while (remaining > 0 && index % 2 == 1 && index > 2**remaining) {
        index = uint256(index) / 2 + 1;
      }

      if (index % 2 == 0) {
        h = keccak256(abi.encodePacked(el, h));
        index = index / 2;
      } else {
        h = keccak256(abi.encodePacked(h, el));
        index = uint256(index) / 2 + 1;
      }
    }

    return h == root;
  }
}

// File: contracts/lib/LeafLib.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.4.22 <0.8.0;


contract LeafLib is MerkleProof {
  mapping(address => uint256) public amounts;
  mapping(bytes32 => bool) public isRoot;
  bytes32[] public roots;

  function addRoot(bytes32 root) public {
    require(!isRoot[root], "duplicate-root");
    isRoot[root] = true;
    roots.push(root);
  }

  function addLeaf(
    bytes32 root,
    address account,
    uint256 amount,
    bytes memory proof
  ) public {
    require(isRoot[root], "no-root");

    bytes32 h = keccak256(abi.encode(account, amount));

    require(checkProof(proof, root, h), "invalid-proof");

    amounts[account] = amount;
  }
}

// File: contracts/sale/MerkleProofCappedCrowdsale.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.5.17;





contract MerkleProofCappedCrowdsale is Ownable, LeafLib, Crowdsale {
  using SafeMath for uint256;

  mapping(address => bool) public isRootAdder;

  modifier onlyRootAdder() {
    require(msg.sender == owner() || isRootAdder[msg.sender], "no-root-adder");
    _;
  }

  function addRootAdder(address account) external onlyOwner {
    isRootAdder[account] = true;
  }

  function addRoot(bytes32 root) public onlyRootAdder {
    super.addRoot(root);
  }

  mapping(address => uint256) private _contributions;

  /**
   * @dev Returns the amount contributed so far by a specific beneficiary.
   * @param beneficiary Address of contributor
   * @return Beneficiary contribution so far
   */
  function getContribution(address beneficiary) public view returns (uint256) {
    return _contributions[beneficiary];
  }

  /**
   * @param amount cap
   * @param root merkle root
   * @param proof merkle proof
   */
  function buyTokensWithProof(
    uint256 amount,
    bytes32 root,
    bytes calldata proof
  ) external payable {
    addLeaf(root, msg.sender, amount, proof);
    buyTokens(msg.sender);
  }

  function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
    super._preValidatePurchase(beneficiary, weiAmount);
    require(_contributions[beneficiary].add(weiAmount) <= amounts[beneficiary], "MerkleProofCappedCrowdsale: exceeds cap");
  }

  /**
   * @dev Extend parent behavior to update beneficiary contributions.
   * @param beneficiary Token purchaser
   * @param weiAmount Amount of wei contributed
   */
  function _updatePurchasingState(address beneficiary, uint256 weiAmount) internal {
    super._updatePurchasingState(beneficiary, weiAmount);
    _contributions[beneficiary] = _contributions[beneficiary].add(weiAmount);
  }
}

// File: contracts/sale/PublicSale.sol

pragma solidity ^0.5.17;













/**
 * @dev RefundableCrowdsale is only used to prevent `wallet` from receiving Ether
 *      during crowdsale.
 */
contract PublicSale is
  DSMath,
  Ownable,
  Crowdsale,
  AllowanceCrowdsale,
  TimedCrowdsale,
  MerkleProofCappedCrowdsale,
  FinalizableCrowdsale,
  RefundableCrowdsale,
  RoundCrowdsale,
  PricePicker
{
  constructor(
    IERC20 token, // The token being sold
    address payable wallet, // Address where funds are collected
    address tokenWallet, // Address where the token is stored
    uint256 openingTime, // Time when the sale is opened
    uint256 closingTime
  ) public Crowdsale(1, wallet, token) AllowanceCrowdsale(tokenWallet) TimedCrowdsale(openingTime, closingTime) RefundableCrowdsale(1) {}

  ////////////////////////
  // Prices
  ////////////////////////
  function DAI_CFX() public view returns (uint256) {
    return getCurrentRate();
  }

  function ETH_DAI() public view returns (uint256) {
    return getPrice();
  }

  function ETH_CFX() public view returns (uint256) {
    return wdiv(ETH_DAI(), DAI_CFX());
  }

  /**
   * @dev Override Crowdsale#_getTokenAmount
   * @param weiAmount Value in wei to be converted into tokens
   * @return Number of tokens that can be purchased with the specified _weiAmount
   */
  function _getTokenAmount(uint256 weiAmount) internal view returns (uint256) {
    return calcTokenAmountWithEthPrice(weiAmount);
  }

  function calcTokenAmountWithEthPrice(uint256 ethAmount) public view returns (uint256) {
    return wmul(ethAmount, ETH_CFX());
  }

  function isOpen() public view returns (bool) {
    return RoundCrowdsale.isOpen() && TimedCrowdsale.isOpen();
  }

  /**
   * @dev Override FinalizableCrowdsale#finalize
   */
  function finalize() public onlyOwner {
    super.finalize();
  }

  /**
   * @dev Override RefundableCrowdsale#claimRefund
   */
  function claimRefund(address payable) public {
    revert("PublicSale: not supported");
  }

  /**
   * @dev Override RefundableCrowdsale#goalReached
   * @return Whether funding goal was reached
   */
  function goalReached() public view returns (bool) {
    return hasClosed();
  }

  function goal() public view returns (uint256) {
    revert("PublicSale: not supported");
  }

  /**
   * @dev Overrides Crowdsale._preValidatePurchase
   * @param beneficiary Address performing the token purchase
   * @param weiAmount Value in wei involved in the purchase
   */
  function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
    super._preValidatePurchase(beneficiary, weiAmount);
    require(msg.sender == tx.origin, "PublicSale: invalid tx origin");
    this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
  }
}

{
  "compilationTarget": {
    "PublicSale.sol": "PublicSale"
  },
  "evmVersion": "istanbul",
  "libraries": {},
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}