/**
 * Copyright (c) 2018 blockimmo AG license@blockimmo.ch
 * Non-Profit Open Software License 3.0 (NPOSL-3.0)
 * https://opensource.org/licenses/NPOSL-3.0
 */
 

pragma solidity 0.4.25;


/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {

  /**
  * @dev Multiplies two numbers, throws on overflow.
  */
  function mul(uint256 _a, uint256 _b) internal pure returns (uint256 c) {
    // Gas optimization: this is cheaper than asserting 'a' not being zero, but the
    // benefit is lost if 'b' is also tested.
    // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
    if (_a == 0) {
      return 0;
    }

    c = _a * _b;
    assert(c / _a == _b);
    return c;
  }

  /**
  * @dev Integer division of two numbers, truncating the quotient.
  */
  function div(uint256 _a, uint256 _b) internal pure returns (uint256) {
    // assert(_b > 0); // Solidity automatically throws when dividing by 0
    // uint256 c = _a / _b;
    // assert(_a == _b * c + _a % _b); // There is no case in which this doesn't hold
    return _a / _b;
  }

  /**
  * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 _a, uint256 _b) internal pure returns (uint256) {
    assert(_b <= _a);
    return _a - _b;
  }

  /**
  * @dev Adds two numbers, throws on overflow.
  */
  function add(uint256 _a, uint256 _b) internal pure returns (uint256 c) {
    c = _a + _b;
    assert(c >= _a);
    return c;
  }
}


/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * See https://github.com/ethereum/EIPs/issues/179
 */
contract ERC20Basic {
  function totalSupply() public view returns (uint256);
  function balanceOf(address _who) public view returns (uint256);
  function transfer(address _to, uint256 _value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}


/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 is ERC20Basic {
  function allowance(address _owner, address _spender)
    public view returns (uint256);

  function transferFrom(address _from, address _to, uint256 _value)
    public returns (bool);

  function approve(address _spender, uint256 _value) public returns (bool);
  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}


/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure.
 * 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 {
  function safeTransfer(
    ERC20Basic _token,
    address _to,
    uint256 _value
  )
    internal
  {
    require(_token.transfer(_to, _value));
  }

  function safeTransferFrom(
    ERC20 _token,
    address _from,
    address _to,
    uint256 _value
  )
    internal
  {
    require(_token.transferFrom(_from, _to, _value));
  }

  function safeApprove(
    ERC20 _token,
    address _spender,
    uint256 _value
  )
    internal
  {
    require(_token.approve(_spender, _value));
  }
}


/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
  address public owner;


  event OwnershipRenounced(address indexed previousOwner);
  event OwnershipTransferred(
    address indexed previousOwner,
    address indexed newOwner
  );


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  constructor() public {
    owner = msg.sender;
  }

  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   * @notice Renouncing to ownership will leave the contract without an owner.
   * It will not be possible to call the functions with the `onlyOwner`
   * modifier anymore.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipRenounced(owner);
    owner = address(0);
  }

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param _newOwner The address to transfer ownership to.
   */
  function transferOwnership(address _newOwner) public onlyOwner {
    _transferOwnership(_newOwner);
  }

  /**
   * @dev Transfers control of the contract to a newOwner.
   * @param _newOwner The address to transfer ownership to.
   */
  function _transferOwnership(address _newOwner) internal {
    require(_newOwner != address(0));
    emit OwnershipTransferred(owner, _newOwner);
    owner = _newOwner;
  }
}


/**
 * @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 conform
 * the base architecture for crowdsales. They are *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 {
  using SafeMath for uint256;
  using SafeERC20 for ERC20;

  // The token being sold
  ERC20 public token;

  // Address where funds are collected
  address public 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 DetailedERC20 token with 3 decimals called TOK
  // 1 wei will give you 1 unit, or 0.001 TOK.
  uint256 public rate;

  // Amount of wei raised
  uint256 public 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 TokenPurchase(
    address indexed purchaser,
    address indexed beneficiary,
    uint256 value,
    uint256 amount
  );

  /**
   * @param _rate Number of token units a buyer gets per wei
   * @param _wallet Address where collected funds will be forwarded to
   * @param _token Address of the token being sold
   */
  constructor(uint256 _rate, address _wallet, ERC20 _token) public {
    require(_rate > 0);
    require(_wallet != address(0));
    require(_token != address(0));

    rate = _rate;
    wallet = _wallet;
    token = _token;
  }

  // -----------------------------------------
  // Crowdsale external interface
  // -----------------------------------------

  /**
   * @dev fallback function ***DO NOT OVERRIDE***
   */
  function () external payable {
    buyTokens(msg.sender);
  }

  /**
   * @dev low level token purchase ***DO NOT OVERRIDE***
   * @param _beneficiary Address performing the token purchase
   */
  function buyTokens(address _beneficiary) public 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 TokenPurchase(
      msg.sender,
      _beneficiary,
      weiAmount,
      tokens
    );

    _updatePurchasingState(_beneficiary, weiAmount);

    _forwardFunds();
    _postValidatePurchase(_beneficiary, weiAmount);
  }

  // -----------------------------------------
  // Internal interface (extensible)
  // -----------------------------------------

  /**
   * @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
  {
    require(_beneficiary != address(0));
    require(_weiAmount != 0);
  }

  /**
   * @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
  {
    // optional override
  }

  /**
   * @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. Not necessarily emits/sends 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
  {
    // optional override
  }

  /**
   * @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);
  }
}


/**
 * @title TimedCrowdsale
 * @dev Crowdsale accepting contributions only within a time frame.
 */
contract TimedCrowdsale is Crowdsale {
  using SafeMath for uint256;

  uint256 public openingTime;
  uint256 public closingTime;

  /**
   * @dev Reverts if not in crowdsale time range.
   */
  modifier onlyWhileOpen {
    // solium-disable-next-line security/no-block-members
    require(block.timestamp >= openingTime && block.timestamp <= closingTime);
    _;
  }

  /**
   * @dev Constructor, takes crowdsale opening and closing times.
   * @param _openingTime Crowdsale opening time
   * @param _closingTime Crowdsale closing time
   */
  constructor(uint256 _openingTime, uint256 _closingTime) public {
    // solium-disable-next-line security/no-block-members
    require(_openingTime >= block.timestamp);
    require(_closingTime >= _openingTime);

    openingTime = _openingTime;
    closingTime = _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) {
    // solium-disable-next-line security/no-block-members
    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
  {
    super._preValidatePurchase(_beneficiary, _weiAmount);
  }

}


/**
 * @title PostDeliveryCrowdsale
 * @dev Crowdsale that locks tokens from withdrawal until it ends.
 */
contract PostDeliveryCrowdsale is TimedCrowdsale {
  using SafeMath for uint256;

  mapping(address => uint256) public balances;

  /**
   * @dev Withdraw tokens only after crowdsale ends.
   */
  function withdrawTokens() public {
    require(hasClosed());
    uint256 amount = balances[msg.sender];
    require(amount > 0);
    balances[msg.sender] = 0;
    _deliverTokens(msg.sender, amount);
  }

  /**
   * @dev Overrides parent by storing balances instead of issuing tokens right away.
   * @param _beneficiary Token purchaser
   * @param _tokenAmount Amount of tokens purchased
   */
  function _processPurchase(
    address _beneficiary,
    uint256 _tokenAmount
  )
    internal
  {
    balances[_beneficiary] = balances[_beneficiary].add(_tokenAmount);
  }

}


/**
 * @title FinalizableCrowdsale
 * @dev Extension of Crowdsale where an owner can do extra work
 * after finishing.
 */
contract FinalizableCrowdsale is Ownable, TimedCrowdsale {
  using SafeMath for uint256;

  bool public isFinalized = false;

  event Finalized();

  /**
   * @dev Must be called after crowdsale ends, to do some extra finalization
   * work. Calls the contract's finalization function.
   */
  function finalize() public onlyOwner {
    require(!isFinalized);
    require(hasClosed());

    finalization();
    emit Finalized();

    isFinalized = true;
  }

  /**
   * @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 {
  }

}


/**
 * @title Escrow
 * @dev Base escrow contract, holds funds destinated to a payee until they
 * withdraw them. The contract that uses the escrow as its payment method
 * should be its owner, and provide public methods redirecting to the escrow's
 * deposit and withdraw.
 */
contract Escrow is Ownable {
  using SafeMath for uint256;

  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 onlyOwner payable {
    uint256 amount = msg.value;
    deposits[_payee] = deposits[_payee].add(amount);

    emit Deposited(_payee, amount);
  }

  /**
  * @dev Withdraw accumulated balance for a payee.
  * @param _payee The address whose funds will be withdrawn and transferred to.
  */
  function withdraw(address _payee) public onlyOwner {
    uint256 payment = deposits[_payee];
    assert(address(this).balance >= payment);

    deposits[_payee] = 0;

    _payee.transfer(payment);

    emit Withdrawn(_payee, payment);
  }
}


/**
 * @title ConditionalEscrow
 * @dev Base abstract escrow to only allow withdrawal if a condition is met.
 */
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 _payee) public {
    require(withdrawalAllowed(_payee));
    super.withdraw(_payee);
  }
}


/**
 * @title RefundEscrow
 * @dev Escrow that holds funds for a beneficiary, deposited from multiple parties.
 * The contract owner may close the deposit period, and allow for either withdrawal
 * by the beneficiary, or refunds to the depositors.
 */
contract RefundEscrow is Ownable, ConditionalEscrow {
  enum State { Active, Refunding, Closed }

  event Closed();
  event RefundsEnabled();

  State public state;
  address public beneficiary;

  /**
   * @dev Constructor.
   * @param _beneficiary The beneficiary of the deposits.
   */
  constructor(address _beneficiary) public {
    require(_beneficiary != address(0));
    beneficiary = _beneficiary;
    state = State.Active;
  }

  /**
   * @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);
    super.deposit(_refundee);
  }

  /**
   * @dev Allows for the beneficiary to withdraw their funds, rejecting
   * further deposits.
   */
  function close() public onlyOwner {
    require(state == State.Active);
    state = State.Closed;
    emit Closed();
  }

  /**
   * @dev Allows for refunds to take place, rejecting further deposits.
   */
  function enableRefunds() public onlyOwner {
    require(state == State.Active);
    state = State.Refunding;
    emit RefundsEnabled();
  }

  /**
   * @dev Withdraws the beneficiary's funds.
   */
  function beneficiaryWithdraw() public {
    require(state == State.Closed);
    beneficiary.transfer(address(this).balance);
  }

  /**
   * @dev Returns whether refundees can withdraw their deposits (be refunded).
   */
  function withdrawalAllowed(address _payee) public view returns (bool) {
    return state == State.Refunding;
  }
}


/**
 * @title RefundableCrowdsale
 * @dev Extension of Crowdsale contract that adds a funding goal, and
 * the possibility of users getting a refund if goal is not met.
 */
contract RefundableCrowdsale is FinalizableCrowdsale {
  using SafeMath for uint256;

  // minimum amount of funds to be raised in weis
  uint256 public 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);
    escrow = new RefundEscrow(wallet);
    goal = _goal;
  }

  /**
   * @dev Investors can claim refunds here if crowdsale is unsuccessful
   */
  function claimRefund() public {
    require(isFinalized);
    require(!goalReached());

    escrow.withdraw(msg.sender);
  }

  /**
   * @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 owner calls finalize()
   */
  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)(msg.sender);
  }

}


/**
 * @title SplitPayment
 * @dev Base contract that supports multiple payees claiming funds sent to this contract
 * according to the proportion they own.
 */
contract SplitPayment {
  using SafeMath for uint256;

  uint256 public totalShares = 0;
  uint256 public totalReleased = 0;

  mapping(address => uint256) public shares;
  mapping(address => uint256) public released;
  address[] public payees;

  /**
   * @dev Constructor
   */
  constructor(address[] _payees, uint256[] _shares) public payable {
    require(_payees.length == _shares.length);

    for (uint256 i = 0; i < _payees.length; i++) {
      addPayee(_payees[i], _shares[i]);
    }
  }

  /**
   * @dev payable fallback
   */
  function () external payable {}

  /**
   * @dev Claim your share of the balance.
   */
  function claim() public {
    address payee = msg.sender;

    require(shares[payee] > 0);

    uint256 totalReceived = address(this).balance.add(totalReleased);
    uint256 payment = totalReceived.mul(
      shares[payee]).div(
        totalShares).sub(
          released[payee]
    );

    require(payment != 0);
    require(address(this).balance >= payment);

    released[payee] = released[payee].add(payment);
    totalReleased = totalReleased.add(payment);

    payee.transfer(payment);
  }

  /**
   * @dev Add a new payee to the contract.
   * @param _payee The address of the payee to add.
   * @param _shares The number of shares owned by the payee.
   */
  function addPayee(address _payee, uint256 _shares) internal {
    require(_payee != address(0));
    require(_shares > 0);
    require(shares[_payee] == 0);

    payees.push(_payee);
    shares[_payee] = _shares;
    totalShares = totalShares.add(_shares);
  }
}


contract MedianizerInterface {
  function read() public view returns (bytes32);
}


contract MedianizerProxyInterface {
  function medianizer() public view returns (MedianizerInterface);
}


contract WhitelistInterface {
  function checkRole(address _operator, string _role) public view;
  function hasRole(address _operator, string _role) public view returns (bool);
}


contract WhitelistProxyInterface {
  function whitelist() public view returns (WhitelistInterface);
}


contract Payments is Ownable, SplitPayment {
  constructor() public SplitPayment(new address[](0), new uint256[](0)) { }

  function addPayment(address _payee, uint256 _amount) public onlyOwner {
    addPayee(_payee, _amount);
  }
}


/**
 * @title TokenSale
 * @dev Distribute tokens to investors in exchange for Ether.
 *
 * This is the primary mechanism for outright sales of commercial investment properties (and blockimmo's STO, where shares
 * of our company are represented as `TokenizedProperty`) (official pending FINMA approval).
 *
 * Selling:
 *   1. Deploy `TokenizedProperty`. Initially all tokens and ownership of this property will be assigned to the 'deployer'
 *   2. Deploy `ShareholderDAO` and transfer the property's (1) ownership to it
 *   3. Configure and deploy a `TokenSale`
 *     - After completing (1, 2, 3) blockimmo will verify the property as legitimate in `LandRegistry`
 *     - blockimmo will then authorize `this` to the `Whitelist` before seller can proceed to (4)
 *   4. Transfer tokens of `TokenizedProperty` (1) to be sold to `this` (3)
 *   5. Investors are able to buy tokens while the sale is open. 'Deployer' calls `finalize` to complete the sale
 *
 * Note: blockimmo will be responsible for managing initial sales on our platform. This means we will be configuring
 *       and deploying all contracts for sellers. This provides an extra layer of control/security until we've refined
 *       these processes and proven them in the real-world.
 *       Later sales will use SplitPayment contracts to route funds, with examples in the tests.
 *
 * Unsold tokens (of a successful sale) are redistributed proportionally to investors via Airdrop, as described in:
 * https://medium.com/FundFantasy/airdropping-vs-burning-part-1-613a9c6ebf1c
 *
 * If a sale's soft-cap is not reached, investors will be refunded Ether and the seller refunded tokens.
 *
 * For stable token sales (soft and hard-cap in USD instead of Wei), we rely on MakerDAO's on-chain ETH/USD conversion rate
 * https://developer.makerdao.com/feeds/
 * This approach to mitigating Ether volatility seems to best when analyzing trade-offs, short of selling directly in FIAT.
 */
contract TokenSale is RefundableCrowdsale, PostDeliveryCrowdsale {
  using SafeMath for uint256;
  using SafeERC20 for ERC20;

  address public constant MEDIANIZER_PROXY_ADDRESS = 0xe8f99AEa488aB288f4D787f7FD75b158A5685F8A; // 0xec8be1a5630364292e56d01129e8ee8a9578d7d8;
  address public constant WHITELIST_PROXY_ADDRESS = 0x7223b032180CDb06Be7a3D634B1E10032111F367;  // 0x85a84691547b7ccf19d7c31977a7f8c0af1fb25a;

  MedianizerProxyInterface private medianizerProxy = MedianizerProxyInterface(MEDIANIZER_PROXY_ADDRESS);
  WhitelistProxyInterface private whitelistProxy = WhitelistProxyInterface(WHITELIST_PROXY_ADDRESS);

  uint256 public constant MINIMUM_INVESTMENT_WEI = 1e18;
  uint256 public constant CAP_INVESTMENT_WEI = 1e24;

  address public beneficiary;
  uint256 public cap;
  uint256 public totalTokens;
  uint256 public totalTokensSold = 0;
  bool public usd;
  uint256 public usdPerEthOnFinalize;

  Payments public payments = new Payments();

  mapping(address => uint256) public usdInvestment;

  constructor(
    uint256 _openingTime,
    uint256 _closingTime,
    uint256 _rate,
    address _wallet,
    uint256 _cap,
    ERC20 _token,
    uint256 _goal,
    bool _usd  // if true, both `goal` and `cap` are in units of USD. if false, in ETH
  )
    public
    Crowdsale(_rate, address(payments), _token)
    TimedCrowdsale(_openingTime, _closingTime)
    RefundableCrowdsale(_goal)
    PostDeliveryCrowdsale()
  {
    require(_cap > 0, "cap is not > 0");
    require(_goal < _cap, "goal is not < cap");
    require(_wallet != address(0));
    beneficiary = _wallet;
    cap = _cap;
    usd = _usd;
  }

  function capReached() public view returns (bool) {
    return _reached(cap);
  }

  function goalReached() public view returns (bool) {
    return _reached(goal);
  }

  function hasClosed() public view returns (bool) {
    return _reached(cap.mul(99).div(100)) || super.hasClosed();
  }

  function reverse(address _account) public onlyOwner {
    require(!isFinalized);
    WhitelistInterface whitelist = whitelistProxy.whitelist();
    require(!whitelist.hasRole(_account, "authorized"));

    uint256 balance = balances[_account];
    balances[_account] = 0;
    totalTokensSold = totalTokensSold.sub(balance);
    usdInvestment[_account] = 0;
    weiRaised = weiRaised.sub(balance / rate);
    payments.addPayment(_account, balance / rate);
  }

  function withdrawTokens() public {  // airdrop remaining tokens to investors proportionally
    require(isFinalized && goalReached(), "withdrawTokens requires the TokenSale to be successfully finalized");
    uint256 extra = totalTokens.sub(totalTokensSold).mul(balances[msg.sender]) / totalTokensSold;
    balances[msg.sender] = balances[msg.sender].add(extra);
    super.withdrawTokens();
  }

  function finalization() internal {  // ether refunds enabled for investors, refund tokens to seller
    super.finalization();

    totalTokens = token.balanceOf(address(this));

    MedianizerInterface medianizer = medianizerProxy.medianizer();
    usdPerEthOnFinalize = uint256(medianizer.read());

    if (goalReached()) {
      payments.addPayment(beneficiary, weiRaised);
    } else {
      token.safeTransfer(owner, totalTokens);
    }
  }

  function _getUsdAmount(uint256 _weiAmount) internal view returns (uint256) {
    MedianizerInterface medianizer = medianizerProxy.medianizer();
    uint256 usdPerEth = isFinalized ? usdPerEthOnFinalize : uint256(medianizer.read());
    return _weiAmount.mul(usdPerEth).div(1e18).div(1e18);
  }

  function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal {
    require(_weiAmount >= MINIMUM_INVESTMENT_WEI && (balances[_beneficiary] / rate).add(_weiAmount) <= CAP_INVESTMENT_WEI, "_preValidatePurchase invalid _weiAmount");
    super._preValidatePurchase(_beneficiary, _weiAmount);

    WhitelistInterface whitelist = whitelistProxy.whitelist();
    usdInvestment[_beneficiary] = usdInvestment[_beneficiary].add(_getUsdAmount(_weiAmount));
    if (!whitelist.hasRole(_beneficiary, "uncapped")) {
      require(usdInvestment[_beneficiary] <= 100000);
      whitelist.checkRole(_beneficiary, "authorized");
    }

    if (usd) {
      require(_getUsdAmount(weiRaised.add(_weiAmount)) <= cap, "usd raised must not exceed cap");
    } else {
      require(weiRaised.add(_weiAmount) <= cap, "wei raised must not exceed cap");
    }
  }

  function _processPurchase(address _beneficiary, uint256 _tokenAmount) internal {
    totalTokensSold = totalTokensSold.add(_tokenAmount);
    require(totalTokensSold <= token.balanceOf(address(this)), "totalTokensSold raised must not exceed balanceOf `this`");

    super._processPurchase(_beneficiary, _tokenAmount);
  }

  function _reached(uint256 _target) internal view returns (bool) {
    if (usd) {
      return _getUsdAmount(weiRaised) >= _target;
    } else {
      return weiRaised >= _target;
    }
  }
}