contract SilentNotaryCrowdsale is Haltable, Killable, SafeMath {

 /// Period of the ICO stage
 uint constant public DURATION = 14 days;

 /// The duration of ICO
 uint public icoDuration = DURATION;

 //// The token we are selling
 SilentNotaryToken public token;

 /// Escrow wallet
 address public multisigWallet;

 /// Team wallet
 address public teamWallet;

 /// The UNIX timestamp start date of the crowdsale
 uint public startsAt;

 /// the number of tokens already sold through this contract
 uint public tokensSold = 0;

 ///  How many wei of funding we have raised
 uint public weiRaised = 0;

 ///  How many distinct addresses have invested
 uint public investorCount = 0;

 ///  How much wei we have returned back to the contract after a failed crowdfund.
 uint public loadedRefund = 0;

 ///  How much wei we have given back to investors.
 uint public weiRefunded = 0;

 ///  Has this crowdsale been finalized
 bool public finalized;

 ///  How much ETH each address has invested to this crowdsale
 mapping (address => uint256) public investedAmountOf;

 ///  How much tokens this crowdsale has credited for each investor address
 mapping (address => uint256) public tokenAmountOf;

 /// if the funding goal is not reached, investors may withdraw their funds
 uint public constant FUNDING_GOAL = 1000 ether;

 /// topup team wallet after that will topup both - team and multisig wallet by 32% and 68%
 uint constant MULTISIG_WALLET_GOAL = FUNDING_GOAL;

 /// Minimum order quantity 0.1 ether
 uint public constant MIN_INVESTEMENT = 100 finney;

 /// ICO start token price
 uint public constant MIN_PRICE = 10e9;

 /// Maximum token price, if reached ICO will stop
 uint public constant MAX_PRICE = 20e10;

 /// How much ICO tokens to sold
 uint public constant INVESTOR_TOKENS  = 10e11;

 /// Tokens count involved in price calculation
 uint public constant TOTAL_TOKENS_FOR_PRICE = INVESTOR_TOKENS;

 /// last token price
 uint public tokenPrice = MIN_PRICE;

  /// State machine
  /// Preparing: All contract initialization calls and variables have not been set yet
  /// Funding: Active crowdsale
  /// Success: Minimum funding goal reached
  /// Failure: Minimum funding goal not reached before ending time
  /// Finalized: The finalized has been called and succesfully executed
  /// Refunding: Refunds are loaded on the contract for reclaim
 enum State{Unknown, Preparing, Funding, Success, Failure, Finalized, Refunding}

 /// A new investment was made
 event Invested(address investor, uint weiAmount, uint tokenAmount);

 /// Refund was processed for a contributor
 event Refund(address investor, uint weiAmount);

 /// Crowdsale end time has been changed
 event EndsAtChanged(uint endsAt);

 /// New price was calculated
 event PriceChanged(uint oldValue, uint newValue);

 /// Modified allowing execution only if the crowdsale is currently runnin
 modifier inState(State state) {
   require(getState() == state);
   _;
 }

 /// @dev Constructor
 /// @param _token SNTR token address
 /// @param _multisigWallet  multisig wallet address
 /// @param _start  ICO start time
 function SilentNotaryCrowdsale(address _token, address _multisigWallet, address _teamWallet, uint _start) {
   require(_token != 0);
   require(_multisigWallet != 0);
   require(_teamWallet != 0);
   require(_start != 0);

   token = SilentNotaryToken(_token);
   multisigWallet = _multisigWallet;
   teamWallet = _teamWallet;
   startsAt = _start;
 }

 /// @dev Don't expect to just send in money and get tokens.
 function() payable {
   buy();
 }

  /// @dev Make an investment.
  /// @param receiver The Ethereum address who receives the tokens
 function investInternal(address receiver) stopInEmergency private {
   require(getState() == State.Funding);
   require(msg.value >= MIN_INVESTEMENT);

   uint weiAmount = msg.value;

   var multiplier = 10 ** token.decimals();
   uint tokenAmount = safeDiv(safeMul(weiAmount, multiplier), tokenPrice);
   assert(tokenAmount > 0);

   if(investedAmountOf[receiver] == 0) {
      // A new investor
      investorCount++;
   }
   // Update investor
   investedAmountOf[receiver] = safeAdd(investedAmountOf[receiver], weiAmount);
   tokenAmountOf[receiver] = safeAdd(tokenAmountOf[receiver], tokenAmount);
   // Update totals
   weiRaised = safeAdd(weiRaised, weiAmount);
   tokensSold = safeAdd(tokensSold, tokenAmount);

   var newPrice = calculatePrice(tokensSold);
   PriceChanged(tokenPrice, newPrice);
   tokenPrice = newPrice;

   assignTokens(receiver, tokenAmount);
   if(weiRaised <= MULTISIG_WALLET_GOAL)
     multisigWallet.transfer(weiAmount);
   else {
     int remain = int(weiAmount - weiRaised - MULTISIG_WALLET_GOAL);

     if(remain > 0) {
       multisigWallet.transfer(uint(remain));
       weiAmount = safeSub(weiAmount, uint(remain));
     }

     var distributedAmount = safeDiv(safeMul(weiAmount, 32), 100);
     teamWallet.transfer(distributedAmount);
     multisigWallet.transfer(safeSub(weiAmount, distributedAmount));

   }
   // Tell us invest was success
   Invested(receiver, weiAmount, tokenAmount);
 }

  /// @dev Allow anonymous contributions to this crowdsale.
  /// @param receiver The Ethereum address who receives the tokens
 function invest(address receiver) public payable {
   investInternal(receiver);
 }

  /// @dev Pay for funding, get invested tokens back in the sender address.
 function buy() public payable {
   invest(msg.sender);
 }

 /// @dev Finalize a succcesful crowdsale. The owner can triggre a call the contract that provides post-crowdsale actions, like releasing the tokens.
 function finalize() public inState(State.Success) onlyOwner stopInEmergency {
   // If not already finalized
   require(!finalized);

   finalized = true;
   finalizeCrowdsale();
 }

 /// @dev Finalize a succcesful crowdsale.
 function finalizeCrowdsale() internal {
   var multiplier = 10 ** token.decimals();
   uint investorTokens = safeMul(INVESTOR_TOKENS, multiplier);
   if(investorTokens > tokensSold)
     assignTokens(teamWallet, safeSub(investorTokens, tokensSold));
   token.releaseTokenTransfer();
 }

  /// @dev  Allow load refunds back on the contract for the refunding. The team can transfer the funds back on the smart contract in the case the minimum goal was not reached.
 function loadRefund() public payable inState(State.Failure) {
   if(msg.value == 0)
     revert();
   loadedRefund = safeAdd(loadedRefund, msg.value);
 }

 /// @dev  Investors can claim refund.
 function refund() public inState(State.Refunding) {
   uint256 weiValue = investedAmountOf[msg.sender];
   if (weiValue == 0)
     revert();
   investedAmountOf[msg.sender] = 0;
   weiRefunded = safeAdd(weiRefunded, weiValue);
   Refund(msg.sender, weiValue);
   if (!msg.sender.send(weiValue))
     revert();
 }

  /// @dev Crowdfund state machine management.
  /// @return State current state
 function getState() public constant returns (State) {
   if (finalized)
     return State.Finalized;
   if (address(token) == 0 || address(multisigWallet) == 0)
     return State.Preparing;
   if (now >= startsAt && now < startsAt + icoDuration && !isCrowdsaleFull())
     return State.Funding;
   if (isMinimumGoalReached())
       return State.Success;
   if (!isMinimumGoalReached() && weiRaised > 0 && loadedRefund >= weiRaised)
     return State.Refunding;
   return State.Failure;
 }

 /// @dev Prolongate ICO if owner decide it
 function prolongate() public onlyOwner {
   require(icoDuration < DURATION * 2);
   icoDuration += DURATION;
 }

 /// @dev Calculating price, it is not linear function
 /// @param totalRaisedTokens total raised tokens
 /// @return price in wei
 function calculatePrice(uint totalRaisedTokens) internal returns (uint price) {
   int multiplier = int(10**token.decimals());
   int coefficient = int(safeDiv(totalRaisedTokens, TOTAL_TOKENS_FOR_PRICE)) - multiplier;
   int priceDifference = coefficient * int(MAX_PRICE - MIN_PRICE) / multiplier;
   assert(int(MAX_PRICE) >= -priceDifference);
   return uint(priceDifference + int(MAX_PRICE));
 }

  /// @dev Minimum goal was reached
  /// @return true if the crowdsale has raised enough money to be a succes
  function isMinimumGoalReached() public constant returns (bool reached) {
    return weiRaised >= FUNDING_GOAL;
  }

  /// @dev Check crowdsale limit
  /// @return limit reached result
  function isCrowdsaleFull() public constant returns (bool) {
    return tokenPrice >= MAX_PRICE
      || tokensSold >= safeMul(TOTAL_TOKENS_FOR_PRICE,  10 ** token.decimals())
      || now > startsAt + icoDuration;
  }

   /// @dev Dynamically create tokens and assign them to the investor.
   /// @param receiver address
   /// @param tokenAmount tokens amount
  function assignTokens(address receiver, uint tokenAmount) private {
    token.mint(receiver, tokenAmount);
  }
}
/// @title SilentNotary  сrowdsale contract
function calculatePrice(uint totalRaisedTokens) internal returns (uint price) {
   int multiplier = int(10**token.decimals());
   int coefficient = int(safeDiv(totalRaisedTokens, TOTAL_TOKENS_FOR_PRICE)) - multiplier;
   int priceDifference = coefficient * int(MAX_PRICE - MIN_PRICE) / multiplier;
   assert(int(MAX_PRICE) >= -priceDifference);
   return uint(priceDifference + int(MAX_PRICE));
 }
/// @dev Calculating price, it is not linear function
/// @param totalRaisedTokens total raised tokens
/// @return price in wei