/**
 * Math operations with safety checks
 */
contract SafeMath {
  function safeMul(uint a, uint b) internal returns (uint) {
    uint c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function safeDiv(uint a, uint b) internal returns (uint) {
    assert(b > 0);
    uint c = a / b;
    assert(a == b * c + a % b);
    return c;
  }

  function safeSub(uint a, uint b) internal returns (uint) {
    assert(b <= a);
    return a - b;
  }

  function safeAdd(uint a, uint b) internal returns (uint) {
    uint c = a + b;
    assert(c>=a && c>=b);
    return c;
  }

  function max64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a >= b ? a : b;
  }

  function min64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a < b ? a : b;
  }

  function max256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a >= b ? a : b;
  }

  function min256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a < b ? a : b;
  }

  function assert(bool assertion) internal {
    if (!assertion) {
      throw;
    }
  }
}



/**
 * Safe unsigned safe math.
 *
 * https://blog.aragon.one/library-driven-development-in-solidity-2bebcaf88736#.750gwtwli
 *
 * Originally from https://raw.githubusercontent.com/AragonOne/zeppelin-solidity/master/contracts/SafeMathLib.sol
 *
 * Maintained here until merged to mainline zeppelin-solidity.
 *
 */
library SafeMathLib {

  function times(uint a, uint b) returns (uint) {
    uint c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function minus(uint a, uint b) returns (uint) {
    assert(b <= a);
    return a - b;
  }

  function plus(uint a, uint b) returns (uint) {
    uint c = a + b;
    assert(c>=a);
    return c;
  }

  function assert(bool assertion) private {
    if (!assertion) throw;
  }
}




/*
 * Ownable
 *
 * Base contract with an owner.
 * Provides onlyOwner modifier, which prevents function from running if it is called by anyone other than the owner.
 */
contract Ownable {
  address public owner;

  function Ownable() {
    owner = msg.sender;
  }

  modifier onlyOwner() {
    if (msg.sender != owner) {
      throw;
    }
    _;
  }

  function transferOwnership(address newOwner) onlyOwner {
    if (newOwner != address(0)) {
      owner = newOwner;
    }
  }

}


/*
 * Haltable
 *
 * Abstract contract that allows children to implement an
 * emergency stop mechanism. Differs from Pausable by causing a throw when in halt mode.
 *
 *
 * Originally envisioned in FirstBlood ICO contract.
 */
contract Haltable is Ownable {
  bool public halted;

  modifier stopInEmergency {
    if (halted) throw;
    _;
  }

  modifier onlyInEmergency {
    if (!halted) throw;
    _;
  }

  // called by the owner on emergency, triggers stopped state
  function halt() external onlyOwner {
    halted = true;
  }

  // called by the owner on end of emergency, returns to normal state
  function unhalt() external onlyOwner onlyInEmergency {
    halted = false;
  }

}


/**
 * Interface for defining crowdsale pricing.
 */
contract PricingStrategy {

  /** Interface declaration. */
  function isPricingStrategy() public constant returns (bool) {
    return true;
  }

  /** Self check if all references are correctly set.
   *
   * Checks that pricing strategy matches crowdsale parameters.
   */
  function isSane(address crowdsale) public constant returns (bool) {
    return true;
  }

  /**
   * When somebody tries to buy tokens for X eth, calculate how many tokens they get.
   *
   *
   * @param value - What is the value of the transaction send in as wei
   * @param tokensSold - how much tokens have been sold this far
   * @param weiRaised - how much money has been raised this far
   * @param msgSender - who is the investor of this transaction
   * @param decimals - how many decimal units the token has
   * @return Amount of tokens the investor receives
   */
  function calculatePrice(uint value, uint weiRaised, uint tokensSold, address msgSender, uint decimals) public constant returns (uint tokenAmount);
}


/**
 * Finalize agent defines what happens at the end of succeseful crowdsale.
 *
 * - Allocate tokens for founders, bounties and community
 * - Make tokens transferable
 * - etc.
 */
contract FinalizeAgent {

  function isFinalizeAgent() public constant returns(bool) {
    return true;
  }

  /** Return true if we can run finalizeCrowdsale() properly.
   *
   * This is a safety check function that doesn't allow crowdsale to begin
   * unless the finalizer has been set up properly.
   */
  function isSane() public constant returns (bool);

  /** Called once by crowdsale finalize() if the sale was success. */
  function finalizeCrowdsale();

}




/*
 * ERC20 interface
 * see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 {
  uint public totalSupply;
  function balanceOf(address who) constant returns (uint);
  function allowance(address owner, address spender) constant returns (uint);

  function transfer(address to, uint value) returns (bool ok);
  function transferFrom(address from, address to, uint value) returns (bool ok);
  function approve(address spender, uint value) returns (bool ok);
  event Transfer(address indexed from, address indexed to, uint value);
  event Approval(address indexed owner, address indexed spender, uint value);
}


/**
 * A token that defines fractional units as decimals.
 */
contract FractionalERC20 is ERC20 {

  uint public decimals;

}



/**
 * Abstract base contract for token sales.
 *
 * Handle
 * - start and end dates
 * - accepting investments
 * - minimum funding goal and refund
 * - various statistics during the crowdfund
 * - different pricing strategies
 * - different investment policies (require server side customer id, allow only whitelisted addresses)
 *
 */
contract Crowdsale is Haltable {

  using SafeMathLib for uint;

  /* The token we are selling */
  FractionalERC20 public token;

  /* How we are going to price our offering */
  PricingStrategy public pricingStrategy;

  /* Post-success callback */
  FinalizeAgent public finalizeAgent;

  /* tokens will be transfered from this address */
  address public multisigWallet;

  /* if the funding goal is not reached, investors may withdraw their funds */
  uint public minimumFundingGoal;

  /* the UNIX timestamp start date of the crowdsale */
  uint public startsAt;

  /* the UNIX timestamp end date of the crowdsale */
  uint public endsAt;

  /* 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;

  /* Do we need to have unique contributor id for each customer */
  bool public requireCustomerId;

  /**
    * Do we verify that contributor has been cleared on the server side (accredited investors only).
    * This method was first used in FirstBlood crowdsale to ensure all contributors have accepted terms on sale (on the web).
    */
  bool public requiredSignedAddress;

  /* Server side address that signed allowed contributors (Ethereum addresses) that can participate the crowdsale */
  address public signerAddress;

  /** 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;

  /** Addresses that are allowed to invest even before ICO offical opens. For testing, for ICO partners, etc. */
  mapping (address => bool) public earlyParticipantWhitelist;

  /** This is for manul testing for the interaction from owner wallet. You can set it to any value and inspect this in blockchain explorer to see that crowdsale interaction works. */
  uint public ownerTestValue;

  /** State machine
   *
   * - Preparing: All contract initialization calls and variables have not been set yet
   * - Prefunding: We have not passed start time 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, PreFunding, Funding, Success, Failure, Finalized, Refunding}

  // A new investment was made
  event Invested(address investor, uint weiAmount, uint tokenAmount, uint128 customerId);

  // Refund was processed for a contributor
  event Refund(address investor, uint weiAmount);

  // The rules were changed what kind of investments we accept
  event InvestmentPolicyChanged(bool requireCustomerId, bool requiredSignedAddress, address signerAddress);

  // Address early participation whitelist status changed
  event Whitelisted(address addr, bool status);

  // Crowdsale end time has been changed
  event EndsAtChanged(uint endsAt);

  function Crowdsale(address _token, PricingStrategy _pricingStrategy, address _multisigWallet, uint _start, uint _end, uint _minimumFundingGoal) {

    owner = msg.sender;

    token = FractionalERC20(_token);

    setPricingStrategy(_pricingStrategy);

    multisigWallet = _multisigWallet;
    if(multisigWallet == 0) {
        throw;
    }

    if(_start == 0) {
        throw;
    }

    startsAt = _start;

    if(_end == 0) {
        throw;
    }

    endsAt = _end;

    // Don't mess the dates
    if(startsAt >= endsAt) {
        throw;
    }

    // Minimum funding goal can be zero
    minimumFundingGoal = _minimumFundingGoal;
  }

  /**
   * Don't expect to just send in money and get tokens.
   */
  function() payable {
    throw;
  }

  /**
   * Make an investment.
   *
   * Crowdsale must be running for one to invest.
   * We must have not pressed the emergency brake.
   *
   * @param receiver The Ethereum address who receives the tokens
   * @param customerId (optional) UUID v4 to track the successful payments on the server side
   *
   */
  function investInternal(address receiver, uint128 customerId) stopInEmergency private {

    // Determine if it's a good time to accept investment from this participant
    if(getState() == State.PreFunding) {
      // Are we whitelisted for early deposit
      if(!earlyParticipantWhitelist[receiver]) {
        throw;
      }
    } else if(getState() == State.Funding) {
      // Retail participants can only come in when the crowdsale is running
      // pass
    } else {
      // Unwanted state
      throw;
    }

    uint weiAmount = msg.value;
    uint tokenAmount = pricingStrategy.calculatePrice(weiAmount, weiRaised, tokensSold, msg.sender, token.decimals());

    if(tokenAmount == 0) {
      // Dust transaction
      throw;
    }

    if(investedAmountOf[receiver] == 0) {
       // A new investor
       investorCount++;
    }

    // Update investor
    investedAmountOf[receiver] = investedAmountOf[receiver].plus(weiAmount);
    tokenAmountOf[receiver] = tokenAmountOf[receiver].plus(tokenAmount);

    // Update totals
    weiRaised = weiRaised.plus(weiAmount);
    tokensSold = tokensSold.plus(tokenAmount);

    // Check that we did not bust the cap
    if(isBreakingCap(weiAmount, tokenAmount, weiRaised, tokensSold)) {
      throw;
    }

    assignTokens(receiver, tokenAmount);

    // Pocket the money
    if(!multisigWallet.send(weiAmount)) throw;

    // Tell us invest was success
    Invested(receiver, weiAmount, tokenAmount, customerId);
  }

  /**
   * Preallocate tokens for the early investors.
   *
   * Preallocated tokens have been sold before the actual crowdsale opens.
   * This function mints the tokens and moves the crowdsale needle.
   *
   * Investor count is not handled; it is assumed this goes for multiple investors
   * and the token distribution happens outside the smart contract flow.
   *
   * No money is exchanged, as the crowdsale team already have received the payment.
   *
   * @param fullTokens tokens as full tokens - decimal places added internally
   * @param weiPrice Price of a single full token in wei
   *
   */
  function preallocate(address receiver, uint fullTokens, uint weiPrice) public onlyOwner {

    uint tokenAmount = fullTokens * 10**token.decimals();
    uint weiAmount = weiPrice * fullTokens; // This can be also 0, we give out tokens for free

    weiRaised = weiRaised.plus(weiAmount);
    tokensSold = tokensSold.plus(tokenAmount);

    investedAmountOf[receiver] = investedAmountOf[receiver].plus(weiAmount);
    tokenAmountOf[receiver] = tokenAmountOf[receiver].plus(tokenAmount);

    assignTokens(receiver, tokenAmount);

    // Tell us invest was success
    Invested(receiver, weiAmount, tokenAmount, 0);
  }

  /**
   * Allow anonymous contributions to this crowdsale.
   */
  function investWithSignedAddress(address addr, uint128 customerId, uint8 v, bytes32 r, bytes32 s) public payable {
     bytes32 hash = sha256(addr);
     if (ecrecover(hash, v, r, s) != signerAddress) throw;
     if(customerId == 0) throw;  // UUIDv4 sanity check
     investInternal(addr, customerId);
  }

  /**
   * Track who is the customer making the payment so we can send thank you email.
   */
  function investWithCustomerId(address addr, uint128 customerId) public payable {
    if(requiredSignedAddress) throw; // Crowdsale allows only server-side signed participants
    if(customerId == 0) throw;  // UUIDv4 sanity check
    investInternal(addr, customerId);
  }

  /**
   * Allow anonymous contributions to this crowdsale.
   */
  function invest(address addr) public payable {
    if(requireCustomerId) throw; // Crowdsale needs to track partipants for thank you email
    if(requiredSignedAddress) throw; // Crowdsale allows only server-side signed participants
    investInternal(addr, 0);
  }

  /**
   * Invest to tokens, recognize the payer and clear his address.
   *
   */
  function buyWithSignedAddress(uint128 customerId, uint8 v, bytes32 r, bytes32 s) public payable {
    investWithSignedAddress(msg.sender, customerId, v, r, s);
  }

  /**
   * Invest to tokens, recognize the payer.
   *
   */
  function buyWithCustomerId(uint128 customerId) public payable {
    investWithCustomerId(msg.sender, customerId);
  }

  /**
   * The basic entry point to participate the crowdsale process.
   *
   * Pay for funding, get invested tokens back in the sender address.
   */
  function buy() public payable {
    invest(msg.sender);
  }

  /**
   * 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 {

    // Already finalized
    if(finalized) {
      throw;
    }

    // Finalizing is optional. We only call it if we are given a finalizing agent.
    if(address(finalizeAgent) != 0) {
      finalizeAgent.finalizeCrowdsale();
    }

    finalized = true;
  }

  /**
   * Allow to (re)set finalize agent.
   *
   * Design choice: no state restrictions on setting this, so that we can fix fat finger mistakes.
   */
  function setFinalizeAgent(FinalizeAgent addr) onlyOwner {
    finalizeAgent = addr;

    // Don't allow setting bad agent
    if(!finalizeAgent.isFinalizeAgent()) {
      throw;
    }
  }

  /**
   * Set policy do we need to have server-side customer ids for the investments.
   *
   */
  function setRequireCustomerId(bool value) onlyOwner {
    requireCustomerId = value;
    InvestmentPolicyChanged(requireCustomerId, requiredSignedAddress, signerAddress);
  }

  /**
   * Set policy if all investors must be cleared on the server side first.
   *
   * This is e.g. for the accredited investor clearing.
   *
   */
  function setRequireSignedAddress(bool value, address _signerAddress) onlyOwner {
    requiredSignedAddress = value;
    signerAddress = _signerAddress;
    InvestmentPolicyChanged(requireCustomerId, requiredSignedAddress, signerAddress);
  }

  /**
   * Allow addresses to do early participation.
   *
   * TODO: Fix spelling error in the name
   */
  function setEarlyParicipantWhitelist(address addr, bool status) onlyOwner {
    earlyParticipantWhitelist[addr] = status;
    Whitelisted(addr, status);
  }

  /**
   * Allow crowdsale owner to close early or extend the crowdsale.
   *
   * This is useful e.g. for a manual soft cap implementation:
   * - after X amount is reached determine manual closing
   *
   * This may put the crowdsale to an invalid state,
   * but we trust owners know what they are doing.
   *
   */
  function setEndsAt(uint time) onlyOwner {

    if(now > time) {
      throw; // Don't change past
    }

    endsAt = time;
    EndsAtChanged(endsAt);
  }

  /**
   * Allow to (re)set pricing strategy.
   *
   * Design choice: no state restrictions on the set, so that we can fix fat finger mistakes.
   */
  function setPricingStrategy(PricingStrategy _pricingStrategy) onlyOwner {
    pricingStrategy = _pricingStrategy;

    // Don't allow setting bad agent
    if(!pricingStrategy.isPricingStrategy()) {
      throw;
    }
  }

  /**
   * 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) throw;
    loadedRefund = loadedRefund.plus(msg.value);
  }

  /**
   * Investors can claim refund.
   */
  function refund() public inState(State.Refunding) {
    uint256 weiValue = investedAmountOf[msg.sender];
    if (weiValue == 0) throw;
    investedAmountOf[msg.sender] = 0;
    weiRefunded = weiRefunded.plus(weiValue);
    Refund(msg.sender, weiValue);
    if (!msg.sender.send(weiValue)) throw;
  }

  /**
   * @return true if the crowdsale has raised enough money to be a succes
   */
  function isMinimumGoalReached() public constant returns (bool reached) {
    return weiRaised >= minimumFundingGoal;
  }

  /**
   * Check if the contract relationship looks good.
   */
  function isFinalizerSane() public constant returns (bool sane) {
    return finalizeAgent.isSane();
  }

  /**
   * Check if the contract relationship looks good.
   */
  function isPricingSane() public constant returns (bool sane) {
    return pricingStrategy.isSane(address(this));
  }

  /**
   * Crowdfund state machine management.
   *
   * We make it a function and do not assign the result to a variable, so there is no chance of the variable being stale.
   */
  function getState() public constant returns (State) {
    if(finalized) return State.Finalized;
    else if (address(finalizeAgent) == 0) return State.Preparing;
    else if (!finalizeAgent.isSane()) return State.Preparing;
    else if (!pricingStrategy.isSane(address(this))) return State.Preparing;
    else if (block.timestamp < startsAt) return State.PreFunding;
    else if (block.timestamp <= endsAt && !isCrowdsaleFull()) return State.Funding;
    else if (isMinimumGoalReached()) return State.Success;
    else if (!isMinimumGoalReached() && weiRaised > 0 && loadedRefund >= weiRaised) return State.Refunding;
    else return State.Failure;
  }

  /** This is for manual testing of multisig wallet interaction */
  function setOwnerTestValue(uint val) onlyOwner {
    ownerTestValue = val;
  }

  /** Interface marker. */
  function isCrowdsale() public constant returns (bool) {
    return true;
  }

  //
  // Modifiers
  //

  /** Modified allowing execution only if the crowdsale is currently running.  */
  modifier inState(State state) {
    if(getState() != state) throw;
    _;
  }


  //
  // Abstract functions
  //

  /**
   * Check if the current invested breaks our cap rules.
   *
   *
   * The child contract must define their own cap setting rules.
   * We allow a lot of flexibility through different capping strategies (ETH, token count)
   * Called from invest().
   *
   * @param weiAmount The amount of wei the investor tries to invest in the current transaction
   * @param tokenAmount The amount of tokens we try to give to the investor in the current transaction
   * @param weiRaisedTotal What would be our total raised balance after this transaction
   * @param tokensSoldTotal What would be our total sold tokens count after this transaction
   *
   * @return true if taking this investment would break our cap rules
   */
  function isBreakingCap(uint weiAmount, uint tokenAmount, uint weiRaisedTotal, uint tokensSoldTotal) constant returns (bool limitBroken);

  /**
   * Check if the current crowdsale is full and we can no longer sell any tokens.
   */
  function isCrowdsaleFull() public constant returns (bool);

  /**
   * Create new tokens or transfer issued tokens to the investor depending on the cap model.
   */
  function assignTokens(address receiver, uint tokenAmount) private;
}







/**
 * Standard ERC20 token with Short Hand Attack and approve() race condition mitigation.
 *
 * Based on code by FirstBlood:
 * https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is ERC20, SafeMath {

  /* Token supply got increased and a new owner received these tokens */
  event Minted(address receiver, uint amount);

  /* Actual balances of token holders */
  mapping(address => uint) balances;

  /* approve() allowances */
  mapping (address => mapping (address => uint)) allowed;

  /**
   *
   * Fix for the ERC20 short address attack
   *
   * http://vessenes.com/the-erc20-short-address-attack-explained/
   */
  modifier onlyPayloadSize(uint size) {
     if(msg.data.length != size + 4) {
       throw;
     }
     _;
  }

  function transfer(address _to, uint _value) onlyPayloadSize(2 * 32) returns (bool success) {
    balances[msg.sender] = safeSub(balances[msg.sender], _value);
    balances[_to] = safeAdd(balances[_to], _value);
    Transfer(msg.sender, _to, _value);
    return true;
  }

  function transferFrom(address _from, address _to, uint _value) returns (bool success) {
    uint _allowance = allowed[_from][msg.sender];

    // Check is not needed because safeSub(_allowance, _value) will already throw if this condition is not met
    // if (_value > _allowance) throw;

    balances[_to] = safeAdd(balances[_to], _value);
    balances[_from] = safeSub(balances[_from], _value);
    allowed[_from][msg.sender] = safeSub(_allowance, _value);
    Transfer(_from, _to, _value);
    return true;
  }

  function balanceOf(address _owner) constant returns (uint balance) {
    return balances[_owner];
  }

  function approve(address _spender, uint _value) returns (bool success) {

    // To change the approve amount you first have to reduce the addresses`
    //  allowance to zero by calling `approve(_spender, 0)` if it is not
    //  already 0 to mitigate the race condition described here:
    //  https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
    if ((_value != 0) && (allowed[msg.sender][_spender] != 0)) throw;

    allowed[msg.sender][_spender] = _value;
    Approval(msg.sender, _spender, _value);
    return true;
  }

  function allowance(address _owner, address _spender) constant returns (uint remaining) {
    return allowed[_owner][_spender];
  }

  /**
   * Atomic increment of approved spending
   *
   * Works around https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
   *
   */
  function addApproval(address _spender, uint _addedValue)
  onlyPayloadSize(2 * 32)
  returns (bool success) {
      uint oldValue = allowed[msg.sender][_spender];
      allowed[msg.sender][_spender] = safeAdd(oldValue, _addedValue);
      Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
      return true;
  }

  /**
   * Atomic decrement of approved spending.
   *
   * Works around https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
   */
  function subApproval(address _spender, uint _subtractedValue)
  onlyPayloadSize(2 * 32)
  returns (bool success) {

      uint oldVal = allowed[msg.sender][_spender];

      if (_subtractedValue > oldVal) {
          allowed[msg.sender][_spender] = 0;
      } else {
          allowed[msg.sender][_spender] = safeSub(oldVal, _subtractedValue);
      }
      Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
      return true;
  }

}



/**
 * Collect funds from presale investors, buy tokens for them in a single transaction and distribute out tokens.
 *
 * - Collect funds from pre-sale investors
 * - Send funds to the crowdsale when it opens
 * - Allow owner to set the crowdsale
 * - Have refund after X days as a safety hatch if the crowdsale doesn't materilize
 * - Allow unlimited investors
 * - Tokens are distributed on PreICOProxyBuyer smart contract first
 * - The original investors can claim their tokens from the smart contract after the token transfer has been released
 * - All functions can be halted by owner if something goes wrong
 *
 */
contract PreICOProxyBuyer is Ownable, Haltable, SafeMath {

  /** How many investors we have now */
  uint public investorCount;

  /** How many wei we have raised totla. */
  uint public weiRaisedTotal;

  /** Who are our investors (iterable) */
  address[] public investors;

  /** How much they have invested */
  mapping(address => uint) public balances;

  /** How many tokens investors have claimed */
  mapping(address => uint) public claimed;

  /** When our refund freeze is over (UNIT timestamp) */
  uint public freezeEndsAt;

  /** What is the minimum buy in */
  uint public weiMinimumLimit;

  /** How many weis total we are allowed to collect. */
  uint public weiCap;

  /** How many tokens were bought */
  uint public tokensBought;

   /** How many investors have claimed their tokens */
  uint public claimCount;

  uint public totalClaimed;

  /** Our ICO contract where we will move the funds */
  Crowdsale public crowdsale;

  /** What is our current state. */
  enum State{Unknown, Funding, Distributing, Refunding}

  /** Somebody loaded their investment money */
  event Invested(address investor, uint value);

  /** Refund claimed */
  event Refunded(address investor, uint value);

  /** We executed our buy */
  event TokensBoughts(uint count);

  /** We distributed tokens to an investor */
  event Distributed(address investors, uint count);

  /**
   * Create presale contract where lock up period is given days
   */
  function PreICOProxyBuyer(address _owner, uint _freezeEndsAt, uint _weiMinimumLimit, uint _weiCap) {

    owner = _owner;

    // Give argument
    if(_freezeEndsAt == 0) {
      throw;
    }

    // Give argument
    if(_weiMinimumLimit == 0) {
      throw;
    }

    weiMinimumLimit = _weiMinimumLimit;
    weiCap = _weiCap;
    freezeEndsAt = _freezeEndsAt;
  }

  /**
   * Get the token we are distributing.
   */
  function getToken() public constant returns(FractionalERC20) {
    if(address(crowdsale) == 0)  {
      throw;
    }

    return crowdsale.token();
  }

  /**
   * Participate to a presale.
   */
  function invest() public stopInEmergency payable {

    // Cannot invest anymore through crowdsale when moving has begun
    if(getState() != State.Funding) throw;

    if(msg.value == 0) throw; // No empty buys

    address investor = msg.sender;

    bool existing = balances[investor] > 0;

    balances[investor] = safeAdd(balances[investor], msg.value);

    // Need to fulfill minimum limit
    if(balances[investor] < weiMinimumLimit) {
      throw;
    }

    // This is a new investor
    if(!existing) {
      investors.push(investor);
      investorCount++;
    }

    weiRaisedTotal = safeAdd(weiRaisedTotal, msg.value);
    if(weiRaisedTotal > weiCap) {
      throw;
    }

    Invested(investor, msg.value);
  }

  /**
   * Load funds to the crowdsale for all investors.
   *
   *
   */
  function buyForEverybody() stopInEmergency public {

    if(getState() != State.Funding) {
      // Only allow buy once
      throw;
    }

    // Crowdsale not yet set
    if(address(crowdsale) == 0) throw;

    // Buy tokens on the contract
    crowdsale.invest.value(weiRaisedTotal)(address(this));

    // Record how many tokens we got
    tokensBought = getToken().balanceOf(address(this));

    if(tokensBought == 0) {
      // Did not get any tokens
      throw;
    }

    TokensBoughts(tokensBought);
  }

  /**
   * How may tokens each investor gets.
   */
  function getClaimAmount(address investor) public constant returns (uint) {

    // Claims can be only made if we manage to buy tokens
    if(getState() != State.Distributing) {
      throw;
    }
    return safeMul(balances[investor], tokensBought) / weiRaisedTotal;
  }

  /**
   * How many tokens remain unclaimed for an investor.
   */
  function getClaimLeft(address investor) public constant returns (uint) {
    return safeSub(getClaimAmount(investor), claimed[investor]);
  }

  /**
   * Claim all remaining tokens for this investor.
   */
  function claimAll() {
    claim(getClaimLeft(msg.sender));
  }

  /**
   * Claim N bought tokens to the investor as the msg sender.
   *
   */
  function claim(uint amount) stopInEmergency {
    address investor = msg.sender;

    if(amount == 0) {
      throw;
    }

    if(getClaimLeft(investor) < amount) {
      // Woops we cannot get more than we have left
      throw;
    }

    // We track who many investor have (partially) claimed their tokens
    if(claimed[investor] == 0) {
      claimCount++;
    }

    claimed[investor] = safeAdd(claimed[investor], amount);
    totalClaimed = safeAdd(totalClaimed, amount);
    getToken().transfer(investor, amount);

    Distributed(investor, amount);
  }

  /**
   * ICO never happened. Allow refund.
   */
  function refund() stopInEmergency {

    // Trying to ask refund too soon
    if(getState() != State.Refunding) throw;

    address investor = msg.sender;
    if(balances[investor] == 0) throw;
    uint amount = balances[investor];
    delete balances[investor];
    if(!investor.send(amount)) throw;
    Refunded(investor, amount);
  }

  /**
   * Set the target crowdsale where we will move presale funds when the crowdsale opens.
   */
  function setCrowdsale(Crowdsale _crowdsale) public onlyOwner {
    crowdsale = _crowdsale;

    // Check interface
    if(!crowdsale.isCrowdsale()) true;
  }

  /**
   * Resolve the contract umambigious state.
   */
  function getState() public returns(State) {
    if(tokensBought == 0) {
      if(now >= freezeEndsAt) {
         return State.Refunding;
      } else {
        return State.Funding;
      }
    } else {
      return State.Distributing;
    }
  }

  /** Explicitly call function from your wallet. */
  function() payable {
    throw;
  }
}