contract Crowdsale is Haltable {

  using SafeMathLib for uint;

  /* The token we are selling */
  ERC20 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;

  /* The party who holds the full token pool and has approve()'ed tokens for this crowdsale */
  address public beneficiary;

  /* 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;

  /** 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;

  /** State machine
   *
   * - Prefunding: We have not started 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, PreFunding, Funding, Success, Failure, Finalized, Refunding}

  event Invested(address investor, uint weiAmount, uint tokenAmount);
  event Refund(address investor, uint weiAmount);

  function Crowdsale(address _token, address _pricingStrategy, address _multisigWallet, address _beneficiary, uint _start, uint _end, uint _minimumFundingGoal) {

    owner = msg.sender;

    token = ERC20(_token);

    pricingStrategy = PricingStrategy(_pricingStrategy);

    multisigWallet = _multisigWallet;
    if(multisigWallet == 0) {
        throw;
    }

    // TODO: remove beneficiary from the base class
    beneficiary = _beneficiary;
    if(beneficiary == 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.
   *
   *
   */
  function invest(address receiver) inState(State.Funding) stopInEmergency payable public {

    uint weiAmount = msg.value;
    uint tokenAmount = pricingStrategy.calculatePrice(weiAmount, weiRaised, tokensSold);

    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(tokenAmount, weiAmount, weiRaised, tokensSold)) {
      throw;
    }

    assignTokens(receiver, tokenAmount);

    // Pocket the money
    if(!multisigWallet.send(weiAmount)) throw;

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

  /**
   * 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.
   *
   * Anybody can call to trigger the end of the crowdsale.
   *
   * Call the contract that provides post-crowdsale actions, like releasing the tokens.
   */
  function finalize() public inState(State.Success) 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;
  }

  function setFinalizeAgent(FinalizeAgent addr) onlyOwner inState(State.PreFunding) {
    finalizeAgent = addr;

    // Don't allow setting bad agent
    if(!finalizeAgent.isFinalizeAgent()) {
      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;
  }

  /**
   * 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 (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;
  }

  //
  // 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 countafter 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;
}
/**
 * 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
 *
 */
function assignTokens(address receiver, uint tokenAmount) private;
/**
 * Create new tokens or transfer issued tokens to the investor depending on the cap model.
 */