pragma solidity ^0.4.15;

/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
  function mul(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function div(uint256 a, uint256 b) internal constant 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 c;
  }

  function sub(uint256 a, uint256 b) internal constant returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}


contract ERC20 {
  /// @notice Send `_amount` tokens to `_to` from `msg.sender`
  /// @param _to The address of the recipient
  /// @param _amount The amount of tokens to be transferred
  /// @return Whether the transfer was successful or not
  function transfer(address _to, uint256 _amount) returns (bool success);

  /// @notice Send `_amount` tokens to `_to` from `_from` on the condition it
  ///  is approved by `_from`
  /// @param _from The address holding the tokens being transferred
  /// @param _to The address of the recipient
  /// @param _amount The amount of tokens to be transferred
  /// @return True if the transfer was successful
  function transferFrom(address _from, address _to, uint256 _amount
  ) returns (bool success);

  /// @param _owner The address that's balance is being requested
  /// @return The balance of `_owner` at the current block
  function balanceOf(address _owner) constant returns (uint256 balance);

  /// @notice `msg.sender` approves `_spender` to spend `_amount` tokens on
  ///  its behalf. This is a modified version of the ERC20 approve function
  ///  to be a little bit safer
  /// @param _spender The address of the account able to transfer the tokens
  /// @param _amount The amount of tokens to be approved for transfer
  /// @return True if the approval was successful
  function approve(address _spender, uint256 _amount) returns (bool success);

  /// @dev This function makes it easy to read the `allowed[]` map
  /// @param _owner The address of the account that owns the token
  /// @param _spender The address of the account able to transfer the tokens
  /// @return Amount of remaining tokens of _owner that _spender is allowed
  ///  to spend
  function allowance(address _owner, address _spender
  ) constant returns (uint256 remaining);

  /// @notice `msg.sender` approves `_spender` to send `_amount` tokens on
  ///  its behalf, and then a function is triggered in the contract that is
  ///  being approved, `_spender`. This allows users to use their tokens to
  ///  interact with contracts in one function call instead of two
  /// @param _spender The address of the contract able to transfer the tokens
  /// @param _amount The amount of tokens to be approved for transfer
  /// @return True if the function call was successful
  function approveAndCall(address _spender, uint256 _amount, bytes _extraData
  ) returns (bool success);

  /// @dev This function makes it easy to get the total number of tokens
  /// @return The total number of tokens
  function totalSupply() constant returns (uint);
}


/*
    Copyright 2016, Jordi Baylina

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/// @title MiniMeToken Contract
/// @author Jordi Baylina
/// @dev This token contract's goal is to make it easy for anyone to clone this
///  token using the token distribution at a given block, this will allow DAO's
///  and DApps to upgrade their features in a decentralized manner without
///  affecting the original token
/// @dev It is ERC20 compliant, but still needs to under go further testing.


/// @dev The token controller contract must implement these functions
contract TokenController {
    /// @notice Called when `_owner` sends ether to the MiniMe Token contract
    /// @param _owner The address that sent the ether to create tokens
    /// @return True if the ether is accepted, false if it throws
    function proxyPayment(address _owner) payable returns(bool);

    /// @notice Notifies the controller about a token transfer allowing the
    ///  controller to react if desired
    /// @param _from The origin of the transfer
    /// @param _to The destination of the transfer
    /// @param _amount The amount of the transfer
    /// @return False if the controller does not authorize the transfer
    function onTransfer(address _from, address _to, uint _amount) returns(bool);

    /// @notice Notifies the controller about an approval allowing the
    ///  controller to react if desired
    /// @param _owner The address that calls `approve()`
    /// @param _spender The spender in the `approve()` call
    /// @param _amount The amount in the `approve()` call
    /// @return False if the controller does not authorize the approval
    function onApprove(address _owner, address _spender, uint _amount)
        returns(bool);
}

contract Controlled {
    /// @notice The address of the controller is the only address that can call
    ///  a function with this modifier
    modifier onlyController { require(msg.sender == controller); _; }

    address public controller;

    function Controlled() { controller = msg.sender;}

    /// @notice Changes the controller of the contract
    /// @param _newController The new controller of the contract
    function changeController(address _newController) onlyController {
        controller = _newController;
    }
}

contract ApproveAndCallFallBack {
    function receiveApproval(address from, uint256 _amount, address _token, bytes _data);
}

/// @dev The actual token contract, the default controller is the msg.sender
///  that deploys the contract, so usually this token will be deployed by a
///  token controller contract, which Giveth will call a "Campaign"
contract MiniMeToken is Controlled {

    string public name;                //The Token's name: e.g. DigixDAO Tokens
    uint8 public decimals;             //Number of decimals of the smallest unit
    string public symbol;              //An identifier: e.g. REP
    string public version = 'MMT_0.1'; //An arbitrary versioning scheme


    /// @dev `Checkpoint` is the structure that attaches a block number to a
    ///  given value, the block number attached is the one that last changed the
    ///  value
    struct  Checkpoint {

        // `fromBlock` is the block number that the value was generated from
        uint128 fromBlock;

        // `value` is the amount of tokens at a specific block number
        uint128 value;
    }

    // `parentToken` is the Token address that was cloned to produce this token;
    //  it will be 0x0 for a token that was not cloned
    MiniMeToken public parentToken;

    // `parentSnapShotBlock` is the block number from the Parent Token that was
    //  used to determine the initial distribution of the Clone Token
    uint public parentSnapShotBlock;

    // `creationBlock` is the block number that the Clone Token was created
    uint public creationBlock;

    // `balances` is the map that tracks the balance of each address, in this
    //  contract when the balance changes the block number that the change
    //  occurred is also included in the map
    mapping (address => Checkpoint[]) balances;

    // `allowed` tracks any extra transfer rights as in all ERC20 tokens
    mapping (address => mapping (address => uint256)) allowed;

    // Tracks the history of the `totalSupply` of the token
    Checkpoint[] totalSupplyHistory;

    // Flag that determines if the token is transferable or not.
    bool public transfersEnabled;

    // The factory used to create new clone tokens
    MiniMeTokenFactory public tokenFactory;

////////////////
// Constructor
////////////////

    /// @notice Constructor to create a MiniMeToken
    /// @param _tokenFactory The address of the MiniMeTokenFactory contract that
    ///  will create the Clone token contracts, the token factory needs to be
    ///  deployed first
    /// @param _parentToken Address of the parent token, set to 0x0 if it is a
    ///  new token
    /// @param _parentSnapShotBlock Block of the parent token that will
    ///  determine the initial distribution of the clone token, set to 0 if it
    ///  is a new token
    /// @param _tokenName Name of the new token
    /// @param _decimalUnits Number of decimals of the new token
    /// @param _tokenSymbol Token Symbol for the new token
    /// @param _transfersEnabled If true, tokens will be able to be transferred
    function MiniMeToken(
        address _tokenFactory,
        address _parentToken,
        uint _parentSnapShotBlock,
        string _tokenName,
        uint8 _decimalUnits,
        string _tokenSymbol,
        bool _transfersEnabled
    ) {
        tokenFactory = MiniMeTokenFactory(_tokenFactory);
        name = _tokenName;                                 // Set the name
        decimals = _decimalUnits;                          // Set the decimals
        symbol = _tokenSymbol;                             // Set the symbol
        parentToken = MiniMeToken(_parentToken);
        parentSnapShotBlock = _parentSnapShotBlock;
        transfersEnabled = _transfersEnabled;
        creationBlock = block.number;
    }


///////////////////
// ERC20 Methods
///////////////////

    /// @notice Send `_amount` tokens to `_to` from `msg.sender`
    /// @param _to The address of the recipient
    /// @param _amount The amount of tokens to be transferred
    /// @return Whether the transfer was successful or not
    function transfer(address _to, uint256 _amount) returns (bool success) {
        require(transfersEnabled);
        return doTransfer(msg.sender, _to, _amount);
    }

    /// @notice Send `_amount` tokens to `_to` from `_from` on the condition it
    ///  is approved by `_from`
    /// @param _from The address holding the tokens being transferred
    /// @param _to The address of the recipient
    /// @param _amount The amount of tokens to be transferred
    /// @return True if the transfer was successful
    function transferFrom(address _from, address _to, uint256 _amount
    ) returns (bool success) {

        // The controller of this contract can move tokens around at will,
        //  this is important to recognize! Confirm that you trust the
        //  controller of this contract, which in most situations should be
        //  another open source smart contract or 0x0
        if (msg.sender != controller) {
            require(transfersEnabled);

            // The standard ERC 20 transferFrom functionality
            if (allowed[_from][msg.sender] < _amount) return false;
            allowed[_from][msg.sender] -= _amount;
        }
        return doTransfer(_from, _to, _amount);
    }

    /// @dev This is the actual transfer function in the token contract, it can
    ///  only be called by other functions in this contract.
    /// @param _from The address holding the tokens being transferred
    /// @param _to The address of the recipient
    /// @param _amount The amount of tokens to be transferred
    /// @return True if the transfer was successful
    function doTransfer(address _from, address _to, uint _amount
    ) internal returns(bool) {

           if (_amount == 0) {
               return true;
           }

           require(parentSnapShotBlock < block.number);

           // Do not allow transfer to 0x0 or the token contract itself
           require((_to != 0) && (_to != address(this)));

           // If the amount being transfered is more than the balance of the
           //  account the transfer returns false
           var previousBalanceFrom = balanceOfAt(_from, block.number);
           if (previousBalanceFrom < _amount) {
               return false;
           }

           // Alerts the token controller of the transfer
           if (isContract(controller)) {
               require(TokenController(controller).onTransfer(_from, _to, _amount));
           }

           // First update the balance array with the new value for the address
           //  sending the tokens
           updateValueAtNow(balances[_from], previousBalanceFrom - _amount);

           // Then update the balance array with the new value for the address
           //  receiving the tokens
           var previousBalanceTo = balanceOfAt(_to, block.number);
           require(previousBalanceTo + _amount >= previousBalanceTo); // Check for overflow
           updateValueAtNow(balances[_to], previousBalanceTo + _amount);

           // An event to make the transfer easy to find on the blockchain
           Transfer(_from, _to, _amount);

           return true;
    }

    /// @param _owner The address that's balance is being requested
    /// @return The balance of `_owner` at the current block
    function balanceOf(address _owner) constant returns (uint256 balance) {
        return balanceOfAt(_owner, block.number);
    }

    /// @notice `msg.sender` approves `_spender` to spend `_amount` tokens on
    ///  its behalf. This is a modified version of the ERC20 approve function
    ///  to be a little bit safer
    /// @param _spender The address of the account able to transfer the tokens
    /// @param _amount The amount of tokens to be approved for transfer
    /// @return True if the approval was successful
    function approve(address _spender, uint256 _amount) returns (bool success) {
        require(transfersEnabled);

        // 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
        // Recommended by Bokky Poobah to remove this check
        // require((_amount == 0) || (allowed[msg.sender][_spender] == 0));

        // Alerts the token controller of the approve function call
        if (isContract(controller)) {
            require(TokenController(controller).onApprove(msg.sender, _spender, _amount));
        }

        allowed[msg.sender][_spender] = _amount;
        Approval(msg.sender, _spender, _amount);
        return true;
    }

    /// @dev This function makes it easy to read the `allowed[]` map
    /// @param _owner The address of the account that owns the token
    /// @param _spender The address of the account able to transfer the tokens
    /// @return Amount of remaining tokens of _owner that _spender is allowed
    ///  to spend
    function allowance(address _owner, address _spender
    ) constant returns (uint256 remaining) {
        return allowed[_owner][_spender];
    }

    /// @notice `msg.sender` approves `_spender` to send `_amount` tokens on
    ///  its behalf, and then a function is triggered in the contract that is
    ///  being approved, `_spender`. This allows users to use their tokens to
    ///  interact with contracts in one function call instead of two
    /// @param _spender The address of the contract able to transfer the tokens
    /// @param _amount The amount of tokens to be approved for transfer
    /// @return True if the function call was successful
    function approveAndCall(address _spender, uint256 _amount, bytes _extraData
    ) returns (bool success) {
        require(approve(_spender, _amount));

        ApproveAndCallFallBack(_spender).receiveApproval(
            msg.sender,
            _amount,
            this,
            _extraData
        );

        return true;
    }

    /// @dev This function makes it easy to get the total number of tokens
    /// @return The total number of tokens
    function totalSupply() constant returns (uint) {
        return totalSupplyAt(block.number);
    }


////////////////
// Query balance and totalSupply in History
////////////////

    /// @dev Queries the balance of `_owner` at a specific `_blockNumber`
    /// @param _owner The address from which the balance will be retrieved
    /// @param _blockNumber The block number when the balance is queried
    /// @return The balance at `_blockNumber`
    function balanceOfAt(address _owner, uint _blockNumber) constant
        returns (uint) {

        // These next few lines are used when the balance of the token is
        //  requested before a check point was ever created for this token, it
        //  requires that the `parentToken.balanceOfAt` be queried at the
        //  genesis block for that token as this contains initial balance of
        //  this token
        if ((balances[_owner].length == 0)
            || (balances[_owner][0].fromBlock > _blockNumber)) {
            if (address(parentToken) != 0) {
                return parentToken.balanceOfAt(_owner, min(_blockNumber, parentSnapShotBlock));
            } else {
                // Has no parent
                return 0;
            }

        // This will return the expected balance during normal situations
        } else {
            return getValueAt(balances[_owner], _blockNumber);
        }
    }

    /// @notice Total amount of tokens at a specific `_blockNumber`.
    /// @param _blockNumber The block number when the totalSupply is queried
    /// @return The total amount of tokens at `_blockNumber`
    function totalSupplyAt(uint _blockNumber) constant returns(uint) {

        // These next few lines are used when the totalSupply of the token is
        //  requested before a check point was ever created for this token, it
        //  requires that the `parentToken.totalSupplyAt` be queried at the
        //  genesis block for this token as that contains totalSupply of this
        //  token at this block number.
        if ((totalSupplyHistory.length == 0)
            || (totalSupplyHistory[0].fromBlock > _blockNumber)) {
            if (address(parentToken) != 0) {
                return parentToken.totalSupplyAt(min(_blockNumber, parentSnapShotBlock));
            } else {
                return 0;
            }

        // This will return the expected totalSupply during normal situations
        } else {
            return getValueAt(totalSupplyHistory, _blockNumber);
        }
    }

////////////////
// Clone Token Method
////////////////

    /// @notice Creates a new clone token with the initial distribution being
    ///  this token at `_snapshotBlock`
    /// @param _cloneTokenName Name of the clone token
    /// @param _cloneDecimalUnits Number of decimals of the smallest unit
    /// @param _cloneTokenSymbol Symbol of the clone token
    /// @param _snapshotBlock Block when the distribution of the parent token is
    ///  copied to set the initial distribution of the new clone token;
    ///  if the block is zero than the actual block, the current block is used
    /// @param _transfersEnabled True if transfers are allowed in the clone
    /// @return The address of the new MiniMeToken Contract
    function createCloneToken(
        string _cloneTokenName,
        uint8 _cloneDecimalUnits,
        string _cloneTokenSymbol,
        uint _snapshotBlock,
        bool _transfersEnabled
        ) returns(address) {
        if (_snapshotBlock == 0) _snapshotBlock = block.number;
        MiniMeToken cloneToken = tokenFactory.createCloneToken(
            this,
            _snapshotBlock,
            _cloneTokenName,
            _cloneDecimalUnits,
            _cloneTokenSymbol,
            _transfersEnabled
            );

        cloneToken.changeController(msg.sender);

        // An event to make the token easy to find on the blockchain
        NewCloneToken(address(cloneToken), _snapshotBlock);
        return address(cloneToken);
    }

////////////////
// Generate and destroy tokens
////////////////

    /// @notice Generates `_amount` tokens that are assigned to `_owner`
    /// @param _owner The address that will be assigned the new tokens
    /// @param _amount The quantity of tokens generated
    /// @return True if the tokens are generated correctly
    function generateTokens(address _owner, uint _amount
    ) onlyController returns (bool) {
        uint curTotalSupply = totalSupply();
        require(curTotalSupply + _amount >= curTotalSupply); // Check for overflow
        uint previousBalanceTo = balanceOf(_owner);
        require(previousBalanceTo + _amount >= previousBalanceTo); // Check for overflow
        updateValueAtNow(totalSupplyHistory, curTotalSupply + _amount);
        updateValueAtNow(balances[_owner], previousBalanceTo + _amount);
        Transfer(0, _owner, _amount);
        return true;
    }


    /// @notice Burns `_amount` tokens from `_owner`
    /// @param _owner The address that will lose the tokens
    /// @param _amount The quantity of tokens to burn
    /// @return True if the tokens are burned correctly
    function destroyTokens(address _owner, uint _amount
    ) onlyController returns (bool) {
        uint curTotalSupply = totalSupply();
        require(curTotalSupply >= _amount);
        uint previousBalanceFrom = balanceOf(_owner);
        require(previousBalanceFrom >= _amount);
        updateValueAtNow(totalSupplyHistory, curTotalSupply - _amount);
        updateValueAtNow(balances[_owner], previousBalanceFrom - _amount);
        Transfer(_owner, 0, _amount);
        return true;
    }

////////////////
// Enable tokens transfers
////////////////


    /// @notice Enables token holders to transfer their tokens freely if true
    /// @param _transfersEnabled True if transfers are allowed in the clone
    function enableTransfers(bool _transfersEnabled) onlyController {
        transfersEnabled = _transfersEnabled;
    }

////////////////
// Internal helper functions to query and set a value in a snapshot array
////////////////

    /// @dev `getValueAt` retrieves the number of tokens at a given block number
    /// @param checkpoints The history of values being queried
    /// @param _block The block number to retrieve the value at
    /// @return The number of tokens being queried
    function getValueAt(Checkpoint[] storage checkpoints, uint _block
    ) constant internal returns (uint) {
        if (checkpoints.length == 0) return 0;

        // Shortcut for the actual value
        if (_block >= checkpoints[checkpoints.length-1].fromBlock)
            return checkpoints[checkpoints.length-1].value;
        if (_block < checkpoints[0].fromBlock) return 0;

        // Binary search of the value in the array
        uint min = 0;
        uint max = checkpoints.length-1;
        while (max > min) {
            uint mid = (max + min + 1)/ 2;
            if (checkpoints[mid].fromBlock<=_block) {
                min = mid;
            } else {
                max = mid-1;
            }
        }
        return checkpoints[min].value;
    }

    /// @dev `updateValueAtNow` used to update the `balances` map and the
    ///  `totalSupplyHistory`
    /// @param checkpoints The history of data being updated
    /// @param _value The new number of tokens
    function updateValueAtNow(Checkpoint[] storage checkpoints, uint _value
    ) internal  {
        if ((checkpoints.length == 0)
        || (checkpoints[checkpoints.length -1].fromBlock < block.number)) {
               Checkpoint storage newCheckPoint = checkpoints[ checkpoints.length++ ];
               newCheckPoint.fromBlock =  uint128(block.number);
               newCheckPoint.value = uint128(_value);
           } else {
               Checkpoint storage oldCheckPoint = checkpoints[checkpoints.length-1];
               oldCheckPoint.value = uint128(_value);
           }
    }

    /// @dev Internal function to determine if an address is a contract
    /// @param _addr The address being queried
    /// @return True if `_addr` is a contract
    function isContract(address _addr) constant internal returns(bool) {
        uint size;
        if (_addr == 0) return false;
        assembly {
            size := extcodesize(_addr)
        }
        return size>0;
    }

    /// @dev Helper function to return a min betwen the two uints
    function min(uint a, uint b) internal returns (uint) {
        return a < b ? a : b;
    }

    /// @notice The fallback function: If the contract's controller has not been
    ///  set to 0, then the `proxyPayment` method is called which relays the
    ///  ether and creates tokens as described in the token controller contract
    function ()  payable {
        require(isContract(controller));
        require(TokenController(controller).proxyPayment.value(msg.value)(msg.sender));
    }

//////////
// Safety Methods
//////////

    /// @notice This method can be used by the controller to extract mistakenly
    ///  sent tokens to this contract.
    /// @param _token The address of the token contract that you want to recover
    ///  set to 0 in case you want to extract ether.
    function claimTokens(address _token) onlyController {
        if (_token == 0x0) {
            controller.transfer(this.balance);
            return;
        }

        MiniMeToken token = MiniMeToken(_token);
        uint balance = token.balanceOf(this);
        token.transfer(controller, balance);
        ClaimedTokens(_token, controller, balance);
    }

////////////////
// Events
////////////////
    event ClaimedTokens(address indexed _token, address indexed _controller, uint _amount);
    event Transfer(address indexed _from, address indexed _to, uint256 _amount);
    event NewCloneToken(address indexed _cloneToken, uint _snapshotBlock);
    event Approval(
        address indexed _owner,
        address indexed _spender,
        uint256 _amount
        );

}


////////////////
// MiniMeTokenFactory
////////////////

/// @dev This contract is used to generate clone contracts from a contract.
///  In solidity this is the way to create a contract from a contract of the
///  same class
contract MiniMeTokenFactory {

    /// @notice Update the DApp by creating a new token with new functionalities
    ///  the msg.sender becomes the controller of this clone token
    /// @param _parentToken Address of the token being cloned
    /// @param _snapshotBlock Block of the parent token that will
    ///  determine the initial distribution of the clone token
    /// @param _tokenName Name of the new token
    /// @param _decimalUnits Number of decimals of the new token
    /// @param _tokenSymbol Token Symbol for the new token
    /// @param _transfersEnabled If true, tokens will be able to be transferred
    /// @return The address of the new token contract
    function createCloneToken(
        address _parentToken,
        uint _snapshotBlock,
        string _tokenName,
        uint8 _decimalUnits,
        string _tokenSymbol,
        bool _transfersEnabled
    ) returns (MiniMeToken) {
        MiniMeToken newToken = new MiniMeToken(
            this,
            _parentToken,
            _snapshotBlock,
            _tokenName,
            _decimalUnits,
            _tokenSymbol,
            _transfersEnabled
            );

        newToken.changeController(msg.sender);
        return newToken;
    }
}

/**
 * @title Aigang Contribution contract
 *
 *  By contributing ETH to this smart contract you agree to the following terms and conditions:
 *  https://github.com/AigangNetwork/aigang-crowdsale-contracts/Aigang-T&Cs(171020_clean).docx
 *
 */

contract Contribution is Controlled, TokenController {
  using SafeMath for uint256;

  MiniMeToken public aix;
  bool public transferable;
  address public contributionWallet;
  address public remainderHolder;
  address public devHolder;
  address public communityHolder;
  address public exchanger;

  address public collector;
  uint256 public collectorWeiCap;
  uint256 public collectorWeiCollected;

  uint256 public totalWeiCap;             // Total Wei to be collected
  uint256 public totalWeiCollected;       // How much Wei has been collected
  uint256 public weiPreCollected;
  uint256 public notCollectedAmountAfter24Hours;
  uint256 public twentyPercentWithBonus;
  uint256 public thirtyPercentWithBonus;

  uint256 public minimumPerTransaction = 0.01 ether;

  uint256 public numWhitelistedInvestors;
  mapping (address => bool) public canPurchase;
  mapping (address => uint256) public individualWeiCollected;

  uint256 public startTime;
  uint256 public endTime;

  uint256 public initializedTime;
  uint256 public finalizedTime;

  uint256 public initializedBlock;
  uint256 public finalizedBlock;

  bool public paused;

  modifier initialized() {
    require(initializedBlock != 0);
    _;
  }

  modifier contributionOpen() {
    // collector can start depositing 2 days prior
    if (msg.sender == collector) {
      require(getBlockTimestamp().add(2 days) >= startTime);
    } else {
      require(getBlockTimestamp() >= startTime);
    }
    require(getBlockTimestamp() <= endTime);
    require(finalizedTime == 0);
    _;
  }

  modifier notPaused() {
    require(!paused);
    _;
  }

  function Contribution(address _aix) {
    require(_aix != 0x0);
    aix = MiniMeToken(_aix);
  }

  function initialize(
      address _apt,
      address _exchanger,
      address _contributionWallet,
      address _remainderHolder,
      address _devHolder,
      address _communityHolder,
      address _collector,
      uint256 _collectorWeiCap,
      uint256 _totalWeiCap,
      uint256 _startTime,
      uint256 _endTime
  ) public onlyController {
    // Initialize only once
    require(initializedBlock == 0);
    require(initializedTime == 0);
    assert(aix.totalSupply() == 0);
    assert(aix.controller() == address(this));
    assert(aix.decimals() == 18);  // Same amount of decimals as ETH

    require(_contributionWallet != 0x0);
    contributionWallet = _contributionWallet;

    require(_remainderHolder != 0x0);
    remainderHolder = _remainderHolder;

    require(_devHolder != 0x0);
    devHolder = _devHolder;

    require(_communityHolder != 0x0);
    communityHolder = _communityHolder;

    require(_collector != 0x0);
    collector = _collector;

    require(_collectorWeiCap > 0);
    require(_collectorWeiCap <= _totalWeiCap);
    collectorWeiCap = _collectorWeiCap;

    assert(_startTime >= getBlockTimestamp());
    require(_startTime < _endTime);
    startTime = _startTime;
    endTime = _endTime;

    require(_totalWeiCap > 0);
    totalWeiCap = _totalWeiCap;

    initializedBlock = getBlockNumber();
    initializedTime = getBlockTimestamp();

    require(_apt != 0x0);
    require(_exchanger != 0x0);

    weiPreCollected = MiniMeToken(_apt).totalSupplyAt(initializedBlock);

    // Exchangerate from apt to aix 2500 considering 25% bonus.
    require(aix.generateTokens(_exchanger, weiPreCollected.mul(2500)));
    exchanger = _exchanger;

    Initialized(initializedBlock);
  }

  /// @notice interface for founders to blacklist investors
  /// @param _investors array of investors
  function blacklistAddresses(address[] _investors) public onlyController {
    for (uint256 i = 0; i < _investors.length; i++) {
      blacklist(_investors[i]);
    }
  }

  /// @notice interface for founders to whitelist investors
  /// @param _investors array of investors
  function whitelistAddresses(address[] _investors) public onlyController {
    for (uint256 i = 0; i < _investors.length; i++) {
      whitelist(_investors[i]);
    }
  }

  function whitelist(address investor) public onlyController {
    if (canPurchase[investor]) return;
    numWhitelistedInvestors++;
    canPurchase[investor] = true;
  }

  function blacklist(address investor) public onlyController {
    if (!canPurchase[investor]) return;
    numWhitelistedInvestors--;
    canPurchase[investor] = false;
  }

  // ETH-AIX exchange rate
  function exchangeRate() constant public initialized returns (uint256) {
    if (getBlockTimestamp() <= startTime + 1 hours) {
      // 15% Bonus
      return 2300;
    }

    if (getBlockTimestamp() <= startTime + 2 hours) {
      // 10% Bonus
      return 2200;
    }

    if (getBlockTimestamp() <= startTime + 1 days) {
      return 2000;
    }

    uint256 collectedAfter24Hours = notCollectedAmountAfter24Hours.sub(weiToCollect());

    if (collectedAfter24Hours <= twentyPercentWithBonus) {
      // 15% Bonus
      return 2300;
    }

    if (collectedAfter24Hours <= twentyPercentWithBonus + thirtyPercentWithBonus) {
      // 10% Bonus
      return 2200;
    }

    return 2000;
  }

  function tokensToGenerate(uint256 toFund) constant public returns (uint256) {
    // collector gets 15% bonus
    if (msg.sender == collector) {
      return toFund.mul(2300);
    }

    return toFund.mul(exchangeRate());
  }

  /// @notice If anybody sends Ether directly to this contract, consider he is
  /// getting AIXs.
  function () public payable notPaused {
    proxyPayment(msg.sender);
  }

  //////////
  // TokenController functions
  //////////

  /// @notice This method will generally be called by the AIX token contract to
  ///  acquire AIXs. Or directly from third parties that want to acquire AIXs in
  ///  behalf of a token holder.
  /// @param _th AIX holder where the AIXs will be minted.
  function proxyPayment(address _th) public payable notPaused initialized contributionOpen returns (bool) {
    require(_th != 0x0);
    doBuy(_th);
    return true;
  }

  function onTransfer(address _from, address, uint256) public returns (bool) {
    if (_from == exchanger) {
      return true;
    }
    return transferable;
  }

  function onApprove(address _from, address, uint256) public returns (bool) {
    if (_from == exchanger) {
      return true;
    }
    return transferable;
  }

  function allowTransfers(bool _transferable) onlyController {
    transferable = _transferable;
  }

  function doBuy(address _th) internal {
    // whitelisting only during the first day
    if (getBlockTimestamp() <= startTime + 1 days) {
      require(canPurchase[_th] || msg.sender == collector);
    } else if (notCollectedAmountAfter24Hours == 0) {
      notCollectedAmountAfter24Hours = weiToCollect();
      twentyPercentWithBonus = notCollectedAmountAfter24Hours.mul(20).div(100);
      thirtyPercentWithBonus = notCollectedAmountAfter24Hours.mul(30).div(100);
    }

    require(msg.value >= minimumPerTransaction);
    uint256 toFund = msg.value;
    uint256 toCollect = weiToCollectByInvestor(_th);

    if (toCollect > 0) {
      // Check total supply cap reached, sell the all remaining tokens
      if (toFund > toCollect) {
        toFund = toCollect;
      }
      uint256 tokensGenerated = tokensToGenerate(toFund);
      require(tokensGenerated > 0);
      require(aix.generateTokens(_th, tokensGenerated));

      contributionWallet.transfer(toFund);
      individualWeiCollected[_th] = individualWeiCollected[_th].add(toFund);
      totalWeiCollected = totalWeiCollected.add(toFund);
      NewSale(_th, toFund, tokensGenerated);
    } else {
      toFund = 0;
    }

    uint256 toReturn = msg.value.sub(toFund);
    if (toReturn > 0) {
      _th.transfer(toReturn);
    }
  }

  /// @notice This method will can be called by the controller before the contribution period
  ///  end or by anybody after the `endTime`. This method finalizes the contribution period
  ///  by creating the remaining tokens and transferring the controller to the configured
  ///  controller.
  function finalize() public initialized {
    require(finalizedBlock == 0);
    require(finalizedTime == 0);
    require(getBlockTimestamp() >= startTime);
    require(msg.sender == controller || getBlockTimestamp() > endTime || weiToCollect() == 0);

    // remainder will be minted and locked for 1 year.
    // This was decided to be removed.
    // aix.generateTokens(remainderHolder, weiToCollect().mul(2000));

    // AIX generated so far is 51% of total
    uint256 tokenCap = aix.totalSupply().mul(100).div(51);
    // dev Wallet will have 20% of the total Tokens and will be able to retrieve quarterly.
    aix.generateTokens(devHolder, tokenCap.mul(20).div(100));
    // community Wallet will have access to 29% of the total Tokens.
    aix.generateTokens(communityHolder, tokenCap.mul(29).div(100));

    finalizedBlock = getBlockNumber();
    finalizedTime = getBlockTimestamp();

    Finalized(finalizedBlock);
  }

  //////////
  // Constant functions
  //////////

  /// @return Total eth that still available for collection in weis.
  function weiToCollect() public constant returns(uint256) {
    return totalWeiCap > totalWeiCollected ? totalWeiCap.sub(totalWeiCollected) : 0;
  }

  /// @return Total eth that still available for collection in weis.
  function weiToCollectByInvestor(address investor) public constant returns(uint256) {
    uint256 cap;
    uint256 collected;
    // adding 1 day as a placeholder for X hours.
    // This should change into a variable or coded into the contract.
    if (investor == collector) {
      cap = collectorWeiCap;
      collected = individualWeiCollected[investor];
    } else if (getBlockTimestamp() <= startTime + 1 days) {
      cap = totalWeiCap.div(numWhitelistedInvestors);
      collected = individualWeiCollected[investor];
    } else {
      cap = totalWeiCap;
      collected = totalWeiCollected;
    }
    return cap > collected ? cap.sub(collected) : 0;
  }

  //////////
  // Testing specific methods
  //////////

  /// @notice This function is overridden by the test Mocks.
  function getBlockNumber() internal constant returns (uint256) {
    return block.number;
  }

  function getBlockTimestamp() internal constant returns (uint256) {
    return block.timestamp;
  }

  //////////
  // Safety Methods
  //////////

  /// @notice This method can be used by the controller to extract mistakenly
  ///  sent tokens to this contract.
  /// @param _token The address of the token contract that you want to recover
  ///  set to 0 in case you want to extract ether.
  function claimTokens(address _token) public onlyController {
    if (aix.controller() == address(this)) {
      aix.claimTokens(_token);
    }

    if (_token == 0x0) {
      controller.transfer(this.balance);
      return;
    }

    ERC20 token = ERC20(_token);
    uint256 balance = token.balanceOf(this);
    token.transfer(controller, balance);
    ClaimedTokens(_token, controller, balance);
  }

  /// @notice Pauses the contribution if there is any issue
  function pauseContribution(bool _paused) onlyController {
    paused = _paused;
  }

  event ClaimedTokens(address indexed _token, address indexed _controller, uint256 _amount);
  event NewSale(address indexed _th, uint256 _amount, uint256 _tokens);
  event Initialized(uint _now);
  event Finalized(uint _now);
}