// Vulnerability label: NC1
pragma solidity ^0.4.11;

/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/179
 */
contract ERC20Basic {
  uint256 public totalSupply;
  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 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 OwnershipTransferred(address indexed previousOwner, address indexed newOwner);


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  function Ownable()  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 transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) onlyOwner public {
    require(newOwner != address(0));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

}













/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
  function mul(uint256 a, uint256 b) internal view returns (uint256) {
    uint256 c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function div(uint256 a, uint256 b) internal view 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 view returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal view returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}



/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
contract BasicToken is ERC20Basic {
  using SafeMath for uint256;

  mapping(address => uint256) balances;

  /**
  * @dev transfer token for a specified address
  * @param _to The address to transfer to.
  * @param _value The amount to be transferred.
  */
  function transfer(address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));

    // SafeMath.sub will throw if there is not enough balance.
    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    Transfer(msg.sender, _to, _value);
    return true;
  }

  /**
  * @dev Gets the balance of the specified address.
  * @param _owner The address to query the the balance of.
  * @return An uint256 representing the amount owned by the passed address.
  */
  function balanceOf(address _owner) public view returns (uint256 balance) {
    return balances[_owner];
  }

}







/**
 * @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 Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * @dev https://github.com/ethereum/EIPs/issues/20
 * @dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is ERC20, BasicToken {

  mapping (address => mapping (address => uint256)) allowed;


  /**
   * @dev Transfer tokens from one address to another
   * @param _from address The address which you want to send tokens from
   * @param _to address The address which you want to transfer to
   * @param _value uint256 the amount of tokens to be transferred
   */
  function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));

    uint256 _allowance = allowed[_from][msg.sender];

    // Check is not needed because sub(_allowance, _value) will already throw if this condition is not met
    // require (_value <= _allowance);

    balances[_from] = balances[_from].sub(_value);
    balances[_to] = balances[_to].add(_value);
    allowed[_from][msg.sender] = _allowance.sub(_value);
    Transfer(_from, _to, _value);
    return true;
  }

  /**
   * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
   *
   * Beware that changing an allowance with this method brings the risk that someone may use both the old
   * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
   * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
   * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
   * @param _spender The address which will spend the funds.
   * @param _value The amount of tokens to be spent.
   */
  function approve(address _spender, uint256 _value) public returns (bool) {
    allowed[msg.sender][_spender] = _value;
    Approval(msg.sender, _spender, _value);
    return true;
  }

  /**
   * @dev Function to check the amount of tokens that an owner allowed to a spender.
   * @param _owner address The address which owns the funds.
   * @param _spender address The address which will spend the funds.
   * @return A uint256 specifying the amount of tokens still available for the spender.
   */
  function allowance(address _owner, address _spender) public view returns (uint256 remaining) {
    return allowed[_owner][_spender];
  }

  /**
   * approve should be called when allowed[_spender] == 0. To increment
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   */
  function increaseApproval (address _spender, uint _addedValue) public returns (bool success) {
    allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

  function decreaseApproval (address _spender, uint _subtractedValue) public returns (bool success) {
    uint oldValue = allowed[msg.sender][_spender];
    if (_subtractedValue > oldValue) {
      allowed[msg.sender][_spender] = 0;
    } else {
      allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
    }
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

}







/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
contract Pausable is Ownable {
  event Pause();
  event Unpause();

  bool public paused = false;


  /**
   * @dev Modifier to make a function callable only when the contract is not paused.
   */
  modifier whenNotPaused() {
    require(!paused);
    _;
  }

  /**
   * @dev Modifier to make a function callable only when the contract is paused.
   */
  modifier whenPaused() {
    require(paused);
    _;
  }

  /**
   * @dev called by the owner to pause, triggers stopped state
   */
  function pause() onlyOwner whenNotPaused public {
    paused = true;
    emit Pause();
  }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
  function unpause() onlyOwner whenPaused public {
    paused = false;
    emit Unpause();
  }
}



/**
 * @title Element Token
 * @dev ERC20 Element Token)
 *
 * All initial tokens are assigned to the creator of
 * this contract.
 *
 */
contract ElementToken is StandardToken, Pausable {

  string public name = "";               // Set the token name for display
  string public symbol = "";             // Set the token symbol for display
  uint8 public decimals = 0;             // Set the token symbol for display

  /**
   * @dev Don't allow tokens to be sent to the contract
   */
  modifier rejectTokensToContract(address _to) {
    require(_to != address(this));
    _;
  }

  /**
   * @dev ElementToken Constructor
   * Runs only on initial contract creation.
   */
  function ElementToken(string _name, string _symbol, uint256 _tokens, uint8 _decimals)  public {
    name = _name;
    symbol = _symbol;
    decimals = _decimals;
    totalSupply = _tokens * 10**uint256(decimals);          // Set the total supply
    balances[msg.sender] = totalSupply;                      // Creator address is assigned all
    Transfer(0x0, msg.sender, totalSupply);                  // create Transfer event for minting
  }

  /**
   * @dev Transfer token for a specified address when not paused
   * @param _to The address to transfer to.
   * @param _value The amount to be transferred.
   */
  function transfer(address _to, uint256 _value) rejectTokensToContract(_to) public whenNotPaused returns (bool) {
    return super.transfer(_to, _value);
  }

  /**
   * @dev Transfer tokens from one address to another when not paused
   * @param _from address The address which you want to send tokens from
   * @param _to address The address which you want to transfer to
   * @param _value uint256 the amount of tokens to be transferred
   */
  function transferFrom(address _from, address _to, uint256 _value) rejectTokensToContract(_to) public whenNotPaused returns (bool) {
    return super.transferFrom(_from, _to, _value);
  }

  /**
   * @dev Aprove the passed address to spend the specified amount of tokens on behalf of msg.sender when not paused.
   * @param _spender The address which will spend the funds.
   * @param _value The amount of tokens to be spent.
   */
  function approve(address _spender, uint256 _value) public whenNotPaused returns (bool) {
    return super.approve(_spender, _value);
  }

  /**
   * Adding whenNotPaused
   */
  function increaseApproval (address _spender, uint _addedValue) public whenNotPaused returns (bool success) {
    return super.increaseApproval(_spender, _addedValue);
  }

  /**
   * Adding whenNotPaused
   */
  function decreaseApproval (address _spender, uint _subtractedValue) public whenNotPaused returns (bool success) {
    return super.decreaseApproval(_spender, _subtractedValue);
  }

}

contract Multiownable {

    // VARIABLES

    uint256 public ownersGeneration;
    uint256 public howManyOwnersDecide;
    address[] public owners;
    bytes32[] public allOperations;
    address internal insideCallSender;
    uint256 internal insideCallCount;

    // Reverse lookup tables for owners and allOperations
    mapping(address => uint) public ownersIndices; // Starts from 1
    mapping(bytes32 => uint) public allOperationsIndicies;

    // Owners voting mask per operations
    mapping(bytes32 => uint256) public votesMaskByOperation;
    mapping(bytes32 => uint256) public votesCountByOperation;

    // EVENTS

    event OwnershipTransferred(address[] previousOwners, uint howManyOwnersDecide, address[] newOwners, uint newHowManyOwnersDecide);
    event OperationCreated(bytes32 operation, uint howMany, uint ownersCount, address proposer);
    event OperationUpvoted(bytes32 operation, uint votes, uint howMany, uint ownersCount, address upvoter);
    event OperationPerformed(bytes32 operation, uint howMany, uint ownersCount, address performer);
    event OperationDownvoted(bytes32 operation, uint votes, uint ownersCount,  address downvoter);
    event OperationCancelled(bytes32 operation, address lastCanceller);
    
    // ACCESSORS

    function isOwner(address wallet) public view returns(bool) {
        return ownersIndices[wallet] > 0;
    }

    function ownersCount() public view returns(uint) {
        return owners.length;
    }

    function allOperationsCount() public view returns(uint) {
        return allOperations.length;
    }

    // MODIFIERS

    /**
    * @dev Allows to perform method by any of the owners
    */
    modifier onlyAnyOwner {
        if (checkHowManyOwners(1)) {
            bool update = (insideCallSender == address(0));
            if (update) {
                insideCallSender = msg.sender;
                insideCallCount = 1;
            }
            _;
            if (update) {
                insideCallSender = address(0);
                insideCallCount = 0;
            }
        }
    }

    /**
    * @dev Allows to perform method only after many owners call it with the same arguments
    */
    modifier onlyManyOwners {
        if (checkHowManyOwners(howManyOwnersDecide)) {
            bool update = (insideCallSender == address(0));
            if (update) {
                insideCallSender = msg.sender;
                insideCallCount = howManyOwnersDecide;
            }
            _;
            if (update) {
                insideCallSender = address(0);
                insideCallCount = 0;
            }
        }
    }

    /**
    * @dev Allows to perform method only after all owners call it with the same arguments
    */
    modifier onlyAllOwners {
        if (checkHowManyOwners(owners.length)) {
            bool update = (insideCallSender == address(0));
            if (update) {
                insideCallSender = msg.sender;
                insideCallCount = owners.length;
            }
            _;
            if (update) {
                insideCallSender = address(0);
                insideCallCount = 0;
            }
        }
    }

    /**
    * @dev Allows to perform method only after some owners call it with the same arguments
    */
    modifier onlySomeOwners(uint howMany) {
        require(howMany > 0, "onlySomeOwners: howMany argument is zero");
        require(howMany <= owners.length, "onlySomeOwners: howMany argument exceeds the number of owners");
        
        if (checkHowManyOwners(howMany)) {
            bool update = (insideCallSender == address(0));
            if (update) {
                insideCallSender = msg.sender;
                insideCallCount = howMany;
            }
            _;
            if (update) {
                insideCallSender = address(0);
                insideCallCount = 0;
            }
        }
    }

    // CONSTRUCTOR

    constructor() public {
        owners.push(msg.sender);
        ownersIndices[msg.sender] = 1;
        howManyOwnersDecide = 1;
    }

    // INTERNAL METHODS

    /**
     * @dev onlyManyOwners modifier helper
     */
    function checkHowManyOwners(uint howMany) internal returns(bool) {
        if (insideCallSender == msg.sender) {
            require(howMany <= insideCallCount, "checkHowManyOwners: nested owners modifier check require more owners");
            return true;
        }

        uint ownerIndex = ownersIndices[msg.sender] - 1;
        require(ownerIndex < owners.length, "checkHowManyOwners: msg.sender is not an owner");
        bytes32 operation = keccak256(abi.encodePacked(msg.data, ownersGeneration));

        require((votesMaskByOperation[operation] & (2 ** ownerIndex)) == 0, "checkHowManyOwners: owner already voted for the operation");
        votesMaskByOperation[operation] |= (2 ** ownerIndex);
        uint operationVotesCount = votesCountByOperation[operation] + 1;
        votesCountByOperation[operation] = operationVotesCount;
        if (operationVotesCount == 1) {
            allOperationsIndicies[operation] = allOperations.length;
            allOperations.push(operation);
            emit OperationCreated(operation, howMany, owners.length, msg.sender);
        }
        emit OperationUpvoted(operation, operationVotesCount, howMany, owners.length, msg.sender);

        // If enough owners confirmed the same operation
        if (votesCountByOperation[operation] == howMany) {
            deleteOperation(operation);
            emit OperationPerformed(operation, howMany, owners.length, msg.sender);
            return true;
        }

        return false;
    }

    /**
    * @dev Used to delete cancelled or performed operation
    * @param operation defines which operation to delete
    */
    function deleteOperation(bytes32 operation) internal {
        uint index = allOperationsIndicies[operation];
        if (index < allOperations.length - 1) { // Not last
            allOperations[index] = allOperations[allOperations.length - 1];
            allOperationsIndicies[allOperations[index]] = index;
        }
        //allOperations.length-1
        allOperations.push(allOperations[allOperations.length-1]);

        delete votesMaskByOperation[operation];
        delete votesCountByOperation[operation];
        delete allOperationsIndicies[operation];
    }

    // PUBLIC METHODS

    /**
    * @dev Allows owners to change their mind by cacnelling votesMaskByOperation operations
    * @param operation defines which operation to delete
    */
    function cancelPending(bytes32 operation) public onlyAnyOwner {
        uint ownerIndex = ownersIndices[msg.sender] - 1;
        require((votesMaskByOperation[operation] & (2 ** ownerIndex)) != 0, "cancelPending: operation not found for this user");
        votesMaskByOperation[operation] &= ~(2 ** ownerIndex);
        uint operationVotesCount = votesCountByOperation[operation] - 1;
        votesCountByOperation[operation] = operationVotesCount;
        emit OperationDownvoted(operation, operationVotesCount, owners.length, msg.sender);
        if (operationVotesCount == 0) {
            deleteOperation(operation);
            emit OperationCancelled(operation, msg.sender);
        }
    }

    /**
    * @dev Allows owners to change ownership
    * @param newOwners defines array of addresses of new owners
    */
    function transferOwnership(address[] memory newOwners) public {
        transferOwnershipWithHowMany(newOwners, newOwners.length);
    }

    /**
    * @dev Allows owners to change ownership
    * @param newOwners defines array of addresses of new owners
    * @param newHowManyOwnersDecide defines how many owners can decide
    */
    function transferOwnershipWithHowMany(address[] memory newOwners, uint256 newHowManyOwnersDecide) public onlyManyOwners {
        require(newOwners.length > 0, "transferOwnershipWithHowMany: owners array is empty");
        require(newOwners.length <= 256, "transferOwnershipWithHowMany: owners count is greater then 256");
        require(newHowManyOwnersDecide > 0, "transferOwnershipWithHowMany: newHowManyOwnersDecide equal to 0");
        require(newHowManyOwnersDecide <= newOwners.length, "transferOwnershipWithHowMany: newHowManyOwnersDecide exceeds the number of owners");

        // Reset owners reverse lookup table
        for (uint j = 0; j < owners.length; j++) {
            delete ownersIndices[owners[j]];
        }
        for (uint i = 0; i < newOwners.length; i++) {
            require(newOwners[i] != address(0), "transferOwnershipWithHowMany: owners array contains zero");
            require(ownersIndices[newOwners[i]] == 0, "transferOwnershipWithHowMany: owners array contains duplicates");
            ownersIndices[newOwners[i]] = i + 1;
        }
        
        emit OwnershipTransferred(owners, howManyOwnersDecide, newOwners, newHowManyOwnersDecide);
        owners = newOwners;
        howManyOwnersDecide = newHowManyOwnersDecide;
        // allOperations.length = 0;
        allOperations.push(allOperations[0]);
        ownersGeneration++;
    }

}

contract ethBridge is Multiownable {
    ElementToken private token;

    mapping(address => uint256) public tokensSent;
    mapping(address => uint256) public tokensRecieved;
    mapping(address => uint256) public tokensRecievedButNotSent;
 
    constructor (address _token) public {
        token = ElementToken(_token);
    }
 
    uint256 amountToSent;
    bool transferStatus;
    
    bool avoidReentrancy = false;
 
    function sendTokens(uint256 amount) public {
        require(msg.sender != address(0), "Zero account");
        require(amount > 0,"Amount of tokens should be more then 0");
        require(token.balanceOf(msg.sender) >= amount,"Not enough balance");
        
        transferStatus = token.transferFrom(msg.sender, address(this), amount);
        if (transferStatus == true) {
            tokensRecieved[msg.sender] += amount;
        }
    }
 
    function writeTransaction(address user, uint256 amount) public onlyAllOwners {
        require(user != address(0), "Zero account");
        require(amount > 0,"Amount of tokens should be more then 0");
        require(!avoidReentrancy);
        
        avoidReentrancy = true;
        tokensRecievedButNotSent[user] += amount;
        avoidReentrancy = false;
    }

    function recieveTokens(uint256[] memory commissions) public payable {
        if (tokensRecievedButNotSent[msg.sender] != 0) {
            require(commissions.length == owners.length, "The number of commissions and owners does not match");
            uint256 sum;
            for(uint i = 0; i < commissions.length; i++) {
                sum += commissions[i];
            }
            require(msg.value >= sum, "Not enough ETH (The amount of ETH is less than the amount of commissions.)");
            require(msg.value >= owners.length * 150000 * 10**9, "Not enough ETH (The amount of ETH is less than the internal commission.)");
        
            for (i = 0; i < owners.length; i++) {
                uint256 commission = commissions[i];
                owners[i].transfer(commission);
            }
            
            amountToSent = tokensRecievedButNotSent[msg.sender] - tokensSent[msg.sender];
            token.transfer(msg.sender, amountToSent);
            tokensSent[msg.sender] += amountToSent;
        }
    }
 
    function withdrawTokens(uint256 amount, address reciever) public onlyAllOwners {
        require(amount > 0,"Amount of tokens should be more then 0");
        require(reciever != address(0), "Zero account");
        require(token.balanceOf(address(this)) >= amount,"Not enough balance");
        
        token.transfer(reciever, amount);
    }
    
    function withdrawEther(uint256 amount, address reciever) public onlyAllOwners {
        require(amount > 0,"Amount of tokens should be more then 0");
        require(reciever != address(0), "Zero account");
        require(address(this).balance >= amount,"Not enough balance");

        reciever.transfer(amount);
    }
}