DEC

DEC

pragma solidity 0.4.25;

library SafeMath {

  /**
  * @dev Multiplies two numbers, throws on overflow.
  */
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    if (a == 0) {
      return 0;
    }
    uint256 c = a * b;
    assert(c / a == b);
    return c;
  }

  /**
  * @dev Integer division of two numbers, truncating the quotient.
  */
  function div(uint256 a, uint256 b) internal pure 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;
  }

  /**
  * @dev Substracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  /**
  * @dev Adds two numbers, throws on overflow.
  */
  function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}



contract Ownable {
  address private _owner;

  event OwnershipTransferred(
    address indexed previousOwner,
    address indexed newOwner
  );

  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  constructor() internal {
    _owner = msg.sender;
    emit OwnershipTransferred(address(0), _owner);
  }

  /**
   * @return the address of the owner.
   */
  function owner() public view returns(address) {
    return _owner;
  }

  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(isOwner());
    _;
  }

  /**
   * @return true if `msg.sender` is the owner of the contract.
   */
  function isOwner() public view returns(bool) {
    return msg.sender == _owner;
  }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   * @notice Renouncing to ownership will leave the contract without an owner.
   * It will not be possible to call the functions with the `onlyOwner`
   * modifier anymore.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipTransferred(_owner, address(0));
    _owner = address(0);
  }

  /**
   * @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) public onlyOwner {
    _transferOwnership(newOwner);
  }

  /**
   * @dev Transfers control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function _transferOwnership(address newOwner) internal {
    require(newOwner != address(0));
    emit OwnershipTransferred(_owner, newOwner);
    _owner = newOwner;
  }
}

contract ERC820Registry {
    function getManager(address addr) public view returns(address);
    function setManager(address addr, address newManager) public;
    function getInterfaceImplementer(address addr, bytes32 iHash) public constant returns (address);
    function setInterfaceImplementer(address addr, bytes32 iHash, address implementer) public;
}

contract ERC820Implementer {
    ERC820Registry erc820Registry = ERC820Registry(0x991a1bcb077599290d7305493c9A630c20f8b798);

    function setInterfaceImplementation(string ifaceLabel, address impl) internal {
        bytes32 ifaceHash = keccak256(abi.encodePacked(ifaceLabel));
        erc820Registry.setInterfaceImplementer(this, ifaceHash, impl);
    }

    function interfaceAddr(address addr, string ifaceLabel) internal constant returns(address) {
        bytes32 ifaceHash = keccak256(abi.encodePacked(ifaceLabel));
        return erc820Registry.getInterfaceImplementer(addr, ifaceHash);
    }

    function delegateManagement(address newManager) internal {
        erc820Registry.setManager(this, newManager);
    }
}

interface ERC777TokensSender {
    function tokensToSend(address operator, address from, address to, uint amount, bytes userData,bytes operatorData) external;
}

interface ERC777TokensRecipient {
    function tokensReceived(address operator, address from, address to, uint amount, bytes userData, bytes operatorData) external;
}

interface DECAirdropInterface{
    function pushTokens( uint256, address ) external;
    function pullTokens( address ) external;
    function nodeBlockedBalance( address ) external returns( uint256 );
}

contract DEC is ERC820Implementer, Ownable {
    
    using SafeMath for uint256;
    
    DECAirdropInterface DECAirdrop;
    address DECAirdropAddress;
    
    
    string public name = "Dec Nodes";
    string public symbol = "DEC";
    uint8  public decimals = 18;
    uint256 public granularity = 1;
    uint256 public totalSupply;
    
    
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Sent(address indexed operator, address indexed from, address indexed to, uint256 amount, bytes userData, bytes operatorData);
    event AuthorizedOperator(address indexed operator, address indexed tokenHolder);
    event RevokedOperator(address indexed operator, address indexed tokenHolder);
    event Approval(address indexed owner, address indexed spender, uint256 value);
    
    
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => bool)) public isOperatorFor;
    

    
    
    function setDECAirdropContract( address _address ) public onlyOwner
    {
        DECAirdrop = DECAirdropInterface( _address );
        DECAirdropAddress = _address;
    }
    
    function DECAirdropSend( address _from, address _to, uint256 _amount ) public 
    {
        require( msg.sender == DECAirdropAddress );
        
        _transfer( _from, _to, _amount );
    }
    
    function pushTokens( uint256 _amount ) public
    {
        DECAirdrop.pushTokens( _amount, msg.sender );
    }
    function pullTokens() public
    {
        DECAirdrop.pullTokens( msg.sender );
    }

    
    
    /**
    * @notice Send `_amount` of tokens to address `_to` passing `_userData` to the recipient
    * @param _to The address of the recipient
    * @param _amount The number of tokens to be sent
    * @param _userData Data generated by the user to be sent to the recipient
    */
    function send(address _to, uint256 _amount, bytes _userData) public {
        doSend(msg.sender, _to, _amount, _userData, msg.sender, "", true);
    }

    

    /**
    * @notice Authorize a third party `_operator` to manage (send) `msg.sender`'s tokens.
    * @param _operator The operator that wants to be Authorized
    */
    function authorizeOperator(address _operator) public {
        require(_operator != msg.sender);
        isOperatorFor[_operator][msg.sender] = true;
        emit AuthorizedOperator(_operator, msg.sender);
    }

    /**
    * @notice Revoke a third party `_operator`'s rights to manage (send) `msg.sender`'s tokens.
    * @param _operator The operator that wants to be Revoked
    */
    function revokeOperator(address _operator) public {
        require(_operator != msg.sender);
        isOperatorFor[_operator][msg.sender] = false;
        emit RevokedOperator(_operator, msg.sender);
    }

    /**
    * @notice Send `_amount` of tokens on behalf of the address `from` to the address `to`.
    * @param _from The address holding the tokens being sent
    * @param _to The address of the recipient
    * @param _amount The number of tokens to be sent
    * @param _userData Data generated by the user to be sent to the recipient
    * @param _operatorData Data generated by the operator to be sent to the recipient
    */
    function operatorSend(address _from, address _to, uint256 _amount, bytes _userData, bytes _operatorData) public {
        require(isOperatorFor[msg.sender][_from]);
        doSend(_from, _to, _amount, _userData, msg.sender, _operatorData, true);
    }

    /* -- Helper Functions -- */
    /**
    * @notice Internal function that ensures `_amount` is multiple of the granularity
    * @param _amount The quantity that want's to be checked
    */
    function requireMultiple(uint256 _amount) internal view {
        require(_amount.div(granularity).mul(granularity) == _amount);
    }

    /**
    * @notice Check whether an address is a regular address or not.
    * @param _addr Address of the contract that has to be checked
    * @return `true` if `_addr` is a regular address (not a contract)
    */
    function isRegularAddress(address _addr) internal constant returns(bool) {
        if (_addr == 0) { return false; }
        uint size;
        assembly { size := extcodesize(_addr) } // solhint-disable-line no-inline-assembly
        return size == 0;
    }

    /**
    * @notice Helper function that checks for ERC777TokensSender on the sender and calls it.
    *  May throw according to `_preventLocking`
    * @param _from The address holding the tokens being sent
    * @param _to The address of the recipient
    * @param _amount The amount of tokens to be sent
    * @param _userData Data generated by the user to be passed to the recipient
    * @param _operatorData Data generated by the operator to be passed to the recipient
    *  implementing `ERC777TokensSender`.
    *  ERC777 native Send functions MUST set this parameter to `true`, and backwards compatible ERC20 transfer
    *  functions SHOULD set this parameter to `false`.
    */
    function callSender(
        address _operator,
        address _from,
        address _to,
        uint256 _amount,
        bytes _userData,
        bytes _operatorData
    ) private {
        address senderImplementation = interfaceAddr(_from, "ERC777TokensSender");
        if (senderImplementation != 0) {
            ERC777TokensSender(senderImplementation).tokensToSend(
                _operator, _from, _to, _amount, _userData, _operatorData);
        }
    }

    /**
    * @notice Helper function that checks for ERC777TokensRecipient on the recipient and calls it.
    *  May throw according to `_preventLocking`
    * @param _from The address holding the tokens being sent
    * @param _to The address of the recipient
    * @param _amount The number of tokens to be sent
    * @param _userData Data generated by the user to be passed to the recipient
    * @param _operatorData Data generated by the operator to be passed to the recipient
    * @param _preventLocking `true` if you want this function to throw when tokens are sent to a contract not
    *  implementing `ERC777TokensRecipient`.
    *  ERC777 native Send functions MUST set this parameter to `true`, and backwards compatible ERC20 transfer
    *  functions SHOULD set this parameter to `false`.
    */
    function callRecipient(
        address _operator,
        address _from,
        address _to,
        uint256 _amount,
        bytes _userData,
        bytes _operatorData,
        bool _preventLocking
    ) private {
        address recipientImplementation = interfaceAddr(_to, "ERC777TokensRecipient");
        if (recipientImplementation != 0) {
            ERC777TokensRecipient(recipientImplementation).tokensReceived(
                _operator, _from, _to, _amount, _userData, _operatorData);
        } else if (_preventLocking) {
            require(isRegularAddress(_to));
        }
    }

    /**
    * @notice Helper function actually performing the sending of tokens.
    * @param _from The address holding the tokens being sent
    * @param _to The address of the recipient
    * @param _amount The number of tokens to be sent
    * @param _userData Data generated by the user to be passed to the recipient
    * @param _operatorData Data generated by the operator to be passed to the recipient
    * @param _preventLocking `true` if you want this function to throw when tokens are sent to a contract not
    *  implementing `erc777_tokenHolder`.
    *  ERC777 native Send functions MUST set this parameter to `true`, and backwards compatible ERC20 transfer
    *  functions SHOULD set this parameter to `false`.
    */
    function doSend(
        address _from,
        address _to,
        uint256 _amount,
        bytes _userData,
        address _operator,
        bytes _operatorData,
        bool _preventLocking
    )
        private
    {
        requireMultiple(_amount);
        require( DECAirdrop.nodeBlockedBalance(_to) <= 0 );

        callSender(_operator, _from, _to, _amount, _userData, _operatorData);

        require(_to != 0x0); 
        require(balanceOf[_from] >= _amount); 

        balanceOf[_from] = balanceOf[_from].sub(_amount);
        balanceOf[_to] = balanceOf[_to].add(_amount);

        callRecipient(_operator, _from, _to, _amount, _userData, _operatorData, _preventLocking);

        emit Sent(_operator, _from, _to, _amount, _userData, _operatorData);
        emit Transfer(_from, _to, _amount);
    }



    function _transfer(address _from, address _to, uint256 _value) internal {
        doSend(_from, _to, _value, "", _from, "", false);
    }

    /**
     * @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) {
        doSend(msg.sender, _to, _value, "", msg.sender, "", false);
        return true;
    }

    /**
     * @dev Transfer tokens from one address to another. Technically this is not ERC20 transferFrom but more ERC777 operatorSend.
     * @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(isOperatorFor[msg.sender][_from]);
        doSend(_from, _to, _value, "", msg.sender, "", true);
        emit Transfer(_from, _to, _value);
        return true;
    }

    /**

     * @dev Originally in ERC20 this function to check the amount of tokens that an owner allowed to a spender.
     *
     * Function was added purly for backward compatibility with ERC20. Use operator logic from ERC777 instead.
     * @param _owner address The address which owns the funds.
     * @param _spender address The address which will spend the funds.
     * @return A returning uint256 balanceOf _spender if it's active operator and 0 if not.
     */
    function allowance(address _owner, address _spender) public view returns (uint256 _amount) {
        if (isOperatorFor[_spender][_owner]) {
            _amount = balanceOf[_owner];
        } else {
            _amount = 0;
        }
    }

    /**
     * @dev Approve the passed address to spend tokens on behalf of msg.sender.
     *
     * This function is more authorizeOperator and revokeOperator from ERC777 that Approve from ERC20.
     * Approve concept has several issues (e.g. https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729),
     * so I prefer to use operator concept. If you want to revoke approval, just put 0 into _value.
     * @param _spender The address which will spend the funds.
     * @param _value Fake value to be compatible with ERC20 requirements.
     */
    function approve(address _spender, uint256 _value) public returns (bool) {
        require(_spender != msg.sender);

        if (_value > 0) {
            // Authorizing operator
            isOperatorFor[_spender][msg.sender] = true;
            emit AuthorizedOperator(_spender, msg.sender);
        } else {
            // Revoking operator
            isOperatorFor[_spender][msg.sender] = false;
            emit RevokedOperator(_spender, msg.sender);
        }

        emit Approval(msg.sender, _spender, _value);
        return true;
    }
    
    
}