pragma solidity ^0.4.24;

/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/179
 */
contract ERC20Basic {
  function totalSupply() public view returns (uint256);
  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 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 SafeMath
 * @dev Math operations with safety checks that throw on error
 * @notice https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/math/SafeMath.sol
 */
library SafeMath {
	/**
	 * SafeMath mul function
	 * @dev function for safe multiply, throws on overflow.
	 **/
	function mul(uint256 a, uint256 b) internal pure returns (uint256) {
		uint256 c = a * b;
		assert(a == 0 || c / a == b);
		return c;
	}

	/**
	 * SafeMath div funciotn
	 * @dev function for safe devide, throws on overflow.
	 **/
	function div(uint256 a, uint256 b) internal pure returns (uint256) {
		uint256 c = a / b;
		return c;
	}

	/**
	 * SafeMath sub function
	 * @dev function for safe subtraction, throws on overflow.
	 **/
	function sub(uint256 a, uint256 b) internal pure returns (uint256) {
		assert(b <= a);
		return a - b;
	}

	/**
	 * SafeMath add function
	 * @dev Adds two numbers, throws on overflow.
	 */
	function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
		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;

  uint256 totalSupply_;

  /**
  * @dev total number of tokens in existence
  */
  function totalSupply() public view returns (uint256) {
    return totalSupply_;
  }

  /**
  * @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));
    require(_value <= balances[msg.sender]);

    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    emit 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) {
    return balances[_owner];
  }

}

/**
 * @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)) internal 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));
    require(_value <= balances[_from]);
    require(_value <= allowed[_from][msg.sender]);

    balances[_from] = balances[_from].sub(_value);
    balances[_to] = balances[_to].add(_value);
    allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
    emit 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;
    emit 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) {
    return allowed[_owner][_spender];
  }

  /**
   * @dev Increase the amount of tokens that an owner allowed to a 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
   * @param _spender The address which will spend the funds.
   * @param _addedValue The amount of tokens to increase the allowance by.
   */
  function increaseApproval(address _spender, uint _addedValue) public returns (bool) {
    allowed[msg.sender][_spender] = (
      allowed[msg.sender][_spender].add(_addedValue));
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

  /**
   * @dev Decrease the amount of tokens that an owner allowed to a spender.
   *
   * approve should be called when allowed[_spender] == 0. To decrement
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _subtractedValue The amount of tokens to decrease the allowance by.
   */
  function decreaseApproval(address _spender, uint _subtractedValue) public returns (bool) {
    uint oldValue = allowed[msg.sender][_spender];

    if (_subtractedValue > oldValue) {
      allowed[msg.sender][_spender] = 0;
    } else {
      allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
    }

    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

}

/**
 * @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 OwnershipRenounced(address indexed previousOwner);
  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  constructor() 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) public onlyOwner {
    require(newOwner != address(0));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipRenounced(owner);
    owner = address(0);
  }
}

/**
 * @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 || msg.sender == owner);
    _;
  }

  /**
   * @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() public onlyOwner {
        require(!paused);
        paused = true;
        emit Pause();
    }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
  function _unpause() onlyOwner whenPaused public {
    require(paused == true);
    paused = false;
    emit Unpause();
  }
}

/**
 * @title Pausable token
 * @dev StandardToken modified with pausable transfers.
 **/
contract CucunToken is StandardToken, Pausable {
    string public name;// = "Cucu Token";
    string public symbol;// = "CUCU";
    uint256 public decimals;// = 8;
    uint256 public initial_supply;// = 100000000000;// 1000 억

    bool public isPauseOn = false;

    modifier ifNotPaused(){
      require(!isPauseOn || msg.sender == owner);
      _;
    }

    function _doPause() public{
      require(msg.sender == owner);
      isPauseOn = true;
    }

    function _doUnpause() public{
      require(msg.sender == owner);
      isPauseOn = false;
    }

    /**
     * @dev Transfer tokens when not paused
     **/
    function transfer(address _to, uint256 _value) public ifNotPaused returns (bool) {
        return super.transfer(_to, _value);
    }

    /**
     * @dev transferFrom function to tansfer tokens when token is not paused
     **/
    function transferFrom(address _from, address _to, uint256 _value) public ifNotPaused returns (bool) {
        return super.transferFrom(_from, _to, _value);
    }

    /**
     * @dev approve spender when not paused
     **/
    function approve(address _spender, uint256 _value) public ifNotPaused returns (bool) {
        return super.approve(_spender, _value);
    }

    /**
     * @dev increaseApproval of spender when not paused
     **/
    function increaseApproval(address _spender, uint _addedValue) public ifNotPaused returns (bool success) {
        return super.increaseApproval(_spender, _addedValue);
    }

    /**
     * @dev decreaseApproval of spender when not paused
     **/
    function decreaseApproval(address _spender, uint _subtractedValue) public ifNotPaused returns (bool success) {
        return super.decreaseApproval(_spender, _subtractedValue);
    }


    // Mint more tokens
    function _mint(uint mint_amt) public onlyOwner{
        totalSupply_ = totalSupply_.add(mint_amt);
        balances[owner] = balances[owner].add(mint_amt);
    }

    /**
   * Pausable Token Constructor
   * @dev Create and issue tokens to msg.sender.
   */
  constructor() public {
    name = "Cucu Token";
    symbol = "CUCU";
    decimals = 8;
    initial_supply = 10000000000000000000;

    totalSupply_ = initial_supply;
    balances[msg.sender] = initial_supply;
  }
}