pragma solidity ^0.4.24;




contract Ownable {
  address public owner;

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


  
  constructor() public {
    owner = 0x20c248b62789cfA91953aa476697B1eac7537279;
  }

  
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }

  
  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

}




library SafeMath {

  
  function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
    if (a == 0) {
      return 0;
    }
    c = a * b;
    assert(c / a == b);
    return c;
  }

  
  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    
    
    
    return a / b;
  }

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

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




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);
}




contract BasicToken is ERC20Basic {
  using SafeMath for uint256;

  mapping(address => uint256) balances;

  uint256 totalSupply_;

  
  function totalSupply() public view returns (uint256) {
    return totalSupply_;
  }

  
  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;
  }

  
  function balanceOf(address _owner) public view returns (uint256) {
    return balances[_owner];
  }

}




contract BurnableToken is BasicToken {

  event Burn(address indexed burner, uint256 value);

  
  function burn(uint256 _value) public {
    _burn(msg.sender, _value);
  }

  function _burn(address _who, uint256 _value) internal {
    require(_value <= balances[_who]);
    
    

    balances[_who] = balances[_who].sub(_value);
    totalSupply_ = totalSupply_.sub(_value);
    emit Burn(_who, _value);
    emit Transfer(_who, address(0), _value);
  }
}




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);
}




contract StandardToken is ERC20, BasicToken {

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


  
  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;
  }

  
  function approve(address _spender, uint256 _value) public returns (bool) {
    allowed[msg.sender][_spender] = _value;
    emit Approval(msg.sender, _spender, _value);
    return true;
  }

  
  function allowance(address _owner, address _spender) public view returns (uint256) {
    return allowed[_owner][_spender];
  }

  
  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;
  }

  
  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;
  }

}
 
contract MEHC is StandardToken, BurnableToken, Ownable {
    
    string  public constant name = "Massive Health Coin";
    string  public constant symbol = "MEHC";
    uint8   public constant decimals = 18;
    uint256 public constant INITIAL_SUPPLY      = 2100000000 * (10 ** uint256(decimals));

    mapping(address => bool) public balanceLocked;    
    
    
    uint public amountRaised;
    uint256 public buyPrice = 20000;
    bool public crowdsaleClosed ;
    bool public transferEnabled = true;


    constructor() public {
      totalSupply_ = INITIAL_SUPPLY;
      balances[msg.sender] = INITIAL_SUPPLY;
      emit Transfer(0x0, msg.sender, INITIAL_SUPPLY);
    }
 

    function _transfer(address _from, address _to, uint _value) internal {     
        require (balances[_from] >= _value);               
        require (balances[_to] + _value > balances[_to]); 
   
        balances[_from] = balances[_from].sub(_value);                         
        balances[_to] = balances[_to].add(_value);                            
 
        emit Transfer(_from, _to, _value);
    }

    function setPrice( uint256 newBuyPrice) onlyOwner public {
        buyPrice = newBuyPrice;
    }

    function closeBuy(bool closebuy) onlyOwner public {
        crowdsaleClosed = closebuy;
    }

    function () external payable {
        require(!crowdsaleClosed);
        uint amount = msg.value ;               
        amountRaised = amountRaised.add(amount);
        _transfer(owner, msg.sender, amount.mul(buyPrice)); 
        owner.transfer(amount);
    }
 
    function enableTransfer(bool _enable) onlyOwner external {
        transferEnabled = _enable;
    }

    function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
        require(transferEnabled);
        require(!balanceLocked[_from] );

        return super.transferFrom(_from, _to, _value);
    }

    function transfer(address _to, uint256 _value) public returns (bool) {
        require(transferEnabled);
        require(!balanceLocked[msg.sender] );
        
        return super.transfer(_to, _value);
    }    
  
    function lock ( address[] _addr ) onlyOwner external  {
        for (uint i = 0; i < _addr.length; i++) {
          balanceLocked[_addr[i]] =  true;  
        }
    }
    
   
    function unlock ( address[] _addr ) onlyOwner external  {
        for (uint i = 0; i < _addr.length; i++) {
          balanceLocked[_addr[i]] =  false;  
        }
    }
 
        
}