pragma solidity ^0.4.18;

library SafeMath {

  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;
  }

  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;
  }

  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) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}

contract Ownable {

  address public owner;
  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

  function Ownable() public {
    owner = msg.sender;
  }

  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }

  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

}


contract ERC20 is Ownable {
  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);
  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);
  event Approval(address indexed owner, address indexed spender, uint256 value);

}

contract GeoGems is ERC20 {
  using SafeMath for uint256;

  mapping(address => uint256) balances;

    string public name;
    string public symbol;
    uint8 public decimals;
    uint256 totalSupply_;
    address public vaultAddress;

  function totalSupply() public view returns (uint256) {
    return totalSupply_;
  }

  function GeoGems(address _vaultAddress) public {
        name = "Geo Gems";
        symbol = "GG";
        decimals = 2;
        totalSupply_ = 5000000000000 * (10 ** uint256(decimals));
        vaultAddress = _vaultAddress; 
        balances[_vaultAddress] = totalSupply_;
 
        emit Transfer(0x0, _vaultAddress, totalSupply_);
        
  }
    
  function transfer(address _to, uint256 _value) public returns (bool) {
    require(0x0 != msg.sender);
    require(_to != address(0));
    require(_value <= balances[msg.sender]);

    // SafeMath.sub will throw if there is not enough balance.
    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 balance) {
    return balances[_owner];
  }

  mapping (address => mapping (address => uint256)) internal allowed;

  function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));
    require(0x0 != msg.sender);
    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) {
    require(_spender != address(0));
    require(0x0 != msg.sender);
    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;
  }

  event Mint(address indexed to, uint256 amount);
  event MintFinished();

  bool public mintingFinished = false;


  modifier canMint() {
    require(!mintingFinished);
    _;
  }

  function mint(address _to, uint256 _amount) onlyOwner canMint public returns (bool) {
    //assert(totalSupply_.add(_amount) <= 10000000000000 * (10 ** uint256(decimals)));
    totalSupply_ = totalSupply_.add(_amount);
    balances[_to] = balances[_to].add(_amount);
    emit Mint(_to, _amount);
    emit Transfer(address(0), _to, _amount);
    return true;
  }
  event NameChangedTo (string value);
  event SymbolChangedTo (string value);
  
  function setName(string _name) onlyOwner public {
        name = _name;
        emit NameChangedTo(_name);
    }
    
  function setSymbol(string _symbol) onlyOwner public {
        symbol = _symbol;
        emit SymbolChangedTo(_symbol);
    }


  function finishMinting() onlyOwner canMint public returns (bool) {
    mintingFinished = true;
    emit MintFinished();
    return true;
  }

}