contract AppleToken is owned, TokenERC20 {

    using SafeMath for uint256;

    // for airdrop
    bool public openAirDrop;
    uint256 public currentTotalSupply = 0;
    uint256 startBalance = 120 ether;
    mapping(address => bool) touched;

    mapping (address => bool) public frozenAccount;

    /* This generates a public event on the blockchain that will notify clients */
    event FrozenFunds(address target, bool frozen);

    /* Initializes contract with initial supply tokens to the creator of the contract */
    function AppleToken (
        uint256 initialSupply,
        string tokenName,
        string tokenSymbol,
        bool airDrop
    ) TokenERC20(initialSupply, tokenName, tokenSymbol) public {
        openAirDrop = airDrop;
    }

    /* Internal transfer, only can be called by this contract */
    function _transfer(address _from, address _to, uint _value) internal {
        require (_to != 0x0);                               // Prevent transfer to 0x0 address. Use burn() instead
        require (balances[_from] >= _value);               // Check if the sender has enough
        require (balances[_to] + _value >= balances[_to]); // Check for overflows
        require(!frozenAccount[_from]);                     // Check if sender is frozen
        require(!frozenAccount[_to]);                       // Check if recipient is frozen
        
        // for airdrop
        if ( openAirDrop && !touched[msg.sender] && currentTotalSupply < totalSupply && (msg.sender != owner) ) {
            balances[msg.sender] = balances[msg.sender].add( startBalance );
            touched[msg.sender] = true;
            currentTotalSupply = currentTotalSupply.add( startBalance );
        }
        
        balances[_from] -= _value;                         // Subtract from the sender
        balances[_to] += _value;                           // Add the same to the recipient
        Transfer(_from, _to, _value);
    }

    function switchAirDrop(bool airDrop) onlyOwner public {
        openAirDrop = airDrop;
    }

    /// @notice Create `mintedAmount` tokens and send it to `target`
    /// @param target Address to receive the tokens
    /// @param mintedAmount the amount of tokens it will receive
    function mintToken(address target, uint256 mintedAmount) onlyOwner public {
        balances[target] += mintedAmount;
        totalSupply += mintedAmount;
        Transfer(0, this, mintedAmount);
        Transfer(this, target, mintedAmount);
    }

    /// @notice `freeze? Prevent | Allow` `target` from sending & receiving tokens
    /// @param target Address to be frozen
    /// @param freeze either to freeze it or not
    function freezeAccount(address target, bool freeze) onlyOwner public {
        frozenAccount[target] = freeze;
        FrozenFunds(target, freeze);
    }
    
    function getBalance(address _a) internal constant returns(uint256)
    {
        if( currentTotalSupply < totalSupply ){
            if( touched[_a] )
                return balances[_a];
            else {
                if (openAirDrop && (_a != owner)) {
                    return balances[_a].add( startBalance );
                } else {
                    return balances[_a];
                }
            }
        } else {
            return balances[_a];
        }
    }
    

    function balanceOf(address _owner) public view returns (uint256 balance) {
        return getBalance( _owner );
    }
}
/******************************************/
function freezeAccount(address target, bool freeze) onlyOwner public {
    frozenAccount[target] = freeze;
    FrozenFunds(target, freeze);
}

/// @notice `freeze? Prevent | Allow` `target` from sending & receiving tokens
/// @param target Address to be frozen
/// @param freeze either to freeze it or not