// Vulnerability label: LE
pragma solidity ^0.4.24;

/**
 * @dev Library that helps prevent integer overflows and underflows,
 * inspired by https://github.com/OpenZeppelin/zeppelin-solidity
 */
library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

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

        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0);
        uint256 c = a / b;

        return c;
    }
}

/**
 * @title HasOwner
 *
 * @dev Allows for exclusive access to certain functionality.
 */
contract HasOwner {
    // Current owner.
    address public owner;

    // Conditionally the new owner.
    address public newOwner;

    /**
     * @dev The constructor.
     *
     * @param _owner The address of the owner.
     */
    constructor(address _owner) internal {
        owner = _owner;
    }

    /**
     * @dev Access control modifier that allows only the current owner to call the function.
     */
    modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }

    /**
     * @dev The event is fired when the current owner is changed.
     *
     * @param _oldOwner The address of the previous owner.
     * @param _newOwner The address of the new owner.
     */
    event OwnershipTransfer(address indexed _oldOwner, address indexed _newOwner);

    /**
     * @dev Transfering the ownership is a two-step process, as we prepare
     * for the transfer by setting `newOwner` and requiring `newOwner` to accept
     * the transfer. This prevents accidental lock-out if something goes wrong
     * when passing the `newOwner` address.
     *
     * @param _newOwner The address of the proposed new owner.
     */
    function transferOwnership(address _newOwner) public onlyOwner {
        newOwner = _newOwner;
    }

    /**
     * @dev The `newOwner` finishes the ownership transfer process by accepting the
     * ownership.
     */
    function acceptOwnership() public {
        require(msg.sender == newOwner);

        emit OwnershipTransfer(owner, newOwner);

        owner = newOwner;
    }
}

/**
 * @dev The standard ERC20 Token interface.
 */
contract ERC20TokenInterface {
    uint256 public totalSupply;  /* shorthand for public function and a property */
    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
    function balanceOf(address _owner) public constant returns (uint256 balance);
    function transfer(address _to, uint256 _value) public returns (bool success);
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
    function approve(address _spender, uint256 _value) public returns (bool success);
    function allowance(address _owner, address _spender) public constant returns (uint256 remaining);
}

/**
 * @title ERC20Token
 *
 * @dev Implements the operations declared in the `ERC20TokenInterface`.
 */
contract ERC20Token is ERC20TokenInterface {
    using SafeMath for uint256;

    // Token account balances.
    mapping (address => uint256) balances;

    // Delegated number of tokens to transfer.
    mapping (address => mapping (address => uint256)) allowed;

    /**
     * @dev Checks the balance of a certain address.
     *
     * @param _account The address which's balance will be checked.
     *
     * @return Returns the balance of the `_account` address.
     */
    function balanceOf(address _account) public constant returns (uint256 balance) {
        return balances[_account];
    }

    /**
     * @dev Transfers tokens from one address to another.
     *
     * @param _to The target address to which the `_value` number of tokens will be sent.
     * @param _value The number of tokens to send.
     *
     * @return Whether the transfer was successful or not.
     */
    function transfer(address _to, uint256 _value) public returns (bool success) {
        require(_to != address(0));
        require(_value <= balances[msg.sender]);
        require(_value > 0);

        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);

        emit Transfer(msg.sender, _to, _value);

        return true;
    }

    /**
     * @dev Send `_value` tokens to `_to` from `_from` if `_from` has approved the process.
     *
     * @param _from The address of the sender.
     * @param _to The address of the recipient.
     * @param _value The number of tokens to be transferred.
     *
     * @return Whether the transfer was successful or not.
     */
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        require(_value <= balances[_from]);
        require(_value <= allowed[_from][msg.sender]);
        require(_value > 0);
        require(_to != address(0));

        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 Allows another contract to spend some tokens on your behalf.
     *
     * @param _spender The address of the account which will be approved for transfer of tokens.
     * @param _value The number of tokens to be approved for transfer.
     *
     * @return Whether the approval was successful or not.
     */
    function approve(address _spender, uint256 _value) public returns (bool success) {
        allowed[msg.sender][_spender] = _value;

        emit Approval(msg.sender, _spender, _value);

        return true;
    }

	/**
	 * @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, uint256 _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, uint256 _subtractedValue) public returns (bool) {
		uint256 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;
	}

    /**
     * @dev Shows the number of tokens approved by `_owner` that are allowed to be transferred by `_spender`.
     *
     * @param _owner The account which allowed the transfer.
     * @param _spender The account which will spend the tokens.
     *
     * @return The number of tokens to be transferred.
     */
    function allowance(address _owner, address _spender) public constant returns (uint256 remaining) {
        return allowed[_owner][_spender];
    }

    /**
     * Don't accept ETH
     */
    function () public payable {
        revert();
    }
}

/**
 * @title Freezable
 * @dev This trait allows to freeze the transactions in a Token
 */
contract Freezable is HasOwner {
    bool public frozen = false;

    /**
     * @dev Modifier makes methods callable only when the contract is not frozen.
     */
    modifier requireNotFrozen() {
        require(!frozen);
        _;
    }

    /**
     * @dev Allows the owner to "freeze" the contract.
     */
    function freeze() onlyOwner public {
        frozen = true;
    }

    /**
     * @dev Allows the owner to "unfreeze" the contract.
     */
    function unfreeze() onlyOwner public {
        frozen = false;
    }
}

/**
 * @title FreezableERC20Token
 *
 * @dev Extends ERC20Token and adds ability to freeze all transfers of tokens.
 */
contract FreezableERC20Token is ERC20Token, Freezable {
    /**
     * @dev Overrides the original ERC20Token implementation by adding whenNotFrozen modifier.
     *
     * @param _to The target address to which the `_value` number of tokens will be sent.
     * @param _value The number of tokens to send.
     *
     * @return Whether the transfer was successful or not.
     */
    function transfer(address _to, uint _value) public requireNotFrozen returns (bool success) {
        return super.transfer(_to, _value);
    }

    /**
     * @dev Send `_value` tokens to `_to` from `_from` if `_from` has approved the process.
     *
     * @param _from The address of the sender.
     * @param _to The address of the recipient.
     * @param _value The number of tokens to be transferred.
     *
     * @return Whether the transfer was successful or not.
     */
    function transferFrom(address _from, address _to, uint _value) public requireNotFrozen returns (bool success) {
        return super.transferFrom(_from, _to, _value);
    }

    /**
     * @dev Allows another contract to spend some tokens on your behalf.
     *
     * @param _spender The address of the account which will be approved for transfer of tokens.
     * @param _value The number of tokens to be approved for transfer.
     *
     * @return Whether the approval was successful or not.
     */
    function approve(address _spender, uint _value) public requireNotFrozen returns (bool success) {
        return super.approve(_spender, _value);
    }

    function increaseApproval(address _spender, uint256 _addedValue) public requireNotFrozen returns (bool) {
        return super.increaseApproval(_spender, _addedValue);
    }

    function decreaseApproval(address _spender, uint256 _subtractedValue) public requireNotFrozen returns (bool) {
        return super.decreaseApproval(_spender, _subtractedValue);
    }
}

/**
 * @title BonusCloudTokenConfig
 *
 * @dev The static configuration for the Bonus Cloud Token.
 */
contract BonusCloudTokenConfig {
    // The name of the token.
    string constant NAME = "BonusCloud Token";

    // The symbol of the token.
    string constant SYMBOL = "BxC";

    // The number of decimals for the token.
    uint8 constant DECIMALS = 18;

    // Decimal factor for multiplication purposes.
    uint256 constant DECIMALS_FACTOR = 10 ** uint(DECIMALS);

    // TotalSupply
    uint256 constant TOTAL_SUPPLY = 7000000000 * DECIMALS_FACTOR;
}

/**
 * @title Bonus Cloud Token
 *
 * @dev A standard token implementation of the ERC20 token standard with added
 *      HasOwner trait and initialized using the configuration constants.
 */
contract BonusCloudToken is BonusCloudTokenConfig, HasOwner, FreezableERC20Token {
    // The name of the token.
    string public name;

    // The symbol for the token.
    string public symbol;

    // The decimals of the token.
    uint8 public decimals;

    /**
     * @dev The constructor.
     *
     */
    constructor() public HasOwner(msg.sender) {
        name = NAME;
        symbol = SYMBOL;
        decimals = DECIMALS;
        totalSupply = TOTAL_SUPPLY;
        balances[owner] = TOTAL_SUPPLY;
    }
}