pragma solidity 0.4.24;


/**
 * @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;
    address public pendingOwner;
    address public manager;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    event ManagerUpdated(address newManager);

   /**
   * @dev Throws if called by any account other than the owner.
   */
    modifier onlyOwner() {
        require(msg.sender == owner);
        _;
    }

    /**
     * @dev Modifier throws if called by any account other than the manager.
     */
    modifier onlyManager() {
        require(msg.sender == manager);
        _;
    }

    /**
    * @dev Modifier throws if called by any account other than the pendingOwner.
    */
    modifier onlyPendingOwner() {
        require(msg.sender == pendingOwner);
        _;
    }

    constructor() public {
        owner = msg.sender;
    }

    /**
    * @dev Allows the current owner to set the pendingOwner address.
    * @param newOwner The address to transfer ownership to.
    */
    function transferOwnership(address newOwner) public onlyOwner {
        pendingOwner = newOwner;
    }

    /**
    * @dev Allows the pendingOwner address to finalize the transfer.
    */
    function claimOwnership() public onlyPendingOwner {
        emit OwnershipTransferred(owner, pendingOwner);
        owner = pendingOwner;
        pendingOwner = address(0);
    }

    /**
    * @dev Sets the manager address.
    * @param _manager The manager address.
    */
    function setManager(address _manager) public onlyOwner {
        require(_manager != address(0));
        manager = _manager;
        emit ManagerUpdated(manager);
    }

}

/**
 * @title Whitelist
 * @dev The Whitelist contract has a whitelist of addresses, and provides basic authorization control functions.
 * @dev This simplifies the implementation of "user permissions".
 */
contract Whitelist is Ownable {
    mapping(address => bool) public whitelist;

    event WhitelistedAddressAdded(address addr);
    event WhitelistedAddressRemoved(address addr);

    /**
     * @dev Throws if called by any account that's not whitelisted.
     */
    modifier onlyWhitelisted() {
        require(whitelist[msg.sender]);
        _;
    }

    /**
     * @dev add an address to the whitelist
     * @param addr address
     * @return true if the address was added to the whitelist, false if the address was already in the whitelist
     */
    function addAddressToWhitelist(address addr) public onlyOwner returns(bool success) {
        if (!whitelist[addr]) {
            whitelist[addr] = true;
            emit WhitelistedAddressAdded(addr);
            success = true;
        }
    }

    /**
     * @dev add addresses to the whitelist
     * @param addrs addresses
     * @return true if at least one address was added to the whitelist,
     * false if all addresses were already in the whitelist
     */
    function addAddressesToWhitelist(address[] addrs) public onlyOwner returns(bool success) {
        for (uint256 i = 0; i < addrs.length; i++) {
            if (addAddressToWhitelist(addrs[i])) {
                success = true;
            }
        }
    }

    /**
     * @dev remove an address from the whitelist
     * @param addr address
     * @return true if the address was removed from the whitelist,
     * false if the address wasn't in the whitelist in the first place
     */
    function removeAddressFromWhitelist(address addr) public onlyOwner returns(bool success) {
        if (whitelist[addr]) {
            whitelist[addr] = false;
            emit WhitelistedAddressRemoved(addr);
            success = true;
        }
    }

    /**
     * @dev remove addresses from the whitelist
     * @param addrs addresses
     * @return true if at least one address was removed from the whitelist,
     * false if all addresses weren't in the whitelist in the first place
     */
    function removeAddressesFromWhitelist(address[] addrs) public onlyOwner returns(bool success) {
        for (uint256 i = 0; i < addrs.length; i++) {
            if (removeAddressFromWhitelist(addrs[i])) {
                success = true;
            }
        }
    }

}

/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
contract Pausable is Whitelist {
    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) || (whitelist[msg.sender]));
        _;
    }

    /**
     * @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 whenNotPaused {
        paused = true;
        emit Pause();
    }

    /**
     * @dev called by the owner to unpause, returns to normal state
     */
    function unpause() public onlyOwner whenPaused {
        paused = false;
        emit Unpause();
    }
}


/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * 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
 */
library SafeMath {

    /**
    * @dev Multiplies two numbers, throws on overflow.
    */
    function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
        // Gas optimization: this is cheaper than asserting 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
        if (a == 0) {
            return 0;
        }

        c = a * b;
        assert(c / a == b);
        return c;
    }

    /**
    * @dev Integer division of two numbers, truncating the quotient.
    */
    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 a / b;
    }

    /**
    * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
    */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(b <= a);
        return a - b;
    }

    /**
    * @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) public balances;

    uint256 public 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.
 * https://github.com/ethereum/EIPs/issues/20
 * 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,
        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;
    }

}


/**
 * @title Pausable token
 * @dev StandardToken modified with pausable transfers.
 **/
contract PausableToken is StandardToken, Pausable {

    function transfer(
        address _to,
        uint256 _value
    )
        public
        whenNotPaused
        returns (bool)
    {
        return super.transfer(_to, _value);
    }

    function transferFrom(
        address _from,
        address _to,
        uint256 _value
    )
        public
        whenNotPaused
        returns (bool)
    {
        return super.transferFrom(_from, _to, _value);
    }

    function approve(
        address _spender,
        uint256 _value
    )
        public
        whenNotPaused
        returns (bool)
    {
        return super.approve(_spender, _value);
    }

    function increaseApproval(
        address _spender,
        uint256 _addedValue
    )
        public
        whenNotPaused
        returns (bool success)
    {
        return super.increaseApproval(_spender, _addedValue);
    }

    function decreaseApproval(
        address _spender,
        uint256 _subtractedValue
    )
        public
        whenNotPaused
        returns (bool success)
    {
        return super.decreaseApproval(_spender, _subtractedValue);
    }
}


/**
 * @title Mintable token
 * @dev Simple ERC20 Token example, with mintable token creation
 * Based on code by TokenMarketNet: https://github.com/TokenMarketNet/ico/blob/master/contracts/MintableToken.sol
 */
contract MintableToken is PausableToken {
    event Mint(address indexed to, uint256 amount);
    event MintFinished();

    bool public mintingFinished = false;

    modifier canMint() {
        require(!mintingFinished);
        _;
    }

    /**
     * @dev Function to mint tokens
     * @param _to The address that will receive the minted tokens.
     * @param _amount The amount of tokens to mint.
     * @return A boolean that indicates if the operation was successful.
     */
    function mint(
        address _to,
        uint256 _amount
    )
        public
        onlyManager
        canMint
        returns (bool)
    {
        totalSupply_ = totalSupply_.add(_amount);
        balances[_to] = balances[_to].add(_amount);
        emit Mint(_to, _amount);
        emit Transfer(address(0), _to, _amount);
        return true;
    }

  /**
   * @dev Function to stop minting new tokens.
   * @return True if the operation was successful.
   */
    function finishMinting() public onlyOwner canMint  returns (bool) {
        mintingFinished = true;
        emit MintFinished();
        return true;
    }
}


/**
 * @title SimpleToken
 * @dev Very simple ERC20 Token example, where all tokens are pre-assigned to the creator.
 * Note they can later distribute these tokens as they wish using `transfer` and other
 * `StandardToken` functions.
 */
contract BeamToken is MintableToken {

    string public constant name = "Beams"; // solium-disable-line uppercase
    string public constant symbol = "BEAM"; // solBeamCrowdsaleContractium-disable-line uppercase
    uint8 public constant decimals = 18; // solium-disable-line uppercase

    mapping (address => bool) public isLocked;

    uint256 public constant INITIAL_SUPPLY = 0;

    constructor() public {
        totalSupply_ = INITIAL_SUPPLY;
    }

    function setLock(address _who, bool _lock) public onlyOwner {
        require(isLocked[_who] != _lock);
        isLocked[_who] = _lock;
    }

    /**
     * @dev Modifier to make a function callable only when the caller is not in locklist.
     */
    modifier whenNotLocked() {
        require(!isLocked[msg.sender]);
        _;
    }

    function transfer(
        address _to,
        uint256 _value
    )
        public
        whenNotLocked
        returns (bool)
    {
        return super.transfer(_to, _value);
    }

    function transferFrom(
        address _from,
        address _to,
        uint256 _value
    )
        public
        whenNotLocked
        returns (bool)
    {
        return super.transferFrom(_from, _to, _value);
    }

    function approve(
        address _spender,
        uint256 _value
    )
        public
        whenNotLocked
        returns (bool)
    {
        return super.approve(_spender, _value);
    }

    function increaseApproval(
        address _spender,
        uint256 _addedValue
    )
        public
        whenNotLocked
        returns (bool success)
    {
        return super.increaseApproval(_spender, _addedValue);
    }

    function decreaseApproval(
        address _spender,
        uint256 _subtractedValue
    )
        public
        whenNotLocked
        returns (bool success)
    {
        return super.decreaseApproval(_spender, _subtractedValue);
    }
}