/**
 * Source Code first verified at https://etherscan.io on Monday, March 25, 2019
 (UTC) */

pragma solidity ^0.5.0;

/**
 * @title SafeMath
 * @dev Unsigned math operations with safety checks that revert on error
 * @author nabirkin @cryptoalpha
 */
library SafeMath {
    /**
    * @dev Multiplies two unsigned integers, reverts on overflow.
    */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring '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;
        }

        uint256 c = a * b;
        require(c / a == b);

        return c;
    }

    /**
    * @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
    */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
    * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
    */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

    /**
    * @dev Adds two unsigned integers, reverts on overflow.
    */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    /**
    * @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
    * reverts when dividing by zero.
    */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }
}

contract CryptoAlphaToken {
    string public name = "CryptoAlphaToken";
    string public symbol = "CAT";
    uint8 public decimals = 0;
    uint256 private _cap = 10000;

    using SafeMath for uint256;

    mapping (address => uint256) private _balances;
    mapping (address => uint) private _mintTimestamps;
    uint256 private _totalSupply;
    address private _minter;

    event MinterTransferred(address indexed previousMinter, address indexed newMinter);
    event Transfer(address indexed from, address indexed to, uint256 value);

    constructor() public {
        _minter = msg.sender;
        emit MinterTransferred(address(0), _minter);
    }

    /**
     * @dev Total number of tokens in existence
     */
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    /**
    * @dev Gets the balance of the specified address.
    * @param owner The address to query 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];
    }

    /**
    * @dev Gets timestamp of the mint operation by the specified address.
    * @param owner The address to query the mint timestamp of.
    * @return An uint representing the seconds since unix epoch.
    */
    function mintTimestampOf(address owner) public view returns (uint) {
        return _mintTimestamps[owner];
    }

    /**
    * @return the cap for the token minting.
    */
    function cap() public view returns (uint256) {
        return _cap;
    }

    /**
     * @dev Function to mint tokens
     * @param to The address that will receive the minted tokens.
     * @param value The amount of tokens to mint.
     * @return A boolean that indicates if the operation was successful.
     */
    function mint(address to, uint256 value) public onlyMinter returns (bool) {
        _mint(to, value);
        return true;
    }

    /**
     * @dev Internal function that mints an amount of the token and assigns it to
     * an account. This encapsulates the modification of balances such that the
     * proper events are emitted.
     * @param account The account that will receive the created tokens.
     * @param value The amount that will be created.
     */
    function _mint(address account, uint256 value) internal {
        require(totalSupply().add(value) <= _cap);
        require(account != address(0));
        require(_balances[account] == 0);

        _totalSupply = _totalSupply.add(value);
        _balances[account] = value;
        _mintTimestamps[account] = now;
        emit Transfer(address(0), account, value);
    }


    /**
    * @return the address of the minter.
    */
    function minter() public view returns (address) {
        return _minter;
    }

    /**
     * @dev Throws if called by any account other than the minter.
     */
    modifier onlyMinter() {
        require(isMinter());
        _;
    }

    /**
    * @return true if `msg.sender` is the minter of the contract.
    */
    function isMinter() public view returns (bool) {
        return msg.sender == _minter;
    }

    /**
    * @dev Allows the current minter to transfer control of the contract to a newMinter.
    * @param newMinter The address to transfer mintership to.
    */
    function transferMintership(address newMinter) public onlyMinter {
        require(newMinter != address(0));
        emit MinterTransferred(_minter, newMinter);
        _minter = newMinter;
    }
}