pragma solidity ^0.5.0;

library SafeMath {
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) return 0;

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: division by zero");
        uint256 c = a / b;

        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        uint256 c = a - b;

        return c;
    }

    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0, "SafeMath: modulo by zero");
        return a % b;
    }
}

library Roles {
    struct Role {
        mapping (address => bool) bearer;
    }

    function add(Role storage role, address account) internal {
        require(!has(role, account), "Roles: account already has role");
        role.bearer[account] = true;
    }

    function remove(Role storage role, address account) internal {
        require(has(role, account), "Roles: account does not have role");
        role.bearer[account] = false;
    }

    function has(Role storage role, address account) internal view returns (bool) {
        require(account != address(0), "Roles: account is the zero account");
        return role.bearer[account];
    }
}

contract PauserRole {
    using Roles for Roles.Role;

    event PauserAdded(address indexed account);
    event PauserRemoved(address indexed account);

    Roles.Role private _pausers;

    constructor() internal {
        _addPauser(msg.sender);
    }

    modifier onlyPauser() {
        require(isPauser(msg.sender), "PauserRole: caller does not have the Pauser role");
        _;
    }

    function isPauser(address account) public view returns (bool) {
        return _pausers.has(account);
    }

    function addPauser(address account) public onlyPauser {
        _addPauser(account);
    }

    function renouncePauser() public {
        _removePauser(msg.sender);
    }

    function _addPauser(address account) internal {
        _pausers.add(account);
        emit PauserAdded(account);
    }

    function _removePauser(address account) internal {
        _pausers.remove(account);
        emit PauserRemoved(account);
    }
}

contract AdministratorRole {
    using Roles for Roles.Role;

    event AdministractorTransfered(address indexed previousAdmin, address indexed newAdmin);
    event LockerAdded(address indexed account);
    event LockerRemoved(address indexed account);

    address private _admin;
    Roles.Role private _lockers;

    constructor() internal {
        _admin = msg.sender;

        emit AdministractorTransfered(address(0), _admin);
    }

    function administrator() public view returns (address) {
        return _admin;
    }

    modifier onlyAdministrator() {
        require(isAdministrator(), "AdministratorRole: caller is not the administrator");
        _;
    }

    function isAdministrator() public view returns (bool) {
        return msg.sender == _admin;
    }

    function transferAdministrator(address newAdmin) public onlyAdministrator {
        _transferAdministrator(newAdmin);
    }

    function _transferAdministrator(address newAdmin) internal {
        require(newAdmin != address(0), "Ownable: new owner is the zero address");
        emit AdministractorTransfered(_admin, newAdmin);
        _admin = newAdmin;
    }

    modifier lockerExists(address account) {
        require(isLocker(account), "AdministratorRole: account is not a locker");
        _;
    }

    modifier lockerNotExists(address account) {
        require(!isLocker(account), "AdministratorRole: account is a locker");
        _;
    }

    modifier onlyUnlocker() {
        require(!isLocker(msg.sender), "AdministratorRole: caller is a locker");
        _;
    }

    modifier onlyLocker() {
        require(isLocker(msg.sender), "AdministratorRole: caller is not a locker");
        _;
    }

    function isLocker(address account) public view returns (bool) {
        return _lockers.has(account);
    }

    function addLocker(address account) public onlyAdministrator lockerNotExists(account) {
        _addLocker(account);
    }

    function removeLocker(address account) public onlyAdministrator lockerExists(account) {
        _removeLocker(account);
    }

    function _addLocker(address account) internal {
        _lockers.add(account);
        emit LockerAdded(account);
    }

    function _removeLocker(address account) internal {
        _lockers.remove(account);
        emit LockerRemoved(account);
    }
}

contract Ownable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    constructor() internal {
        _owner = msg.sender;

        emit OwnershipTransferred(address(0), _owner);
    }

    function owner() public view returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(isOwner(), "Ownable: caller is not the owner");
        _;
    }

    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

contract Pausable is PauserRole {
    event Paused(address account);
    event Unpaused(address account);

    bool private _paused;

    constructor() internal {
        _paused = false;
    }

    function paused() public view returns (bool) {
        return _paused;
    }

    modifier whenNotPaused() {
        require(!_paused, "Pausable: paused");
        _;
    }

    modifier whenPaused() {
        require(_paused, "Pausable: not paused");
        _;
    }

    function pause() public onlyPauser whenNotPaused {
        _paused = true;
        emit Paused(msg.sender);
    }

    function unpause() public onlyPauser whenPaused {
        _paused = false;
        emit Unpaused(msg.sender);
    }
}

interface IERC20 {
    function transfer(address to, uint256 value) external returns (bool);

    function approve(address spender, uint256 value) external returns (bool);

    function transferFrom(address from, address to, uint256 value) external returns (bool);

    function totalSupply() external view returns (uint256);

    function balanceOf(address who) external view returns (uint256);

    function allowance(address owner, address spender) external view returns (uint256);

    event Transfer(address indexed from, address indexed to, uint256 value);

    event Approval(address indexed owner, address indexed spender, uint256 value);
}

contract ERC20 is IERC20, AdministratorRole, Pausable {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowed;

    uint256 private _totalSupply;

    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(address owner) public view returns (uint256) {
        return _balances[owner];
    }

    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowed[owner][spender];
    }

    function transfer(address to, uint256 value) public whenNotPaused onlyUnlocker returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    function approve(address spender, uint256 value) public whenNotPaused onlyUnlocker returns (bool) {
        if (value != 0 && _allowed[msg.sender][spender] != 0) return false;
        _approve(msg.sender, spender, value);
        return true;
    }

    function transferFrom(address from, address to, uint256 value) public whenNotPaused lockerNotExists(from) returns (bool) {
        _transfer(from, to, value);
        _approve(from, msg.sender, _allowed[from][msg.sender].sub(value));
        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue) public whenNotPaused onlyUnlocker returns (bool) {
        _approve(msg.sender, spender, _allowed[msg.sender][spender].add(addedValue));
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public whenNotPaused onlyUnlocker returns (bool) {
        _approve(msg.sender, spender, _allowed[msg.sender][spender].sub(subtractedValue));
        return true;
    }

    function _transfer(address from, address to, uint256 value) internal {
        require(to != address(0), "ERC20: transfer to zero address");

        _balances[from] = _balances[from].sub(value);
        _balances[to] = _balances[to].add(value);
        emit Transfer(from, to, value);
    }

    function _approve(address owner, address spender, uint256 value) internal {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowed[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    function _mint(address account, uint256 value) internal {
        require(account != address(0), "ERC20: mint to zero address");
        _totalSupply = _totalSupply.add(value);
        _balances[account] = _balances[account].add(value);
        emit Transfer(address(0), account, value);
    }
}

contract ERC20Detailed is IERC20 {
    string private _name;
    string private _symbol;
    uint8 private _decimals;

    constructor(string memory name, string memory symbol, uint8 decimals) public {
        _name = name;
        _symbol = symbol;
        _decimals = decimals;
    }

    function name() public view returns (string memory) {
        return _name;
    }

    function symbol() public view returns (string memory) {
        return _symbol;
    }

    function decimals() public view returns (uint8) {
        return _decimals;
    }
}

contract ETMToken is Ownable, ERC20Detailed, ERC20 {
    using SafeMath for uint256;

    uint8 public constant DECIMALS = 18;
    uint256 private INIT_SUPPLY = uint256(210000000).mul(10 ** uint256(DECIMALS));
    bool private _destoried = false;

    constructor() public ERC20Detailed("EnTanMo", "ETM", DECIMALS) {
        _mint(msg.sender, INIT_SUPPLY);
    }

    function destory() public onlyOwner returns (bool) {
        if (!_destoried) {
            selfdestruct(address(0));
            _destoried = true;
            return true;
        }

        return false;
    }
}