pragma solidity ^0.5.0;


interface IERC20 {
	function totalSupply() external view returns (uint256);
	function balanceOf(address account) external view returns (uint256);
	function transfer(address recipient, uint256 amount) external returns (bool);
	function allowance(address owner, address spender) external view returns (uint256);
	function approve(address spender, uint256 amount) external returns (bool);
	function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

	event Transfer(address indexed from, address indexed to, uint256 value);
	event Approval(address indexed owner, address indexed spender, uint256 value);
}

library SafeMath {
	function add(uint256 a, uint256 b) internal pure returns (uint256) {
		uint256 c = a + b;
		require(c >= a, "SafeMath: addition overflow");

		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 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 mod(uint256 a, uint256 b) internal pure returns (uint256) {
		require(b != 0, "SafeMath: modulo by zero");
		return a % b;
	}
}

contract ERC20 is IERC20 {
	using SafeMath for uint256;

	mapping (address => uint256) private _balances;
	mapping (address => mapping (address => uint256)) private _allowances;
	uint256 private _totalSupply;

	function totalSupply() public view returns (uint256) {
		return _totalSupply;
	}

	function balanceOf(address account) public view returns (uint256) {
		return _balances[account];
	}

	function transfer(address recipient, uint256 amount) public returns (bool) {
		_transfer(msg.sender, recipient, amount);
		return true;
	}

	function allowance(address owner, address spender) public view returns (uint256) {
		return _allowances[owner][spender];
	}

	function approve(address spender, uint256 value) public returns (bool) {
		_approve(msg.sender, spender, value);
		return true;
	}

	function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
		_transfer(sender, recipient, amount);
		_approve(sender, msg.sender, _allowances[sender][msg.sender].sub(amount));
		return true;
	}

	function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
		_approve(msg.sender, spender, _allowances[msg.sender][spender].add(addedValue));
		return true;
	}

	function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
		_approve(msg.sender, spender, _allowances[msg.sender][spender].sub(subtractedValue));
		return true;
	}

	function _transfer(address sender, address recipient, uint256 amount) internal {
		require(sender != address(0), "ERC20: transfer from the zero address");
		require(recipient != address(0), "ERC20: transfer to the zero address");

		_balances[sender] = _balances[sender].sub(amount);
		_balances[recipient] = _balances[recipient].add(amount);
		emit Transfer(sender, recipient, amount);
	}

	function _mint(address account, uint256 amount) internal {
		require(account != address(0), "ERC20: mint to the zero address");

		_totalSupply = _totalSupply.add(amount);
		_balances[account] = _balances[account].add(amount);
		emit Transfer(address(0), account, amount);
	}

	function _burn(address account, uint256 value) internal {
		require(account != address(0), "ERC20: burn from the zero address");

		_totalSupply = _totalSupply.sub(value);
		_balances[account] = _balances[account].sub(value);
		emit Transfer(account, address(0), 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");

		_allowances[owner][spender] = value;
		emit Approval(owner, spender, value);
	}

	function _burnFrom(address account, uint256 amount) internal {
		_burn(account, amount);
		_approve(account, msg.sender, _allowances[account][msg.sender].sub(amount));
	}
}

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 ERC20Burnable is ERC20 {
	function burn(uint256 amount) public {
		_burn(msg.sender, amount);
	}

	function burnFrom(address account, uint256 amount) public {
		_burnFrom(account, amount);
	}
}

contract Ownable {
	address private _owner;

	event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

	constructor() internal {
		_owner = msg.sender;
		emit OwnershipTransferred(address(0), _owner);
	}

	modifier onlyOwner() {
		require(msg.sender == _owner, "Ownable: caller is not the owner");
		_;
	}

	function owner() public view returns (address) {
		return _owner;
	}

	function renounceOwnership() public onlyOwner {
		emit OwnershipTransferred(_owner, address(0));
		_owner = address(0);
	}

	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 Lockable is Ownable {
	uint256 constant INFINITY = 300000000000;
	
	bool private _tokenLocked;
	mapping(address => uint256) private _accountLocked;

	event TokenLocked();
	event TokenUnlocked();
	event AccountLocked(address account, uint256 time);
	event AccountUnlocked(address account, uint256 time);

	constructor() internal {
		_tokenLocked = false;
	}

	modifier whenUnlocked(address originator, address from, address to) {
		require(!_tokenLocked, 'Lockable: Token is locked.');
		require(!isAccountLocked(originator), 'Lockable: Account is locked.');

		if (originator != from) {
			require(!isAccountLocked(from), 'Lockable: Account is locked.');
		}

		require(!isAccountLocked(to), 'Lockable: Account is locked.');
		_;
	}

	function isAccountLocked(address account) internal view returns (bool) {
		if (_accountLocked[account] >= block.timestamp) {
			return true;
		} else {
			return false;
		}
	}

	function getTokenLockState() public onlyOwner view returns (bool) {
		return _tokenLocked;
	}

	function getAccountLockState(address account) public onlyOwner view returns (uint256) {
		return _accountLocked[account];
	}

	function getAccountLockState() public view returns (uint256) {
		return _accountLocked[msg.sender];
	}

	function lockToken() public onlyOwner {
		_tokenLocked = true;
		emit TokenLocked();
	}

	function unlockToken() public onlyOwner {
		_tokenLocked = false; 
		emit TokenUnlocked();
	}

	function lockAccount(address account) public onlyOwner {
		_lockAccount(account, INFINITY);
	}

	function lockAccount(address account, uint256 time) public onlyOwner {
		_lockAccount(account, time);
	}

	function _lockAccount(address account, uint256 time) private onlyOwner {
		_accountLocked[account] = time;
		emit AccountLocked(account, time);
	}

	function unlockAccount(address account) public onlyOwner {
		if (_accountLocked[account] != 0) {
			uint256 lockedTimestamp = _accountLocked[account];
			delete _accountLocked[account];
			emit AccountUnlocked(account, lockedTimestamp);
		}
	}
}

contract ERC20Lockable is ERC20, Lockable {
	function transfer(address to, uint256 value) public whenUnlocked(msg.sender, msg.sender, to) returns (bool) {
		return super.transfer(to, value);
	}

	function transferFrom(address from, address to, uint256 value) public whenUnlocked(msg.sender, from, to) returns (bool) {
		return super.transferFrom(from, to, value);
	}

	function approve(address spender, uint256 value) public whenUnlocked(msg.sender, msg.sender, spender) returns (bool) {
		return super.approve(spender, value);
	}

	function increaseAllowance(address spender, uint addedValue) public whenUnlocked(msg.sender, msg.sender, spender) returns (bool) {
		return super.increaseAllowance(spender, addedValue);
	}

	function decreaseAllowance(address spender, uint subtractedValue) public whenUnlocked(msg.sender, msg.sender, spender) returns (bool) {
		return super.decreaseAllowance(spender, subtractedValue);
	}
}

contract MediumToken is ERC20, ERC20Detailed, ERC20Burnable, ERC20Lockable {
	uint256 private _INITIAL_SUPPLY = 1000000000e18;
	string private _TOKEN_NAME = "Medium Token";
	string private _TOKEN_SYMBOL = "MDM";
	uint8 _DECIMALS = 18;

	constructor(address initialWallet) ERC20Detailed(_TOKEN_NAME, _TOKEN_SYMBOL, _DECIMALS) public {
		_mint(initialWallet, _INITIAL_SUPPLY);
	}
}