// SPDX-License-Identifier: MIT
pragma solidity 0.8.5;

abstract contract Context {
  function _msgSender() internal view virtual returns (address) {
    return msg.sender;
  }

  function _msgData() internal view virtual returns (bytes calldata) {
    this;
    // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
    return msg.data;
  }
}

abstract contract Ownable is Context {
  address internal _owner;

  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

  function owner() public view virtual returns (address) {
    return _owner;
  }

  modifier onlyOwner() {
    require(owner() == _msgSender(), "Ownable: caller is not the owner");
    _;
  }

  function renounceOwnership() public virtual onlyOwner {
    emit OwnershipTransferred(_owner, address(0));
    _owner = address(0);
  }

  function transferOwnership(address newOwner) public virtual onlyOwner {
    require(newOwner != address(0), "Ownable: new owner is the zero address");
    emit OwnershipTransferred(_owner, newOwner);
    _owner = newOwner;
  }
}

abstract contract Freezable is Context {
  event Freeze(address indexed holder);
  event Unfreeze(address indexed holder);

  mapping(address => bool) private _frozenAccount;

  modifier whenNotFrozen(address holder) {
    require(!_frozenAccount[holder]);
    _;
  }

  function isFrozen(address holder) public view virtual returns (bool frozen) {
    return _frozenAccount[holder];
  }

  function _freezeAccount(address holder) internal virtual returns (bool success) {
    require(!isFrozen(holder));
    _frozenAccount[holder] = true;
    emit Freeze(holder);
    success = true;
  }

  function _unfreezeAccount(address holder) internal virtual returns (bool success) {
    require(isFrozen(holder));
    _frozenAccount[holder] = false;
    emit Unfreeze(holder);
    success = true;
  }
}

abstract contract Pausable is Context {
  event Paused(address account);
  event Unpaused(address account);

  bool private _paused;

  constructor() {
    _paused = false;
  }

  function paused() public view virtual returns (bool) {
    return _paused;
  }

  modifier whenNotPaused() {
    require(!paused(), "Pausable: paused");
    _;
  }

  modifier whenPaused() {
    require(paused(), "Pausable: not paused");
    _;
  }

  function _pause() internal virtual whenNotPaused {
    _paused = true;
    emit Paused(_msgSender());
  }

  function _unpause() internal virtual whenPaused {
    _paused = false;
    emit Unpaused(_msgSender());
  }
}

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);
}

interface IERC20Metadata is IERC20 {
  function name() external view returns (string memory);

  function symbol() external view returns (string memory);

  function decimals() external view returns (uint8);
}

contract ERC20 is Context, IERC20, IERC20Metadata {
  mapping(address => uint256) private _balances;

  mapping(address => mapping(address => uint256)) private _allowances;

  uint256 private _totalSupply;

  string internal _name;
  string internal _symbol;
  uint8 internal _decimals;

  function name() public view virtual override returns (string memory) {
    return _name;
  }

  function symbol() public view virtual override returns (string memory) {
    return _symbol;
  }

  function decimals() public view virtual override returns (uint8) {
    return _decimals;
  }

  function totalSupply() public view virtual override returns (uint256) {
    return _totalSupply;
  }

  function balanceOf(address account) public view virtual override returns (uint256) {
    return _balances[account];
  }

  function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
    _transfer(_msgSender(), recipient, amount);
    return true;
  }

  function allowance(address owner, address spender) public view virtual override returns (uint256) {
    return _allowances[owner][spender];
  }

  function approve(address spender, uint256 amount) public virtual override returns (bool) {
    _approve(_msgSender(), spender, amount);
    return true;
  }

  function transferFrom(
    address sender,
    address recipient,
    uint256 amount
  ) public virtual override returns (bool) {
    _transfer(sender, recipient, amount);

    uint256 currentAllowance = _allowances[sender][_msgSender()];
    require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
    unchecked {
      _approve(sender, _msgSender(), currentAllowance - amount);
    }

    return true;
  }

  function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
    _approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
    return true;
  }

  function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
    uint256 currentAllowance = _allowances[_msgSender()][spender];
    require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
    unchecked {
      _approve(_msgSender(), spender, currentAllowance - subtractedValue);
    }

    return true;
  }

  function _transfer(
    address sender,
    address recipient,
    uint256 amount
  ) internal virtual {
    require(sender != address(0), "ERC20: transfer from the zero address");
    require(recipient != address(0), "ERC20: transfer to the zero address");

    _beforeTokenTransfer(sender, recipient, amount);

    uint256 senderBalance = _balances[sender];
    require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
    unchecked {
      _balances[sender] = senderBalance - amount;
    }
    _balances[recipient] += amount;

    emit Transfer(sender, recipient, amount);
  }

  function _mint(address account, uint256 amount) internal virtual {
    require(account != address(0), "ERC20: mint to the zero address");

    _beforeTokenTransfer(address(0), account, amount);

    _totalSupply += amount;
    _balances[account] += amount;
    emit Transfer(address(0), account, amount);
  }

  function _burn(address account, uint256 amount) internal virtual {
    require(account != address(0), "ERC20: burn from the zero address");

    _beforeTokenTransfer(account, address(0), amount);

    uint256 accountBalance = _balances[account];
    require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
    unchecked {
      _balances[account] = accountBalance - amount;
    }
    _totalSupply -= amount;

    emit Transfer(account, address(0), amount);
  }

  function _approve(
    address owner,
    address spender,
    uint256 amount
  ) internal virtual {
    require(owner != address(0), "ERC20: approve from the zero address");
    require(spender != address(0), "ERC20: approve to the zero address");

    _allowances[owner][spender] = amount;
    emit Approval(owner, spender, amount);
  }

  function _beforeTokenTransfer(
    address from,
    address to,
    uint256 amount
  ) internal virtual {}
}

abstract contract ERC20Burnable is Context, ERC20, Ownable {
  function burn(uint256 amount) public virtual {
    _burn(_msgSender(), amount);
  }

  function burnFrom(address account, uint256 amount) public virtual {
    uint256 currentAllowance = allowance(account, _msgSender());
    require(currentAllowance >= amount, "ERC20: burn amount exceeds allowance");
    unchecked {
      _approve(account, _msgSender(), currentAllowance - amount);
    }
    _burn(account, amount);
  }
}

contract Token is ERC20, Pausable, Freezable, ERC20Burnable {
  bool private initialized = false;

  function initialize(
    address initalizeOwner,
    string memory initalizeName,
    string memory initalizeSymbol,
    uint8 initalizeDecimals,
    uint256 initalizeSupply
  ) external {
    require(!initialized, "Token: already initialized");

    _owner = initalizeOwner;
    _name = initalizeName;
    _symbol = initalizeSymbol;
    _decimals = initalizeDecimals;
    _mint(initalizeOwner, initalizeSupply * (10**initalizeDecimals));

    initialized = true;
  }

  function pause() public onlyOwner {
    _pause();
  }

  function unpause() public onlyOwner {
    _unpause();
  }

  function freezeAccount(address holder) public onlyOwner {
    _freezeAccount(holder);
  }

  function unfreezeAccount(address holder) public onlyOwner {
    _unfreezeAccount(holder);
  }

  function _beforeTokenTransfer(
    address from,
    address to,
    uint256 amount
  ) internal override whenNotPaused whenNotFrozen(from) {
    super._beforeTokenTransfer(from, to, amount);
  }
}