// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/ERC20.sol)
// File: @openzeppelin/contracts/utils/Context.sol

// // ███████████████████████████████████████████████████████████████████████████████████████████████████████
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// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: 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
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol


// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;


/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

// File: $WASHLY.sol


// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;




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) {
    return sub(a, b, "SafeMath: subtraction overflow");
  }

  function sub(
    uint256 a,
    uint256 b,
    string memory errorMessage
  ) internal pure returns (uint256) {
    require(b <= a, errorMessage);
    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) {
    return div(a, b, "SafeMath: division by zero");
  }

  function div(
    uint256 a,
    uint256 b,
    string memory errorMessage
  ) internal pure returns (uint256) {
    require(b > 0, errorMessage);
    uint256 c = a / b;
    return c;
  }
}

interface IUniswapV2Factory {
  event PairCreated(address indexed token0, address indexed token1, address pair, uint256);

  function getPair(address tokenA, address tokenB) external view returns (address pair);

  function createPair(address tokenA, address tokenB) external returns (address pair);
}

interface IUniswapV2Router01 {
  function factory() external pure returns (address);

  function WETH() external pure returns (address);

  function addLiquidityETH(
    address token,
    uint256 amountTokenDesired,
    uint256 amountTokenMin,
    uint256 amountETHMin,
    address to,
    uint256 deadline
  )
    external
    payable
    returns (
      uint256 amountToken,
      uint256 amountETH,
      uint256 liquidity
    );
}

interface IUniswapV2Router02 is IUniswapV2Router01 {
  function swapExactTokensForETHSupportingFeeOnTransferTokens(
    uint256 amountIn,
    uint256 amountOutMin,
    address[] calldata path,
    address to,
    uint256 deadline
  ) external;
}

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Context {
  address private _owner;
  address private _previousOwner;
  uint256 private _lockTime;

  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

  /**
   * @dev Initializes the contract setting the deployer as the initial owner.
   */
  constructor() {
    address msgSender = _msgSender();
    _owner = msgSender;
    emit OwnershipTransferred(address(0), msgSender);
  }

  /**
   * @dev Returns the address of the current owner.
   */
  function owner() public view returns (address) {
    return _owner;
  }

  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(_owner == _msgSender(), "Ownable: caller is not the owner");
    _;
  }

  /**
   * @dev Leaves the contract without owner. It will not be possible to call
   * `onlyOwner` functions anymore. Can only be called by the current owner.
   *
   * NOTE: Renouncing ownership will leave the contract without an owner,
   * thereby removing any functionality that is only available to the owner.
   */
  function renounceOwnership() public virtual onlyOwner {
    emit OwnershipTransferred(_owner, address(0));
    _owner = address(0);
  }

  /**
   * @dev Transfers ownership of the contract to a new account (`newOwner`).
   * Can only be called by the current owner.
   */
  function transferOwnership(address newOwner) public virtual onlyOwner {
    require(newOwner != address(0), "Ownable: new owner is the zero address");
    emit OwnershipTransferred(_owner, newOwner);
    _owner = newOwner;
  }

  function geUnlockTime() public view returns (uint256) {
    return _lockTime;
  }

  //Locks the contract for owner for the amount of time provided
  function lock(uint256 time) public virtual onlyOwner {
    _previousOwner = _owner;
    _owner = address(0);
    _lockTime = block.timestamp + time;
    emit OwnershipTransferred(_owner, address(0));
  }

  //Unlocks the contract for owner when _lockTime is exceeds
  function unlock() public virtual {
    require(_previousOwner == msg.sender, "You don't have permission to unlock");
    require(block.timestamp > _lockTime, "Contract is locked until 7 days");
    emit OwnershipTransferred(_owner, _previousOwner);
    _owner = _previousOwner;
  }
}

contract Washly is Context, IERC20, IERC20Metadata, Ownable {
  using SafeMath for uint256;

  mapping(address => uint256) private _balances;
  mapping(address => bool) private _isExcludedFromFees;
  mapping(address => bool) public automatedMarketMakerPairs;

  mapping(address => mapping(address => uint256)) private _allowances;

  uint256 internal constant ONE = 10**18;

  uint256 private _totalSupply = 100000000 * ONE;

  string private _name = "washly";
  string private _symbol = "WSHLY";

  address public marketingWallet = 0xE6871BB8fF5d0c432Ee199C65453456353440728;
  address public globalWarmingSupportWallet = 0x0B1B0dEeCf7311BdE009b19593d08Fdd5898E3De;

  uint256 public burningPercentage = 1;
  uint256 public globalWarmingPercentage = 1;
  uint256 public marketingPercentage = 2;
  uint256 private constantFee = burningPercentage + globalWarmingPercentage + marketingPercentage;

  uint256 public lpBuyingPercentage = 3;
  uint256 public lpSellingPercentage = 4;
  uint256 public lpTransferingPercentage = 1;

  address public uniswapV2Pair;

  address public airdropDistributer;

  mapping(address => bool) public isBlacklisted;

  bool public paused = true;

  address public constant DEAD_ADDRESS = 0x000000000000000000000000000000000000dEaD;
  IUniswapV2Router02 public uniswapV2Router;

  bool public takeFees = true;

  event ExcludeFromFees(address indexed account, bool isExcluded);
  event SetAutomatedMarketMakerPair(address indexed pair, bool indexed value);

  modifier onlyAirdropDistributer() {
    require(_msgSender() == airdropDistributer, "airdropDistributer only");
    _;
  }

  /**
   * The default value of {decimals} is 18. To select a different value for
   * {decimals} you should overload it.
   */
  constructor() {
    _updateUniswapV2Router(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D); //);
    // exclude from paying fees or having max transaction amount
    excludeFromFees(owner(), true);
    excludeFromFees(marketingWallet, true);
    excludeFromFees(globalWarmingSupportWallet, true);
    excludeFromFees(address(this), true);

    _balances[owner()] = _totalSupply.sub(8000000 * ONE);
    emit Transfer(address(0), owner(), _balances[owner()]);
  }

  function setAirdropDistributer(address _airdropDistributer) external onlyOwner {
    require(airdropDistributer == address(0), "airdrop distributer already set");
    airdropDistributer = _airdropDistributer;
  }

  function togglePaused() external onlyOwner {
    paused = !paused;
  }

  function _updateUniswapV2Router(address newAddress) internal returns (address) {
    uniswapV2Router = IUniswapV2Router02(newAddress);

    address _uniswapV2Pair = IUniswapV2Factory(uniswapV2Router.factory()).createPair(address(this), uniswapV2Router.WETH());

    uniswapV2Pair = _uniswapV2Pair;
    automatedMarketMakerPairs[uniswapV2Pair] = true;
    return uniswapV2Pair;
  }

  function distributeAirdrop(address _to, uint256 _amount) external onlyAirdropDistributer {
    _airdrop(_to, _amount);
  }

  function excludeFromFees(address account, bool excluded) public onlyOwner {
    require(_isExcludedFromFees[account] != excluded, "Account already 'excluded'");
    _isExcludedFromFees[account] = excluded;
    emit ExcludeFromFees(account, excluded);
  }

  function setFees(
    uint256 _burningPercentage,
    uint256 _globalWarmingPercentage,
    uint256 _marketingPercentage,
    uint256 _lpBuyingPercentage,
    uint256 _lpSellingPercentage,
    uint256 _lpTransferingPercentage
  ) public onlyOwner {
    burningPercentage = _burningPercentage;
    globalWarmingPercentage = _globalWarmingPercentage;
    marketingPercentage = _marketingPercentage;
    constantFee = burningPercentage + globalWarmingPercentage + marketingPercentage;

    lpBuyingPercentage = _lpBuyingPercentage;
    lpSellingPercentage = _lpSellingPercentage;
    lpTransferingPercentage = _lpTransferingPercentage;
  }

  /**
   * @dev Returns the name of the token.
   */
  function name() public view virtual override returns (string memory) {
    return _name;
  }

  /**
   * @dev Returns the symbol of the token, usually a shorter version of the
   * name.
   */
  function symbol() public view virtual override returns (string memory) {
    return _symbol;
  }

  /**
   * @dev Returns the number of decimals used to get its user representation.
   * For example, if `decimals` equals `2`, a balance of `505` tokens should
   * be displayed to a user as `5.05` (`505 / 10 ** 2`).
   *
   * Tokens usually opt for a value of 18, imitating the relationship between
   * Ether and Wei. This is the value {ERC20} uses, unless this function is
   * overridden;
   *
   * NOTE: This information is only used for _display_ purposes: it in
   * no way affects any of the arithmetic of the contract, including
   * {IERC20-balanceOf} and {IERC20-transfer}.
   */
  function decimals() public view virtual override returns (uint8) {
    return 18;
  }

  /**
   * @dev See {IERC20-totalSupply}.
   */
  function totalSupply() public view virtual override returns (uint256) {
    return _totalSupply;
  }

  /**
   * @dev See {IERC20-balanceOf}.
   */
  function balanceOf(address account) public view virtual override returns (uint256) {
    return _balances[account];
  }

  /**
   * @dev See {IERC20-transfer}.
   *
   * Requirements:
   *
   * - `to` cannot be the zero address.
   * - the caller must have a balance of at least `amount`.
   */
  function transfer(address to, uint256 amount) public virtual override returns (bool) {
    address owner = _msgSender();
    _transfer(owner, to, amount);
    return true;
  }

  /**
   * @dev See {IERC20-allowance}.
   */
  function allowance(address owner, address spender) public view virtual override returns (uint256) {
    return _allowances[owner][spender];
  }

  /**
   * @dev See {IERC20-approve}.
   *
   * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
   * `transferFrom`. This is semantically equivalent to an infinite approval.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   */
  function approve(address spender, uint256 amount) public virtual override returns (bool) {
    address owner = _msgSender();
    _approve(owner, spender, amount);
    return true;
  }

  /**
   * @dev See {IERC20-transferFrom}.
   *
   * Emits an {Approval} event indicating the updated allowance. This is not
   * required by the EIP. See the note at the beginning of {ERC20}.
   *
   * NOTE: Does not update the allowance if the current allowance
   * is the maximum `uint256`.
   *
   * Requirements:
   *
   * - `from` and `to` cannot be the zero address.
   * - `from` must have a balance of at least `amount`.
   * - the caller must have allowance for ``from``'s tokens of at least
   * `amount`.
   */
  function transferFrom(
    address from,
    address to,
    uint256 amount
  ) public virtual override returns (bool) {
    address spender = _msgSender();
    _spendAllowance(from, spender, amount);
    _transfer(from, to, amount);
    return true;
  }

  function setAutomatedMarketMakerPair(address pair, bool value) external onlyOwner {
    require(pair != uniswapV2Pair, "Pair cannot be removed from automatedMarketMakerPairs");
    _setAutomatedMarketMakerPair(pair, value);
  }

  function _setAutomatedMarketMakerPair(address pair, bool value) private {
    require(automatedMarketMakerPairs[pair] != value, "Automated market maker pair is already set to that value");
    automatedMarketMakerPairs[pair] = value;

    emit SetAutomatedMarketMakerPair(pair, value);
  }

  function _airdrop(address account, uint256 amount) internal virtual {
    require(account != address(0), "ERC20: mint to the zero address");

    _beforeTokenTransfer(address(0), account, amount);

    unchecked {
      // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
      _balances[account] += amount;
    }
    emit Transfer(address(0), account, amount);

    _afterTokenTransfer(address(0), account, amount);
  }

  /**
   * @dev Atomically increases the allowance granted to `spender` by the caller.
   *
   * This is an alternative to {approve} that can be used as a mitigation for
   * problems described in {IERC20-approve}.
   *
   * Emits an {Approval} event indicating the updated allowance.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   */
  function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
    address owner = _msgSender();
    _approve(owner, spender, allowance(owner, spender) + addedValue);
    return true;
  }

  /**
   * @dev Atomically decreases the allowance granted to `spender` by the caller.
   *
   * This is an alternative to {approve} that can be used as a mitigation for
   * problems described in {IERC20-approve}.
   *
   * Emits an {Approval} event indicating the updated allowance.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   * - `spender` must have allowance for the caller of at least
   * `subtractedValue`.
   */
  function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
    address owner = _msgSender();
    uint256 currentAllowance = allowance(owner, spender);
    require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
    unchecked {
      _approve(owner, spender, currentAllowance - subtractedValue);
    }

    return true;
  }

  function setBlacklisted(address _user, bool _isBlacklisted) external onlyOwner {
    isBlacklisted[_user] = _isBlacklisted;
  }

  function setTakeFees(bool _takeFees) external onlyOwner {
    require(takeFees != _takeFees, "Updating to current value, takeFees");
    takeFees = _takeFees;
  }

  function _transfer(
    address from,
    address to,
    uint256 amount
  ) internal virtual {
    bool takeFee = true;
    if (_isExcludedFromFees[from] || _isExcludedFromFees[to] || !takeFees || from == owner() || to == owner()) {
      takeFee = false;
    }
    if (paused) {
      require(from == owner() || to == owner(), "Contract is paused");
    }
    uint256 fees;
    if (takeFee) {
      uint256 burnFee = amount.mul(burningPercentage).div(100);
      _erc20Transfer(from, DEAD_ADDRESS, burnFee);

      uint256 globalWarmingFee = amount.mul(globalWarmingPercentage).div(100);
      _erc20Transfer(from, globalWarmingSupportWallet, globalWarmingFee);

      uint256 marketingFee = amount.mul(marketingPercentage).div(100);
      _erc20Transfer(from, marketingWallet, marketingFee);

      uint256 staticFees = burnFee + globalWarmingFee + marketingFee;

      uint256 lpFees;
      if (automatedMarketMakerPairs[to]) {
        lpFees = amount.mul(lpSellingPercentage).div(100);
      } else if (automatedMarketMakerPairs[from]) {
        lpFees = amount.mul(lpBuyingPercentage).div(100);
      } else {
        lpFees = amount.mul(lpTransferingPercentage).div(100);
      }
      _erc20Transfer(from, uniswapV2Pair, lpFees);
      //amount = amount.sub(fees);
      fees = staticFees + lpFees;
    }

    _erc20Transfer(from, to, amount.sub(fees));
  }

  /**
   * @dev Moves `amount` of tokens from `from` to `to`.
   *
   * This internal function is equivalent to {transfer}, and can be used to
   * e.g. implement automatic token fees, slashing mechanisms, etc.
   *
   * Emits a {Transfer} event.
   *
   * Requirements:
   *
   * - `from` cannot be the zero address.
   * - `to` cannot be the zero address.
   * - `from` must have a balance of at least `amount`.
   */
  function _erc20Transfer(
    address from,
    address to,
    uint256 amount
  ) internal virtual {
    require(from != address(0), "ERC20: transfer from the zero address");
    require(to != address(0), "ERC20: transfer to the zero address");
    require(!isBlacklisted[from] && !isBlacklisted[to], "blacklisted account tx");

    _beforeTokenTransfer(from, to, amount);

    uint256 fromBalance = _balances[from];
    require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
    unchecked {
      _balances[from] = fromBalance - amount;
      // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
      // decrementing then incrementing.
      _balances[to] += amount;
    }

    emit Transfer(from, to, amount);

    _afterTokenTransfer(from, to, amount);
  }

  /** @dev Creates `amount` tokens and assigns them to `account`, increasing
   * the total supply.
   *
   * Emits a {Transfer} event with `from` set to the zero address.
   *
   * Requirements:
   *
   * - `account` cannot be the zero address.
   */
  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;
    unchecked {
      // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
      _balances[account] += amount;
    }
    emit Transfer(address(0), account, amount);

    _afterTokenTransfer(address(0), account, amount);
  }

  /**
   * @dev Destroys `amount` tokens from `account`, reducing the
   * total supply.
   *
   * Emits a {Transfer} event with `to` set to the zero address.
   *
   * Requirements:
   *
   * - `account` cannot be the zero address.
   * - `account` must have at least `amount` tokens.
   */
  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;
      // Overflow not possible: amount <= accountBalance <= totalSupply.
      _totalSupply -= amount;
    }

    emit Transfer(account, address(0), amount);

    _afterTokenTransfer(account, address(0), amount);
  }

  /**
   * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
   *
   * This internal function is equivalent to `approve`, and can be used to
   * e.g. set automatic allowances for certain subsystems, etc.
   *
   * Emits an {Approval} event.
   *
   * Requirements:
   *
   * - `owner` cannot be the zero address.
   * - `spender` cannot be the zero address.
   */
  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);
  }

  /**
   * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
   *
   * Does not update the allowance amount in case of infinite allowance.
   * Revert if not enough allowance is available.
   *
   * Might emit an {Approval} event.
   */
  function _spendAllowance(
    address owner,
    address spender,
    uint256 amount
  ) internal virtual {
    uint256 currentAllowance = allowance(owner, spender);
    if (currentAllowance != type(uint256).max) {
      require(currentAllowance >= amount, "ERC20: insufficient allowance");
      unchecked {
        _approve(owner, spender, currentAllowance - amount);
      }
    }
  }

  /**
   * @dev Hook that is called before any transfer of tokens. This includes
   * minting and burning.
   *
   * Calling conditions:
   *
   * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
   * will be transferred to `to`.
   * - when `from` is zero, `amount` tokens will be minted for `to`.
   * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
   * - `from` and `to` are never both zero.
   *
   * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
   */
  function _beforeTokenTransfer(
    address from,
    address to,
    uint256 amount
  ) internal virtual {}

  /**
   * @dev Hook that is called after any transfer of tokens. This includes
   * minting and burning.
   *
   * Calling conditions:
   *
   * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
   * has been transferred to `to`.
   * - when `from` is zero, `amount` tokens have been minted for `to`.
   * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
   * - `from` and `to` are never both zero.
   *
   * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
   */
  function _afterTokenTransfer(
    address from,
    address to,
    uint256 amount
  ) internal virtual {}
}