// SPDX-License-Identifier: GPL-3.0

pragma solidity ^0.8.0;

import "@openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC20/extensions/ERC20BurnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC20/extensions/ERC20PausableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";

contract UpgradeableERC20 is
    ERC20Upgradeable,
    ERC20BurnableUpgradeable,
    ERC20PausableUpgradeable,
    OwnableUpgradeable
{
    uint8 private _decimals;

    function initialize(string memory tokenName_, string memory symbol_)
        public
        initializer
    {
        __ERC20_init(tokenName_, symbol_);
        __Ownable_init();
        _decimals = 6;
        ERC20Upgradeable._mint(_msgSender(), (33333333 * _decimals));
    }

    function decimals() public view virtual override returns (uint8) {
        return _decimals;
    }

    function mint(address account, uint256 amount) public virtual onlyOwner {
        _mint(account, amount);
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual override(ERC20Upgradeable, ERC20PausableUpgradeable) {
        ERC20PausableUpgradeable._beforeTokenTransfer(from, to, amount);
        ERC20Upgradeable._beforeTokenTransfer(from, to, amount);
    }
}