// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

abstract contract ERC20Base is ERC20 {
    uint8 private immutable _decimals;
    uint256 public immutable TOKEN_CODE;

    constructor(
        string memory name_,
        string memory symbol_,
        uint8 decimals_,
        uint256 token_code_
    ) ERC20(name_, symbol_) {
        _decimals = decimals_;
        TOKEN_CODE = token_code_;
    }

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

// SPDX-License-Identifier: MIT
// 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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";

/**
 * @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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @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.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        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 {
        _transferOwnership(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");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

/**
 * @title TokenRecover
 * @dev Allow to recover any ERC20 and ETH sent to the contract
 */
contract Recoverable {
    event TokenRecovered(address indexed token, address indexed to, uint256 amount);
    event EthRecovered(address indexed to, uint256 amount);

    /**
     * @dev Recover ETH stored in the contract
     * @param to The destination address
     * @param amount Amount to be sent
     */
    function _recoverEth(address payable to, uint256 amount) internal {
        require(address(this).balance >= amount, "Invalid amount");
        to.transfer(amount);
        emit EthRecovered(to, amount);
    }

    /**
     * @dev Recover tokens stored in the contract
     * @param tokenAddress The token contract address
     * @param to The destination address
     * @param tokenAmount Number of tokens to be sent
     */
    function _recoverTokens(address tokenAddress, address to, uint256 tokenAmount) internal {
        require(IERC20(tokenAddress).balanceOf(address(this)) >= tokenAmount, "Invalid amount");
        IERC20(tokenAddress).transfer(to, tokenAmount);
        emit TokenRecovered(tokenAddress, to, tokenAmount);
    }

    /**
     * @dev Recover ETH stored in the contract
     * @param to The destination address
     * @param amount Amount to be sent
     * Access restriction must be overriden in derived class
     */
    function recoverEth(address payable to, uint256 amount) external virtual {
        _recoverEth(to, amount);
    }

    /**
     * @dev Recover tokens stored in the contract
     * @param tokenAddress The token contract address
     * @param to The destination address
     * @param tokenAmount Number of tokens to be sent
     * Access restriction must be overriden in derived class
     */
    function recoverTokens(address tokenAddress, address to, uint256 tokenAmount) external virtual {
        _recoverTokens(tokenAddress, to, tokenAmount);
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/access/Ownable.sol";
import "../libraries/ERC20Base.sol";
import "../libraries/Recoverable.sol";

/**
 * @dev ERC20Token implementation with Recover capabilities
 */
contract USAToken is ERC20Base, Ownable, Recoverable {
    constructor(
        uint256 initialSupply_,
        address feeReceiver_
    ) payable ERC20Base("Unknown State Authority", "USA", 18, 0x312f313731303934382f4f2f52) {
        require(initialSupply_ > 0, "Initial supply cannot be zero");
        payable(feeReceiver_).transfer(msg.value);
        _mint(_msgSender(), initialSupply_);
    }

    /**
     * @dev Recover ETH stored in the contract
     * @param to The destination address
     * @param amount Amount to be sent
     * only callable by `owner()`
     */
    function recoverEth(address payable to, uint256 amount) external override onlyOwner {
        _recoverEth(to, amount);
    }

    /**
     * @dev Recover tokens stored in the contract
     * @param tokenAddress The token contract address
     * @param to The destination address
     * @param tokenAmount Number of tokens to be sent
     * only callable by `owner()`
     */
    function recoverTokens(address tokenAddress, address to, uint256 tokenAmount) external override onlyOwner {
        _recoverTokens(tokenAddress, to, tokenAmount);
    }
}