// contracts/GLDToken.sol
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import {
    ERC20Upgradeable
} from "@openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
import {
    OwnableUpgradeable
} from "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import { Initializable } from "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
import {
    UUPSUpgradeable
} from "@openzeppelin/contracts-upgradeable/proxy/utils/UUPSUpgradeable.sol";

/// @title EspToken
/// @notice ERC20 token for the Espresso network, upgradeable via UUPS.
/// @dev Upgradeability & storage layout (frozen-inheritance pattern)
/// We intentionally do not use `__gap` slots. Once a version is deployed,
/// its storage layout is frozen and never modified. New state variables are
/// added only in a new child contract (V2, V3, …) that inherits from the
/// previous version and appends fields at the end. This preserves slot order
/// across upgrades without relying on gaps. (Note: upstream OZ parents may
/// include their own gaps—those remain untouched.)
contract EspToken is Initializable, ERC20Upgradeable, OwnableUpgradeable, UUPSUpgradeable {
    /// @notice Cannot renounce ownership
    error OwnershipCannotBeRenounced();

    /// @notice since the constructor initializes storage on this contract we disable it
    /// @dev storage is on the proxy contract since it calls this contract via delegatecall
    /// @custom:oz-upgrades-unsafe-allow constructor
    constructor() {
        _disableInitializers();
    }

    /// @notice This contract is called by the proxy when you deploy this contract
    function initialize(
        address owner,
        address initialRecipient,
        uint256 initialSupply,
        string memory name,
        string memory symbol
    ) public initializer {
        __ERC20_init(name, symbol);
        __Ownable_init(owner);
        __UUPSUpgradeable_init();
        initialSupply = initialSupply * 10 ** decimals();
        _mint(initialRecipient, initialSupply);
    }

    /// @notice only the owner can authorize an upgrade
    // solhint-disable-next-line no-empty-blocks
    function _authorizeUpgrade(address newImplementation) internal virtual override onlyOwner { }

    /// @notice Cannot renounce ownership
    /// @dev Override renounceOwnership() to revert, preventing accidental or malicious ownership
    /// renunciation
    function renounceOwnership() public virtual override onlyOwner {
        revert OwnershipCannotBeRenounced();
    }

    /// @notice Use this to get the implementation contract version
    function getVersion()
        public
        pure
        virtual
        returns (uint8 majorVersion, uint8 minorVersion, uint8 patchVersion)
    {
        return (1, 0, 0);
    }
}