// SPDX-License-Identifier: GPL-2.0-or-later
// Gearbox Protocol. Generalized leverage for DeFi protocols
// (c) Gearbox Foundation, 2024.
pragma solidity ^0.8.23;

import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "@1inch/solidity-utils/contracts/libraries/SafeERC20.sol";
import {ERC20ZapperBase} from "../ERC20ZapperBase.sol";
import {ZapperBase} from "../ZapperBase.sol";

/// @title Underlying trait
/// @notice Implements tokenIn <-> underlying conversion functions for zappers with underlying as input token
abstract contract UnderlyingTrait is ERC20ZapperBase {
    using SafeERC20 for IERC20;

    /// @inheritdoc ZapperBase
    /// @dev Returns `underlying`
    function tokenIn() public view override returns (address) {
        return underlying;
    }

    /// @inheritdoc ZapperBase
    /// @dev Does nothing
    function _previewTokenInToUnderlying(uint256 tokenInAmount) internal pure override returns (uint256 assets) {}

    /// @inheritdoc ZapperBase
    /// @dev Does nothing
    function _previewUnderlyingToTokenIn(uint256 assets) internal pure override returns (uint256 tokenInAmount) {}

    /// @inheritdoc ZapperBase
    function _tokenInToUnderlying(uint256 tokenInAmount) internal override returns (uint256 assets) {
        IERC20(underlying).safeTransferFrom(msg.sender, address(this), tokenInAmount);
        assets = tokenInAmount;
    }

    /// @inheritdoc ZapperBase
    /// @dev Does nothing
    function _underlyingToTokenIn(uint256 assets, address receiver) internal override returns (uint256 tokenInAmount) {}
}