// SPDX-License-Identifier: BUSL-1.1
// Gearbox Protocol. Generalized leverage for DeFi protocols
// (c) Gearbox Holdings, 2022
pragma solidity ^0.8.10;

import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";

/// @title Claimable
/// @dev Implements logic for a two-step ownership transfer on top of Ownable
contract Claimable is Ownable {
    /// @dev The new owner that has not claimed ownership yet
    address public pendingOwner;

    /// @dev A modifier that restricts the function to the pending owner only
    modifier onlyPendingOwner() {
        if (msg.sender != pendingOwner) {
            revert("Claimable: Sender is not pending owner");
        }
        _;
    }

    /// @dev Sets pending owner to the new owner, but does not
    /// transfer ownership yet
    /// @param newOwner The address to become the future owner
    function transferOwnership(address newOwner) public override onlyOwner {
        require(
            newOwner != address(0),
            "Claimable: new owner is the zero address"
        );
        pendingOwner = newOwner;
    }

    /// @dev Used by the pending owner to claim ownership after transferOwnership
    function claimOwnership() external onlyPendingOwner {
        _transferOwnership(pendingOwner);
        pendingOwner = address(0);
    }
}