// SPDX-License-Identifier: MIT
pragma solidity >=0.7.6 <0.9;

interface IGovernanceVotePower {
    /**
     * @notice Delegate all governance vote power of `msg.sender` to `_to`.
     * @param _to The address of the recipient
     **/
    function delegate(address _to) external;

    /**
     * @notice Undelegate all governance vote power that `msg.sender` has delegated.
     **/
    function undelegate() external;

    /**
    * @notice Get the governance vote power of `_who` at block `_blockNumber`
    * @param _who The address to get voting power.
    * @param _blockNumber The block number at which to fetch.
    * @return Governance vote power of `_who` at `_blockNumber`.
    */
    function votePowerOfAt(address _who, uint256 _blockNumber) external view returns(uint256);
}