// SPDX-License-Identifier: LGPL-3.0-only
pragma solidity >=0.7.0 <0.9.0;

/**
 * @title IOwnerManager - Interface for contract which manages Safe owners and a threshold to authorize transactions.
 * @author @safe-global/safe-protocol
 */
interface IOwnerManager {
    event AddedOwner(address indexed owner);
    event RemovedOwner(address indexed owner);
    event ChangedThreshold(uint256 threshold);

    /**
     * @notice Adds the owner `owner` to the Safe and updates the threshold to `_threshold`.
     * @dev This can only be done via a Safe transaction.
     * @param owner New owner address.
     * @param _threshold New threshold.
     */
    function addOwnerWithThreshold(address owner, uint256 _threshold) external;

    /**
     * @notice Removes the owner `owner` from the Safe and updates the threshold to `_threshold`.
     * @dev This can only be done via a Safe transaction.
     * @param prevOwner Owner that pointed to the owner to be removed in the linked list
     * @param owner Owner address to be removed.
     * @param _threshold New threshold.
     */
    function removeOwner(address prevOwner, address owner, uint256 _threshold) external;

    /**
     * @notice Replaces the owner `oldOwner` in the Safe with `newOwner`.
     * @dev This can only be done via a Safe transaction.
     * @param prevOwner Owner that pointed to the owner to be replaced in the linked list
     * @param oldOwner Owner address to be replaced.
     * @param newOwner New owner address.
     */
    function swapOwner(address prevOwner, address oldOwner, address newOwner) external;

    /**
     * @notice Changes the threshold of the Safe to `_threshold`.
     * @dev This can only be done via a Safe transaction.
     * @param _threshold New threshold.
     */
    function changeThreshold(uint256 _threshold) external;

    /**
     * @notice Returns the number of required confirmations for a Safe transaction aka the threshold.
     * @return Threshold number.
     */
    function getThreshold() external view returns (uint256);

    /**
     * @notice Returns if `owner` is an owner of the Safe.
     * @return Boolean if `owner` is an owner of the Safe.
     */
    function isOwner(address owner) external view returns (bool);

    /**
     * @notice Returns a list of Safe owners.
     * @return Array of Safe owners.
     */
    function getOwners() external view returns (address[] memory);
}