contract AddressToAddressWhiteList is
    TimeLockUpgradeV2
{
    using AddressArrayUtils for address[];

    /* ============ State Variables ============ */

    address[] public keys;
    mapping(address => address) public whitelist;

    /* ============ Events ============ */

    event PairAdded(
        address indexed key,
        address value
    );

    event PairRemoved(
        address indexed key,
        address value
    );

    /* ============ Constructor ============ */

    /**
     * Constructor function for AddressToAddressWhiteList
     *
     * Allow initial addresses to be passed in so a separate transaction is not required for each.
     * Each key type address passed is matched with a corresponding value type token address at the same index.
     * The _initialKeys and _initialValues arrays must be equal length.
     *
     * @param _initialKeys         Starting set of key type addresses to whitelist
     * @param _initialValues       Starting set of value type addresses to whitelist
     */
    constructor(
        address[] memory _initialKeys,
        address[] memory _initialValues
    )
        public
    {
        require(
            _initialKeys.length == _initialValues.length,
            "AddressToAddressWhiteList.constructor: Address array lengths must match."
        );

        // Add each of initial addresses to state
        for (uint256 i = 0; i < _initialKeys.length; i++) {
            address keyTypeAddressToAdd = _initialKeys[i];

            // Require keys are unique
            require(
                whitelist[keyTypeAddressToAdd] == address(0),
                "AddressToAddressWhiteList.constructor: Key must be unique."
            );

            // Require values are non zero addresses
            require(
                _initialValues[i] != address(0),
                "AddressToAddressWhiteList.constructor: Value must be non zero."
            );

            keys.push(keyTypeAddressToAdd);
            whitelist[keyTypeAddressToAdd] = _initialValues[i];
        }
    }

    /* ============ External Functions ============ */

    /**
     * Add an address to the whitelist
     *
     * @param _key     Key type address to add to the whitelist
     * @param _value   Value type address to add to the whitelist under _key
     */
    function addPair(
        address _key,
        address _value
    )
        external
        timeLockUpgrade
    {
        require(
            whitelist[_key] == address(0),
            "AddressToAddressWhiteList.addPair: Address pair already exists."
        );

        require(
            _value != address(0),
            "AddressToAddressWhiteList.addPair: Value must be non zero."
        );

        keys.push(_key);
        whitelist[_key] = _value;

        emit PairAdded(_key, _value);
    }

    /**
     * Remove a address to address pair from the whitelist
     *
     * @param _key    Key type address to remove to the whitelist
     */
    function removePair(
        address _key
    )
        external
        timeLockUpgrade
    {
        address valueToRemove = whitelist[_key];

        require(
            valueToRemove != address(0),
            "AddressToAddressWhiteList.removePair: key type address is not current whitelisted."
        );

        keys = keys.remove(_key);
        whitelist[_key] = address(0);

        emit PairRemoved(_key, valueToRemove);
    }

    /**
     * Edit value type address associated with a key
     *
     * @param _key       Key type address to add to the whitelist
     * @param _value     Value type address to add to the whitelist under _key
     */
    function editPair(
        address _key,
        address _value
    )
        external
        timeLockUpgrade
    {
        require(
            whitelist[_key] != address(0),
            "AddressToAddressWhiteList.editPair: Address pair must exist."
        );

        require(
            _value != address(0),
            "AddressToAddressWhiteList.editPair: New value must be non zero."
        );

        emit PairRemoved(
            _key,
            whitelist[_key]
        );

        // Set new value type address for passed key type address
        whitelist[_key] = _value;

        emit PairAdded(
            _key,
            _value
        );
    }

    /**
     * Return array of all whitelisted addresses
     *
     * @return address[]      Array of key type addresses
     */
    function validAddresses()
        external
        view
        returns (address[] memory)
    {
        return keys;
    }

    /**
     * Return array of value type addresses based on passed in key type addresses
     *
     * @param  _key                Array of key type addresses to get value type addresses for
     * @return address[]           Array of value type addresses
     */
    function getValues(
        address[] calldata _key
    )
        external
        view
        returns (address[] memory)
    {
        // Get length of passed array
        uint256 arrayLength = _key.length;

        // Instantiate value type addresses array
        address[] memory values = new address[](arrayLength);

        for (uint256 i = 0; i < arrayLength; i++) {
            // Get value type address for key type address at index i
            values[i] = getValue(
                _key[i]
            );
        }

        return values;
    }

    /**
     * Return value type address associated with a passed key type address
     *
     * @param  _key               Address of key type
     * @return address            Address associated with _key
     */
    function getValue(
        address _key
    )
        public
        view
        returns (address)
    {
        // Require key to have matching value type address
        require(
            whitelist[_key] != address(0),
            "AddressToAddressWhiteList.getValue: No value for that address."
        );

        // Return address associated with key
        return whitelist[_key];
    }

    /**
     * Verifies an array of addresses against the whitelist
     *
     * @param  _keys                Array of key type addresses to check if value exists
     * @return bool                 Whether all addresses in the list are whitelisted
     */
    function areValidAddresses(
        address[] calldata _keys
    )
        external
        view
        returns (bool)
    {
        // Get length of passed array
        uint256 arrayLength = _keys.length;

        for (uint256 i = 0; i < arrayLength; i++) {
            // Return false if key type address doesn't have matching value type address
            if (whitelist[_keys[i]] == address(0)) {
                return false;
            }
        }

        return true;
    }
}
/**
 * @title AddressToAddressWhiteList
 * @author Set Protocol
 *
 * WhiteList that matches addresses to other addresses
 */
function removePair(
        address _key
    )
        external
        timeLockUpgrade
    {
        address valueToRemove = whitelist[_key];

        require(
            valueToRemove != address(0),
            "AddressToAddressWhiteList.removePair: key type address is not current whitelisted."
        );

        keys = keys.remove(_key);
        whitelist[_key] = address(0);

        emit PairRemoved(_key, valueToRemove);
    }
/**
 * Remove a address to address pair from the whitelist
 *
 * @param _key    Key type address to remove to the whitelist
 */