pragma solidity >=0.8.4;

interface RNS {
    // Logged when the owner of a node assigns a new owner to a subnode.
    event NewOwner(bytes32 indexed node, bytes32 indexed label, address owner);

    // Logged when the owner of a node transfers ownership to a new account.
    event Transfer(bytes32 indexed node, address owner);

    // Logged when the resolver for a node changes.
    event NewResolver(bytes32 indexed node, address resolver);

    // Logged when the TTL of a node changes
    event NewTTL(bytes32 indexed node, uint64 ttl);

    // Logged when an operator is added or removed.
    event ApprovalForAll(
        address indexed owner,
        address indexed operator,
        bool approved
    );

    function setRecord(
        bytes32 node,
        address owner,
        address resolver,
        uint64 ttl
    ) external;

    function setSubnodeRecord(
        bytes32 node,
        bytes32 label,
        address owner,
        address resolver,
        uint64 ttl
    ) external;

    function setSubnodeOwner(
        bytes32 node,
        bytes32 label,
        address owner
    ) external returns (bytes32);

    function setResolver(bytes32 node, address resolver) external;

    function setOwner(bytes32 node, address owner) external;

    function setTTL(bytes32 node, uint64 ttl) external;

    function setApprovalForAll(address operator, bool approved) external;

    function owner(bytes32 node) external view returns (address);

    function resolver(bytes32 node) external view returns (address);

    function ttl(bytes32 node) external view returns (uint64);

    function recordExists(bytes32 node) external view returns (bool);

    function isApprovedForAll(
        address owner,
        address operator
    ) external view returns (bool);
}

pragma solidity ^0.8.4;

import "@openzeppelin/contracts/access/Ownable.sol";

contract Controllable is Ownable {
    mapping(address => bool) public controllers;

    event ControllerChanged(address indexed controller, bool enabled);

    modifier onlyController() {
        require(
            controllers[msg.sender],
            "Controllable: Caller is not a controller"
        );
        _;
    }

    function setController(address controller, bool enabled) public onlyOwner {
        controllers[controller] = enabled;
        emit ControllerChanged(controller, enabled);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

pragma solidity >=0.8.4;

import "../registry/RNS.sol";
import "./IReverseRegistrar.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "../root/Controllable.sol";

abstract contract NameResolver {
    function setName(bytes32 node, string memory name) public virtual;
}

bytes32 constant lookup = 0x3031323334353637383961626364656600000000000000000000000000000000;

bytes32 constant ADDR_REVERSE_NODE = 0x91d1777781884d03a6757a803996e38de2a42967fb37eeaca72729271025a9e2;

// namehash('addr.reverse')

contract ReverseRegistrar is Ownable, Controllable, IReverseRegistrar {
    RNS public immutable ens;
    NameResolver public defaultResolver;

    event ReverseClaimed(address indexed addr, bytes32 indexed node);
    event DefaultResolverChanged(NameResolver indexed resolver);

    /**
     * @dev Constructor
     * @param ensAddr The address of the RNS registry.
     */
    constructor(RNS ensAddr) {
        ens = ensAddr;

        // Assign ownership of the reverse record to our deployer
        ReverseRegistrar oldRegistrar = ReverseRegistrar(
            ensAddr.owner(ADDR_REVERSE_NODE)
        );
        if (address(oldRegistrar) != address(0x0)) {
            oldRegistrar.claim(msg.sender);
        }
    }

    modifier authorised(address addr) {
        require(
            addr == msg.sender ||
                controllers[msg.sender] ||
                ens.isApprovedForAll(addr, msg.sender) ||
                ownsContract(addr),
            "ReverseRegistrar: Caller is not a controller or authorised by address or the address itself"
        );
        _;
    }

    function setDefaultResolver(address resolver) public override onlyOwner {
        require(
            address(resolver) != address(0),
            "ReverseRegistrar: Resolver address must not be 0"
        );
        defaultResolver = NameResolver(resolver);
        emit DefaultResolverChanged(NameResolver(resolver));
    }

    /**
     * @dev Transfers ownership of the reverse RNS record associated with the
     *      calling account.
     * @param owner The address to set as the owner of the reverse record in RNS.
     * @return The RNS node hash of the reverse record.
     */
    function claim(address owner) public override returns (bytes32) {
        return claimForAddr(msg.sender, owner, address(defaultResolver));
    }

    /**
     * @dev Transfers ownership of the reverse RNS record associated with the
     *      calling account.
     * @param addr The reverse record to set
     * @param owner The address to set as the owner of the reverse record in RNS.
     * @param resolver The resolver of the reverse node
     * @return The RNS node hash of the reverse record.
     */
    function claimForAddr(
        address addr,
        address owner,
        address resolver
    ) public override authorised(addr) returns (bytes32) {
        bytes32 labelHash = sha3HexAddress(addr);
        bytes32 reverseNode = keccak256(
            abi.encodePacked(ADDR_REVERSE_NODE, labelHash)
        );
        emit ReverseClaimed(addr, reverseNode);
        ens.setSubnodeRecord(ADDR_REVERSE_NODE, labelHash, owner, resolver, 0);
        return reverseNode;
    }

    /**
     * @dev Transfers ownership of the reverse RNS record associated with the
     *      calling account.
     * @param owner The address to set as the owner of the reverse record in RNS.
     * @param resolver The address of the resolver to set; 0 to leave unchanged.
     * @return The RNS node hash of the reverse record.
     */
    function claimWithResolver(
        address owner,
        address resolver
    ) public override returns (bytes32) {
        return claimForAddr(msg.sender, owner, resolver);
    }

    /**
     * @dev Sets the `name()` record for the reverse RNS record associated with
     * the calling account. First updates the resolver to the default reverse
     * resolver if necessary.
     * @param name The name to set for this address.
     * @return The RNS node hash of the reverse record.
     */
    function setName(string memory name) public override returns (bytes32) {
        return
            setNameForAddr(
                msg.sender,
                msg.sender,
                address(defaultResolver),
                name
            );
    }

    /**
     * @dev Sets the `name()` record for the reverse RNS record associated with
     * the account provided. Updates the resolver to a designated resolver
     * Only callable by controllers and authorised users
     * @param addr The reverse record to set
     * @param owner The owner of the reverse node
     * @param resolver The resolver of the reverse node
     * @param name The name to set for this address.
     * @return The RNS node hash of the reverse record.
     */
    function setNameForAddr(
        address addr,
        address owner,
        address resolver,
        string memory name
    ) public override returns (bytes32) {
        bytes32 node = claimForAddr(addr, owner, resolver);
        NameResolver(resolver).setName(node, name);
        return node;
    }

    /**
     * @dev Returns the node hash for a given account's reverse records.
     * @param addr The address to hash
     * @return The RNS node hash.
     */
    function node(address addr) public pure override returns (bytes32) {
        return
            keccak256(
                abi.encodePacked(ADDR_REVERSE_NODE, sha3HexAddress(addr))
            );
    }

    /**
     * @dev An optimised function to compute the sha3 of the lower-case
     *      hexadecimal representation of an Ethereum address.
     * @param addr The address to hash
     * @return ret The SHA3 hash of the lower-case hexadecimal encoding of the
     *         input address.
     */
    function sha3HexAddress(address addr) private pure returns (bytes32 ret) {
        assembly {
            for {
                let i := 40
            } gt(i, 0) {

            } {
                i := sub(i, 1)
                mstore8(i, byte(and(addr, 0xf), lookup))
                addr := div(addr, 0x10)
                i := sub(i, 1)
                mstore8(i, byte(and(addr, 0xf), lookup))
                addr := div(addr, 0x10)
            }

            ret := keccak256(0, 40)
        }
    }

    function ownsContract(address addr) internal view returns (bool) {
        try Ownable(addr).owner() returns (address owner) {
            return owner == msg.sender;
        } catch {
            return false;
        }
    }
}

pragma solidity >=0.8.4;

interface IReverseRegistrar {
    function setDefaultResolver(address resolver) external;

    function claim(address owner) external returns (bytes32);

    function claimForAddr(
        address addr,
        address owner,
        address resolver
    ) external returns (bytes32);

    function claimWithResolver(
        address owner,
        address resolver
    ) external returns (bytes32);

    function setName(string memory name) external returns (bytes32);

    function setNameForAddr(
        address addr,
        address owner,
        address resolver,
        string memory name
    ) external returns (bytes32);

    function node(address addr) external pure returns (bytes32);
}