/**
Author: Loopring Foundation (Loopring Project Ltd)
*/

pragma solidity ^0.6.6;


// Taken from Argent's code base - https://github.com/argentlabs/argent-contracts/blob/develop/contracts/ens/ENS.sol
// with few modifications.
/**
 * ENS Registry interface.
 */
interface ENSRegistry {
    // 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);

    function setSubnodeOwner(bytes32 node, bytes32 label, address owner) external;
    function setResolver(bytes32 node, address resolver) external;
    function setOwner(bytes32 node, address owner) external;
    function setTTL(bytes32 node, uint64 ttl) 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);
}

/**
 * ENS Resolver interface.
 */
abstract contract ENSResolver {
    function addr(bytes32 _node) public view virtual returns (address);
    function setAddr(bytes32 _node, address _addr) public virtual;
    function name(bytes32 _node) public view virtual returns (string memory);
    function setName(bytes32 _node, string memory _name) public virtual;
}

/**
 * ENS Reverse Registrar interface.
 */
abstract contract ENSReverseRegistrar {
    function claim(address _owner) public virtual returns (bytes32 _node);
    function claimWithResolver(address _owner, address _resolver) public virtual returns (bytes32);
    function setName(string memory _name) public virtual returns (bytes32);
    function node(address _addr) public view virtual returns (bytes32);
}

/**
 * The ENS registry contract.
 */
contract ENSRegistryImpl is ENSRegistry {
    struct Record {
        address owner;
        address resolver;
        uint64 ttl;
    }

    mapping (bytes32 => Record) records;

    // Permits modifications only by the owner of the specified node.
    modifier only_owner(bytes32 node) {
        require(records[node].owner == msg.sender);
        _;
    }

    /**
     * @dev Constructs a new ENS registrar.
     */
    constructor() public {
        records[0x0].owner = msg.sender;
    }

    /**
     * @dev Transfers ownership of a node to a new address. May only be called by the current owner of the node.
     * @param node The node to transfer ownership of.
     * @param owner The address of the new owner.
     */
    function setOwner(bytes32 node, address owner) external override only_owner(node) {
        emit Transfer(node, owner);
        records[node].owner = owner;
    }

    /**
     * @dev Transfers ownership of a subnode keccak256(node, label) to a new address. May only be called by the owner of the parent node.
     * @param node The parent node.
     * @param label The hash of the label specifying the subnode.
     * @param owner The address of the new owner.
     */
    function setSubnodeOwner(bytes32 node, bytes32 label, address owner) external override only_owner(node) {
        bytes32 subnode = keccak256(abi.encodePacked(node, label));
        emit NewOwner(node, label, owner);
        records[subnode].owner = owner;
    }

    /**
     * @dev Sets the resolver address for the specified node.
     * @param node The node to update.
     * @param resolver The address of the resolver.
     */
    function setResolver(bytes32 node, address resolver) external override only_owner(node) {
        emit NewResolver(node, resolver);
        records[node].resolver = resolver;
    }

    /**
     * @dev Sets the TTL for the specified node.
     * @param node The node to update.
     * @param ttl The TTL in seconds.
     */
    function setTTL(bytes32 node, uint64 ttl) external override only_owner(node) {
        emit NewTTL(node, ttl);
        records[node].ttl = ttl;
    }

    /**
     * @dev Returns the address that owns the specified node.
     * @param node The specified node.
     * @return address of the owner.
     */
    function owner(bytes32 node) external view override returns (address) {
        return records[node].owner;
    }

    /**
     * @dev Returns the address of the resolver for the specified node.
     * @param node The specified node.
     * @return address of the resolver.
     */
    function resolver(bytes32 node) external view override returns (address) {
        return records[node].resolver;
    }

    /**
     * @dev Returns the TTL of a node, and any records associated with it.
     * @param node The specified node.
     * @return ttl of the node.
     */
    function ttl(bytes32 node) external view override returns (uint64) {
        return records[node].ttl;
    }

}