Testing out the creation of a simple decentralised domain naming service

faytey7dns.sol

//SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

    /// @author Faith M. Roberts
    /// @title A Simple Decentralized Domain Naming Service Contract.
contract Faytey7Dns {

    address public owner;

    constructor(){
        owner = msg.sender;
    }

    /// @dev Setting up the complex variable

    struct Domain {
        string DName;
        address Address;
        string Duration;
        bool exists;
    }

        // Mapping the struct to a variable
    mapping (string => Domain) public nameservice;
    mapping (address => bool) public Account;

        // Events to be emitted in the contract whenever there's a function call.
    event LogRegisteredDomain(string _DName, address _Address, string message);
    event LogDomainLookupStatus(bool);
    event LogReassignedDomainName(string _DName, string _NewDomain, string message);

        // Function to register new domain.
    function registerDomain(string memory _DName, address _Address, string memory _Duration) public returns(bool){
                
        require(!Account[msg.sender], "This Account Already Exists!!!");

        require(nameservice[_DName].exists == false, "Domain already exists!!!");

        Domain memory _newDomain = Domain(_DName,_Address,_Duration, true);

        nameservice[_DName] = _newDomain;

        emit LogRegisteredDomain(_DName,_Address, "Successfully registered");

        Account[msg.sender] = true;

        return true;
    }

        // Function to look up proposed names availability
    function domainNameLookup(string memory _DName) public view returns (address, string memory){
        require(nameservice[_DName].exists == true, "This Domain is currently Available");
        return(nameservice[_DName].Address,nameservice[_DName].Duration);
    }

        // Modifiers can be used to change the body of a function.
        // If this modifier is used, it will prepend a check that only passes
        // if the function is called from the owners address.
    modifier OnlyOwner(){
        require(isOwner());
        _;
    }
        // This function is used to confirm the caller of 
        // the reassign address name is the owner.
    function isOwner() public view returns(bool){
        return msg.sender == owner;
    }

        //Function to change the domain name to an available name
    function reassignAddressName(string memory _DName, string memory _NewDomain) public OnlyOwner returns(bool) {
        require(nameservice[_DName].exists == true, "This Domain is currently Available");
        nameservice[_DName].DName = _NewDomain;
        emit LogReassignedDomainName(_DName, _NewDomain, "Successfully reassigned");
        return true;
    }

}