pragma solidity >=0.4.22 <0.7.0;


contract uBloggerRegistry {
    mapping(address => string) public address2Name;
    mapping(string => address) public name2Address;
    int256 numOfAccounts;
    address admin;
    bool registrationDisabled;    

    constructor () public {
        numOfAccounts = 0;
        admin = msg.sender;
        registrationDisabled = false;
    }
    
    function registerAccount(string memory accountName) public returns (int result) {
        if (registrationDisabled == true) {
            // Registration is disabled.
            result = -1;
        }else if ( bytes(accountName).length == 0 || bytes(accountName).length > 10) {
            // length of the accountName is invalid
            result = -2;
        } else if (bytes(address2Name[msg.sender]).length != 0 ) {
            // msg.sender already has a name registered
            result = -3;
        } else if (name2Address[accountName] != address(0) )  {
            // accountName is already taken
            result = -4;
        } else {
            address2Name[msg.sender] = accountName;
            name2Address[accountName] = msg.sender;
            numOfAccounts++;
            result = 0;
        }
   }

    function deleteAccount() public returns (int result) {
        if (bytes(address2Name[msg.sender]).length != 0 ) {
            string memory _accountName = address2Name[msg.sender];
            delete address2Name[msg.sender];
            delete name2Address[_accountName];
            numOfAccounts -= 1;
            result = 0;
        } else {
            // User does not have an account registered
            result = -1;
        }
    }
   
    function getNumOfAccounts() public view returns (int result) {
       result = numOfAccounts;
    }

    function openRegistrations() public returns (int result) {
        if (admin == msg.sender) {
            registrationDisabled = false;
        } else {
            result = -1;
        }
    }

    function closeRegistrations() public returns (int result) {
        if (admin == msg.sender) {
            registrationDisabled = true;
        } else {
            result = -1;
        }
    }
    
    function getAdmin() public view returns(address _address) {
        _address = admin;
    }
    
    function getAccountName(address _address) public view returns(string memory _name) {
        _name = address2Name[_address];
    }
    
}