accessmanagment.sol

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

contract Access {
    event GrantRole(bytes32 indexed role, address indexed account);
    event RevokeRole(bytes32 indexed role, address indexed account);

    mapping(bytes32 => mapping(address => bool)) public roles;

    modifier onlyRole(bytes32 _role) {
        require(roles[_role][msg.sender], "it is not authorized role");
        _;
    }

    constructor() {
        //Person which deploys contract is Admin
        _grantRole(Admin, msg.sender);
    }

    // Used for definig roles
    bytes32 private constant Admin = keccak256(abi.encodePacked("Admin"));
    bytes32 private constant User = keccak256(abi.encodePacked("User"));

    //Function defines the role inside of SC internaly
    function _grantRole(bytes32 _role, address _account) internal {
        roles[_role][_account] = true;
        emit GrantRole(_role, _account);
    }

    //Function defines the role inside of SC externaly and can be only called if msg.sender has Admin role granted
    function grantRole(bytes32 _role, address _account)
        external
        onlyRole(Admin)
    {
        _grantRole(_role, _account);
    }

    //Only Admin can revoke contract and role
    function revokeRole(bytes32 _role, address _account)
        external
        onlyRole(Admin)
    {
        roles[_role][_account] = false;
        emit RevokeRole(_role, _account);
    }
}