DIARandomOracle.sol

pragma solidity ^0.8.0;

contract DIARandomOracle {

struct Random { 
   string randomness;
   string signature;
   string previousSignature;
}
 
    mapping (uint256 => Random) public values;
    uint256 public lastRound = 0;

    address public oracleUpdater;
    
    event OracleUpdate(string key, uint128 value, uint128 timestamp);
    event UpdaterAddressChange(address newUpdater);
    
    constructor() {
        oracleUpdater = msg.sender;
    }

    function setRandomValue(uint256 _round, string memory _randomness,string memory _signature,string memory _previousSignature) public {
             require(msg.sender == oracleUpdater,"not a updater");
             require(lastRound<_round, "old round");
             lastRound = _round;
             values[_round] = Random(_randomness,_signature,_previousSignature);
    }
    
    function getValue(uint256 _round) external view returns ( Random memory) {
        return values[_round];
    }
    
    function updateOracleUpdaterAddress(address newOracleUpdaterAddress) public {
        require(msg.sender == oracleUpdater,"not a updater");
        oracleUpdater = newOracleUpdaterAddress;
        emit UpdaterAddressChange(newOracleUpdaterAddress);
    }

    function getRandomValueFromRound(uint256 _round ) external view returns (string memory){
        return values[_round].randomness;
    }
     function getRandomValueFromRoundWithSignature(uint256 _round ) external view returns (Random memory){
        return values[_round];
    }

    function getLastRound()public view returns(uint256){
        return lastRound;
    }
}