Winner-Audited.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.20;

contract Winner is ReentrancyGuard, Pausable {
    address public owner;
    address public currentleader;
    uint256 public lastDepositedAmount;
    uint256 public currentLeaderReward;
    uint256 public nextLeaderReward;
    bool public rewardClaimed;
    uint256 public immutable challengeEnd;
    uint256 public challengeEndBlock;
    
    mapping(address => uint256) public rewards;
    mapping(address => uint256) public refunds;
    event NewLeader(address indexed leader, uint256 amount);
    event RewardClaimed(address indexed winner, uint256 amount);

    constructor(uint256 _challengeBlocks) payable {
        require(msg.value == 10 ether, "Require an initial 10 Ethers reward");
        require(msg.value == _initialReward, "Incorrect initial reward");
        require(_challengeBlocks > 0, "Challenge block must be greater than 0");
        
        owner = msg.sender;
        currentleader = address(0);
        lastDepositedAmount = msg.value;
        currentLeaderReward = 0;
        nextLeaderReward = msg.value;
        rewardClaimed = false;
        challengeEndBlock = block.number + _challengeBlocks;
        biddingEnd = challengeEnd - 1 hours;
    }

    function pause() external {
        require(msg.sender == owner, "Not owner");
        _pause();
    }

    function unpause() external {
        require(msg.sender == owner, "Not owner");
        _unpause();
    }
    
    function claimLeader() external payable noReentrant whenNotPaused {
        require(block.timestamp < biddingEnd, "Bidding period has ended");
        require(block.timestamp < challengeEnd, "Challenge is finished");
        require(msg.sender != currentleader, "You are the current leader");
        require(msg.value > lastDepositedAmount, "You must pay more than the current leader");
        require(msg.value >= 1 ether, "Deposit must be at least 1 Ether");

        if (currentleader == address(0)) {
            currentleader = msg.sender;
            lastDepositedAmount = msg.value;
            currentLeaderReward = nextLeaderReward;
            nextLeaderReward += lastDepositedAmount / 10;
        }
        else {
            uint256 refundAmount = lastDepositedAmount * 9 / 10;
            address prevLeader = currentleader;
            refunds[prevLeader] += refundAmount;
            currentleader = msg.sender;
            lastDepositedAmount = msg.value;
            currentLeaderReward = nextLeaderReward;
            nextLeaderReward += lastDepositedAmount / 10;
        }
        
        emit NewLeader(currentleader, lastDepositedAmount);
    }
    
    function withdrawRefund() external {
        uint256 amount = refunds[msg.sender];
        require(amount > 0, "No refund available");
        refunds[msg.sender] = 0;
        
        (bool success, ) = msg.sender.call{value: amount}("");
        require(success, "Failed to send Ether");
    }

      
    function claimPrincipalAndReward() external noReentrant {
        require(block.timestamp >= challengeEnd, "Challenge is not finished yet");
        require(msg.sender == currentleader, "You are not the winner");
        require(!rewardClaimed, "Reward was claimed");
        
        rewardClaimed = true;
        uint256 amount = lastDepositedAmount + currentLeaderReward;
        rewards[currentleader] += amount;
        
        emit RewardClaimed(msg.sender, amount);
    }
    
    function withdrawReward() external {
        uint256 amount = rewards[msg.sender];
        require(amount > 0, "No reward available");
        rewards[msg.sender] = 0;
        
        (bool success, ) = msg.sender.call{value: amount}("");
        require(success, "Failed to send Ether");
    }

    function getEtherBalance() external view returns (uint256) {
        return address(this).balance;
    }

    function isChallengeEnd() external view returns (bool) {
        return block.number >= challengeEndBlock;
    }
}