functions added into Contracts to improve

src/HelloWormhole.sol

@@ -6,13 +6,20 @@ import "wormhole-solidity-sdk/interfaces/IWormholeReceiver.sol";
 
 contract HelloWormhole is IWormholeReceiver {
     event GreetingReceived(string greeting, uint16 senderChain, address sender);
+    event EtherReceived(address indexed sender, uint256 amount);
+    event ReceivedNonZeroEther(address indexed sender, uint256 amount);
 
     uint256 constant GAS_LIMIT = 50_000;
 
     IWormholeRelayer public immutable wormholeRelayer;
 
     string public latestGreeting;
 
+    modifier onlyWormholeRelayer() {
+        require(msg.sender == address(wormholeRelayer), "Only relayer allowed");
+        _;
+    }
+
     constructor(address _wormholeRelayer) {
         wormholeRelayer = IWormholeRelayer(_wormholeRelayer);
     }
@@ -33,7 +40,7 @@ contract HelloWormhole is IWormholeReceiver {
         string memory greeting
     ) public payable {
         uint256 cost = quoteCrossChainGreeting(targetChain);
-        require(msg.value == cost);
+        require(msg.value == cost, "Incorrect amount sent");
         wormholeRelayer.sendPayloadToEvm{value: cost}(
             targetChain,
             targetAddress,
@@ -49,9 +56,7 @@ contract HelloWormhole is IWormholeReceiver {
         bytes32, // address that called 'sendPayloadToEvm' (HelloWormhole contract address)
         uint16 sourceChain,
         bytes32 // unique identifier of delivery
-    ) public payable override {
-        require(msg.sender == address(wormholeRelayer), "Only relayer allowed");
-
+    ) public payable override onlyWormholeRelayer {
         // Parse the payload and do the corresponding actions!
         (string memory greeting, address sender) = abi.decode(
             payload,
@@ -60,4 +65,19 @@ contract HelloWormhole is IWormholeReceiver {
         latestGreeting = greeting;
         emit GreetingReceived(latestGreeting, sourceChain, sender);
     }
+
+    // Fallback function to handle unexpected Ether transfers
+    receive() external payable {
+        // Handle unexpected Ether transfers (if necessary)
+        emit EtherReceived(msg.sender, msg.value);
+
+        // Perform additional logic based on the received amount
+        if (msg.value > 0) {
+            // Perform some action or trigger an event based on the received amount
+            emit ReceivedNonZeroEther(msg.sender, msg.value);
+        } else {
+            // Reject the transfer if the received amount is zero
+            revert("Received zero Ether");
+        }
+    }
 }

src/extensions/HelloWormholeConfirmation.sol

@@ -24,8 +24,12 @@ contract HelloWormholeConfirmation is Base, IWormholeReceiver {
 
     constructor(
         address _wormholeRelayer,
-        address _wormhole
-    ) Base(_wormholeRelayer, _wormhole) {}
+        address _wormhole,
+        uint16 _chainId
+    ) Base(_wormholeRelayer, _wormhole) {
+        chainId = _chainId;
+    }
+
 
     function quoteCrossChainGreeting(
         uint16 targetChain,
@@ -44,26 +48,33 @@ contract HelloWormholeConfirmation is Base, IWormholeReceiver {
         uint16 targetChain,
         address targetAddress,
         string memory greeting,
-        uint256 receiverValueForSecondDeliveryPayment
+        uint256 receiverValueForSecondDeliveryPayment,
+        uint16 refundChain,
+        address refundAddress
     ) public payable {
         uint256 cost = quoteCrossChainGreeting(
             targetChain,
             receiverValueForSecondDeliveryPayment
         );
-        require(msg.value == cost);
-
+        require(msg.value == cost, "Incorrect amount sent");
+
+        // Additional check to ensure targetAddress is a valid Ethereum address
+        require(targetAddress != address(0), "Invalid target address");
+
+        // Ensure refundAddress is a valid Ethereum address
+        require(refundAddress != address(0), "Invalid refund address");
+
         wormholeRelayer.sendPayloadToEvm{value: cost}(
             targetChain,
             targetAddress,
             abi.encode(MessageType.GREETING, greeting, msg.sender), // payload
             receiverValueForSecondDeliveryPayment, // will be used to pay for the confirmation
             SENDING_GAS_LIMIT,
-            // we add a refund chain and address as the requester of the cross chain greeting
-            chainId,
-            msg.sender
+            refundChain,
+            refundAddress
         );
     }
-
+    
     function quoteConfirmation(
         uint16 targetChain
     ) public view returns (uint256 cost) {

src/extensions/HelloWormholeProtections.sol

@@ -7,8 +7,12 @@ import "wormhole-solidity-sdk/WormholeRelayerSDK.sol";
 
 contract HelloWormholeProtections is Base, IWormholeReceiver {
     event GreetingReceived(string greeting, uint16 senderChain, address sender);
+    event RelayerUpdated(address newRelayer);
+    event GreetingSet(string newGreeting);
+
 
     uint256 constant GAS_LIMIT = 50_000;
+    address owner = msg.sender;
 
     string public latestGreeting;
 
@@ -17,6 +21,11 @@ contract HelloWormholeProtections is Base, IWormholeReceiver {
         address _wormhole
     ) Base(_wormholeRelayer, _wormhole) {}
 
+    modifier onlyOwner {
+        require(msg.sender == owner, "Not the owner");
+        _;
+    }
+
     function quoteCrossChainGreeting(
         uint16 targetChain
     ) public view returns (uint256 cost) {
@@ -37,8 +46,8 @@ contract HelloWormholeProtections is Base, IWormholeReceiver {
         wormholeRelayer.sendPayloadToEvm{value: cost}(
             targetChain,
             targetAddress,
-            abi.encode(greeting, msg.sender), // payload
-            0, // no receiver value needed since we're just passing a message
+            abi.encode(greeting, msg.sender),
+            0,
             GAS_LIMIT
         );
     }
@@ -64,4 +73,15 @@ contract HelloWormholeProtections is Base, IWormholeReceiver {
 
         emit GreetingReceived(latestGreeting, sourceChain, sender);
     }
+
+    // Function to get the current balance of the contract
+    function getContractBalance() public view onlyOwner returns (uint256) {
+        return address(this).balance;
+    }
+
+     // Function to set a new greeting message
+     function setGreeting(string memory newGreeting) public onlyOwner {
+        latestGreeting = newGreeting;
+        emit GreetingSet(newGreeting);
+    }
 }