Implement outbound and inbound amount transforms

solidity/contracts/token/extensions/HypNativeScaled.sol

@@ -17,62 +17,15 @@ contract HypNativeScaled is HypNative {
         scale = _scale;
     }
 
-    /**
-     * @inheritdoc HypNative
-     * @dev Sends scaled `msg.value` (divided by `scale`) to `_recipient`.
-     */
-    function transferRemote(
-        uint32 _destination,
-        bytes32 _recipient,
+    function _outbound(
         uint256 _amount
-    ) external payable override returns (bytes32 messageId) {
-        require(msg.value >= _amount, "Native: amount exceeds msg.value");
-        uint256 _hookPayment = msg.value - _amount;
-        uint256 _scaledAmount = _amount / scale;
-        return
-            _transferRemote(
-                _destination,
-                _recipient,
-                _scaledAmount,
-                _hookPayment
-            );
+    ) internal view override returns (uint256) {
+        return _amount / scale;
     }
 
-    /**
-     * @inheritdoc TokenRouter
-     * @dev uses (`msg.value` - `_amount`) as hook payment.
-     */
-    function transferRemote(
-        uint32 _destination,
-        bytes32 _recipient,
-        uint256 _amount,
-        bytes calldata _hookMetadata,
-        address _hook
-    ) external payable override returns (bytes32 messageId) {
-        require(msg.value >= _amount, "Native: amount exceeds msg.value");
-        uint256 _hookPayment = msg.value - _amount;
-        uint256 _scaledAmount = _amount / scale;
-        return
-            _transferRemote(
-                _destination,
-                _recipient,
-                _scaledAmount,
-                _hookPayment,
-                _hookMetadata,
-                _hook
-            );
-    }
-
-    /**
-     * @dev Sends scaled `_amount` (multiplied by `scale`) to `_recipient`.
-     * @inheritdoc TokenRouter
-     */
-    function _transferTo(
-        address _recipient,
-        uint256 _amount,
-        bytes calldata metadata // no metadata
-    ) internal override {
-        uint256 scaledAmount = _amount * scale;
-        HypNative._transferTo(_recipient, scaledAmount, metadata);
+    function _inbound(
+        uint256 _amount
+    ) internal view override returns (uint256) {
+        return _amount * scale;
     }
 }

solidity/contracts/token/libs/TokenRouter.sol

@@ -116,9 +116,11 @@ abstract contract TokenRouter is GasRouter {
         address _hook
     ) internal virtual returns (bytes32 messageId) {
         bytes memory _tokenMetadata = _transferFromSender(_amountOrId);
+
+        uint256 outboundAmount = _outbound(_amountOrId);
         bytes memory _tokenMessage = TokenMessage.format(
             _recipient,
-            _amountOrId,
+            outboundAmount,
             _tokenMetadata
         );
 
@@ -130,7 +132,19 @@ abstract contract TokenRouter is GasRouter {
             _hook
         );
 
-        emit SentTransferRemote(_destination, _recipient, _amountOrId);
+        emit SentTransferRemote(_destination, _recipient, outboundAmount);
+    }
+
+    function _outbound(
+        uint256 _amountOrId
+    ) internal view virtual returns (uint256) {
+        return _amountOrId;
+    }
+
+    function _inbound(
+        uint256 _amountOrId
+    ) internal view virtual returns (uint256) {
+        return _amountOrId;
     }
 
     /**
@@ -163,7 +177,7 @@ abstract contract TokenRouter is GasRouter {
         bytes32 recipient = _message.recipient();
         uint256 amount = _message.amount();
         bytes calldata metadata = _message.metadata();
-        _transferTo(recipient.bytes32ToAddress(), amount, metadata);
+        _transferTo(recipient.bytes32ToAddress(), _inbound(amount), metadata);
         emit ReceivedTransferRemote(_origin, recipient, amount);
     }
 

solidity/test/token/HypNativeScaled.t.sol

@@ -144,7 +144,7 @@ contract HypNativeScaledTest is Test {
         environment.processNextPendingMessage();
     }
 
-    function test_tranferRemote(uint256 amount) public {
+    function test_transferRemote(uint256 amount) public {
         vm.assume(amount <= mintAmount);
 
         uint256 nativeValue = amount * (10 ** nativeDecimals);