Merge pull request #21 from semiotic-ai/11-add-a-function-to-revoke-a…

…uthorized-signers

feat(collateral-contract): adds ability to thaw and revoke authorized…

src/Collateral.sol

@@ -26,14 +26,20 @@ contract Collateral {
     struct CollateralAccount {
         uint256 balance; // Total collateral balance for a sender-receiver pair
         uint256 amountThawing; // Amount of collateral currently being thawed
-        uint256 thawEndTimestamp; // Block number at which thawing period ends
+        uint256 thawEndTimestamp; // Block number at which thawing period ends (zero if not thawing)
+    }
+
+    struct SenderAuthorization {
+        address sender; // Sender the signer is authorized to sign for
+        uint256 thawEndTimestamp; // Block number at which thawing period ends (zero if not thawing)
     }
 
     // Stores how much collateral each sender has deposited for each receiver, as well as thawing information
     mapping(address sender => mapping(address reciever => CollateralAccount collateralAccount))
         private collateralAccounts;
-    // Map of authorized signers to which sender they are authorized to sign for
-    mapping(address signer => address sender) private authorizedSigners;
+    // Map of signer to authorized signer information
+    mapping(address signer => SenderAuthorization authorizedSigner)
+        private authorizedSigners;
 
     // The ERC20 token used for collateral
     IERC20 public immutable collateralToken;
@@ -48,7 +54,10 @@ contract Collateral {
     AllocationIDTracker public immutable allocationIDTracker;
 
     // The duration (in seconds) in which collateral funds are thawing before they can be withdrawn
-    uint256 public immutable thawingPeriod;
+    uint256 public immutable withdrawCollateralThawingPeriod;
+
+    // The duration (in seconds) in which a signer is thawing before they can be revoked
+    uint256 public immutable revokeSignerThawingPeriod;
 
     /**
      * @dev Emitted when collateral is deposited for a receiver.
@@ -80,6 +89,23 @@ contract Collateral {
         uint256 thawEndTimestamp
     );
 
+    /**
+     * @dev Emitted when a thaw request is made for authorized signer
+     */
+    event ThawSigner(
+        address indexed sender,
+        address indexed authorizedSigner,
+        uint256 thawEndTimestamp
+    );
+
+    /**
+     * @dev Emitted when a authorized signer has been revoked
+     */
+    event RevokeAuthorizedSigner(
+        address indexed sender,
+        address indexed authorizedSigner
+    );
+
     /**
      * @dev Emitted when thawed collateral is withdrawn by the sender.
      */
@@ -99,13 +125,15 @@ contract Collateral {
         address staking_,
         address tapVerifier_,
         address allocationIDTracker_,
-        uint256 thawingPeriod_
+        uint256 withdrawCollateralThawingPeriod_,
+        uint256 revokeSignerThawingPeriod_
     ) {
         collateralToken = IERC20(collateralToken_);
         staking = IStaking(staking_);
         tapVerifier = TAPVerifier(tapVerifier_);
         allocationIDTracker = AllocationIDTracker(allocationIDTracker_);
-        thawingPeriod = thawingPeriod_;
+        withdrawCollateralThawingPeriod = withdrawCollateralThawingPeriod_;
+        revokeSignerThawingPeriod = revokeSignerThawingPeriod_;
     }
 
     /**
@@ -149,7 +177,9 @@ contract Collateral {
         // Increase the amount being thawed
         account.amountThawing = totalThawingRequested;
         // Set when the thaw is complete (thawing period number of seconds after current timestamp)
-        account.thawEndTimestamp = block.timestamp + thawingPeriod;
+        account.thawEndTimestamp =
+            block.timestamp +
+            withdrawCollateralThawingPeriod;
 
         emit Thaw(
             msg.sender,
@@ -197,17 +227,58 @@ contract Collateral {
      */
     function authorizeSigner(address signer, bytes calldata proof) external {
         require(
-            authorizedSigners[signer] == address(0),
+            authorizedSigners[signer].sender == address(0),
             "Signer already authorized"
         );
         require(
             verifyAuthorizedSignerProof(proof, signer),
             "Invalid signer proof"
         );
-        authorizedSigners[signer] = msg.sender;
+        authorizedSigners[signer].sender = msg.sender;
+        authorizedSigners[signer].thawEndTimestamp = 0;
         emit AuthorizeSigner(signer, msg.sender);
     }
 
+    /**
+     * @dev Starts thawing a signer to be removed from the authorized signers list.
+     * @param signer Address of the signer to remove.
+     */
+    function thawSigner(address signer) external {
+        require(
+            authorizedSigners[signer].sender == msg.sender,
+            "Signer not authorized for sender"
+        );
+        authorizedSigners[signer].thawEndTimestamp =
+            block.timestamp +
+            revokeSignerThawingPeriod;
+        emit ThawSigner(
+            authorizedSigners[signer].sender,
+            signer,
+            authorizedSigners[signer].thawEndTimestamp
+        );
+    }
+
+    /**
+     * @dev Revokes a signer from the authorized signers list if thawed.
+     * @param signer Address of the signer to remove.
+     */
+    function revokeAuthorizedSigner(address signer) external {
+        require(
+            authorizedSigners[signer].sender == msg.sender,
+            "Signer not authorized for sender"
+        );
+        require(
+            authorizedSigners[signer].thawEndTimestamp != 0,
+            "Signer not thawing"
+        );
+        require(
+            authorizedSigners[signer].thawEndTimestamp <= block.timestamp,
+            "Signer still thawing"
+        );
+        delete authorizedSigners[signer];
+        emit RevokeAuthorizedSigner(authorizedSigners[signer].sender, signer);
+    }
+
     /**
      * @dev Redeems collateral for a receiver using a signed RAV.
      * @param signedRAV Signed RAV containing the receiver and collateral amount.
@@ -224,11 +295,11 @@ contract Collateral {
     ) external {
         address signer = tapVerifier.recoverRAVSigner(signedRAV);
         require(
-            authorizedSigners[signer] != address(0),
+            authorizedSigners[signer].sender != address(0),
             "Signer not authorized"
         );
 
-        address sender = authorizedSigners[signer];
+        address sender = authorizedSigners[signer].sender;
         address receiver = msg.sender;
         uint256 amount = signedRAV.rav.valueAggregate;
         address allocationId = signedRAV.rav.allocationId;
@@ -285,7 +356,7 @@ contract Collateral {
         address signer,
         address receiver
     ) external view returns (CollateralAccount memory) {
-        return collateralAccounts[authorizedSigners[signer]][receiver];
+        return collateralAccounts[authorizedSigners[signer].sender][receiver];
     }
 
     /**