refactor: re-stake and unstake if evicted or zero rewards

Author: kupermind

contracts/interfaces/IStaking.sol

@@ -5,7 +5,8 @@ pragma solidity ^0.8.30;
 interface IStaking {
     enum StakingState {
         Unstaked,
-        Staked
+        Staked,
+        Evicted
     }
 
     /// @dev Gets set of agent Ids.
@@ -54,4 +55,11 @@ interface IStaking {
     /// @dev Gets available rewards.
     /// @return Available rewards amount.
     function availableRewards() external view returns (uint256);
+
+    /// @dev Checkpoint to allocate rewards up until a current time.
+    /// @return Staking service Ids (excluding evicted ones within a current epoch).
+    /// @return Set of reward-eligible service Ids.
+    /// @return Corresponding set of reward-eligible service rewards.
+    /// @return Evicted service Ids.
+    function checkpoint() external returns (uint256[] memory, uint256[] memory, uint256[] memory, uint256[] memory);
 }

contracts/l2/ExternalStakingDistributor.sol

@@ -169,6 +169,7 @@ contract ExternalStakingDistributor is Implementation, ERC721TokenReceiver {
         uint256 stakingDeposit,
         uint256 stakedBalance
     );
+    event ExternalServiceRestaked(address indexed sender, address indexed stakingProxy, uint256 indexed serviceId);
     event Deployed(uint256 indexed serviceId, address indexed multisig);
     event RewardsDistributed(
         uint256 indexed serviceId,
@@ -683,9 +684,20 @@ contract ExternalStakingDistributor is Implementation, ERC721TokenReceiver {
         // Get staking proxy available rewards amount
         uint256 availableRewards = IStaking(stakingProxy).availableRewards();
 
+        // Check if service is evicted
+        IStaking.StakingState stakingState = IStaking(stakingProxy).getStakingState(serviceId);
+
+        // Check for unstaked state
+        if (stakingState == IStaking.StakingState.Unstaked) {
+            revert ZeroValue();
+        }
+
         // Check for zero rewards balance and access: whitelisted managing agent or owner
-        // msg.sender does not matter if rewards are no longer available
-        if (availableRewards > 0 && !mapManagingAgents[msg.sender] && msg.sender != owner) {
+        // msg.sender does not matter if rewards are no longer available, or if the service is evicted
+        if (
+            stakingState == IStaking.StakingState.Staked && availableRewards > 0
+                && !(mapManagingAgents[msg.sender] || msg.sender == owner)
+        ) {
             revert UnauthorizedAccount(msg.sender);
         }
 
@@ -760,6 +772,58 @@ contract ExternalStakingDistributor is Implementation, ERC721TokenReceiver {
         _locked = 1;
     }
 
+    /// @dev Re-stakes evicted specified service Id.
+    /// @param stakingProxy Staking proxy address.
+    /// @param serviceId Service Id.
+    function reStake(address stakingProxy, uint256 serviceId) external {
+        // Reentrancy guard
+        if (_locked > 1) {
+            revert ReentrancyGuard();
+        }
+        _locked = 2;
+
+        // Check for zero address
+        if (stakingProxy == address(0)) {
+            revert ZeroAddress();
+        }
+
+        // Check for zero value
+        if (serviceId == 0) {
+            revert ZeroValue();
+        }
+
+        // Check if service is evicted
+        IStaking.StakingState stakingState = IStaking(stakingProxy).getStakingState(serviceId);
+
+        // Check for evicted state
+        if (stakingState != IStaking.StakingState.Evicted) {
+            revert ZeroValue();
+        }
+
+        // Check for access: curating agent or managing agent, or owner
+        if (!(mapCuratingAgents[msg.sender] || mapManagingAgents[msg.sender] || msg.sender == owner)) {
+            revert UnauthorizedAccount(msg.sender);
+        }
+
+        // Unstake service
+        uint256 reward = IStaking(stakingProxy).unstake(serviceId);
+
+        if (reward > 0) {
+            // Distribute leftover rewards, if not zero
+            _distributeRewards(stakingProxy, serviceId, reward);
+        }
+
+        // Approve service NFT for re-staking
+        INFToken(serviceRegistry).approve(stakingProxy, serviceId);
+
+        // Stake service
+        IStaking(stakingProxy).stake(serviceId);
+
+        emit ExternalServiceRestaked(msg.sender, stakingProxy, serviceId);
+
+        _locked = 1;
+    }
+
     /// @dev Sets staking proxy types.
     /// @param stakingProxies Set of staking proxies.
     /// @param configs Corresponding set of staking configs.

doc/agent-workflow.md

@@ -47,7 +47,7 @@ contract with the following parameters:
 - `_data`: `encodedData` value from `UserRequestForSignature()` event from [AMB (Home)](https://gnosisscan.io/address/0x75Df5AF045d91108662D8080fD1FEFAd6aA0bb59#events) contract;
 - `_signatures`: from the return value of [`getSignatures()`](https://gnosisscan.io/address/0x7d94ece17e81355326e3359115D4B02411825EdD#readContract#F2) method.
 
-Read full Gnosis guide of how to call execute signatures [here](https://docs.gnosischain.com/bridges/About%20Token%20Bridges/amb-bridge#how-to-call-executesignatures-on-foreign-amb-ethereum).
+Read full Gnosis guide on how to call execute signatures [here](https://docs.gnosischain.com/bridges/About%20Token%20Bridges/amb-bridge#how-to-call-executesignatures-on-foreign-amb-ethereum).
 
 #### Base bridge
 
@@ -126,7 +126,7 @@ Each staked service has a controlling [ActivityModule](../contracts/l2/ActivityM
 to all the LST service activity. In order to claim reward tokens and immediately transfer them to [Collector](../contracts/l2/Collector.sol)
 contract, agents need to call the `claim()` function, which triggers the `checkpoint()` function call as well of a corresponding `stakingProxy` contract.
 
-Events to track staking proxy addresses, stacked service Ids and their corresponding activity modules in [StakingManager](../contracts/l2/StakingManager.sol) proxy contract:
+Events to track staking proxy addresses, staked service Ids and their corresponding activity modules in [StakingManager](../contracts/l2/StakingManager.sol) proxy contract:
 ```solidity
 event Staked(address indexed stakingProxy, uint256 indexed serviceId, address activityModule);
 event Unstaked(address indexed stakingProxy, uint256 indexed serviceId, address activityModule);