From 59fe289eba9e6bfb830cb5ce048c6d2d15a2f276 Mon Sep 17 00:00:00 2001
From: Piotr Dyraga <piotr.dyraga@keep.network>
Date: Tue, 26 Apr 2022 11:43:33 +0200
Subject: [PATCH] Added reward-related functions to IApplication interface

The interface is minimal and does not enforce any specific
requirements on how the rewards are actually accrued.

`function withdrawRewards(address stakingProvider) external`
withdraws application rewards for the given staking provider.
Rewards are withdrawn to the staking provider's beneficiary
address set in the staking contract. Function emits
`RewardsWithdrawn(address indexed stakingProvider, uint96 amount)`
so that applications can easily track the total amount of
rewards accrued so far.

`function availableRewards(address stakingProvider)` Returns
the amount of application rewards available for withdrawal for
the given staking provider.
---
 contracts/staking/IApplication.sol     | 16 ++++++++++++++++
 contracts/test/TokenStakingTestSet.sol | 10 +++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/contracts/staking/IApplication.sol b/contracts/staking/IApplication.sol
index e55ce206..c241c52a 100644
--- a/contracts/staking/IApplication.sol
+++ b/contracts/staking/IApplication.sol
@@ -22,6 +22,15 @@ pragma solidity 0.8.9;
 ///         staking provider are eligible to slash the stake delegated to that
 ///         staking provider.
 interface IApplication {
+    /// @dev Event emitted by `withdrawRewards` function.
+    event RewardsWithdrawn(address indexed stakingProvider, uint96 amount);
+
+    /// @notice Withdraws application rewards for the given staking provider.
+    ///         Rewards are withdrawn to the staking provider's beneficiary
+    ///         address set in the staking contract.
+    /// @dev Emits `RewardsWithdrawn` event.
+    function withdrawRewards(address stakingProvider) external;
+
     /// @notice Used by T staking contract to inform the application that the
     ///         authorized amount for the given staking provider increased.
     ///         The application may do any necessary housekeeping. The
@@ -57,6 +66,13 @@ interface IApplication {
         uint96 toAmount
     ) external;
 
+    /// @notice Returns the amount of application rewards available for
+    ///         withdrawal for the given staking provider.
+    function availableRewards(address stakingProvider)
+        external
+        view
+        returns (uint96);
+
     /// @notice The minimum authorization amount required for the staking
     ///         provider so that they can participate in the application.
     function minimumAuthorization() external view returns (uint96);
diff --git a/contracts/test/TokenStakingTestSet.sol b/contracts/test/TokenStakingTestSet.sol
index 954e3c8f..36c1e143 100644
--- a/contracts/test/TokenStakingTestSet.sol
+++ b/contracts/test/TokenStakingTestSet.sol
@@ -209,6 +209,10 @@ contract ApplicationMock is IApplication {
         tokenStaking = _tokenStaking;
     }
 
+    function withdrawRewards(address) external {
+        // does nothing
+    }
+
     function authorizationIncreased(
         address stakingProvider,
         uint96,
@@ -272,7 +276,11 @@ contract ApplicationMock is IApplication {
         stakingProviderStruct.authorized = toAmount;
     }
 
-    function minimumAuthorization() external view returns (uint96) {
+    function availableRewards(address) external pure returns (uint96) {
+        return 0;
+    }
+
+    function minimumAuthorization() external pure returns (uint96) {
         return 0;
     }
 }