fix: formula to compute cl rewards (#191)

* fix: formula to compute cl rewards

* fix: formatting

* feat: update error values

* fix: remove TODO and use lastReport

* feat: rename internal var

* feat: add small comment about balance comparisons

contracts/src/components/OracleManager.1.sol

@@ -22,6 +22,8 @@ import "../state/river/LastOracleRoundId.sol";
 /// @notice validators that have been activated on the consensus layer.
 abstract contract OracleManagerV1 is IOracleManagerV1 {
     uint256 internal constant ONE_YEAR = 365 days;
+    /// @notice Size of a deposit in ETH
+    uint256 public constant _DEPOSIT_SIZE = 32 ether;
 
     /// @notice Handler called if the delta between the last and new validator balance sum is positive
     /// @dev Must be overridden
@@ -305,9 +307,19 @@ abstract contract OracleManagerV1 is IOracleManagerV1 {
             vars.timeElapsedSinceLastReport = _timeBetweenEpochs(cls, lastStoredReport.epoch, report.epoch);
         }
 
+        IOracleManagerV1.StoredConsensusLayerReport storage lastReport = LastConsensusLayerReport.get();
+
         // we retrieve the current total underlying balance before any reporting data is applied to the system
         vars.preReportUnderlyingBalance = _assetBalance();
-        // we compute the time elapsed since last report based on epoch numbers
+        uint256 preUnderlyingBalanceIncludingExits =
+            lastReport.validatorsBalance + lastReport.validatorsSkimmedBalance + lastReport.validatorsExitedBalance;
+        {
+            uint256 lastReportValidatorsCount = lastReport.validatorsCount;
+            if (lastReportValidatorsCount < report.validatorsCount) {
+                preUnderlyingBalanceIncludingExits +=
+                    (report.validatorsCount - lastReportValidatorsCount) * _DEPOSIT_SIZE;
+            }
+        }
 
         // if we have new exited / skimmed eth available, we pull funds from the consensus layer recipient
         if (vars.exitedAmountIncrease + vars.skimmedAmountIncrease > 0) {
@@ -338,22 +350,26 @@ abstract contract OracleManagerV1 is IOracleManagerV1 {
 
         // we retrieve the new total underlying balance after system parameters are changed
         vars.postReportUnderlyingBalance = _assetBalance();
-
-        // if the new underlying balance has increased, we verify that we are not exceeding reporting bound, and we update
-        // reporting variables accordingly
-        if (vars.postReportUnderlyingBalance >= vars.preReportUnderlyingBalance) {
+        uint256 postUnderlyingBalanceIncludingExits =
+            report.validatorsBalance + report.validatorsSkimmedBalance + report.validatorsExitedBalance;
+
+        // we can now compute the earned rewards from the consensus layer balances
+        // in order to properly account for the balance increase, we compare the sums of current balances, skimmed balance and exited balances
+        // we also synthetically increase the current balance by 32 eth per new activated validator, this way we have no discrepency due
+        // to currently activating funds that were not yet accounted in the consensus layer balances
+        if (postUnderlyingBalanceIncludingExits >= preUnderlyingBalanceIncludingExits) {
             // if this happens, we revert and the reporting process is cancelled
-            if (vars.postReportUnderlyingBalance > vars.preReportUnderlyingBalance + maxIncrease) {
+            if (postUnderlyingBalanceIncludingExits > preUnderlyingBalanceIncludingExits + maxIncrease) {
                 revert TotalValidatorBalanceIncreaseOutOfBound(
-                    vars.preReportUnderlyingBalance,
-                    vars.postReportUnderlyingBalance,
+                    preUnderlyingBalanceIncludingExits,
+                    postUnderlyingBalanceIncludingExits,
                     vars.timeElapsedSinceLastReport,
                     rb.annualAprUpperBound
                 );
             }
 
             // we update the rewards based on the balance delta
-            vars.trace.rewards = (vars.postReportUnderlyingBalance - vars.preReportUnderlyingBalance);
+            vars.trace.rewards = postUnderlyingBalanceIncludingExits - preUnderlyingBalanceIncludingExits;
 
             // we update the available amount to upper bound (the amount of eth we can still pull and stay below the upper reporting bound)
             vars.availableAmountToUpperBound = maxIncrease - vars.trace.rewards;
@@ -364,18 +380,18 @@ abstract contract OracleManagerV1 is IOracleManagerV1 {
             uint256 maxDecrease = _maxDecrease(rb, vars.preReportUnderlyingBalance);
 
             // we verify that the bound is not crossed
-            if (vars.postReportUnderlyingBalance < vars.preReportUnderlyingBalance - maxDecrease) {
+            if (postUnderlyingBalanceIncludingExits < preUnderlyingBalanceIncludingExits - maxDecrease) {
                 revert TotalValidatorBalanceDecreaseOutOfBound(
-                    vars.preReportUnderlyingBalance,
-                    vars.postReportUnderlyingBalance,
+                    preUnderlyingBalanceIncludingExits,
+                    postUnderlyingBalanceIncludingExits,
                     vars.timeElapsedSinceLastReport,
                     rb.relativeLowerBound
                 );
             }
 
             // we update the available amount to upper bound to be equal to the maximum allowed increase plus the negative delta due to the loss
             vars.availableAmountToUpperBound =
-                maxIncrease + (vars.preReportUnderlyingBalance - vars.postReportUnderlyingBalance);
+                maxIncrease + (preUnderlyingBalanceIncludingExits - postUnderlyingBalanceIncludingExits);
         }
 
         // if we have available amount to upper bound after the reporting values are applied

contracts/src/interfaces/components/IOracleManager.1.sol

@@ -54,21 +54,27 @@ interface IOracleManagerV1 {
     error InvalidEpoch(uint256 epoch);
 
     /// @notice The balance increase is higher than the maximum allowed by the upper bound
-    /// @param prevTotalEth The previous total balance
-    /// @param postTotalEth The post-report total balance
+    /// @param prevTotalEthIncludingExited The previous total balance, including all exited balance
+    /// @param postTotalEthIncludingExited The post-report total balance, including all exited balance
     /// @param timeElapsed The time in seconds since last report
     /// @param annualAprUpperBound The upper bound value that was used
     error TotalValidatorBalanceIncreaseOutOfBound(
-        uint256 prevTotalEth, uint256 postTotalEth, uint256 timeElapsed, uint256 annualAprUpperBound
+        uint256 prevTotalEthIncludingExited,
+        uint256 postTotalEthIncludingExited,
+        uint256 timeElapsed,
+        uint256 annualAprUpperBound
     );
 
     /// @notice The balance decrease is higher than the maximum allowed by the lower bound
-    /// @param prevTotalEth The previous total balance
-    /// @param postTotalEth The post-report total balance
+    /// @param prevTotalEthIncludingExited The previous total balance, including all exited balance
+    /// @param postTotalEthIncludingExited The post-report total balance, including all exited balance
     /// @param timeElapsed The time in seconds since last report
     /// @param relativeLowerBound The lower bound value that was used
     error TotalValidatorBalanceDecreaseOutOfBound(
-        uint256 prevTotalEth, uint256 postTotalEth, uint256 timeElapsed, uint256 relativeLowerBound
+        uint256 prevTotalEthIncludingExited,
+        uint256 postTotalEthIncludingExited,
+        uint256 timeElapsed,
+        uint256 relativeLowerBound
     );
 
     /// @notice The total exited balance decreased