From edbae8d42a3929db13965ce5b445449b6372fc6b Mon Sep 17 00:00:00 2001
From: Daniel Wang <99078276+dantaik@users.noreply.github.com>
Date: Fri, 5 Apr 2024 14:53:42 +0800
Subject: [PATCH] feat(protocol): add `lastSyncedBlockId ` for L2 DAO vote
 aggregation (#16654)

Co-authored-by: David <david@taiko.xyz>
---
 packages/protocol/contracts/L1/TaikoData.sol  |  4 ++--
 packages/protocol/contracts/L1/TaikoL1.sol    | 24 +++++++++++++------
 .../contracts/L1/libs/LibVerifying.sol        |  8 +++++--
 3 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/packages/protocol/contracts/L1/TaikoData.sol b/packages/protocol/contracts/L1/TaikoData.sol
index ef19ea6b7f0..99b48b8b368 100644
--- a/packages/protocol/contracts/L1/TaikoData.sol
+++ b/packages/protocol/contracts/L1/TaikoData.sol
@@ -135,8 +135,8 @@ library TaikoData {
     struct SlotA {
         uint64 genesisHeight;
         uint64 genesisTimestamp;
-        uint64 __reservedA1;
-        uint64 __reservedA2;
+        uint64 lastSyncedBlockId;
+        uint64 lastSynecdAt;
     }
 
     struct SlotB {
diff --git a/packages/protocol/contracts/L1/TaikoL1.sol b/packages/protocol/contracts/L1/TaikoL1.sol
index 54412a0cc0a..6f76c668e00 100644
--- a/packages/protocol/contracts/L1/TaikoL1.sol
+++ b/packages/protocol/contracts/L1/TaikoL1.sol
@@ -57,8 +57,6 @@ contract TaikoL1 is EssentialContract, ITaikoL1, TaikoEvents, TaikoErrors {
 
     function init2() external onlyOwner reinitializer(2) {
         // reset some previously used slots for future reuse
-        state.slotA.__reservedA1 = 0;
-        state.slotA.__reservedA2 = 0;
         state.slotB.__reservedB1 = 0;
         state.slotB.__reservedB2 = 0;
         state.slotB.__reservedB3 = 0;
@@ -170,15 +168,27 @@ contract TaikoL1 is EssentialContract, ITaikoL1, TaikoEvents, TaikoErrors {
     }
 
     /// @notice Gets the state variables of the TaikoL1 contract.
-    /// @return a_ State variables stored at SlotA.
-    /// @return b_ State variables stored at SlotB.
+    /// @dev This method can be deleted once node/client stops using it.
+    /// @return State variables stored at SlotA.
+    /// @return State variables stored at SlotB.
     function getStateVariables()
         public
         view
-        returns (TaikoData.SlotA memory a_, TaikoData.SlotB memory b_)
+        returns (TaikoData.SlotA memory, TaikoData.SlotB memory)
     {
-        a_ = state.slotA;
-        b_ = state.slotB;
+        return (state.slotA, state.slotB);
+    }
+
+    /// @notice Gets SlotA
+    /// @return  State variables stored at SlotA.
+    function slotA() public view returns (TaikoData.SlotA memory) {
+        return state.slotA;
+    }
+
+    /// @notice Gets SlotB
+    /// @return  State variables stored at SlotB.
+    function slotB() public view returns (TaikoData.SlotB memory) {
+        return state.slotB;
     }
 
     /// @inheritdoc ITaikoL1
diff --git a/packages/protocol/contracts/L1/libs/LibVerifying.sol b/packages/protocol/contracts/L1/libs/LibVerifying.sol
index 71949ad03bc..9b533958398 100644
--- a/packages/protocol/contracts/L1/libs/LibVerifying.sol
+++ b/packages/protocol/contracts/L1/libs/LibVerifying.sol
@@ -228,8 +228,8 @@ library LibVerifying {
                 // Update protocol level state variables
                 _state.slotB.lastVerifiedBlockId = lastVerifiedBlockId;
 
-                // sync chain data
-                _syncChainData(_config, _resolver, lastVerifiedBlockId, stateRoot);
+                // Sync chain data
+                _syncChainData(_state, _config, _resolver, lastVerifiedBlockId, stateRoot);
             }
         }
     }
@@ -240,6 +240,7 @@ library LibVerifying {
     }
 
     function _syncChainData(
+        TaikoData.State storage _state,
         TaikoData.Config memory _config,
         IAddressResolver _resolver,
         uint64 _lastVerifiedBlockId,
@@ -254,6 +255,9 @@ library LibVerifying {
         );
 
         if (_lastVerifiedBlockId > lastSyncedBlock + _config.blockSyncThreshold) {
+            _state.slotA.lastSyncedBlockId = _lastVerifiedBlockId;
+            _state.slotA.lastSynecdAt = uint64(block.timestamp);
+
             signalService.syncChainData(
                 _config.chainId, LibSignals.STATE_ROOT, _lastVerifiedBlockId, _stateRoot
             );