From 3681483efe97c38a488563594c003dabfa23b2de Mon Sep 17 00:00:00 2001
From: Daniel Wang <99078276+dantaik@users.noreply.github.com>
Date: Fri, 9 Dec 2022 16:24:51 +0800
Subject: [PATCH] fix(protocol): update avg proof time and avg block time
 (#391)

---
 packages/protocol/contracts/L1/LibData.sol    |  4 +++-
 .../protocol/contracts/L1/v1/V1Proposing.sol  |  8 +++++++
 .../protocol/contracts/L1/v1/V1Proving.sol    |  3 ++-
 packages/protocol/contracts/L1/v1/V1Utils.sol | 21 +++++++++++++++++--
 .../protocol/contracts/L1/v1/V1Verifying.sol  | 20 +++++++++++++++---
 .../protocol/contracts/libs/LibConstants.sol  |  5 +++++
 6 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/packages/protocol/contracts/L1/LibData.sol b/packages/protocol/contracts/L1/LibData.sol
index d753a798a83..d7d7f884fcc 100644
--- a/packages/protocol/contracts/L1/LibData.sol
+++ b/packages/protocol/contracts/L1/LibData.sol
@@ -63,7 +63,9 @@ library LibData {
         // Changed when a block is proven/finalized
         uint64 latestVerifiedHeight;
         uint64 latestVerifiedId;
-        uint64 avgProofTime; // the proof time moving average
+        // the proof time moving average, note that for each block, only the
+        // first proof's time is considered.
+        uint64 avgProofTime;
         uint64 __reservedC1;
         // Reserved
         uint256[42] __gap;
diff --git a/packages/protocol/contracts/L1/v1/V1Proposing.sol b/packages/protocol/contracts/L1/v1/V1Proposing.sol
index bdd7ed9b1f5..6add00c3b10 100644
--- a/packages/protocol/contracts/L1/v1/V1Proposing.sol
+++ b/packages/protocol/contracts/L1/v1/V1Proposing.sol
@@ -98,6 +98,14 @@ library V1Proposing {
             meta.mixHash = bytes32(block.difficulty);
         }
 
+        state.avgBlockTime = V1Utils
+            .movingAverage({
+                maValue: state.avgBlockTime,
+                newValue: meta.timestamp - state.lastProposedAt,
+                maf: LibConstants.K_BLOCK_TIME_MAF
+            })
+            .toUint64();
+
         state.saveProposedBlock(
             state.nextBlockId,
             LibData.ProposedBlock({
diff --git a/packages/protocol/contracts/L1/v1/V1Proving.sol b/packages/protocol/contracts/L1/v1/V1Proving.sol
index 4182c022a51..0c0158e4e5f 100644
--- a/packages/protocol/contracts/L1/v1/V1Proving.sol
+++ b/packages/protocol/contracts/L1/v1/V1Proving.sol
@@ -269,7 +269,8 @@ library V1Proving {
             );
 
             require(
-                block.timestamp < V1Utils.uncleProofDeadline(state, fc),
+                block.timestamp <
+                    V1Utils.uncleProofDeadline(state, fc, target.id),
                 "L1:tooLate"
             );
 
diff --git a/packages/protocol/contracts/L1/v1/V1Utils.sol b/packages/protocol/contracts/L1/v1/V1Utils.sol
index b339b911899..5b1921ea073 100644
--- a/packages/protocol/contracts/L1/v1/V1Utils.sol
+++ b/packages/protocol/contracts/L1/v1/V1Utils.sol
@@ -96,9 +96,26 @@ library V1Utils {
     // Returns a deterministic deadline for uncle proof submission.
     function uncleProofDeadline(
         LibData.State storage state,
-        LibData.ForkChoice storage fc
+        LibData.ForkChoice storage fc,
+        uint256 blockId
     ) internal view returns (uint64) {
-        return fc.provenAt + state.avgProofTime;
+        if (blockId <= 2 * LibConstants.K_MAX_NUM_BLOCKS) {
+            return fc.provenAt + LibConstants.K_INITIAL_UNCLE_DELAY;
+        } else {
+            return fc.provenAt + state.avgProofTime;
+        }
+    }
+
+    function movingAverage(
+        uint256 maValue,
+        uint256 newValue,
+        uint256 maf
+    ) internal pure returns (uint256) {
+        if (maValue == 0) {
+            return newValue;
+        }
+        uint256 _ma = (maValue * (maf - 1) + newValue) / maf;
+        return _ma > 0 ? _ma : maValue;
     }
 
     function setBit(
diff --git a/packages/protocol/contracts/L1/v1/V1Verifying.sol b/packages/protocol/contracts/L1/v1/V1Verifying.sol
index c57776928f6..9f33dcc1356 100644
--- a/packages/protocol/contracts/L1/v1/V1Verifying.sol
+++ b/packages/protocol/contracts/L1/v1/V1Verifying.sol
@@ -61,15 +61,28 @@ library V1Verifying {
             i++
         ) {
             LibData.ForkChoice storage fc = state.forkChoices[i][latestL2Hash];
+            LibData.ProposedBlock storage target = LibData.getProposedBlock(
+                state,
+                i
+            );
 
             // Uncle proof can not take more than 2x time the first proof did.
-            if (!_isVerifiable(state, fc)) {
+            if (!_isVerifiable(state, fc, i)) {
                 break;
             } else {
                 if (fc.blockHash != LibConstants.K_BLOCK_DEADEND_HASH) {
                     latestL2Height += 1;
                     latestL2Hash = fc.blockHash;
                 }
+
+                state.avgProofTime = V1Utils
+                    .movingAverage({
+                        maValue: state.avgProofTime,
+                        newValue: fc.provenAt - target.proposedAt,
+                        maf: LibConstants.K_PROOF_TIME_MAF
+                    })
+                    .toUint64();
+
                 processed += 1;
                 emit BlockVerified(i, fc.blockHash);
                 _cleanUp(fc);
@@ -98,10 +111,11 @@ library V1Verifying {
 
     function _isVerifiable(
         LibData.State storage state,
-        LibData.ForkChoice storage fc
+        LibData.ForkChoice storage fc,
+        uint256 blockId
     ) private view returns (bool) {
         return
             fc.blockHash != 0 &&
-            block.timestamp > V1Utils.uncleProofDeadline(state, fc);
+            block.timestamp > V1Utils.uncleProofDeadline(state, fc, blockId);
     }
 }
diff --git a/packages/protocol/contracts/libs/LibConstants.sol b/packages/protocol/contracts/libs/LibConstants.sol
index a5782a01250..4804c038d8f 100644
--- a/packages/protocol/contracts/libs/LibConstants.sol
+++ b/packages/protocol/contracts/libs/LibConstants.sol
@@ -26,6 +26,11 @@ library LibConstants {
     uint256 public constant K_TX_MIN_GAS_LIMIT = 21000; // TODO
     uint256 public constant K_ANCHOR_TX_GAS_LIMIT = 250000;
 
+    uint256 public constant K_BLOCK_TIME_MAF = 1024;
+    uint256 public constant K_PROOF_TIME_MAF = 1024;
+
+    uint64 public constant K_INITIAL_UNCLE_DELAY = 60 minutes;
+
     bytes4 public constant K_ANCHOR_TX_SELECTOR =
         bytes4(keccak256("anchor(uint256,bytes32)"));