Add epoch snapshot endBlock attribute (#72)

Author: Mike-CZ

contracts/sfc/SFC.sol

@@ -75,6 +75,10 @@ contract SFC is SFCBase, Version {
         return getEpochSnapshot[epoch].offlineBlocks[validatorID];
     }
 
+    function getEpochEndBlock(uint256 epoch) public view returns (uint256) {
+        return getEpochSnapshot[epoch].endBlock;
+    }
+
     function rewardsStash(address delegator, uint256 validatorID) public view returns (uint256) {
         Rewards memory stash = _rewardsStash[delegator][validatorID];
         return stash.lockupBaseReward + stash.lockupExtraReward + stash.unlockedReward;
@@ -361,6 +365,7 @@ contract SFC is SFCBase, Version {
 
         currentSealedEpoch = currentEpoch();
         snapshot.endTime = _now();
+        snapshot.endBlock = block.number;
         snapshot.baseRewardPerSecond = c.baseRewardPerSecond();
         snapshot.totalSupply = totalSupply;
     }

contracts/sfc/SFCI.sol

@@ -44,6 +44,7 @@ interface SFCI {
         view
         returns (
             uint256 endTime,
+            uint256 endBlock,
             uint256 epochFee,
             uint256 totalBaseRewardWeight,
             uint256 totalTxRewardWeight,
@@ -137,6 +138,8 @@ interface SFCI {
 
     function getEpochOfflineBlocks(uint256 epoch, uint256 validatorID) external view returns (uint256);
 
+    function getEpochEndBlock(uint256 epoch) external view returns (uint256);
+
     function rewardsStash(address delegator, uint256 validatorID) external view returns (uint256);
 
     function getLockedStake(address delegator, uint256 toValidatorID) external view returns (uint256);

contracts/sfc/SFCState.sol

@@ -71,6 +71,7 @@ contract SFCState is Initializable, Ownable {
         mapping(uint256 => uint256) offlineBlocks;
         uint256[] validatorIDs;
         uint256 endTime;
+        uint256 endBlock;
         uint256 epochFee;
         uint256 totalBaseRewardWeight;
         uint256 totalTxRewardWeight;

contracts/test/UnitTestSFC.sol

@@ -120,6 +120,7 @@ interface SFCUnitTestI {
         view
         returns (
             uint256 endTime,
+            uint256 endBlock,
             uint256 epochFee,
             uint256 totalBaseRewardWeight,
             uint256 totalTxRewardWeight,
@@ -215,6 +216,8 @@ interface SFCUnitTestI {
 
     function getEpochOfflineBlocks(uint256 epoch, uint256 validatorID) external view returns (uint256);
 
+    function getEpochEndBlock(uint256 epoch) external view returns (uint256);
+
     function rewardsStash(address delegator, uint256 validatorID) external view returns (uint256);
 
     function getLockedStake(address delegator, uint256 toValidatorID) external view returns (uint256);

test/SFC.ts

@@ -413,6 +413,16 @@ describe('SFC', () => {
         expect(await this.sfc.currentEpoch.call()).to.equal(6);
         expect(await this.sfc.currentSealedEpoch()).to.equal(5);
       });
+
+      it('Should succeed and return endBlock', async function () {
+        const epochNumber = await this.sfc.currentEpoch();
+        await this.sfc.enableNonNodeCalls();
+        await this.sfc.sealEpoch([100, 101, 102], [100, 101, 102], [100, 101, 102], [100, 101, 102], 0);
+        const lastBlock = await ethers.provider.getBlockNumber();
+        // endBlock is on second position
+        expect((await this.sfc.getEpochSnapshot(epochNumber))[1]).to.equal(lastBlock);
+        expect(await this.sfc.getEpochEndBlock(epochNumber)).to.equal(lastBlock);
+      });
     });
   });