Add maturity time

contracts/StakingPool.sol

@@ -21,6 +21,7 @@ contract StakingPool {
     string  public adminContactInfo;
     uint256 public totalStakes;
     uint256 public maxStakers;
+    uint256 public maturityTime;
 
     // Miner fee rate in basis point.
     address public miner;
@@ -41,7 +42,8 @@ contract StakingPool {
         uint256 _minStakes,
         uint256 _minerFeeRateBp,
         uint256 _poolMaintainerFeeRateBp,
-        uint256 _maxStakers
+        uint256 _maxStakers,
+        uint256 _maturityTime
     )
         public
     {
@@ -51,6 +53,7 @@ contract StakingPool {
             _minerFeeRateBp + _poolMaintainerFeeRateBp <= MAX_BP,
             "Fee rate should be in basis point."
         );
+        require(_maturityTime > now, "Maturity time should be later than now.");
         miner = _miner;
         minerContactInfo = _minerContactInfo;
         admin = _admin;
@@ -60,6 +63,7 @@ contract StakingPool {
         minerFeeRateBp = _minerFeeRateBp;
         poolMaintainerFeeRateBp = _poolMaintainerFeeRateBp;
         maxStakers = _maxStakers;
+        maturityTime = _maturityTime; // timestamp(seconds)
     }
 
     modifier onlyMiner() {
@@ -197,24 +201,32 @@ contract StakingPool {
         if (dividend == 0) {
             return;
         }
+        uint256 totalPaid = 0;
         uint256 feeRateBp = minerFeeRateBp + poolMaintainerFeeRateBp;
+        if (maturityTime + 246060 <= now) {
+            feeRateBp = 0;
+        }
+
         uint256 stakerPayout = dividend.mul(MAX_BP - feeRateBp).div(MAX_BP);
-        uint256 totalPaid = 0;
         for (uint256 i = 0; i < stakers.length; i++) {
             StakerInfo storage info = stakerInfo[stakers[i]];
             uint256 toPay = stakerPayout.mul(info.stakes).div(totalStakes);
             totalPaid = totalPaid.add(toPay);
             info.stakes = info.stakes.add(toPay);
         }
-
         totalStakes = totalStakes.add(totalPaid);
 
-        uint256 totalFee = dividend.sub(totalPaid);
-        uint256 feeForMiner = totalFee.mul(minerFeeRateBp).div(feeRateBp);
-        uint256 feeForMaintainer = totalFee.sub(feeForMiner);
-        poolMaintainerFee = poolMaintainerFee.add(feeForMaintainer);
-        minerReward = minerReward.add(feeForMiner);
-        assert(balance >= totalStakes);
+        if (feeRateBp != 0) {
+            uint256 totalFee = dividend.sub(totalPaid);
+            // For miner
+            uint256 feeForMiner = totalFee.mul(minerFeeRateBp).div(feeRateBp);
+            minerReward = minerReward.add(feeForMiner);
+            // For pool maintainer
+            uint256 feeForMaintainer = totalFee.sub(feeForMiner);
+            poolMaintainerFee = poolMaintainerFee.add(feeForMaintainer);
+        }
+
+        assert(balance >= totalStakes.add(minerReward).add(poolMaintainerFee));
     }
 
     function getDividend(uint256 balance) private view returns (uint256) {

test/StakingPool.test.js

@@ -9,6 +9,7 @@ require('chai').use(require('chai-as-promised')).should();
 const revertError = 'VM Exception while processing transaction: revert';
 const toWei = i => web3.utils.toWei(String(i));
 const gasPriceMax = 0;
+const web3SendAsync = promisify(web3.currentProvider.send);
 
 function txGen(from, value) {
   return {
@@ -21,6 +22,30 @@ async function forceSend(target, value, from) {
   await selfDestruct.forceSend(target);
 }
 
+let snapshotId;
+
+async function addDaysOnEVM(days) {
+  const seconds = days * 3600 * 24;
+  await web3SendAsync({
+    jsonrpc: '2.0', method: 'evm_increaseTime', params: [seconds], id: 0,
+  });
+  await web3SendAsync({
+    jsonrpc: '2.0', method: 'evm_mine', params: [], id: 0,
+  });
+}
+
+function snapshotEVM() {
+  return web3SendAsync({
+    jsonrpc: '2.0', method: 'evm_snapshot', id: Date.now() + 1,
+  }).then(({ result }) => { snapshotId = result; });
+}
+
+function revertEVM() {
+  return web3SendAsync({
+    jsonrpc: '2.0', method: 'evm_revert', params: [snapshotId], id: Date.now() + 1,
+  });
+}
+
 contract('StakingPool', async (accounts) => {
   let pool;
   const miner = accounts[9];
@@ -34,6 +59,7 @@ contract('StakingPool', async (accounts) => {
   // None goes to maintainer.
   const poolMaintainerFeeRateBp = 0;
   const maxStakers = 16;
+  const maturityTime = 1893427200; // 2030-01-01
   const minStakes = toWei(1);
 
   beforeEach(async () => {
@@ -47,6 +73,7 @@ contract('StakingPool', async (accounts) => {
       minerFeeRateBp,
       poolMaintainerFeeRateBp,
       maxStakers,
+      maturityTime,
     );
   });
 
@@ -235,7 +262,7 @@ contract('StakingPool', async (accounts) => {
   it('should handle maintainer fee correctly', async () => {
     // Start a new pool where the pool takes 12.5% while the miner takes 50%.
     // eslint-disable-next-line max-len
-    pool = await StakingPool.new(miner, minerContactInfo, admin, adminContactInfo, maintainer, minStakes, minerFeeRateBp, 1250, maxStakers);
+    pool = await StakingPool.new(miner, minerContactInfo, admin, adminContactInfo, maintainer, minStakes, minerFeeRateBp, 1250, maxStakers, maturityTime);
     await pool.sendTransaction(txGen(accounts[0], toWei(1)));
     await forceSend(pool.address, toWei(8), treasury);
     // Stakes should be calculated correctly.
@@ -260,7 +287,7 @@ contract('StakingPool', async (accounts) => {
   it('should handle no staker case with pool maintainer', async () => {
     // Start a new pool where the pool takes 12.5% while the miner takes 50%.
     // eslint-disable-next-line max-len
-    pool = await StakingPool.new(miner, minerContactInfo, admin, adminContactInfo, maintainer, minStakes, minerFeeRateBp, 1250, maxStakers);
+    pool = await StakingPool.new(miner, minerContactInfo, admin, adminContactInfo, maintainer, minStakes, minerFeeRateBp, 1250, maxStakers, maturityTime);
 
     await forceSend(pool.address, toWei(10), treasury);
     // Miner should take 50/(50+12.5) * 10 = 8.
@@ -271,6 +298,31 @@ contract('StakingPool', async (accounts) => {
     assert.equal((await pool.estimatePoolMaintainerFee()), toWei(2));
   });
 
+  it('should handle maturity time correctly', async () => {
+    await pool.sendTransaction(txGen(accounts[0], toWei(42)));
+    await forceSend(pool.address, toWei(8), treasury);
+    // State has not been updated.
+    let minerReward = await pool.minerReward();
+    assert.equal(minerReward, 0);
+    await pool.withdrawStakes(toWei(10));
+    // 50% of coinbase rewards goes to miner.
+    minerReward = await pool.minerReward();
+    assert.equal(minerReward, toWei(4));
+
+    // After ten years.
+    await snapshotEVM();
+    await addDaysOnEVM(3650);
+    await forceSend(pool.address, toWei(8), treasury);
+    // State has not been updated.
+    minerReward = await pool.minerReward();
+    assert.equal(minerReward, toWei(4));
+    await pool.withdrawStakes(toWei(10));
+    // Rewards for miner shouldn't be updated.
+    minerReward = await pool.minerReward();
+    assert.equal(minerReward, toWei(4));
+    await revertEVM();
+  });
+
   it('should update miner and admin contact infomation correctly', async () => {
     assert.equal(((await pool.minerContactInfo())), minerContactInfo);
     assert.equal(((await pool.adminContactInfo())), adminContactInfo);