Customized masterchef smart contract (staking ETH and give reward in ETH)

.gitignore

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+/node_modules/
+/artifacts/
+/cache/
+/data/

INSTALL.md

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+# CSPD-Staking-Contract
+
+## Install
+    yarn install
+
+After that need to add `config.js` file. Example you can find in `config.example.js` file.
+
+## Added plugins
+* [**@openzeppelin/contracts@4.2.0**](https://github.com/OpenZeppelin/openzeppelin-contracts/tree/v4.2.0/contracts) - Standart OpenZeppelin's contract library.
+
+* [**hardhat**](https://hardhat.org/getting-started/) - Solidity development environment.
+
+* [**hardhat-abi-exporter**](https://hardhat.org/plugins/hardhat-abi-exporter.html) - Exports smart contract ABIs on compilation. It will run automatically on compilation.
+
+* [**hardhat-contract-sizer**](https://hardhat.org/plugins/hardhat-contract-sizer.html) - Writes bytecode sizes of smart contracts. It will run automatically on compilation.
+
+* [**hardhat-gas-reporter**](https://hardhat.org/plugins/hardhat-gas-reporter.html) - Writes information of gas usage in tests. It will run automatically on tests.
+
+* [**hardhat-spdx-license-identifier**](https://hardhat.org/plugins/hardhat-spdx-license-identifier.html) - Writes SPDX License Identifier into sol files. It will run automatically on compilation.
+
+* [**hardhat-tracer**](https://hardhat.org/plugins/hardhat-tracer.html) - Prints events when running tests.
+
+* [**solidity-coverage**](https://hardhat.org/plugins/solidity-coverage.html) - Solidity code coverage plugin.
+
+* [**@nomiclabs/hardhat-etherscan**](https://hardhat.org/plugins/nomiclabs-hardhat-etherscan.html) - Automatic verification on etherscan, bscscan and others.
+
+* [**@nomiclabs/hardhat-solhint**](https://hardhat.org/plugins/nomiclabs-hardhat-solhint.html) - Solidity linter
+
+* [**prettier**](https://www.npmjs.com/package/prettier) - Formatter. Run with script `prettier` of npm.

README.md

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-# Smart Contract Challenge
-
-## A) Challenge
-
-### 1) Setup a project and create a contract
+# Ether staking and get reward per week
 
 #### Summary
 
@@ -24,32 +20,67 @@ Example:
 > **A** should get their deposit + all the rewards.
 > **B** should only get their deposit because rewards were sent to the pool before they participated.
 
-#### Goal
-
-Design and code a contract for ETHPool, take all the assumptions you need to move forward.
-
-You can use any development tools you prefer: Hardhat, Truffle, Brownie, Solidity, Vyper.
-
-Useful resources:
-
-- Solidity Docs: https://docs.soliditylang.org/en/v0.8.4
-- Educational Resource: https://github.com/austintgriffith/scaffold-eth
-- Project Starter: https://github.com/abarmat/solidity-starter
-
-### 2) Write tests
-
-Make sure that all your code is tested properly
-
-### 3) Deploy your contract
-
-Deploy the contract to any Ethereum testnet of your preference. Keep record of the deployed address.
-
-Bonus:
-
-- Verify the contract in Etherscan
-
-### 4) Interact with the contract
-
-Create a script (or a Hardhat task) to query the total amount of ETH held in the contract.
-
-_You can use any library you prefer: Ethers.js, Web3.js, Web3.py, eth-brownie_
+# Keep staking principle.
+First week: 
+- A deposit 100, B deposit 150 and T deposit 500
+- A withdraw 100 + 200 = 300 
+- ** B don't withdraw
+- Pool Ether: 100 + 150 + 500 - 300 = 450
+- B reward: 500 * 150 / 250 = 300
+
+Second week:
+- C deposit 100 and T deposit 500
+- Total balance: 450 + 100 + 500 = 1050
+- Then B available withdraw amount ???
+- Not this: 1050 * 150 / (150 + 100) = 630
+
+** B will be able to withdraw: 
+300 + 500 * 150 / (150 + 100) = 600
+
+Test network contract: https://rinkeby.etherscan.io/address/0x00322a7E8e774157B3f160245Ac6365ae024D9f3#code
+
+### Test Result
+
+```solidity
+ ·-----------------|-------------·
+ |  Contract Name  ·  Size (Kb)  │
+ ··················|··············
+ |  console        ·       0.08  │
+ ··················|··············
+ |  SafeMath       ·       0.08  │
+ ··················|··············
+ |  Staking        ·       3.05  │
+ ·-----------------|-------------·
+
+  Token test
+    √ Add Admin
+    √ Stake
+    √ Get Pending Reward
+    √ UnSake
+    √ Next week
+    √ Next week: Get Pending Reward
+
+·------------------------------|---------------------------|-------------|-----------------------------·
+|     Solc version: 0.8.0      ·  Optimizer enabled: true  ·  Runs: 200  ·  Block limit: 30000000 gas  │
+·······························|···························|·············|······························
+|  Methods                                                                                             │
+·············|·················|·············|·············|·············|···············|··············
+|  Contract  ·  Method         ·  Min        ·  Max        ·  Avg        ·  # calls      ·  usd (avg)  │
+·············|·················|·············|·············|·············|···············|··············
+|  Staking   ·  addAdmin       ·      47394  ·      47406  ·      47400  ·            2  ·          -  │
+·············|·················|·············|·············|·············|···············|··············
+|  Staking   ·  depositReward  ·      54178  ·      59653  ·      56916  ·            2  ·          -  │
+·············|·················|·············|·············|·············|···············|··············
+|  Staking   ·  stake          ·      54877  ·      74777  ·      67210  ·            3  ·          -  │
+·············|·················|·············|·············|·············|···············|··············
+|  Staking   ·  unStake        ·          -  ·          -  ·      50834  ·            1  ·          -  │
+·············|·················|·············|·············|·············|···············|··············
+|  Deployments                 ·                                         ·  % of limit   ·             │
+·······························|·············|·············|·············|···············|··············
+|  Staking                     ·          -  ·          -  ·     820165  ·        2.7 %  ·          -  │
+·------------------------------|-------------|-------------|-------------|---------------|-------------·
+
+  6 passing (806ms)
+
+
+```

config.js

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+module.exports = {
+    // global constants
+    testnetAccounts: ["..."],
+    mainnetAccounts: ["..."],
+    infuraIdProject: "...",
+    apiKey: "...",
+    coinmarketcapApi: "...",
+
+    // deploy constants
+    initialSupply: "1000",
+};

contracts/Staking.sol

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+// SPDX-License-Identifier: UNLICENSED
+
+/**
+ * Staking contract
+*/
+
+import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
+import "@openzeppelin/contracts/access/Ownable.sol";
+import "@openzeppelin/contracts/utils/math/SafeMath.sol";
+
+pragma solidity ^0.8.0;
+
+/**
+ * @dev Staking module
+ * ETHPool provides a service where people can deposit ETH and they will receive weekly rewards.
+ * Users must be able to take out their deposits along with their portion of rewards at any time.
+ * New rewards are deposited manually into the pool by the ETHPool team each week using a contract function.
+ */
+
+contract Staking is Ownable, ReentrancyGuard {
+    using SafeMath for uint256;
+
+    // Info of each user.
+    struct UserInfo {
+        uint256 amount;
+        uint256 rewardDebt;
+        uint256 pendingAmount;
+    }
+
+    mapping (address => UserInfo) public userInfo;
+
+    mapping(address => bool) public admins;
+
+    uint256 public lastRewardBlock;
+    uint256 public accRewardPerShare;
+
+    uint256 public totalStakedAmount;
+
+    uint256 public rewardBalance;
+
+
+
+    event AddAdmin(address indexed admin);
+    event RemoveAdmin(address indexed admin);
+
+    event Stake(address indexed user, uint256 amount);
+    event ReStake(address indexed user, uint256 amount);
+    event DepositReward(address indexed user, uint256 amount);
+    event UnStake(address indexed user, uint256 unStakeAmount, uint256 rewardAmount);
+
+    /**
+     * @dev Throws if called by any account other than the admin.
+     */
+    modifier onlyAdmin() {
+        require(admins[msg.sender], "caller is not the admin");
+        _;
+    }
+
+    constructor(
+    ) {
+        lastRewardBlock = block.number;
+        admins[owner()] = true;
+    }
+
+    function addAdmin(address _address) external onlyOwner {
+        require(_address != address(0x0), "address error");
+        admins[_address] = true;
+        emit AddAdmin(_address);
+    }
+
+    function removeAdmin(address _address) external onlyOwner {
+        require(admins[_address], "this address is not admin!");
+        admins[_address] = false;
+        emit RemoveAdmin(_address);
+    }
+
+    function getETHBalanceOfPool() external view returns (uint256) {
+        return address(this).balance;
+    }
+
+    function depositReward() external payable onlyAdmin {
+        require(msg.value > 0, "amount is 0");
+        uint amount = msg.value;
+        if (totalStakedAmount > 0)
+            accRewardPerShare = accRewardPerShare.add(rewardBalance.mul(10 ** 12).div(totalStakedAmount));
+        rewardBalance = amount;
+        emit DepositReward(msg.sender, amount);
+        lastRewardBlock = block.number;
+    }
+
+    function getPending(address _user) external view returns (uint256) {
+        uint256 pending = _getPending(_user);
+        return pending;
+    }
+
+    function _getPending(address _user) private view returns (uint256) {
+        UserInfo storage user = userInfo[_user];
+        uint256 acc = accRewardPerShare;
+        if (block.number > lastRewardBlock && totalStakedAmount != 0 && rewardBalance > 0) {
+            acc = acc.add(rewardBalance.mul(10 ** 12).div(totalStakedAmount));
+        }
+        return user.amount.mul(acc).div(10 ** 12).sub(user.rewardDebt).add(user.pendingAmount);
+    }
+
+    function stake() external payable {
+        require(msg.value > 0, "stake amount is 0");
+        uint256 _amount = msg.value;
+        UserInfo storage user = userInfo[msg.sender];
+        if (user.amount > 0) {
+            uint256 pending = user.amount.mul(accRewardPerShare).div(10 ** 12).sub(user.rewardDebt);
+            user.pendingAmount = user.pendingAmount.add(pending);
+        }
+
+        totalStakedAmount = totalStakedAmount.add(_amount);
+        user.amount = user.amount.add(_amount);
+        user.rewardDebt = user.amount.mul(accRewardPerShare).div(10 ** 12);
+        emit Stake(msg.sender, _amount);
+    }
+
+    function unStake() external payable {
+        UserInfo storage user = userInfo[msg.sender];
+        require(user.amount > 0, "You didn't stake!");
+        uint256 rewardAmount = _getPending(msg.sender);
+        uint256 stakedAmount = user.amount;
+        uint256 withdrawAmount = stakedAmount + rewardAmount;
+        bool isSent = payable(msg.sender).send(withdrawAmount);
+        require(isSent, "Failed to send ETH");
+        rewardBalance = rewardBalance.sub(rewardAmount);
+        totalStakedAmount = totalStakedAmount.sub(stakedAmount);
+        user.pendingAmount = 0;
+        user.amount = 0;
+        user.rewardDebt = 0;
+        emit UnStake(msg.sender, stakedAmount, rewardAmount);
+    }
+}