From 2dda5dac7bbb246aac83f7d2e12998ca490cf167 Mon Sep 17 00:00:00 2001
From: KOSASIH <kosasihg88@gmail.com>
Date: Fri, 9 Aug 2024 00:47:56 +0700
Subject: [PATCH] Create Lending.sol

---
 .../ethereum/contracts/Lending.sol            | 95 +++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 pi-nexus-smart-contracts/ethereum/contracts/Lending.sol

diff --git a/pi-nexus-smart-contracts/ethereum/contracts/Lending.sol b/pi-nexus-smart-contracts/ethereum/contracts/Lending.sol
new file mode 100644
index 000000000..cb17a6865
--- /dev/null
+++ b/pi-nexus-smart-contracts/ethereum/contracts/Lending.sol
@@ -0,0 +1,95 @@
+// Lending.sol
+
+pragma solidity ^0.8.0;
+
+import "https://github.com/OpenZeppelin/openzeppelin-solidity/contracts/token/ERC20/SafeERC20.sol";
+import "https://github.com/OpenZeppelin/openzeppelin-solidity/contracts/utils/ReentrancyGuard.sol";
+
+contract Lending {
+    using SafeERC20 for address;
+
+    // Mapping of lending pools
+    mapping (address => LendingPool) public lendingPools;
+
+    // Event emitted when a new lending pool is created
+    event LendingPoolCreated(address indexed creator, address indexed asset, uint256 interestRate);
+
+    // Event emitted when a lending pool is updated
+    event LendingPoolUpdated(address indexed creator, address indexed asset, uint256 interestRate);
+
+    // Event emitted when a lending pool is closed
+    event LendingPoolClosed(address indexed creator, address indexed asset);
+
+    // Struct to store lending pool metadata
+    struct LendingPool {
+        address asset;
+        uint256 interestRate;
+        uint256 totalSupply;
+        uint256 totalBorrowed;
+        mapping (address => uint256) borrowerBalances;
+    }
+
+    // Modifier to prevent reentrancy attacks
+    modifier nonReentrant() {
+        require(!_isReentrant, "Reentrancy detected");
+        _isReentrant = true;
+        _;
+        _isReentrant = false;
+    }
+
+    // Create a new lending pool
+    function createLendingPool(address asset, uint256 interestRate) public nonReentrant {
+        require(asset != address(0), "Invalid asset");
+        require(interestRate > 0, "Invalid interest rate");
+        LendingPool storage pool = lendingPools[msg.sender];
+        pool.asset = asset;
+        pool.interestRate = interestRate;
+        pool.totalSupply = 0;
+        pool.totalBorrowed = 0;
+        emit LendingPoolCreated(msg.sender, asset, interestRate);
+    }
+
+    // Deposit assets into a lending pool
+    function deposit(address asset, uint256 amount) public nonReentrant {
+        require(asset != address(0), "Invalid asset");
+        require(amount > 0, "Invalid amount");
+        LendingPool storage pool = lendingPools[msg.sender];
+        require(pool.asset == asset, "Asset mismatch");
+        pool.totalSupply += amount;
+        asset.safeTransferFrom(msg.sender, address(this), amount);
+    }
+
+    // Borrow assets from a lending pool
+    function borrow(address asset, uint256 amount) public nonReentrant {
+        require(asset != address(0), "Invalid asset");
+        require(amount > 0, "Invalid amount");
+        LendingPool storage pool = lendingPools[msg.sender];
+        require(pool.asset == asset, "Asset mismatch");
+        require(pool.totalSupply >= amount, "Insufficient liquidity");
+        pool.totalBorrowed += amount;
+        asset.safeTransfer(msg.sender, amount);
+        borrowerBalances[msg.sender] += amount;
+    }
+
+    // Repay borrowed assets
+    function repay(address asset, uint256 amount) public nonReentrant {
+        require(asset != address(0), "Invalid asset");
+        require(amount > 0, "Invalid amount");
+        LendingPool storage pool = lendingPools[msg.sender];
+        require(pool.asset == asset, "Asset mismatch");
+        require(borrowerBalances[msg.sender] >= amount, "Insufficient balance");
+        pool.totalBorrowed -= amount;
+        borrowerBalances[msg.sender] -= amount;
+        asset.safeTransferFrom(msg.sender, address(this), amount);
+    }
+
+    // Close a lending pool
+    function closeLendingPool(address asset) public nonReentrant {
+        require(asset != address(0), "Invalid asset");
+        LendingPool storage pool = lendingPools[msg.sender];
+        require(pool.asset == asset, "Asset mismatch");
+        require(pool.totalBorrowed == 0, "Pool is not fully repaid");
+        delete lendingPools[msg.sender];
+        emit LendingPoolClosed(msg.sender, asset);
+    }
+}