Vault.sol (Manajemen Agunan dan Stablecoin)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "./Stablecoin.sol";

contract Vault {
    Stablecoin public stablecoin;
    mapping(address => uint256) public collateral;
    mapping(address => uint256) public debt;
    uint256 public constant COLLATERALIZATION_RATIO = 150; // 150%

    constructor(address _stablecoin) {
        stablecoin = Stablecoin(_stablecoin);
    }

    // Pengguna menyetor agunan (ETH)
    function depositCollateral() external payable {
        collateral[msg.sender] += msg.value;
    }

    // Fungsi untuk meminjam stablecoin dengan jaminan
    function borrow(uint256 _amount) external {
        require(collateral[msg.sender] > 0, "No collateral deposited");
        uint256 maxBorrow = (collateral[msg.sender] * 1 ether) / COLLATERALIZATION_RATIO;
        require(debt[msg.sender] + _amount <= maxBorrow, "Exceeds collateral limit");

        debt[msg.sender] += _amount;
        stablecoin.mint(msg.sender, _amount);
    }

    // Fungsi untuk membayar kembali utang dan mendapatkan kembali agunan
    function repay(uint256 _amount) external {
        require(debt[msg.sender] >= _amount, "Amount exceeds debt");
        stablecoin.burnFrom(msg.sender, _amount);
        debt[msg.sender] -= _amount;
    }

    // Fungsi untuk menarik agunan yang telah dibayarkan penuh
    function withdrawCollateral(uint256 _amount) external {
        require(debt[msg.sender] == 0, "Debt must be paid off first");
        require(collateral[msg.sender] >= _amount, "Insufficient collateral");

        collateral[msg.sender] -= _amount;
        payable(msg.sender).transfer(_amount);
    }
}