// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

interface ITrustVault {
    // Events
    event Deposited(address indexed user, uint256 amount, uint256 shares);
    event Withdrawn(address indexed user, uint256 shares, uint256 amount);
    event Borrowed(address indexed user, uint256 amount, uint256 dueDate);
    event Repaid(address indexed user, uint256 loanId, uint256 amount);
    event DefaultRecorded(address indexed user, uint256 loanId);

    // View Functions
    function totalAssets() external view returns (uint256);
    function totalShares() external view returns (uint256);
    function exchangeRate() external view returns (uint256);
    function utilizationRate() external view returns (uint256);
    function borrowRate() external view returns (uint256);
    function supplyRate() external view returns (uint256);

    // User Functions
    function deposit(uint256 amount) external returns (uint256 shares);
    function withdraw(uint256 shares) external returns (uint256 amount);
    function borrow(uint256 amount, uint256 duration) external returns (uint256 loanId);
    function repay(uint256 loanId) external;

    // View User State
    function balanceOf(address user) external view returns (uint256);
    function getUserLoans(address user) external view returns (Loan[] memory);
}

struct Loan {
    uint256 id;
    address borrower;
    uint256 principal;
    uint256 interest;
    uint256 dueDate;
    LoanStatus status;
}

enum LoanStatus {
    ACTIVE,
    REPAID,
    DEFAULTED
}

function deposit(uint256 amount) external returns (uint256 shares);

function borrow(uint256 amount, uint256 duration) external returns (uint256 loanId);

function repay(uint256 loanId) external;

function calculateBorrowRate(uint256 utilization) public pure returns (uint256) {
    // Base rate: 2%
    uint256 baseRate = 2e16;

    if (utilization <= 80e16) {
        // Linear increase up to 80% utilization
        return baseRate + (utilization * 3e16) / 80e16;
    } else {
        // Steep increase above 80%
        uint256 excess = utilization - 80e16;
        return 5e16 + (excess * 50e16) / 20e16;
    }
}

function pause() external onlyAdmin;
function unpause() external onlyAdmin;
function emergencyWithdraw() external onlyAdmin;

vault.on("Deposited", (user, amount, shares) => {
  console.log(`${user} deposited ${amount} USDC for ${shares} shares`);
});

vault.on("Borrowed", (user, amount, dueDate) => {
  console.log(`${user} borrowed ${amount} USDC, due ${dueDate}`);
});