FIXTrust

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

interface IERC20 {
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function transfer(address to, uint256 value) external returns (bool);
    function allowance(address owner, address spender) external view returns (uint256);
    function approve(address spender, uint256 value) external returns (bool);
    function transferFrom(address from, address to, uint256 value) external returns (bool);
}

interface IERC20Metadata is IERC20 {
    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
}

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }
    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
    function _contextSuffixLength() internal view virtual returns (uint256) {
        return 0;
    }
}

interface IERC20Errors {
    error ERC20InsufficientBalance(address sender, uint256 balance, uint256 needed);
    error ERC20InvalidSender(address sender);
    error ERC20InvalidReceiver(address receiver);
    error ERC20InsufficientAllowance(address spender, uint256 allowance, uint256 needed);
    error ERC20InvalidApprover(address approver);
    error ERC20InvalidSpender(address spender);
}

interface IERC721Errors {
    error ERC721InvalidOwner(address owner);
    error ERC721NonexistentToken(uint256 tokenId);
    error ERC721IncorrectOwner(address sender, uint256 tokenId, address owner);
    error ERC721InvalidSender(address sender);
    error ERC721InvalidReceiver(address receiver);
    error ERC721InsufficientApproval(address operator, uint256 tokenId);
    error ERC721InvalidApprover(address approver);
    error ERC721InvalidOperator(address operator);
}

interface IERC1155Errors {
    error ERC1155InsufficientBalance(address sender, uint256 balance, uint256 needed, uint256 tokenId);
    error ERC1155InvalidSender(address sender);
    error ERC1155InvalidReceiver(address receiver);
    error ERC1155MissingApprovalForAll(address operator, address owner);
    error ERC1155InvalidApprover(address approver);
    error ERC1155InvalidOperator(address operator);
    error ERC1155InvalidArrayLength(uint256 idsLength, uint256 valuesLength);
}

abstract contract ERC20 is Context, IERC20, IERC20Metadata, IERC20Errors {
    mapping(address account => uint256) private _balances;
    mapping(address account => mapping(address spender => uint256)) private _allowances;
    uint256 private _totalSupply;
    string private _name;
    string private _symbol;
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }
    function name() public view virtual returns (string memory) {
        return _name;
    }
    function symbol() public view virtual returns (string memory) {
        return _symbol;
    }
    function decimals() public view virtual returns (uint8) {
        return 18;
    }
    function totalSupply() public view virtual returns (uint256) {
        return _totalSupply;
    }
    function balanceOf(address account) public view virtual returns (uint256) {
        return _balances[account];
    }
    function transfer(address to, uint256 value) public virtual returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, value);
        return true;
    }
    function allowance(address owner, address spender) public view virtual returns (uint256) {
        return _allowances[owner][spender];
    }
    function approve(address spender, uint256 value) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, value);
        return true;
    }
    function transferFrom(address from, address to, uint256 value) public virtual returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, value);
        _transfer(from, to, value);
        return true;
    }
    function _transfer(address from, address to, uint256 value) internal {
        if (from == address(0)) {
            revert ERC20InvalidSender(address(0));
        }
        if (to == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }
        _update(from, to, value);
    }
    function _update(address from, address to, uint256 value) internal virtual {
        if (from == address(0)) {
            _totalSupply += value;
        } else {
            uint256 fromBalance = _balances[from];
            if (fromBalance < value) {
                revert ERC20InsufficientBalance(from, fromBalance, value);
            }
            unchecked {
                _balances[from] = fromBalance - value;
            }
        }
        if (to == address(0)) {
            unchecked {
                _totalSupply -= value;
            }
        } else {
            unchecked {
                _balances[to] += value;
            }
        }
        emit Transfer(from, to, value);
    }
    function _mint(address account, uint256 value) internal {
        if (account == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }
        _update(address(0), account, value);
    }
    function _burn(address account, uint256 value) internal {
        if (account == address(0)) {
            revert ERC20InvalidSender(address(0));
        }
        _update(account, address(0), value);
    }
    function _approve(address owner, address spender, uint256 value) internal {
        _approve(owner, spender, value, true);
    }
    function _approve(address owner, address spender, uint256 value, bool emitEvent) internal virtual {
        if (owner == address(0)) {
            revert ERC20InvalidApprover(address(0));
        }
        if (spender == address(0)) {
            revert ERC20InvalidSpender(address(0));
        }
        _allowances[owner][spender] = value;
        if (emitEvent) {
            emit Approval(owner, spender, value);
        }
    }
    function _spendAllowance(address owner, address spender, uint256 value) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance < type(uint256).max) {
            if (currentAllowance < value) {
                revert ERC20InsufficientAllowance(spender, currentAllowance, value);
            }
            unchecked {
                _approve(owner, spender, currentAllowance - value, false);
            }
        }
    }
}

abstract contract Ownable is Context {
    address private _owner;
    error OwnableUnauthorizedAccount(address account);
    error OwnableInvalidOwner(address owner);
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    constructor(address initialOwner) {
        if (initialOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(initialOwner);
    }
    modifier onlyOwner() {
        _checkOwner();
        _;
    }
    function owner() public view virtual returns (address) {
        return _owner;
    }
    function _checkOwner() internal view virtual {
        if (owner() != _msgSender()) {
            revert OwnableUnauthorizedAccount(_msgSender());
        }
    }
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }
    function transferOwnership(address newOwner) public virtual onlyOwner {
        if (newOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(newOwner);
    }
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

abstract contract ReentrancyGuard {
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;
    uint256 private _status;
    constructor() {
        _status = _NOT_ENTERED;
    }
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }
    function _nonReentrantBefore() private {
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
        _status = _ENTERED;
    }
    function _nonReentrantAfter() private {
        _status = _NOT_ENTERED;
    }
    function _reentrancyGuardEntered() internal view returns (bool) {
        return _status == _ENTERED;
    }
}

interface AggregatorV3Interface {
  function decimals() external view returns (uint8);
  function description() external view returns (string memory);
  function version() external view returns (uint256);
  function getRoundData(uint80 _roundId) external view returns (uint80 roundId, int256 answer, uint256 startedAt, uint256 updatedAt, uint80 answeredInRound);
  function latestRoundData() external view returns (uint80 roundId, int256 answer, uint256 startedAt, uint256 updatedAt, uint80 answeredInRound);
}

contract FIXTrust is ERC20, Ownable, ReentrancyGuard {
    uint256 public constant TOKEN_PRICE_USD = 33 * 10**16; // 0.33 USD, 18 decimals
    uint256 public constant HARD_CAP = 825 ether; // ~US$3.3M at ~$4k/ETH; buffer ajustado
    uint256 public constant BONUS_END_TIME = 1731542400; // 20/10/2025 23:59 UTC
    uint256 public totalRaised;
    AggregatorV3Interface internal priceFeed;
    event Deposited(address indexed user, uint256 ethAmount, uint256 tokensMinted);
    event Redeemed(address indexed user, uint256 ethAmount, uint256 tokensBurned);
    constructor(address initialOwner) Ownable(initialOwner) ERC20("FIXTrust", "FIXT") {
        priceFeed = AggregatorV3Interface(0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419); // ETH/USD Mainnet
    }
    function deposit() public payable nonReentrant {
        require(msg.value > 0, "Deposit amount must be greater than 0");
        require(totalRaised + msg.value <= HARD_CAP, "Hard cap exceeded");
        uint256 tokensToMint = calculateTokensToMint(msg.value);
        _mint(msg.sender, tokensToMint);
        totalRaised += msg.value;
        emit Deposited(msg.sender, msg.value, tokensToMint);
    }
    function redeem(uint256 tokenAmount) public nonReentrant {
        require(tokenAmount <= balanceOf(msg.sender), "Insufficient token balance");
        require(tokenAmount > 0, "Token amount must be greater than 0");
        (, int256 price, , uint256 updatedAt, ) = priceFeed.latestRoundData();
        require(price > 0, "Invalid price feed");
        require(block.timestamp - updatedAt <= 3600, "Stale price feed"); // 1h max
        uint256 ethAmountUSD = (tokenAmount * TOKEN_PRICE_USD) / 10**18;
        uint256 ethAmount = (ethAmountUSD * 10**8) / uint256(price); // Precision: USD 18 * 10^8 / price 8 = wei 18
        ethAmount = ethAmount - (ethAmount % 1e12); // Dust removal
        require(ethAmount <= address(this).balance, "Insufficient ETH in contract");
        require(ethAmount > 0, "No ETH available");
        _burn(msg.sender, tokenAmount);
        payable(msg.sender).transfer(ethAmount);
        emit Redeemed(msg.sender, ethAmount, tokenAmount);
    }
    function calculateTokensToMint(uint256 ethAmount) internal view returns (uint256) {
        (, int256 price, , uint256 updatedAt, ) = priceFeed.latestRoundData();
        require(price > 0, "Invalid price feed");
        require(block.timestamp - updatedAt <= 3600, "Stale price feed");
        uint256 ethPriceUSD = uint256(price); // 8 decimals
        uint256 ethAmountUSD = (ethAmount * ethPriceUSD) / 10**8; // ETH 18 * price 8 / 10^8 = USD 18
        uint256 tokens = ethAmountUSD / TOKEN_PRICE_USD;
        if (block.timestamp <= BONUS_END_TIME) {
            tokens = (tokens * 110) / 100; // 10% bonus
        }
        return tokens;
    }
}