FlashUSDT

{{
  "language": "Solidity",
  "sources": {
    "FlashUSDT.sol": {
      "content": "// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

/**
 * @title FlashUSDT - Minimal ERC20 with 6 decimals + flash-mint
 * @dev No external dependencies. Ready for Remix.
 */
contract FlashUSDT {
    // ERC20 Storage
    mapping(address => uint256) private _balances;
    mapping(address => mapping(address => uint256)) private _allowances;
    uint256 private _totalSupply;

    string private _name = "Flash USDT";
    string private _symbol = "fUSDT";
    uint8 private _decimals = 6;

    address public owner;
    modifier onlyOwner() {
        require(msg.sender == owner, "Not owner");
        _;
    }

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);

    constructor() {
        owner = msg.sender;
        _mint(msg.sender, 1_000_000 * 10 ** 6); // 1 million fUSDT
    }

    // --- ERC20 Standard Functions ---

    function name() public view returns (string memory) { return _name; }
    function symbol() public view returns (string memory) { return _symbol; }
    function decimals() public view returns (uint8) { return _decimals; }
    function totalSupply() public view returns (uint256) { return _totalSupply; }
    function balanceOf(address account) public view returns (uint256) { return _balances[account]; }

    function transfer(address to, uint256 amount) public returns (bool) {
        _transfer(msg.sender, to, amount);
        return true;
    }

    function allowance(address owner_, address spender) public view returns (uint256) {
        return _allowances[owner_][spender];
    }

    function approve(address spender, uint256 amount) public returns (bool) {
        _approve(msg.sender, spender, amount);
        return true;
    }

    function transferFrom(address from, address to, uint256 amount) public returns (bool) {
        uint256 currentAllowance = _allowances[from][msg.sender];
        require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
        _approve(from, msg.sender, currentAllowance - amount);
        _transfer(from, to, amount);
        return true;
    }

    // --- Internal ---

    function _transfer(address from, address to, uint256 amount) internal {
        require(from != address(0), "ERC20: transfer from zero address");
        require(to != address(0), "ERC20: transfer to zero address");

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        _balances[from] = fromBalance - amount;
        _balances[to] += amount;

        emit Transfer(from, to, amount);
    }

    function _mint(address account, uint256 amount) internal {
        require(account != address(0), "ERC20: mint to zero address");

        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);
    }

    function _burn(address account, uint256 amount) internal {
        require(account != address(0), "ERC20: burn from zero address");

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        _balances[account] = accountBalance - amount;
        _totalSupply -= amount;

        emit Transfer(account, address(0), amount);
    }

    function _approve(address owner_, address spender, uint256 amount) internal {
        require(owner_ != address(0), "ERC20: approve from zero address");
        require(spender != address(0), "ERC20: approve to zero address");

        _allowances[owner_][spender] = amount;
        emit Approval(owner_, spender, amount);
    }

    // --- Owner Functions ---

    function mint(address to, uint256 amount) external onlyOwner {
        _mint(to, amount);
    }

    function burn(uint256 amount) external {
        _burn(msg.sender, amount);
    }

    // --- Flash Mint (Single TX: mint → call → burn) ---

    function flashMint(uint256 amount, address target, bytes calldata data) external {
        // 1. Mint to caller
        _mint(msg.sender, amount);

        // 2. Execute callback
        (bool success, ) = target.call(data);
        require(success, "Flash: callback failed");

        // 3. Burn exactly what was minted
        _burn(msg.sender, amount);
    }
}"
    }
  },
  "settings": {
    "optimizer": {
      "enabled": false,
      "runs": 200
    },
    "outputSelection": {
      "*": {
        "*": [
          "evm.bytecode",
          "evm.deployedBytecode",
          "devdoc",
          "userdoc",
          "metadata",
          "abi"
        ]
      }
    },
    "remappings": []
  }
}}