Account Abstraction

/**
 * ERC-4337 Account implementation with ERC-1271 signature validation
 */
contract Account is Context, IERC165, IERC1271, IAccount, Ownable, UUPSUpgradeable {
    constructor(IEntryPoint anEntryPoint);
    function validateUserOp(PackedUserOperation calldata userOp, bytes32 userOpHash, uint256 missingAccountFunds) external virtual returns (uint256 validationData);
    function executeUserOp(PackedUserOperation calldata userOp, bytes32 userOpHash) external virtual;
    function isValidSignature(bytes32 hash, bytes calldata signature) external view virtual returns (bytes4 magicValue);
    function entryPoint() public view virtual returns (IEntryPoint);
    function execute(address target, uint256 value, bytes calldata data) external virtual requireFromEntryPointOrOwner;
    function executeBatch(address[] calldata targets, uint256[] calldata values, bytes[] calldata data) external virtual requireFromEntryPointOrOwner;
    function proxiableUUID() external view virtual override notDelegated returns (bytes32);
    function upgradeToAndCall(address newImplementation, bytes memory data) public payable virtual onlyProxy;
}

import "@openzeppelin/contracts/account/Account.sol";

contract MyAccount is Account {
    constructor(IEntryPoint anEntryPoint, address initialOwner) 
        Account(anEntryPoint) 
        Ownable(initialOwner) 
    {}
    
    // Execute a transaction
    function executeTransaction(address target, uint256 value, bytes calldata data) external {
        execute(target, value, data);
    }
    
    // Execute multiple transactions
    function executeBatch(
        address[] calldata targets, 
        uint256[] calldata values, 
        bytes[] calldata data
    ) external {
        executeBatch(targets, values, data);
    }
}

/**
 * Signature validation utilities for Account contracts
 */
library AccountUtils {
    function isValidSignature(address account, bytes32 hash, bytes calldata signature) internal view returns (bool);
    function validateSignature(address account, bytes32 hash, bytes calldata signature) internal view;
}

/**
 * Multi-signature extension for Account contracts
 */
abstract contract AccountMultiSig is Account {
    function addOwner(address newOwner) external virtual onlyOwner;
    function removeOwner(address owner) external virtual onlyOwner;
    function changeRequirement(uint256 required) external virtual onlyOwner;
    function getOwners() external view virtual returns (address[] memory);
    function getThreshold() external view virtual returns (uint256);
    function isOwner(address owner) external view virtual returns (bool);
}

/**
 * ERC-4337 User Operation structure
 */
struct PackedUserOperation {
    address sender;
    uint256 nonce;
    bytes initCode;
    bytes callData;
    bytes32 accountGasLimits;
    uint256 preVerificationGas;
    bytes32 gasFees;
    bytes paymasterAndData;
    bytes signature;
}

/**
 * Account validation result
 */
struct ValidationData {
    address aggregator;
    uint48 validAfter;
    uint48 validUntil;
}

/**
 * ERC-4337 Entry Point interface
 */
interface IEntryPoint {
    function handleOps(PackedUserOperation[] calldata ops, address payable beneficiary) external;
    function handleAggregatedOps(UserOpsPerAggregator[] calldata opsPerAggregator, address payable beneficiary) external;
    function depositTo(address account) external payable;
    function balanceOf(address account) external view returns (uint256);
    function withdrawTo(address payable withdrawAddress, uint256 withdrawAmount) external;
}

/**
 * Account interface for ERC-4337 compliance
 */
interface IAccount {
    function validateUserOp(PackedUserOperation calldata userOp, bytes32 userOpHash, uint256 missingAccountFunds) external returns (uint256 validationData);
}

/**
 * Account modifiers and validation
 */
error AccountUnauthorized();
error AccountInvalidSignature();
error AccountInvalidUserOp();