Implement smart contract wallet interface for Account Abstraction #29

Title

Implement smart contract wallet interface for Account Abstraction

Labels

enhancement, account-abstraction, wallet, smart-account

Description

Add interfaces and utilities for interacting with ERC-4337 smart contract accounts (wallets), enabling advanced wallet functionality beyond EOAs.

Requirements

SmartAccount Interface

• Define SmartAccount trait/interface:
  • getAddress() Address - Get deployed account address
  • getNonce(?key: u256) u256 - Get current nonce for key
  • signUserOperation(userOp: UserOperation) []u8 - Sign UserOp
  • encodeExecute(to: Address, value: u256, data: []u8) []u8 - Encode call
  • encodeBatchExecute(calls: []Call) []u8 - Encode batch calls
  • getInitCode() []u8 - Get account deployment code
  • isDeployed() bool - Check if account is deployed

SimpleAccount Implementation

• Implement SimpleAccount (ERC-4337 reference implementation):
  • Based on official SimpleAccount.sol
  • Single owner validation
  • Execute and executeBatch support
  • EIP-712 UserOperation signing

Account Factory Support

• Add AccountFactory interface:
  • getAccountAddress(owner: Address, salt: u256) Address - Predict address
  • createAccount(owner: Address, salt: u256) Address - Deploy account
  • getInitCode(owner: Address, salt: u256) []u8 - Get init code

Utilities

• Helper functions:
  • txToUserOp(tx: Transaction, account: SmartAccount) UserOperation - Convert tx
  • signUserOperationHash(hash: Hash, signer: Wallet) []u8
  • validateUserOpSignature(userOp: UserOperation, account: SmartAccount) bool

Common Account Types Support

• Framework for custom account implementations:
  • Multi-sig accounts
  • Session key accounts
  • Social recovery accounts
  • Modular accounts (ERC-6900)

File Structure

src/account_abstraction/
  ├── account.zig              # SmartAccount interface
  ├── simple_account.zig       # SimpleAccount implementation
  ├── factory.zig              # Account factory utilities
  └── utils.zig                # Helper functions

Example Usage

// Create a simple account
const factory = try SimpleAccountFactory.init(allocator, factory_address);
const account = try factory.createAccount(owner_wallet, 0);

// Use the account
const userOp = try account.execute(
    recipient_address,
    @as(u256, 1_000_000_000_000_000_000), // 1 ETH
    &[_]u8{}, // empty data
);

const signed_userOp = try account.signUserOperation(userOp);
const hash = try bundler.sendUserOperation(signed_userOp, entry_point);

References

• SimpleAccount: https://github.com/eth-infinitism/account-abstraction/blob/develop/contracts/samples/SimpleAccount.sol
• ERC-4337: https://eips.ethereum.org/EIPS/eip-4337
• Viem accounts: https://github.com/wevm/viem/tree/main/src/account-abstraction