//! Example of signing a permit hash using a wallet.

use alloy::{

primitives::{address, keccak256, U256},

signers::{local::PrivateKeySigner, Signer},

sol,

sol_types::{eip712_domain, SolStruct},

};

use eyre::Result;

use serde::Serialize;

sol! {

#[allow(missing_docs)]

#[derive(Serialize)]

struct Permit {

address owner;

address spender;

uint256 value;

uint256 nonce;

uint256 deadline;

}

}

#[tokio::main]

async fn main() -> Result<()> {

// Set up a random signer.

let signer = PrivateKeySigner::random();

let domain = eip712_domain! {

name: "Uniswap V2",

version: "1",

chain_id: 1,

verifying_contract: address!("B4e16d0168e52d35CaCD2c6185b44281Ec28C9Dc"),

salt: keccak256("test"),

};

let permit = Permit {

owner: signer.address(),

spender: address!("B4e16d0168e52d35CaCD2c6185b44281Ec28C9Dc"),

value: U256::from(100),

nonce: U256::from(0),

deadline: U256::from(0),

};

// Derive the EIP-712 signing hash.

let hash = permit.eip712_signing_hash(&domain);

// Sign the hash asynchronously with the wallet.

let signature = signer.sign_hash(&hash).await?;

println!(

"Recovered address matches wallet address: {}",

signature.recover_address_from_prehash(&hash)? == signer.address()

);

println!("Wallet signature matches: {}", signer.sign_hash(&hash).await? == signature);

Ok(())

}