utils.rs

use {
    anyhow::{anyhow, Result},
    ethers::{contract::ContractCall, middleware::Middleware},
    std::sync::Arc,
    tracing,
};

pub async fn send_and_confirm<A: Middleware>(contract_call: ContractCall<A, ()>) -> Result<()> {
    let call_name = contract_call.function.name.as_str();
    let pending_tx = contract_call
        .send()
        .await
        .map_err(|e| anyhow!("Error submitting transaction({}) {:?}", call_name, e))?;

    let tx_result = pending_tx
        .await
        .map_err(|e| {
            anyhow!(
                "Error waiting for transaction({}) receipt: {:?}",
                call_name,
                e
            )
        })?
        .ok_or_else(|| {
            anyhow!(
                "Can't verify the transaction({}), probably dropped from mempool",
                call_name
            )
        })?;

    tracing::info!(
        transaction_hash = &tx_result.transaction_hash.to_string(),
        "Confirmed transaction({}). Receipt: {:?}",
        call_name,
        tx_result,
    );
    Ok(())
}

/// Estimate the cost (in wei) of a transaction consuming gas_used gas.
pub async fn estimate_tx_cost<T: Middleware + 'static>(
    middleware: Arc<T>,
    use_legacy_tx: bool,
    gas_used: u128,
) -> Result<u128> {
    let gas_price: u128 = if use_legacy_tx {
        middleware
            .get_gas_price()
            .await
            .map_err(|e| anyhow!("Failed to fetch gas price. error: {:?}", e))?
            .try_into()
            .map_err(|e| anyhow!("gas price doesn't fit into 128 bits. error: {:?}", e))?
    } else {
        // This is not obvious but the implementation of estimate_eip1559_fees in ethers.rs
        // for a middleware that has a GasOracleMiddleware inside is to ignore the passed-in callback
        // and use whatever the gas oracle returns.
        let (max_fee_per_gas, max_priority_fee_per_gas) =
            middleware.estimate_eip1559_fees(None).await?;

        (max_fee_per_gas + max_priority_fee_per_gas)
            .try_into()
            .map_err(|e| anyhow!("gas price doesn't fit into 128 bits. error: {:?}", e))?
    };

    Ok(gas_price * gas_used)
}