feat(cast): add --cost to cast estimate the eth cost at current gas price

Author: 0xvv

crates/cast/bin/cmd/estimate.rs

@@ -31,6 +31,12 @@ pub struct EstimateArgs {
     #[arg(long, short = 'B')]
     block: Option<BlockId>,
 
+    /// Calculate the cost of a transaction using the network gas price.
+    ///
+    /// If not specified the amount of gas will be estimated.
+    #[arg(long)]
+    cost: bool,
+
     #[command(subcommand)]
     command: Option<EstimateSubcommands>,
 
@@ -67,7 +73,7 @@ pub enum EstimateSubcommands {
 
 impl EstimateArgs {
     pub async fn run(self) -> Result<()> {
-        let Self { to, mut sig, mut args, mut tx, block, eth, command } = self;
+        let Self { to, mut sig, mut args, mut tx, block, cost, eth, command } = self;
 
         let config = Config::from(&eth);
         let provider = utils::get_provider(&config)?;
@@ -100,7 +106,14 @@ impl EstimateArgs {
             .await?;
 
         let gas = provider.estimate_gas(&tx).block(block.unwrap_or_default()).await?;
-        sh_println!("{gas}")?;
+        if cost {
+            let gas_price_wei = provider.get_gas_price().await?;
+            let cost = gas_price_wei * gas as u128;
+            let cost_eth = cost as f64 / 1e18;
+            sh_println!("{cost_eth}")?;
+        } else {
+            sh_println!("{gas}")?;
+        }
         Ok(())
     }
 }

crates/cast/tests/cli/main.rs

@@ -522,6 +522,31 @@ casttest!(estimate_function_gas, |_prj, cmd| {
     assert!(output.ge(&0));
 });
 
+// tests that `cast estimate --cost` is working correctly.
+casttest!(estimate_function_cost, |_prj, cmd| {
+    let eth_rpc_url = next_http_rpc_endpoint();
+
+    // ensure we get a positive non-error value for cost estimate
+    let output: f64 = cmd
+        .args([
+            "estimate",
+            "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045", // vitalik.eth
+            "--value",
+            "100",
+            "deposit()",
+            "--rpc-url",
+            eth_rpc_url.as_str(),
+            "--cost",
+        ])
+        .assert_success()
+        .get_output()
+        .stdout_lossy()
+        .trim()
+        .parse()
+        .unwrap();
+    assert!(output.ge(&0.0));
+});
+
 // tests that `cast estimate --create` is working correctly.
 casttest!(estimate_contract_deploy_gas, |_prj, cmd| {
     let eth_rpc_url = next_http_rpc_endpoint();