/// Print the error message and exit with code 2.
/// JSON deserialization errors produce a friendlier message matching Python's
/// JSONDecodeError handling.
pub fn handle_error(e: anyhow::Error) -> ! {
    if is_json_error(&*e) {
        eprintln!(
            "Unexpected response returned. Please check the configuration or the server's operational status."
        );
    } else {
        eprintln!("Error: {}", e);
    }
    std::process::exit(2);
}

/// Walk the error source chain to detect `serde_json` parse errors.
fn is_json_error(e: &(dyn std::error::Error + 'static)) -> bool {
    let mut source: Option<&(dyn std::error::Error + 'static)> = Some(e);
    while let Some(err) = source {
        if err.downcast_ref::<serde_json::Error>().is_some() {
            return true;
        }
        source = err.source();
    }
    false
}