use ngr::backend::BackendError;
use rustyline::error::ReadlineError;
use rustyline::DefaultEditor;

fn main() -> Result<(), BackendError> {
    let mut editor = DefaultEditor::new().expect("rustyline works");
    let mut line_no = 0;
    let mut state = ngr::REPL::default();

    println!("No Good Reason, the Interpreter!");
    loop {
        line_no += 1;
        match editor.readline("> ") {
            Ok(command) => match command.trim() {
                "" => continue,
                ":quit" => break,
                _ => state.process_input(line_no, command),
            },
            Err(ReadlineError::Io(e)) => {
                eprintln!("IO error: {}", e);
                break;
            }
            Err(ReadlineError::Eof) => break,
            Err(ReadlineError::Interrupted) => break,
            #[cfg(not(windows))]
            Err(ReadlineError::Errno(e)) => {
                eprintln!("Unknown syscall error: {}", e);
                break;
            }
            Err(ReadlineError::WindowResized) => continue,
            Err(e) => {
                eprintln!("Unknown internal error: {}", e);
                break;
            }
        }
    }

    Ok(())
}