use rune::{Context, Diagnostics, FromValue, Source, Sources, Vm};
use rune::termcolor::{ColorChoice, StandardStream};
use std::sync::Arc;

#[tokio::main]
async fn main() -> rune::Result<()> {
    let context = Context::with_default_modules()?;
    let runtime = Arc::new(context.runtime());

    let mut sources = Sources::new();
    sources.insert(Source::new(
        "script",
        r#"
        pub fn add(a, b) {
            a + b
        }
        "#,
    ));

    let mut diagnostics = Diagnostics::new();

    let result = rune::prepare(&mut sources)
        .with_context(&context)
        .with_diagnostics(&mut diagnostics)
        .build();

    if !diagnostics.is_empty() {
        let mut writer = StandardStream::stderr(ColorChoice::Always);
        diagnostics.emit(&mut writer, &sources)?;
    }

    let unit = result?;
    let mut vm = Vm::new(runtime, Arc::new(unit));

    let output = vm.call(&["add"], (10i64, 20i64))?;
    let output = i64::from_value(output)?;

    println!("{}", output);
    Ok(())
}