use crate::obj::prelude::*;
use std::{any::Any, sync::LazyLock};

pub static NONE_INST: LazyLock<ObjPtr> = LazyLock::new(|| ObjPtr::new(None::new()));
static NONE_STR: LazyLock<ObjPtr> = LazyLock::new(|| ObjPtr::new(Str::new("None")));

static NONE_ATTRS: LazyLock<AttrsPtr> = LazyLock::new(|| {
    attrs_ptr! {
        //
        "__str__" => builtin_fun_ptr!("__str__", |_vm, args, _state| {
            if args.len() != 1 {
                todo!("Throw exception: arity error");
            }
            BuiltinFunResult::Return(Some(ObjPtr::clone(&NONE_STR)))
        }),
    }
});

#[derive(Debug)]
pub struct None {
    attrs: AttrsPtr,
}

impl None {
    fn new() -> Self {
        let attrs = AttrsPtr::clone(&NONE_ATTRS);
        Self { attrs }
    }
}

impl Obj for None {
    fn attrs(&self) -> AttrsPtr {
        AttrsPtr::clone(&self.attrs)
    }

    fn as_any(&self) -> &(dyn Any + 'static) {
        self
    }
}