use crate::{obj::prelude::*, vm::op::Op};
use std::{collections::BTreeMap, rc::Rc};

pub struct Frame {
    stack: Vec<DynRef>,
    ip: usize,
    return_value: Option<DynRef>,
    locals: BTreeMap<NameId, DynRef>,
    ops: Rc<Vec<Op>>,
}

impl Frame {
    pub fn new(ops: Rc<Vec<Op>>) -> Self {
        Frame {
            stack: Default::default(),
            ip: 0,
            return_value: None,
            locals: Default::default(),
            ops,
        }
    }

    pub fn push(&mut self, obj_ref: DynRef) {
        self.stack.push(obj_ref)
    }

    pub fn pop(&mut self) -> Option<DynRef> {
        self.stack.pop()
    }

    pub fn ip(&self) -> usize {
        self.ip
    }

    pub fn set_ip(&mut self, ip: usize) {
        self.ip = ip;
    }

    pub fn return_value(&self) -> Option<DynRef> {
        self.return_value
    }

    pub fn set_return_value(&mut self, obj_ref: DynRef) {
        self.return_value = Some(obj_ref);
    }

    pub fn get_local(&self, name: NameId) -> Option<DynRef> {
        self.locals.get(&name).copied()
    }

    pub fn set_local(&mut self, sym: NameId, obj_ref: DynRef) -> Option<DynRef> {
        self.locals.insert(sym, obj_ref)
    }

    pub fn ops(&self) -> &Rc<Vec<Op>> {
        &self.ops
    }
}