use crate::obj::prelude::*;

#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ConstHandle(usize);

impl ConstHandle {
    pub fn index(&self) -> usize {
        self.0
    }

    pub fn new(handle: usize) -> Self {
        ConstHandle(handle)
    }
}

#[derive(Debug, Default)]
pub struct ConstPool {
    pool: Vec<ObjRef>,
}

impl ConstPool {
    pub fn new() -> Self {
        Default::default()
    }

    pub fn push(&mut self, value: ObjRef) -> ConstHandle {
        let hdl = ConstHandle::new(self.pool.len());
        self.pool.push(value);
        hdl
    }

    pub fn get(&self, hdl: ConstHandle) -> &ObjRef {
        self.pool.get(hdl.index()).unwrap()
    }

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

impl std::ops::Index<ConstHandle> for ConstPool {
    type Output = ObjRef;

    fn index(&self, hdl: ConstHandle) -> &Self::Output {
        self.get(hdl)
    }
}