use fix_runtime::Machine;

use crate::{BytecodeReader, Mutation, Step, Value};

#[inline(always)]
#[expect(
    clippy::indexing_slicing,
    reason = "local slot index is produced by codegen and bounded by the frame's AllocLocals count"
)]
pub(crate) fn op_load_local<'gc, M: Machine<'gc>>(
    m: &mut M,
    reader: &mut BytecodeReader<'_>,
) -> Step {
    let idx = reader.read_u32() as usize;
    m.push(m.env().borrow().locals[idx]);
    Step::Continue(())
}

#[inline(always)]
#[expect(
    clippy::indexing_slicing,
    reason = "local slot index is produced by codegen and bounded by the target frame's AllocLocals count"
)]
pub(crate) fn op_load_outer<'gc, M: Machine<'gc>>(
    m: &mut M,
    reader: &mut BytecodeReader<'_>,
) -> Step {
    let layer = reader.read_u8();
    let idx = reader.read_u32() as usize;
    let mut cur = m.env();
    for _ in 0..layer {
        let prev = cur.borrow().prev.expect("LoadOuter: env chain too short");
        cur = prev;
    }
    let val = cur.borrow().locals[idx];
    m.push(val);
    Step::Continue(())
}

#[inline(always)]
#[expect(
    clippy::indexing_slicing,
    reason = "local slot index is produced by codegen and bounded by the frame's AllocLocals count"
)]
pub(crate) fn op_store_local<'gc, M: Machine<'gc>>(
    m: &mut M,
    reader: &mut BytecodeReader<'_>,
    mc: &Mutation<'gc>,
) -> Step {
    let idx = reader.read_u32() as usize;
    let val = m.pop();
    m.env().borrow_mut(mc).locals[idx] = val;
    Step::Continue(())
}

#[inline(always)]
pub(crate) fn op_alloc_locals<'gc, M: Machine<'gc>>(
    m: &mut M,
    reader: &mut BytecodeReader<'_>,
    mc: &Mutation<'gc>,
) -> Step {
    let count = reader.read_u32() as usize;
    m.env()
        .borrow_mut(mc)
        .locals
        .extend(std::iter::repeat_n(Value::default(), count));
    Step::Continue(())
}