package vm

import (
	"monkey/internal/code"
	"monkey/internal/object"
	"unsafe"
)

var cache = NewFrameCache(32)

type Frame struct {
	cl          *object.Closure
	ip          int
	basePointer int
}

func NewFrame(cl *object.Closure, basePointer int) *Frame {
	key := uint(uintptr(unsafe.Pointer(cl))) + uint(basePointer)
	if frame, ok := cache.Get(key); ok {
		frame.Reset()
		return frame
	}

	frame := &Frame{
		cl:          cl,
		ip:          -1,
		basePointer: basePointer,
	}

	cache.Put(key, frame)

	return frame
}

// NextOp ...
func (f *Frame) NextOp() code.Opcode {
	return code.Opcode(f.Instructions()[f.ip+1])
}

func (f *Frame) Reset() {
	f.ip = -1
}

func (f *Frame) Instructions() code.Instructions {
	return f.cl.Fn.Instructions
}