#include <stdio.h>
#include <stdlib.h>

#include "vm.h"

struct virtualMachine *initVM() {
  struct virtualMachine *vm = malloc(sizeof(struct virtualMachine));
  vm->stackSize = 0;
  return vm;
}

void push(struct virtualMachine *vm, struct garbageObject *value) {
  if (vm->stackSize >= STACK_MAX) {
    fprintf(stderr, "ERROR: push(): Refusing to overflow the stack!\n");
    // FIXME: Must free memory before exiting
    exit(-1);
  }
  vm->stack[vm->stackSize++] = value;
}

struct garbageObject *pop(struct virtualMachine *vm) {
  if (vm->stackSize < 0) {
    fprintf(stderr,
            "ERROR: pop(): Stack underflow - stack size cannot be negative!");
    // FIXME: Must free memory before exiting
    exit(-1);
  }

  return vm->stack[--vm->stackSize];
}

struct garbageObject *initGarbage(struct virtualMachine *vm,
                                  enum garbageData type) {
  struct garbageObject *obj = malloc(sizeof(struct garbageObject));
  obj->type = type;
  return obj;
}