#define _GNU_SOURCE
#include "Dog.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// why is this function not static?
void _delete(Dog d) {
  free(d->name);
  free(d);
}

// why is this function not static?
void _bark(Dog d) {
  printf("%s says Woof!\n", d->name);
}

static char *_toString(Dog d) {
  char *resultStr;
  asprintf(&resultStr, "Dog(%s, %d)", d->name, d->age);
  return resultStr;
}

static struct dog_vtable_st DOG_VTABLE = {
  .delete = _delete,
  .bark = _bark,
  .toString = _toString
};

int _dog_constructor(Dog d, char *name, int age) {
  size_t namelen = strlen(name);
  d->name = (char *)malloc(sizeof(namelen + 1));
  if (!d->name)
    return 0;
  strcpy(d->name, name);
  d->age = age;
  return 1;
}

Dog new_dog(char *name, int age) {
  Dog dog = (Dog)malloc(sizeof(struct dog_st));
  if (!dog)
    return NULL;
  dog->vtable = &DOG_VTABLE;
  if (!_dog_constructor(dog, name, age)) {
    free(dog);
    return NULL;
  }
  return dog;
}