#define _GNU_SOURCE
#include <stdio.h>

#include <stdlib.h>
#include <string.h>

#include "person_v1.h"

// It's often useful to separate the notions of "allocate space" from "initialize."
// We do that here.
// 
// On success, this method returns the Person pointer it was passed.
// On failure, it returns NULL.
//
// The 'static' here makes the scope of '_person_init' just the rest of
// this file (i.e., not global scope).
// There is a convention in many languages to use names that begin with one
// or more underscores to indicate the method should be considered "private".
static Person *_person_init(Person *p, const char *name) {
  p->name = strdup(name);
  if ( p->name == NULL ) return NULL;
  return p;
}

Person *person_new(const char *name) {
  if (name == NULL) {
    return NULL;
  }
  Person *p = malloc(sizeof(Person));
  if (!p) {
    return NULL;
  }
  if ( _person_init(p, name) == NULL ) {
    free(p);
    return NULL;
  }
  return p;
}

// Returns 0 on success, -1 on failure.
int person_delete(Person *p) {
  if ( p == NULL) return -1; 
  free(p->name);   // free() works even if its argument is NULL
  p->name = NULL;  // Not really necessary, but a good habit...
  free(p);
  return 0;  // Assume it always works :)
}

const char *person_get_name(const Person *p) {
  if ( p == NULL) return NULL;
  return p->name;
}

char *person_toString(const Person *p) {
  char *s = NULL;
  if (p==NULL) return NULL;
  if (asprintf(&s, "Name: %s\n", p->name) <= 0) return NULL;
  return s;
}