#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <string.h>
#include "numbers.h"
#include "bintree.h"

//TODO: getDuplicate und createNumbers implementieren
/*  *   * Erzeugen eines Arrays mit der vom Nutzer eingegebenen Anzahl an Zufallszahlen.
  * Sicherstellen, dass beim Befüllen keine Duplikate entstehen.
  * Duplizieren eines zufälligen Eintrags im Array.
  * in `getDuplicate()`: Sortieren des Arrays und Erkennen der doppelten Zahl durch Vergleich benachbarter Elemente. */

// Returns len random numbers between 1 and 2x len in random order which are all different, except for two entries.
// Returns NULL on errors. Use your implementation of the binary search tree to check for possible duplicates while
// creating random numbers.
unsigned int *createNumbers(unsigned int len)
{
  srand(time(NULL));

  unsigned int *numbers = malloc (sizeof(unsigned int) * (len+1));
  unsigned int newNumber;

  for (unsigned int i = 0; i < len; i++) {
    int unique = 0;

    while (!unique) {
    unique = 1;
    newNumber = rand () % (2*len) + 1;

      for (unsigned int j = 0; j < i; j++) {
        if (numbers[j] == newNumber) {
          unique = 0;
          break;
        }
      }
    }
    numbers[i] = newNumber;
  }

  unsigned int duplicate = numbers[rand () % len]; 
  numbers[len] = duplicate;

  return numbers;
}

int compare (const void *a, const void *b) {
  unsigned int *x = a;
  unsigned int *y = b;
  if (*x < *y) {
    return -1;
  }
  else if (*x > *y) {
    return 1;
  }
  else {
    return 0;
  }
}
// Returns only the only number in numbers which is present twice. Returns zero on errors.
unsigned int getDuplicate(unsigned int numbers[], unsigned int lenPlusOne)
{
  if (lenPlusOne < 2) {
    return 0;
  }

qsort(numbers,lenPlusOne, sizeof(unsigned int), compare);

for (int i = 0; i < lenPlusOne-1; i++) {
  if (numbers[i] == numbers [i+1]) {
    return numbers[i];
  }
}
  return 0;
}