#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.

srand(time(NULL)); // Generator initialisieren
int zufallsZahl = rand(); // Zufallszahl generieren
*/

// 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 *arr = malloc(len * sizeof(unsigned int));

	if(arr == NULL)
		return NULL;

    for(int i = 0; i < len; i++)
        arr[i] = 0;

    for(int j = 0; j < len; j++) {
	    do {
		    arr[j] = (rand() % (2 * len)) + 1;
	    	if (j >= 1) {
	    		for (int k = 0; k < j; k++) {
	    			if (arr[j] == arr[k]) {
	    				arr[j] = 0;
	    				break;
	    			}
	    		}
	    	}
	    } while (arr[j] == 0);
    }

	unsigned int strc = 0;
	unsigned int strv = 0;
	do {
		strv = rand() % len;
		strc = rand() % len;
	} while (strv == strc);

	arr[strv] = arr[strc];

	return arr;
}

// Returns only the only number in numbers which is present twice. Returns zero on errors.
unsigned int getDuplicate(const unsigned int numbers[], unsigned int len)
{
	unsigned int duplicate = 0;
	unsigned int counter = 0;
	for(int i = 0; i < (len - 1); i++) {
		for(int j = 1; j < (len - i); j++) {
			if(numbers[i] == numbers[i+j]) {
				duplicate = numbers[i];
 				counter++;
			}
		}
	}
 	if(counter != 1)
 		duplicate = 0;

    return duplicate;
}