#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. */
int compareFct(const void *a, const void *b)
    {
  		return *(int*)a - *(int*)b;
    }

// 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)
{
	if (len <= 2)
		return NULL;
	TreeNode *root = NULL;
	srand(time(NULL));
	unsigned int *numbers = malloc(sizeof(unsigned int)*len);
	int counter = 0;
	while (treeSize(root) < len) {
		unsigned int num = rand()%(2*len)+1;
		int isDuplicate = 0;
		root = addToTree(root, &num,sizeof(num), compareFct, &isDuplicate);
		if (isDuplicate == 0) {
			numbers[counter] = num;
			counter++;
		}
	}
	unsigned int duplicate = rand()%(len);
	unsigned int duplicateIdx = rand()%(len);
	numbers[duplicate] = numbers[duplicateIdx];
	return numbers;
}

// 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)
{
	if (numbers == NULL || len == 0) {
		return 0;
	}
	unsigned int *numbersCpy = malloc(sizeof(unsigned int)*len);
	if (numbersCpy == NULL) {
		return 0;
	}
	for (int i = 0; i < len; i++) {
		numbersCpy[i] = numbers[i];
	}

	qsort(numbersCpy, len, sizeof(unsigned int), compareFct);
	for (unsigned int i = 0; i < len-1; i++) {
		if (numbersCpy[i] == numbersCpy[i+1]) {
			const unsigned int duplicate = numbersCpy[i];
			free(numbersCpy);
			return duplicate;
		}

	}
	free(numbersCpy);
	return 0;
}