#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){

	if(len == 1){
		printf("Minimum length is 2");
		return NULL;
	}
	srand(time(NULL));
	unsigned int *numbers = malloc(len * sizeof(unsigned int)); //reserving memory for array
	if(!numbers){
		printf("Error allocating Memory");
		return NULL;
	}

	for (int i = 0; i < len; i++){
		numbers[i] = rand() % (2 * len) + 1; //creates randorm number between 1 and 2x len
		if(getDuplicate(numbers, i+1)){ //We use i+1 to refer to current initialised array length
			i--;  //If there a douplicate has been created, i gets 1 lower therefore overwriting it in next iteration
		}
	}
	//Creating Duplicate
	unsigned int duplicationSuccess = 0;
	while (duplicationSuccess == 0){
		unsigned int duplicateInitialIndex = rand()%len; //Getting random index for creating duplicate
		unsigned int duplicateReplaceIndex = rand ()%len; //Index of Number replaced by duplicateInitialIndex

		if(duplicateInitialIndex == duplicateReplaceIndex)
			continue; //returning process if chosen duplicate is replacing itsself

		duplicationSuccess = 1;
		numbers[duplicateReplaceIndex] = numbers [duplicateInitialIndex];
		}



	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)
{
	unsigned int *sortedNumbers = malloc(len * sizeof(unsigned int));
	if(!sortedNumbers){
		printf("Error allocating memory");
		return 0;
	}

	//Creating Copy of Numbers Array
	for (int i = 0; i < len; i++){
		sortedNumbers[i] = numbers[i];
	}

	unsigned int duplicate = 0;
	unsigned int temp = 0;
	unsigned int duplicateCount = 0;

	//Sorting sortedNumbers
	for (int i = 0; i < len; i++){
		for(int j = 0; j< len - 1; j++){
			if(sortedNumbers[j]> sortedNumbers[j+1]){ //Switching Elements
				temp = sortedNumbers[j];
				sortedNumbers[j] = sortedNumbers[j+1];
				sortedNumbers[j+1] = temp;
			}



		}
	}
	//identifying duplicates

	for(int i = 0; i < len; i++){
	    if(sortedNumbers[i] == sortedNumbers[i+1]){
			duplicate = sortedNumbers[i];
			duplicateCount++;
		}

	}


	free(sortedNumbers);
	if(duplicateCount != 1){
		return 0;
	}


	return duplicate;

}