#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<time.h>

typedef struct Student ST;

struct Student {
	char ime[15];
	char prezime[15];
	int indeks;
	int orderNum;
	struct Student *next;
};

ST *Alloc(ST *newitem);
int Insert(ST *head, ST *newitem);
int ReadFIle(ST *head);
int Print(ST *head);
int Kopiraj(ST *head, ST* sort);
int Copy(ST *sort, ST* head);
int SortInput(ST *sort, ST *newitem);
int Brisi_iste(ST *sort);
int Delete(ST *sort, ST *head);
int DeleteList(ST *sort);

int main(void)
{
	ST head = { 0 };
	ST sort_head = { 0 };

	srand((unsigned)time);

	head.next = NULL;
	sort_head.next = NULL;

	//procitaj indeks,ime i prezime iz dtk
	ReadFIle(&head);

	// a. napravi novu listu i spremi studente + orderNum
	Kopiraj(&head, &sort_head);
	Print(&sort_head);

	// b. izbrisi studente s istim orderNum
	Brisi_iste(&sort_head);
	Print(&sort_head);

	//Izbrisi liste ( oslobodi mem ) 
	DeleteList(&head);
	DeleteList(&sort_head);
	Print(&sort_head);


	return 0;
}

ST *Alloc(ST *newitem)
{
	newitem = (ST*)malloc(sizeof(ST));

	if (newitem == NULL)
	{
		printf("GRESKA1 !");
		return NULL;
	}

	return newitem;
}
int Insert(ST *head, ST *newitem)
{
	newitem->next = head->next;
	head->next = newitem;

	return 0;
}
int Print(ST *head)
{
	head = head->next;

	if (head == NULL)
	{
		printf("Empty list\n");
		return 0;
	}

	printf("Ispis liste:\n");
	while (head != NULL)
	{
		printf("%d %s %s %d\n", head->indeks, head->ime, head->prezime, head->orderNum);
		head = head->next;
	}
	return 0;
}
int ReadFIle(ST *head)
{
	FILE *fp = NULL;
	ST *newitem = NULL;

	fp = fopen("Studenti2.txt", "r");
	if (fp == NULL)
	{
		printf("GRESKA2!");
		return 0;
	}

	while (!(feof(fp)))
	{
		newitem = Alloc(newitem);
		fscanf(fp, "%d %s %s", &newitem->indeks, newitem->ime, newitem->prezime);
		newitem->orderNum = rand() % 5 + 1;
		Insert(head, newitem);
	}

	fclose(fp);

	return 0;
}
int Kopiraj(ST *head, ST* sort)
{
	head = head->next;

	while (head != NULL)
	{
		Copy(sort, head);
		head = head->next;
	}

	return 0;
}
int Copy(ST *sort, ST* head)
{
	ST *newitem = NULL;

	newitem = Alloc(newitem);

	newitem->indeks = head->indeks;
	newitem->orderNum = head->orderNum;
	strcpy(newitem->ime, head->ime);
	strcpy(newitem->prezime, head->prezime);

	SortInput(sort, newitem);

	return 0;
}
int SortInput(ST *sort, ST *newitem)
{
	ST *tmp = NULL;

	tmp = sort;
	sort = sort->next;

	while (sort != NULL && strcmp(sort->prezime, newitem->prezime) < 0)
	{
		tmp = sort;
		sort = sort->next;
	}

	Insert(tmp, newitem);

	return 0;
}
int Brisi_iste(ST *sort)
{
	ST *prev_sort = NULL;
	int i = 0;


	prev_sort = sort;
	sort = sort->next;

	while (sort != NULL)
	{
		i = Delete(sort, sort);

		if (i != 0)
		{
			prev_sort->next = sort->next;
			free(sort);
			sort = prev_sort->next;
			continue;

		}
		else
		{
			prev_sort = sort;
			sort = sort->next;
		}
	}


	return 0;
}
int Delete(ST *sort, ST *head)
{
	ST *prev_head = NULL;
	int i = 0;
	ST *tmp = NULL;

	tmp = head;
	prev_head = head;
	head = head->next;

	while (head != NULL)
	{
		if (sort->orderNum == head->orderNum)
		{
			prev_head->next = head->next;
			free(head);
			head = prev_head->next;
			i = 1;
		}
		else
		{
			prev_head = head;
			head = head->next;
		}

	}

	//Print(tmp);

	return i;
}
int DeleteList(ST *sort)
{
	ST *head = NULL;

	head = sort;
	sort = sort->next;

	while (head->next != NULL)
	{
		head->next = sort->next;
		free(sort);
		sort = head->next;
	}

	return 0;
}