#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;
}