#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_NAME 30
#define MAX_INDEX 12
#define MAX_SIZE 100

typedef struct student_st {
    char index[MAX_INDEX];
    char ime[MAX_NAME];
    char prezime[MAX_NAME];
    unsigned poeni;
} STUDENT;

FILE *safe_open(char*, char*);
void ucitavanje (FILE *, STUDENT *, int *);
void a(STUDENT *, int);
void b(STUDENT *, int);
void c(STUDENT *, int, char *);
void d(STUDENT *, int);

int main(int brArg, char *args[]) {

    STUDENT niz[MAX_SIZE];
    int n;
    FILE *in;

    if (brArg != 3) {
      puts("Niste dobro pozvali program.");
      exit(EXIT_FAILURE);
    }

    in = safe_open(args[1], "r");

    ucitavanje(in, niz, &n);
    a(niz, n);
    b(niz, n);
    c(niz, n, args[2]);
    d(niz, n);

    fclose(in);

    return 0;
}

FILE *safe_open(char *name, char *mode) {
    FILE *fp = fopen(name, mode);

    if(fp == NULL) {
        printf("Doslo je do greske prilikom otvaranja fajla %s.\n", name);
        exit(EXIT_FAILURE);
    }

    return fp;
}

void ucitavanje (FILE *in, STUDENT *niz, int *i) {
    STUDENT temp;
    int br = 0;

    while(fscanf(in, "%s %s %s %u", temp.index, temp.ime, temp.prezime, &temp.poeni)!=EOF) {
        strcpy(niz[br].index, temp.index);
        strcpy(niz[br].ime, temp.ime);
        strcpy(niz[br].prezime, temp.prezime);
        niz[br].poeni = temp.poeni;
        br++;
    }

    *i = br;
}

void a (STUDENT *niz, int n) {
    FILE *s;
    int j, i;
    STUDENT temp;

    s = safe_open("sortirani.txt", "w");

    for(i = 0; i< n -1; ++i)
        for(j = i + 1; j < n ; ++j) {
            if(strcmp(niz[i].index, niz[j].index)>0) {
                strcpy(temp.index, niz[i].index);
                strcpy(temp.ime, niz[i].ime);
                strcpy(temp.prezime, niz[i].prezime);
                temp.poeni = niz[i].poeni;

                strcpy(niz[i].index, niz[j].index);
                strcpy(niz[i].ime, niz[j].ime);
                strcpy(niz[i].prezime, niz[j].prezime);
                niz[i].poeni = niz[j].poeni;

                strcpy(niz[j].index, temp.index);
                strcpy(niz[j].ime, temp.ime);
                strcpy(niz[j].prezime, temp.prezime);
                niz[j].poeni = temp.poeni;
            }
        }

    for(i = 0; i <n; i++) {
        fprintf(s, "%s %s %s %u\n", niz[i].index, niz[i].ime, niz[i].prezime, niz[i].poeni);
    }

    fclose(s);
}

void b (STUDENT *niz, int n) {
    int i = 1, maxs, mins;;

    maxs = strlen(niz[0].prezime);
    mins = strlen(niz[0].prezime);

    for(; i < n; i++) {
        if(strlen(niz[i].prezime) > maxs) {
            maxs = strlen(niz[i].prezime);
        } else if(strlen(niz[i].prezime) < mins) {
            mins = strlen(niz[i].prezime);
        }
    }

    for(i = 0; i < n; i++) {
        if(strlen(niz[i].prezime) == maxs) {
            printf("Najduze prezime je : %s.\n", niz[i].prezime);
        }

        if(strlen(niz[i].prezime) == mins) {
            printf("Najkrace prezime je : %s.\n", niz[i].prezime);
        }
    }
}

void c (STUDENT *niz, int n, char *ppoeni) {
    FILE *p;
    int i = 0;

    char naziv[100];
    strcpy(naziv, "preko_");
    strcat(naziv, ppoeni);
    strcat(naziv, "_poena.txt");

    p = safe_open(naziv, "w");

    for(; i < n; i++) {
        if(niz[i].poeni > atoi(ppoeni))
            fprintf(p, "%s %s %s %u\n", niz[i].index, niz[i].ime, niz[i].prezime, niz[i].poeni);
    }

    fclose(p);
}

void d (STUDENT *niz, int n) {
    FILE *p;
    int i = 0, dimena = 0;

    p = safe_open("izlaz.txt", "w");

    for(; i < n; i++) {
        dimena += strlen(niz[i].ime);
    }

    fprintf(p, "Prosecna duzina prezimena je: %d.\n", dimena/n);

    fclose(p);
}