#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define PHONEBOOK_FILE "imenik.dat"
#define INPUT_FILE     "ulaz.txt"
#define OUTPUT_FILE    "izlaz.txt"

#define NAME_LEN    31
#define NUM_LEN     11
#define MAX_ENTRIES 300

#define EXIT_IO_ERROR -1

#define IO_ERROR(f) perror(f), exit(EXIT_IO_ERROR)

typedef struct entry {
    char name[NAME_LEN], num[NUM_LEN];
} Entry;

typedef Entry Phonebook[MAX_ENTRIES];

int read_phonebook(Phonebook pb)
{
    int n;
    FILE *pb_file;

    if (!(pb_file = fopen(PHONEBOOK_FILE, "rb"))) {
        IO_ERROR(PHONEBOOK_FILE);
    }

    // Returns the number of successfully read entries
    n = fread(pb, sizeof(Entry), MAX_ENTRIES, pb_file);
    fclose(pb_file);
    return n;
}

char *get_num_for(Phonebook pb, int n, char *name)
{
    int i;
    for (i = 0; i < n; ++i) {
        if (strcmp(pb[i].name, name) == 0) {
            return pb[i].num;
        }
    }
    return NULL;
}

void process_input(Phonebook pb, int n)
{
    FILE *input, *output;
    int c;
    char name[NAME_LEN], *num;

    if (!(input = fopen(INPUT_FILE, "r"))) {
        IO_ERROR(INPUT_FILE);
    }
    if (!(output = fopen(OUTPUT_FILE, "w"))) {
        IO_ERROR(OUTPUT_FILE);
    }

    while ((c = getc(input)) != EOF) {
        if (c != '[') {
            putc(c, output);
        } else {
            fscanf(input, "%30[^]]]", name);
            num = get_num_for(pb, n, name);
            if (num) {
                fprintf(output, "%s", num);
            } else {
                fprintf(output, "[%s]", name);
            }
        }
    }

    fclose(input);
    fclose(output);
}

/* Test function for making a binary phonebook file */
void make_phonebook()
{
    FILE *pb_file;
    Phonebook pb;
    int i, n;

    if (!(pb_file = fopen(PHONEBOOK_FILE, "wb"))) {
        IO_ERROR(PHONEBOOK_FILE);
    }

    printf("Broj zapisa: ");
    scanf("%d", &n);
    if (n < 1 || n > MAX_ENTRIES) {
        return;
    }

    for (i = 0; i < n; ++i) {
        printf("Zapis %d:\n", i);
        scanf("%s %s", pb[i].name, pb[i].num);
    }

    fwrite(pb, sizeof(Entry), i, pb_file);
    fclose(pb_file);
}

int main(void)
{
    Phonebook pb;
    int n;

    //make_phonebook();

    n = read_phonebook(pb);
    process_input(pb, n);

    return EXIT_SUCCESS;
}