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

#include <unistd.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <limits.h> // necesar pentru PATH_MAX

#define SECTOR_SIZE 4096

void reverse(char *sir)
{
    int lg = strlen(sir) - 1;
    for (int i = 0; i <= lg / 2; i++)
    {
        char aux = sir[i];
        sir[i] = sir[lg - i];
        sir[lg - i] = aux;
    }
}

void afiseaza(char *map_addr, int length)
{
    char aux[SECTOR_SIZE] = {0};
    for (int i = length - 1; i >= 0; i--)
        if (map_addr[i] != '\n')
        {
            int lg = strlen(aux);
            aux[lg++] = map_addr[i];
            aux[lg] = '\0';
        }
        else
        {
            if (strlen(aux) > 0)
            {
                reverse(aux);
                printf("%s\n", aux);
            }
            aux[0] = '\0';
        }
    if (strlen(aux) > 0)
    {
        reverse(aux);
        printf("%s\n", aux);
    }
}

void recursive(int f, int length, int offset, int PageSize)
{
    int ok = 0;
    if (length > PageSize)
    {
        recursive(f, length - PageSize, offset + PageSize, PageSize);
        ok = 1;
    }
    if (ok == 1)
        length = PageSize;
    char *map_addr = mmap(NULL, length, PROT_READ, MAP_PRIVATE, f, offset);
    afiseaza(map_addr, length);
    if (munmap(map_addr, length) == -1)
    {
        perror("Erroare la munmap.");
        exit(4);
    }
}

void scrieFisier(char *numeFisier)
{
    int f = open(numeFisier, O_RDONLY);

    if (f == -1)
    {
        perror("A aparut o eroare cand am incercat sa deschide fisierul");
        exit(2);
    }

    long PageSize = sysconf(_SC_PAGE_SIZE);
    struct stat sb;

    if (PageSize == -1)
    {
        perror("Eroare la sysconf");
        exit(1);
    }

    if (fstat(f, &sb) == -1)
    {
        perror("Eroare la fstat");
        exit(2);
    }

    recursive(f, sb.st_size, 0, PageSize);
}

int main(int argc, char **argv)
{
    if (argc < 2)
    {
        printf("Introdu numele unui sau mai multor fisiere.");
        exit(1);
    }

    for (int i = 1; i < argc; i++)
        scrieFisier(argv[i]);
    printf("\n");
}