#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

char buffer[SECTOR_SIZE], comanda[10];
int bytes_read;

int main(int argc, char **argv)
{
    struct stat sb;

    long PageSize = sysconf(_SC_PAGE_SIZE);

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

    if (argc < 3)
    {
        printf("Optiuni insuficiente.");
        exit(1);
    }

    int f1 = open(argv[1], O_RDONLY);

    if (f1 < 0)
    {
        perror("Error on opening file");
        exit(1);
    }

    int f2 = open(argv[2], O_RDWR);

    if (f2 > 0)
    {
        printf("Doriti sa suprascrieti continutul ? da/nu \n");
        scanf("%10s", &comanda);
        if (strcmp(comanda, "da") != 0)
        {
            printf("\nNu ai acordat permisiunea \n");
            exit(5);
        }
    }
    else
    {
        f2 = open(argv[2], O_RDWR | O_CREAT);
        chmod(argv[2], S_IRUSR | S_IWUSR);
    }

    if (fstat(f1, &sb) == -1)
    {
        perror("Eroare la fstat");
        exit(4);
    }

    int offset = 0;
    int length = sb.st_size;

    if (ftruncate(f2, length) == -1)
        {
            perror("Eroare la trunchiere");
            exit(5);
        }

    while (length > PageSize)
    {
        afiseaza(f1, f2, PageSize, offset);
        length -= PageSize;
        offset += PageSize;
    }
    afiseaza(f1, f2, length, offset);

    if (close(f1) == -1 || close(f2) == -1)
    {
        perror("Error on closing files");
        exit(9);
    }

    return 0;
}

void afiseaza(int f1, int f2, int length, int offset)
{
    char *map_addr1 = mmap(NULL, length, PROT_READ, MAP_SHARED, f1, offset);
    char *map_addr2 = mmap(NULL, length, PROT_WRITE, MAP_SHARED, f2, offset);

    if (map_addr1 == MAP_FAILED || map_addr2 == MAP_FAILED)
    {
        perror("Eroare la mmap.");
        exit(3);
    }

    for (int i = 0; i < length; i++)
        if(map_addr1[i]>='a' && map_addr1[i]<='z')
            map_addr2[offset+i]=map_addr1[i]-'a'+'A';
        else map_addr2[offset+i]=map_addr1[i];

    if (-1 == msync(map_addr2, length, MS_SYNC))
    {
        perror("Erroar la msync");
        exit(1);
    }

    if (munmap(map_addr1, length) == -1 || munmap(map_addr2, length) == -1)
    {
        perror("Erroare la munmap.");
        exit(2);
    }
}