#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>

int main(int argc, char *argv[]) {
    if (argc != 3) {
        fprintf(stderr, "Usage: %s <source_file> <destination_file>\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    const char *src_path = argv[1];
    const char *dst_path = argv[2];

    int src_fd = open(src_path, O_RDONLY);
    if (src_fd == -1) {
        perror("Erreur lors de l'ouverture du fichier source");
        exit(EXIT_FAILURE);
    }

    struct stat sb;
    if (fstat(src_fd, &sb) == -1) {
        perror("Erreur lors de fstat");
        close(src_fd);
        exit(EXIT_FAILURE);
    }

    size_t file_size = sb.st_size;

    int dst_fd = open(dst_path, O_RDWR | O_CREAT | O_TRUNC, 0644);
    if (dst_fd == -1) {
        perror("Erreur lors de l'ouverture du fichier de destination");
        close(src_fd);
        exit(EXIT_FAILURE);
    }

    if (ftruncate(dst_fd, file_size) == -1) {
        perror("Erreur lors de ftruncate");
        close(src_fd);
        close(dst_fd);
        exit(EXIT_FAILURE);
    }

    void *src_map = mmap(NULL, file_size, PROT_READ, MAP_PRIVATE, src_fd, 0);
    if (src_map == MAP_FAILED) {
        perror("Erreur lors de mmap (source)");
        close(src_fd);
        close(dst_fd);
        exit(EXIT_FAILURE);
    }

    void *dst_map = mmap(NULL, file_size, PROT_WRITE, MAP_SHARED, dst_fd, 0);
    if (dst_map == MAP_FAILED) {
        perror("Erreur lors de mmap (destination)");
        munmap(src_map, file_size);
        close(src_fd);
        close(dst_fd);
        exit(EXIT_FAILURE);
    }

    memcpy(dst_map, src_map, file_size);

    munmap(src_map, file_size);
    munmap(dst_map, file_size);
    close(src_fd);
    close(dst_fd);

    printf("Copie réussie de '%s' vers '%s'\n", src_path, dst_path);

    return 0;
}