#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>
#include <sys/stat.h>
#include <pwd.h>
#include <grp.h>
#include <time.h>
#include <unistd.h>

void print_file_info(const char *path, const char *filename) {
    char fullpath[4096];
    snprintf(fullpath, sizeof(fullpath), "%s/%s", path, filename);

    struct stat st;
    if (lstat(fullpath, &st) == -1) {
        perror("lstat");
        return;
    }

    // File type and permissions
    char perms[11] = "----------";
    if (S_ISDIR(st.st_mode)) perms[0] = 'd';
    else if (S_ISLNK(st.st_mode)) perms[0] = 'l';
    else if (S_ISCHR(st.st_mode)) perms[0] = 'c';
    else if (S_ISBLK(st.st_mode)) perms[0] = 'b';
    else if (S_ISFIFO(st.st_mode)) perms[0] = 'p';
    else if (S_ISSOCK(st.st_mode)) perms[0] = 's';

    if (st.st_mode & S_IRUSR) perms[1] = 'r';
    if (st.st_mode & S_IWUSR) perms[2] = 'w';
    if (st.st_mode & S_IXUSR) perms[3] = 'x';
    if (st.st_mode & S_IRGRP) perms[4] = 'r';
    if (st.st_mode & S_IWGRP) perms[5] = 'w';
    if (st.st_mode & S_IXGRP) perms[6] = 'x';
    if (st.st_mode & S_IROTH) perms[7] = 'r';
    if (st.st_mode & S_IWOTH) perms[8] = 'w';
    if (st.st_mode & S_IXOTH) perms[9] = 'x';

    // User and group names
    struct passwd *pw = getpwuid(st.st_uid);
    struct group *gr = getgrgid(st.st_gid);

    // Modification time
    char timebuf[64];
    struct tm *mtm = localtime(&st.st_mtime);
    strftime(timebuf, sizeof(timebuf), "%b %e %H:%M", mtm);

    // Output format similar to ls -l
    printf("%s %3lu %s %s %8ld %s %s\n",
           perms,
           st.st_nlink,
           pw ? pw->pw_name : "???",
           gr ? gr->gr_name : "???",
           st.st_size,
           timebuf,
           filename);
}

int main(int argc, char *argv[]) {
    printf("argc = %d\n", argc);
    for (int i = 0; i < argc; ++i) {
        printf("argv[%d] = '%s'\n", i, argv[i]);
    }
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <target-directory>\n", argv[0]);
        return EXIT_FAILURE;
    }

    const char *dirpath = argv[1];
    DIR *dir = opendir(dirpath);
    if (!dir) {
        perror("opendir");
        return EXIT_FAILURE;
    }

    struct dirent *entry;
    while ((entry = readdir(dir))) {
        if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
            continue;
        print_file_info(dirpath, entry->d_name);
    }

    closedir(dir);
    return EXIT_SUCCESS;
}