#include <iostream>
#include <unistd.h> 
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <pwd.h>
#include <time.h>

using namespace std;

void TellAboutTime(string label, timespec theTime){
   cout << "\t" << label <<" "  << asctime(localtime(&theTime.tv_sec));
   cout << "\t\tand " << theTime.tv_nsec << " nanoseconds " << endl;
   return;
}

void TellAboutUser(uid_t uid) {
    struct passwd * pwd;
    cout << "\tThe user id is " << uid << endl;
    pwd = getpwuid(uid);
    if (pwd == NULL) {
       perror("getpwuid"); 
    } else {
       cout << "\t\tThat is " << pwd->pw_name << endl;
    }

    return;
}

void TellAboutGroup(gid_t gid){
   cout << "\tThe group id is " << gid << endl;
   return;
}

void TellPerms(mode_t mode) {
    // also S_ISGID, S_ISVTX
    if (S_ISUID & mode) {
       cout << "\t\t\tsetuid" << endl;
    }

    // also S_IxGRP, S_IxOTH
    if (S_IRUSR & mode) {
       cout << "\t\t\tuser read" << endl;
    }
    if (S_IWUSR & mode) {
       cout << "\t\t\tuser write" << endl;
    }
    if (S_IXUSR & mode) {
       cout << "\t\t\tuser execute" << endl;
    }
}

void TellAboutMode(mode_t mode) {
    // way 1 to find file type.
    if (S_ISREG(mode) ) {
       cout << "\tThis is a regular file " << endl;
    } else  if (S_ISDIR(mode) ) {
       cout << "\tThis is a directory " << endl;
    }

    // way 2 to find file type.
    switch (mode & S_IFMT) {
       case S_IFREG : cout << "\t\tRegular File" << endl; break;
       case S_IFDIR : cout << "\t\tDirectory File" << endl; break;
       case S_IFCHR : cout << "\t\tCharacter Device" << endl; break;
       case S_IFBLK : cout << "\t\tBlock Device" << endl; break;
       case S_IFIFO : cout << "\t\tPipe" << endl; break;
       case S_IFSOCK : cout << "\t\tSocket" << endl; break;
       case S_IFLNK : cout << "\t\tSymbolic Link" << endl; break;
    }

    TellPerms(mode);

    return;
}

void TellAbout(char * file) {
   int rv;
   struct stat fileInfo;

   rv = lstat(file, &fileInfo);
   if (rv != 0) {
      cerr <<  file << endl;
      perror("stat failed ");
   } else {
      cout << file << " has the following properties " << endl;
      cout << "\tIt is on device " << major(fileInfo.st_dev) 
           << "." << minor(fileInfo.st_dev) << endl;
      cout << "\tThe inode is " << fileInfo.st_ino << endl;
      cout << "\tThis file has " << fileInfo.st_nlink << " links " << endl;
      cout << "\tFile Size " << fileInfo.st_size << " bytes or " 
           << fileInfo.st_size/1014 << "K" << endl;
      TellAboutMode(fileInfo.st_mode);
      TellAboutUser(fileInfo.st_uid);
      TellAboutGroup(fileInfo.st_gid);
      TellAboutTime("Access Time", fileInfo.st_atim);
      TellAboutTime("Modification Time", fileInfo.st_mtim);
      TellAboutTime("Change Time", fileInfo.st_ctim);
   }

   cout << endl;
   return;
}


int main(int argc, char * argv[]) {
    int i;

    for(i=1;i<argc;i++) {
       TellAbout(argv[i]);
    }

    return 0;
}