/* dired.c -- Playing with stats of files -- Given as command line parameter 
              a file name, we print out its name, and,
	      if it is a directory, we do the same recursively
              for all its elements.
 */

#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

extern int errno;

// It returns 1 iff path denotes a directory.
int isDir(const char *path)
{
  struct stat buffer;
  
  if (stat(path, &buffer) < 0){
    fprintf(stderr, "stat: %s\n", strerror(errno));
    return 0;
  };
  if(S_ISDIR(buffer.st_mode))
    return 1;
  else
    return 0;
}

// If the file denoted by pathname is a directory,
// print out information about its descendants 
// one per line, indenting n+4 spaces.
void print_descendants(const char *pathname, int n)
{
  if (isDir(pathname)) {
    DIR *d;
    struct dirent *p;
    char path[512];
    
    if ((d = opendir(pathname)) == NULL){
      fprintf(stderr, "opendir %s  %s\n", path, strerror(errno));
      return;
    } 
    p = readdir(d); // skip .
    p = readdir(d); // skip ..
    n = n+4;
    while ((p = readdir(d)) != NULL) {
      int k;
      for (k=0; k<n; ++k)
	putchar(' ');
      printf("%s\n", p->d_name);
      strcpy(path, pathname);
      strcat(path, "/");
      strcat(path, p->d_name);
      print_descendants(path, n);
    }
    closedir(d);
  }
}

int main(int argc, char *argv[])
{
  if (argc != 2) {
    printf("usage: %s dirname\n", argv[0]);
    exit(0);
  }
  printf("%s\n", argv[1]);
  print_descendants(argv[1], 0);
  return 0;
}