/* ndistinct.c from CS360 midterm exam on 3/9/2021. */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/stat.h>
#include "jrb.h"

/* Since inodes are longs, you need to write your own comparison function. */

int compare(Jval v1, Jval v2)
{
  if (v1.l < v2.l) return -1;
  if (v1.l > v2.l) return 1;
  return 0;
}

/* Use opendir() / readdir() to enumerate files.
   Use stat to find each files' inode number.
   Store the inodes in a red-black tree so that you can discover duplicates. */

int main()
{
  JRB tree;                 /* The tree. */
  DIR *d;                   /* The open directory. */
  struct dirent *de;        /* Each file in the directory. */
  struct stat buf;          /* The file's metadata. */
  int ndistinct;            /* The number of distinct files. */

  /* Do initialization */

  tree = make_jrb();
  d = opendir(".");
  if (d == NULL) { perror("."); exit(1); }
  ndistinct = 0;

  /* Enumerate the files and look up each inode in the tree.
     Only insert an inode if it's not there already. */

  for (de = readdir(d); de != NULL; de = readdir(d)) {
    if (stat(de->d_name, &buf) != 0) { perror(de->d_name); exit(1); }
    if (jrb_find_gen(tree, new_jval_l(buf.st_ino), compare) == NULL) {
      ndistinct++;
      jrb_insert_gen(tree, new_jval_l(buf.st_ino), new_jval_i(0), compare);
    }
  }

  /* Print the final answer.  I don't close the directory or free the tree,
     because that is done automatically when the program ends. */

  printf("%d\n", ndistinct);
  return 0;
}