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

char *PERM[] = {
  "---", "--x", "-w-", "-wx",
  "r--", "r-x", "rw-", "rwx",
};

static void list(char * FILE_NAME, struct stat STR_BUF);
static int printout(char* dir, char* FILE_NAME);

int main(int argc, char** argv)
{
	struct stat STR_BUF;
	//If no arguments, list current directory
	if (argc < 2 ){
		//printf("argc<0case\n");
		list(".", STR_BUF);
		exit(0);
	}

	//Process arguments
	while(--argv){
		//see what the file is.
		if (stat(*++argv, &STR_BUF) < 0){
			perror(*argv);
			continue;
		}
		//if it's a directory we list it,
		//otherwise just print the info about the file
		if((S_ISDIR(STR_BUF.st_mode & S_IFMT))&&(*argv != "."||"..")){
			printf("aaaaaa\n");
			list(*++argv, STR_BUF);
			
		}
		else{
			list(*++argv, STR_BUF);
			//printout(".", *argv);
      break;
		}
	}
	exit(0);
}

//list --read a directory and list the files it contains.

void list(char * FILE_NAME, struct stat STR_BUF)
{
	DIR *dp;
	struct dirent *dir;
	
	//Open direct *dir;
	//printf("List is called\n");
	if ((dp = opendir(FILE_NAME)) == NULL){
		fprintf(stderr, "%s: cannot open.\n", FILE_NAME);
		return;
	}
	
	
	//For each entry
	while ((dir = readdir(dp)) != NULL){
		//skip removed files.
		if(dir->d_ino == 0)
		{continue;}
		//print it out;
		if((S_ISDIR(STR_BUF.st_mode & S_IFMT))&&(FILE_NAME != "."||"..")){
			printf("@@");
			list(dir->d_name, STR_BUF);
			
		}else{
			//printf("PrintOut is called\n");
      printout(FILE_NAME, dir->d_name);
		}
	}
	closedir(dp);
}
//print out --print out the information about a file

int printout(char* dir, char* FILE_NAME)
{
	int i, j;
	char PERM_INIT[10];
	struct stat STR_BUF;
	char NAME_MOD[1024];
	//make full path FILE_NAME,
	//so we have a legal path.
	sprintf(NAME_MOD, "%s/%s", dir, FILE_NAME);
	
	//at this point we know the file exists,
	//so this won't fail.
	stat(NAME_MOD, &STR_BUF);
	
	//Print size in kbytes.
	printf("%5d ", (int)((STR_BUF.st_size + 1023)/1024));
	
	//get file type.
	switch(STR_BUF.st_mode & S_IFMT){
  case S_IFREG: putchar('-'); break;//regular mask
  case S_IFDIR: putchar('d'); break;//directory mask
  case S_IFCHR: putchar('c'); break;//character mask
  case S_IFBLK: putchar('b'); break;//block mask
  default:      putchar('?'); break;
	}
	
	*PERM_INIT = 0x00;
	for(i=2; i>=0; i--){
		//Since we are subscripting, we don't need the 
		//constants. Just get a value between 0 and 7.
		j=(STR_BUF.st_mode >> (i*3)) & 07;
		
		//get perm bits
		strcat(PERM_INIT, PERM[j]);
	}
	//Handle special bits which replace the 'x' in places.
	if((STR_BUF.st_mode & S_ISUID) != 0){
		PERM_INIT[2] = 's';
	}
	if((STR_BUF.st_mode & S_ISGID) != 0){
		PERM_INIT[5] = 's';
	}
	if((STR_BUF.st_mode & S_ISVTX) != 0){
		PERM_INIT[8] = 't';
	}
	
	// Print permissions, number of links,
	// user and group ids.
	
	printf("%s%3d %5d/%-5d ", PERM_INIT, STR_BUF.st_nlink, STR_BUF.st_uid, STR_BUF.st_gid);
	
	//Print the size of the file in bytes and the last modification time.
	//The ctime routine converts a time to ASCII;
	
	printf("%7d %.12s ", (int)STR_BUF.st_size, ctime(&STR_BUF.st_mtime)+4);
	
	//Finally, print the filename
	printf("%s\n", FILE_NAME);

  return 0;
}

.: cannot open.