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

/* Directory:		/
   Symlink:		@
   Executable:		*
   FIFO:		|
   Socket:		=
*/
#define T_DIR 0x2f
#define T_LNK 0x40
#define T_EXC 0x2a
#define T_FFO 0x7c
#define T_SOC 0x3d

#define MON(n)  (n == 0) ? "Jan" :\
		(n == 1) ? "Feb" :\
		(n == 2) ? "Mar" :\
		(n == 3) ? "Apr" :\
		(n == 4) ? "May" :\
		(n == 5) ? "Jun" :\
		(n == 6) ? "Jul" :\
		(n == 7) ? "Aug" :\
		(n == 8) ? "Sep" :\
		(n == 9) ? "Oct" :\
		(n ==10) ? "Nov" :\
		(n ==11) ? "Dec" : "n/a"

int no, fi, di, ln, pi, so, bd, cd, or, ex;
void sls(char *);
char *itos(int);
char e[4086][2][200];

int main(int argc, char *argv[]) {
  int i, j, n, p, z;
  char *cenv = getenv("LS_COLORS"), *cwd;
  struct stat _stat;
  struct dirent **dircontents;

  i = j = p = z = 0;

  if (cenv)
    while (*cenv) {  /* get the environmental stuff for the color options
			and fill it in the array ( e[][][] ) */
      switch(*cenv) {
        case ':': if (z) { e[p][1][j] = 0; p++; } /* is this our first time? */
                  else z = 1;
                  i = j = 0;
                  break;
        case '=': e[p][0][j] = 0;
                  i = 1;
                  j = 0;
                  break;
        default:  e[p][i][j] = *cenv;
                  j++;
                  break;
      }

      cenv++;
    }

  if (p)
    for (i=0; i<p; i++)
      switch(e[i][0][0]) {
        case 'n': no = i; break; /* normal */
        case 'f': fi = i; break; /* file */
        case 'd': di = i; break; /* directory */
        case 'l': ln = i; break; /* symlink */
        case 'p': pi = i; break; /* pipe */
        case 's': so = i; break; /* socket */
        case 'b': bd = i; break; /* block device */
        case 'c': cd = i; break; /* char device */
        case 'o': or = i; break; /* orphan (missing link) */
        case 'e': ex = i; break; /* executable */
      }

  else {
    strcpy(e[0][0], "n/a"); /* in case someone wants to see this ;) */
    strcpy(e[0][1], "0");

    no = fi = di = ln = pi = so = bd = cd = or = ex = 0;
  }

  if (argc < 2) {
    if ((n = scandir(".", &dircontents, 0, alphasort)) < 0) {
      fprintf(stderr, "%s: %s: %s\n", argv[0], ".", strerror(errno));
      exit(1);
    }

    for(i=0; i<n; i++) sls(dircontents[i]->d_name);
    return 0;
  }

  for (i=1; i<argc; i++) {
    if (lstat(argv[i], &_stat) < 0)
      fprintf(stderr, "%s: %s: %s\n", argv[0], argv[i], strerror(errno));
    else if (S_ISDIR(_stat.st_mode)) {
           if ((n = scandir(argv[i], &dircontents, 0, alphasort)) < 0) {
             fprintf(stderr, "%s: %s: %s\n", argv[0], argv[i], strerror(errno));
             exit(1);
	   }
	   cwd = (char *) get_current_dir_name();
           chdir(argv[i]);
           for(j=0; j<n; j++) sls(dircontents[j]->d_name);
	   chdir(cwd);
    } else sls(argv[i]);
  }
  
  return 0;
}

void sls(char *name) {
  int islnk = 0;
  char *_user, *_group, lbuffer[256];
  struct tm *time_s;
  struct passwd *_pinfo;
  struct group *_ginfo;
  struct stat _stat;

  if ((lstat(name, &_stat)) < 0) {
    fprintf(stderr, "%s: %s\n", name, strerror(errno));
    return;
  }

  if ((_stat.st_mode & S_IFMT) == S_IFLNK) {
    islnk = 1;
    memset(lbuffer, 0, 256);
    readlink(name, lbuffer, 256);
  }

  time_s = localtime(&_stat.st_mtime); /* get modification time */

  _user = ((_pinfo = getpwuid(_stat.st_uid)) == 0) ? itos(_stat.st_uid) :
    _pinfo->pw_name; /* owner */
  _group = ((_ginfo = getgrgid(_stat.st_gid)) == 0) ? itos(_stat.st_gid) :
    _ginfo->gr_name; /* group */

  printf("%c%c%c%c%c%c%c%c%c%c %3d %8.8s %8.8s%9d %s %2d %2.2d:%2.2d "
	"\033[%sm%s\033[0m%c%s%s\n",
		/* i dunno, too complex to comment
		just get everything we want to know
		about our file in the form:
		mode links  user group size modification-time filename
		result is like any other ls */
	((_stat.st_mode & S_IFMT) == S_IFLNK) ? 'l' : /* symlink */
	((_stat.st_mode & S_IFMT) == S_IFDIR) ? 'd' : /* directory */
	((_stat.st_mode & S_IFMT) == S_IFCHR) ? 'c' : /* char device */
	((_stat.st_mode & S_IFMT) == S_IFBLK) ? 'b' : /* block device */
	((_stat.st_mode & S_IFMT) == S_IFIFO) ? 'p' : /* pipe */
	((_stat.st_mode & S_IFMT) == S_IFSOCK) ? 's' : '-', /* socket */
	(_stat.st_mode & S_IRUSR) ? 'r' : '-', /* user readable */
	(_stat.st_mode & S_IWUSR) ? 'w' : '-', /* user writable */
	((_stat.st_mode & S_IXUSR) &&
	  !(_stat.st_mode & S_ISUID)) ? 'x' : /* user executable */
	    (_stat.st_mode & S_ISUID) ? 's' : '-', /* setuid */
	(_stat.st_mode & S_IRGRP) ? 'r' : '-', /* group readable */
	(_stat.st_mode & S_IWGRP) ? 'w' : '-', /* group writable */
	((_stat.st_mode & S_IXGRP) &&
	  !(_stat.st_mode & S_ISGID)) ? 'x' : /* group executable */
	    (_stat.st_mode & S_ISGID) ? 's' : '-', /* setgid */
	(_stat.st_mode & S_IROTH) ? 'r' : '-', /* other readable */
	(_stat.st_mode & S_IWOTH) ? 'w' : '-', /* other writable */
	((_stat.st_mode & S_IXOTH) &&
	  !(_stat.st_mode & S_ISVTX)) ? 'x' : /* other executable */
	    (_stat.st_mode & S_ISVTX) ? 't' : '-', /* sticky */
	_stat.st_nlink, _user, _group, _stat.st_size,
	MON(time_s->tm_mon), time_s->tm_mday, time_s->tm_hour, time_s->tm_min,
		/* color starts here */
	((_stat.st_mode & S_IFMT) == S_IFLNK) ? e[ln][1] :
	((_stat.st_mode & S_IFMT) == S_IFDIR) ? e[di][1] :
	((_stat.st_mode & S_IFMT) == S_IFCHR) ? e[cd][1] :
	((_stat.st_mode & S_IFMT) == S_IFBLK) ? e[bd][1] :
	((_stat.st_mode & S_IFMT) == S_IFIFO) ? e[pi][1] :
	((_stat.st_mode & S_IFMT) == S_IFSOCK)? e[so][1] :
	((_stat.st_mode & S_IXUSR) &&
	  !(_stat.st_mode & S_ISUID)) ? e[ex][1] :
	    (_stat.st_mode & S_ISUID) ? e[ex][1] :
	((_stat.st_mode & S_IXGRP) &&
	  !(_stat.st_mode & S_ISGID)) ? e[ex][1] :
	    (_stat.st_mode & S_ISGID) ? e[ex][1] :
	((_stat.st_mode & S_IXOTH) &&
	  !(_stat.st_mode & S_ISVTX)) ? e[ex][1] :
	    (_stat.st_mode & S_ISVTX) ? e[ex][1] : e[fi][1],
	name,
		/* types */
	((_stat.st_mode & S_IFMT) == S_IFLNK) ? T_LNK :
	((_stat.st_mode & S_IFMT) == S_IFDIR) ? T_DIR :
	((_stat.st_mode & S_IFMT) == S_IFIFO) ? T_FFO :
	((_stat.st_mode & S_IFMT) == S_IFSOCK)? T_SOC :
	(_stat.st_mode & S_IXUSR) ? T_EXC :
	(_stat.st_mode & S_IXGRP) ? T_EXC :
	(_stat.st_mode & S_IXOTH) ? T_EXC : ' ',
		/* if this is a symlink, print where it'll take us */
	(islnk) ? " -> " : "", (islnk) ? lbuffer : "");
}


/* simple function to convert from integers to strings
   needed if the owner or group names are missing. uses sprintf */
char *itos(int number) {
  char *_buffer;

  if ((_buffer = malloc(10)) == NULL) {
    fprintf(stderr, "unable to allocate memory\n");
    exit(1);
  }

  memset(_buffer, 0, 10);
  sprintf(_buffer, "%d", number);

  return _buffer;
}