#!/usr/bin/perl -w

my $base_dir  = "/home";
my $web_dir   = "/WWW";
my @home_dirs = ("ug01", "ug02", "ug03", "ug04", "honours");
my $default_regex = 
   "<H3>This home page is currently unavailable\.<\/H3>";
my $header_file = "hdr.html";
my $footer_file = "ftr.html";

my @users = sort(&getAllUsers());
my $count = 0;

&printFile($header_file);

for my $user (@users) {

  if (&hasHomePage($user)) {
      print "<li>" . &getLink(&getUserName($user)) . "</li>";
      $count++;
  }
}

print "<li>" . $count . " out of " . $#users . " people have homepages</li>";

&printFile($footer_file);

sub printFile {
  if (!@_) {
    die "printFile missing an argument";
  }

  my $file = shift;

  open(TMPL, $file) || die "Could not open $file: $!";
    print join("", <TMPL>);
  close(TMPL);

}

sub getLink {

  if (!@_) {
    die "getLink missing an argument!";
  }

  my $user = shift;

  return '<a href="/~' . $user . '">' . $user . '</a>';
}

sub getUserName {

  if (!@_) {
    die "getUserName missing an argument!";
  }

  $user = shift;

  $user =~ s/$base_dir//;
  $user =~ s/$web_dir//;
  $user =~ s/\///g;

  map {$user =~ s/$_//} @home_dirs;

  return $user;

}

sub hasHomePage {
  if (!@_) {
    die "No user directory supplied to hasHomePage!";
  }
  
  my $rv = 0;
  my $user = shift;
  my $dir = $user . $web_dir;

  if (!-f $dir . "/index.html") {
    if (-f $dir . "/index.php") {
      $rv = 1;
    }
  } else {

    #note: we may not be able to open the file due to access restrictions
    # though if we can't httpd can't either , so that is a false (even though 
    # the file exists)
    open(USER, $dir . "/index.html") || return 0;

      my $file = join("", <USER>);

      if (!grep {/$default_regex/} $file) {
        
        #strip whitespace and make sure this isn't 0-length
        $file =~ s/\ //g;

        if (length $file != 0) {
          $rv = 1;
        }
      }

    
     close(USER);
  }

  return $rv;
}


sub getAllUsers {

  my @rv = ();

  foreach my $home (@home_dirs) {

    @rv = (@rv, &getUsersFromDir($home)); 
   
  }

  return @rv;

}

sub getUsersFromDir {

  if (!@_) {
    die "Fatal! No home dir provided to getUsersFromDir!";
  }

  my $home = $base_dir . "/" . shift;
  
  opendir(DIR, $home) || 
      die "Can't open directory ($home): $!";

    my @files = map {$home . "/" . $_ } 
                    grep {!/[\+\.]+/ && -d "$home/$_" } readdir(DIR);

  closedir(DIR);
 
  return @files;
}