#!/usr/bin/perl

use strict;
use warnings;

use Email::Valid::Loose qw( );

# If they passed any arguments, complain and exit.
if ( scalar @ARGV ) {
  print "You can't pass any arguments to this script!\n";
  exit 2;
};

# If they didn't provide a terminal definition, then assume xterm.
# Everybody emulates xterm to at least a basic extent.
if ( not exists $ENV{"TERM"} ) {
  $ENV{"TERM"} = "xterm";
  print "I don't know what terminal you're using; guessing xterm...\n";
};

# Disable buffering.
$|++;

# Configure the strictness of our email checks.
my $checker = Email::Valid::Loose->new
  ( "-fqdn"        => 1
  , "-fudge"       => 0
  , "-local_rules" => 0
  , "-mxcheck"     => 1
  , "-tldcheck"    => 0
  );

my ( $email, $username, $password1, $password2 );

while ( 1 ) {

  print "Email address to associate with new user: ";
  chomp ( $email = <STDIN> );

  if ( $email eq "" ) {
    print "You must provide an email address!\n";
    next;
  };

  $email = $checker->address( $email );
  if ( not defined $email ) {
    print "Please, at least pretend to provide a valid email address.\n";
    next;
  };

  last;

};

while ( 1 ) {

  print "Desired username: ";
  chomp ( $username = <STDIN> );

  if ( $username eq "" ) {
    print "You have to enter a username!\n";
    next;
  };
  
  if ( $username =~ /^git-|^ikiwiki-/ ) {
    print "Your username cannot start with git- or ikiwiki-!\n";
    next
  };

  if ( $username !~ /^[a-zA-Z0-9_.][a-zA-Z0-9_.-]+$/ ) {
    print( "Usernames must consist only of letters, digits, underscores, periods, and dashes, and not start with a dash. Usernames are case sensitive.\n" );
    next
  };

  last;

};

while ( 1 ) {

  system( "stty", "-echo" );
  print "Desired password: ";
  chomp ( $password1 = <STDIN> );
  print "\nRetype password: ";
  chomp ( $password2 = <STDIN> );
  print "\n";
  system( "stty", "echo" );

  if ( $password1 ne $password2 ) {
    print "Provided passwords do not match; try again.\n";
    next;
  };

  if ( $password1 eq "" ) {
    print "You have to enter a password!\n";
    next;
  };

  last;

};

my @saltchars =
  ( 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'
  , 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
  , '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'
  , '.', '/'
  );

my $salt = "\$6\$";

foreach my $n ( 1 .. 16 ) {
  $salt .= $saltchars[int ( rand ( scalar @saltchars ) )];
};

$salt .= "\$";

my $crypt = crypt( $password1, $salt );

my $ret = system( "/usr/sbin/useradd", "-c", "$email", "-k", "/var/empty", "-g", "users", "-m", "-p", $crypt, "-s", "/usr/bin/pinyshell", $username );

if ( $ret ) {
  print "An error occured creating the user; most likely, that username is already taken.\n";
  exit 1;
};

print "Your user has been created. Try logging in!\n";

exit 0;