package mydb;
use strict;
use warnings;
use Digest::MD5 qw(md5_hex);
use utf8;

sub new
{
  my $class=shift;
  my $file=shift;
  return undef unless($file);
  my $self={};
  $self->{file}  =$file;
  $self->{table} ={};
  $self->{update}=0;
  $self->{last}  =0;
  bless($self,ref($class)||$class);
  $self->load;
  return $self;
}

sub DESTROY{ shift->save(); }

sub load
{
  my $self=shift;
  $self->{update}=1;
  return 0 unless(-f $self->{file});
  if(open(my $fh, '<', $self->{file}))
  {
    while(<$fh>)
    {
      chomp;
      my ($name,$pass)=map{__unquote($_)}split(/#/,$_,2);
      next unless($name && $pass);
      $self->{table}->{$name}=$pass;
    }
    close($fh);
    $self->{update}=0;
    $self->{last}=-M $self->{file};
  }
}

sub save
{
  my $self=shift;
  if($self->{update} && %{$self->{table}})
  {
    my $str=join("\n",map{__quote($_).'#'.__quote($self->{table}->{$_})}keys(%{$self->{table}}));
    $self->_update();
    if(open(my $fh, '>', $self->{file}))
    {
      print $fh $str;
      close($fh);
      $self->{update}=0;
      return 1;
    }
    return 0
  }
  return 1;
}

sub add
{
  my $self=shift;
  my $name=shift;
  my $pass=shift;
  $self->_update();
  return 0 unless($name && $pass);
  return 0 if(exists($self->{table}->{$name}));
  $self->{table}->{$name}=md5_hex($pass);
  $self->{update}=1;
  return 1;
}

sub del
{
  my $self=shift;
  my $name=shift;
  $self->_update();
  return 0 unless($name && exists($self->{table}->{$name}));
  delete($self->{table}->{$name});
  $self->{update}=1;
  return 1;
}

sub has{ return exists($_[0]->{table}->{$_[1]}); }

sub set
{
  my $self=shift;
  my $name=shift;
  my $pass=shift;
  $self->_update();
  return 0 unless($name && $pass);
  return 0 unless(exists($self->{table}->{$name}));
  $self->{table}->{$name}=md5_hex($pass);
  $self->{update}=1;
  return 1;
}

sub chk
{
  my $self=shift;
  my $name=shift;
  my $pass=shift;
  $self->_update();
  return 0 unless($name && $pass && exists($self->{table}->{$name}) && $self->{table}->{$name} eq md5_hex($pass));
  return 1;
}

sub get
{
  my $self=shift;
  my $name=shift;
  $self->_update();
  return $self->{table}->{name} if($name && exists($self->{table}->{name}));
  return '';
}

########################################################################
sub _update
{
  my $self=shift;
  return $self->load() if(-f $self->{file} && (!$self->{last} || -M $self->{file} != $self->{last}));
  return 1;
}

########################################################################
sub __quote
{
  my $str=shift;
  $str=~s/#/&raute;/g;
  return $str;
}

sub __unquote
{
  my $str=shift;
  $str=~s/\Q&raute;/#/g;
  return $str;
}

1;