# Perl module for note
# general database backend. see docu: perldoc NOTEDB::general
# using Config::General as backend.

package NOTEDB::general;

$NOTEDB::general::VERSION = "1.04";

use strict;
#use Data::Dumper;
use File::Spec;
use Config::General qw(ParseConfig SaveConfig SaveConfigString);
use MIME::Base64;
use FileHandle;
use NOTEDB;

use Fcntl qw(LOCK_EX LOCK_UN);

use Exporter ();
use vars qw(@ISA @EXPORT);
@ISA = qw(NOTEDB Exporter);





sub new {
    my($this, %param) = @_;

    my $class = ref($this) || $this;
    my $self = {};
    bless($self,$class);

    $self->{dbname}  = $param{dbname}   || File::Spec->catfile($ENV{HOME}, ".notedb");

    if(! -e $param{dbname}) {
	open(TT,">$param{dbname}") or die "Could not create $param{dbname}: $!\n";
	close (TT);
    }
    elsif(! -w $param{dbname}) {
	print "$param{dbname} is not writable!\n";
	exit(1);
    }

    $self->{mtime}    = $self->get_stat();
    $self->{unread}   = 1;
    $self->{changed}  = 1;
    $self->{data}     = {};
    $self->{LOCKFILE} = $param{dbname} . "~LOCK";

    return $self;
}


sub DESTROY {
  # clean the desk!
}

sub version {
    my $this = shift;
    return $NOTEDB::general::VERSION;
}

sub get_stat {
  my ($this) = @_;
  my $mtime = (stat($this->{dbname}))[9];
  return $mtime;
}

sub changed {
  my ($this) = @_;
  my $current = $this->get_stat();
  if ($current > $this->{mtime}) {
    $this->{mtime} = $current;
    return $current;
  }
  else {
    return 0;
  }
}

sub set_del_all {
    my $this = shift;
    unlink $this->{dbname};
    open(TT,">$this->{dbname}") or die "Could not create $this->{dbname}: $!\n";
    close (TT);
}


sub get_single {
    my($this, $num) = @_;
    my($address, $note, $date, $n, $t, $buffer, );

    my %data = $this->get_all();

    return ($data{$num}->{note}, $data{$num}->{date});
}


sub get_all {
    my $this = shift;
    my($num, $note, $date, %res);

    if ($this->unchanged) {
	return %{$this->{cache}};
    }

    my %data = $this->_retrieve();

    foreach my $num (keys %data) {
	$res{$num}->{note} = $this->ude($data{$num}->{note});
	$res{$num}->{date} = $this->ude($data{$num}->{date});
    }

    $this->cache(%res);
    return %res;
}

sub import_data {
  my ($this, $data) = @_;
  my %res = $this->_retrieve();
  my $pos = (scalar keys %res) + 1;
  foreach my $num (keys %{$data}) {
    $res{$pos}->{note} = $this->uen($data->{$num}->{note});
    $res{$pos}->{date} = $this->uen($data->{$num}->{date});
    $pos++;
  }
  $this->_store(\%res);
}

sub get_nextnum {
    my $this = shift;
    my($num, $te, $me, $buffer);

    if ($this->unchanged) {
	$num = 1;
	foreach (keys %{$this->{cache}}) {
	    $num++;
	}
        return $num;
    }

    my %data = $this->get_all();
    my @numbers = sort { $a <=> $b } keys %data;
    $num = pop @numbers;
    $num++; 

    return $num;
}

sub get_search {
    my($this, $searchstring) = @_;
    my($buffer, $num, $note, $date, %res, $t, $n, $match);

    my $regex = $this->generate_search($searchstring);
    eval $regex;
    if ($@) {
	print "invalid expression: \"$searchstring\"!\n";
	return;
    }
    $match = 0;

    if ($this->unchanged) {
	foreach my $num (keys %{$this->{cache}}) {
	    $_ = $this->{cache}{$num}->{note};
	    eval $regex;
	    if ($match) {
		$res{$num}->{note} = $this->{cache}{$num}->{note};
		$res{$num}->{date} = $this->{cache}{$num}->{date}
	    }
	    $match = 0;
	}
	return %res;
    }

    my %data =  $this->get_all();

    foreach my $num(sort keys %data) {
	$_ = $data{$num}->{note};
	eval $regex;
	if($match)
	  {
	      $res{$num}->{note} = $data{$num}->{note};
	      $res{$num}->{date} = $data{$num}->{data};
	  }
	$match = 0;
    }

    return %res;
}




sub set_edit {
    my($this, $num, $note, $date) = @_;

    my %data = $this->_retrieve();

    $data{$num} = {
		   note => $this->uen($note),
		   date => $this->uen($date)
		   };

    $this->_store(\%data);

    $this->changed;
}


sub set_new {
    my($this, $num, $note, $date) = @_;
    $this->set_edit($num, $note, $date);
}


sub set_del {
    my($this, $num) = @_;
    my(%data, $note, $date, $T, $setnum, $buffer, $n, $N, $t);

    $setnum = 1;

    %data = $this->_retrieve();
    return "ERROR" if (! exists $data{$num});

    delete $data{$num};

    $this->_store(\%data);

    $this->changed;

    return;
}

sub set_recountnums {
    my($this) = @_;
    my(%orig, %data, $note, $date, $T, $setnum, $buffer, $n, $N, $t);

    $setnum = 1;
    %orig = $this->_retrieve();

    foreach $N (sort {$a <=> $b} keys %orig) {
      $data{$setnum} = {
			note => $orig{$N}->{note},
			date => $orig{$N}->{date}
		       };
	$setnum++;
    }

    $this->_store(\%data);

    $this->changed;

    return;
}

sub uen {
    my ($this, $raw) = @_;
    my($crypted);
    if($NOTEDB::crypt_supported == 1) {
	eval {
	    $crypted = $this->{cipher}->encrypt($raw);
	};
	print $@;
    }
    else {
	$crypted = $raw;
    }
    my $coded = encode_base64($crypted);
    chomp $coded;
    return $coded;
}

sub ude {
    my ($this, $crypted) = @_;
    my($raw);
    if($NOTEDB::crypt_supported == 1) {
	eval {
	    $raw = $this->{cipher}->decrypt(decode_base64($crypted));
	};
    }
    else {
	$raw = decode_base64($crypted)
    }
    return $raw;
}



sub _store {
  my ($this, $data) = @_;
  open NOTE, ">$this->{dbname}" or die "could not open $this->{dbname}: $!\n";
  flock NOTE, LOCK_EX;

  if (%{$data}) {
    my $content = SaveConfigString($data) or die "could not serialize data: $!\n";
    print NOTE $content;
  }
  else {
    print NOTE "";
  }

  flock NOTE, LOCK_UN;
  close NOTE;

  # finally re-read the db, so that we always have the latest data
  $this->_retrieve();
}

sub _retrieve {
  my ($this) = @_;
  my $file = $this->{dbname};
  if (-s $file) {
    if ($this->{changed} || $this->{unread}) {
      my $fh = new FileHandle "<$this->{dbname}" or die "could not open $this->{dbname}\n";
      flock $fh, LOCK_EX;

      my %data = ParseConfig(-ConfigFile => $fh) or die "could not read to database: $!\n";

      flock $fh, LOCK_UN;
      $fh->close();

      $this->{unread} = 0;
      $this->{data}   = \%data;
      return %data;
    }
    else {
      return %{$this->{data}};
    }
  }
  else {
    return ();
  }
}


1; # keep this!

__END__

=head1 NAME

NOTEDB::general - module lib for accessing a notedb from perl

=head1 SYNOPSIS

	# include the module
	use NOTEDB;

	# create a new NOTEDB object
	$db = new NOTEDB("text", "/home/tom/.notedb", 4096, 24);

	# decide to use encryption
	# $key is the cipher to use for encryption
	# $method must be either Crypt::IDEA or Crypt::DES
	# you need Crypt::CBC, Crypt::IDEA and Crypt::DES to have installed.
	$db->use_crypt($key,$method);

	# do not use encryption
	# this is the default
	$db->no_crypt;

	# get a single note
	($note, $date) = $db->get_single(1);

	# search for a certain note 
	%matching_notes = $db->get_search("somewhat");
	# format of returned hash:
	#$matching_notes{$numberofnote}->{'note' => 'something', 'date' => '23.12.2000 10:33:02'}

	# get all existing notes
	%all_notes = $db->get_all();
	# format of returns hash like the one from get_search above

	# get the next noteid available
	$next_num = $db->get_nextnum();

	# modify a certain note
	$db->set_edit(1, "any text", "23.12.2000 10:33:02");

	# create a new note
	$db->set_new(5, "any new text", "23.12.2000 10:33:02");

	# delete a certain note
	$db->set_del(5);

        # turn on encryption. CryptMethod must be IDEA, DES or BLOWFISH
        $db->use_crypt("passphrase", "CryptMethod");

        # turn off encryption. This is the default.
        $db->no_crypt();


=head1 DESCRIPTION

You can use this module for accessing a note database. This backend uses
a text file for storage and Config::General for accessing the file.

Currently, NOTEDB module is only used by note itself. But feel free to use it
within your own project! Perhaps someone want to implement a web interface to
note...

=head1 USAGE

please see the section SYNOPSIS, it says it all.

=head1 AUTHOR

Thomas Linden <tom@daemon.de>.


=cut