package NILab::IntervalChecker;

=head1 NAME

NILab::IntervalChecker - interval checker

=head1 SYNOPSIS

  use NILab::IntervalChecker;

  # for 6 hours interval
  $obj = NILab::IntervalChecker->new('lastupdate.log', 60 * 60 * 6);

  # for debug
  $obj->{debug} = 1;

  # interval check
  if($obj->check()){
    print "interval ok\n";
  }else{
    print "interval no\n";
  }

=head1 AUTHOR

NI-Lab. http://www.nilab.info/

=head1 LICENSE

Copyright (c) 2005 NI-Lab. All rights reserved.

This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

=head1 HISTORY

Since: 2005-05-13

2005-06-06
  * change debug output. STDOUT to STDERR.

2005-05-13
  * add subroutine check

=cut

#==============================================================================
use strict;
use warnings;

#==============================================================================
# constructor
#==============================================================================
sub new {
  my $class = shift;
  my $self = { # initializeing field value
    filepath => shift,
    interval => shift,
    debug    => 0,
  };

  # my $self = ($#_ == 0) ? { %{ (shift) } } : { @_ }; for hash params?

  bless $self,$class;
  return $self;
}

#==============================================================================
# debug on/off
# $obj->debug(1);
#==============================================================================
#sub debug {
#  my $self = shift;
#  $self->{debug} = shift;
#  return 1;
#}

#==============================================================================
# check
#==============================================================================
sub check {
  my $self     = shift;

  my $filepath = $self->{filepath};
  my $interval = $self->{interval};
  my $debug    = $self->{debug};
  my $FHIN;
  my $FHOUT;

  # get last updating time
  my $last_update_time;
  if(open($FHIN, "$filepath")){
    $last_update_time = readline($FHIN);
    close($FHIN);
    print STDERR "OLD TIME: $last_update_time\n" if $debug;
  }else{
    print STDERR "Could not open the file $filepath for reading.\n" if $debug;
    $last_update_time = 0;
  }

  # check interval time
  if(!((time - $last_update_time) > $interval)){
    print STDERR "Interval NG.\n" if $debug;
    return 0;
  }
  print STDERR "Interval OK.\n" if $debug;

  # write 
  if(!open($FHOUT, ">$filepath")){
    print STDERR "Could not open the file $filepath for writing.\n" if $debug;
    return 0;
  }
  print $FHOUT time;
  close($FHOUT);

  return 1;
}
#==============================================================================

1;