package Spreadsheet::Engine::Function::SUBSTITUTE;

use strict;
use warnings;

use base 'Spreadsheet::Engine::Fn::text';

sub argument_count { -3 => 4 }
sub signature { 't', 't', 't', '!=0' }

sub calculate {
  my ($self, $string, $oldtext, $newtext, $which) = @_;

  if (!$which) {
    $string =~ s/\Q$oldtext\E/$newtext/g if length $oldtext > 0;
  } elsif ($which >= 1) {
    for my $i (1 .. $which) {
      if ($i == $which) {
        $string =~ s/\G(.*?)\Q$oldtext\E/$1$newtext/;
        last;
      }
      last unless $string =~ m/\Q$oldtext\E/g;
    }
  }
  return $string;
}

1;

__END__

=head1 NAME

Spreadsheet::Engine::Function::SUBSTITUTE - Spreadsheet funtion SUBSTITUTE()

=head1 SYNOPSIS

  =SUBSTITUTE(string, oldtext, newtext, [which])

=head1 DESCRIPTION

Substitute the newtext for the oldtext.

=head1 HISTORY

This is a Modified Version of code extracted from SocialCalc::Functions
in SocialCalc 1.1.0

=head1 COPYRIGHT

Portions (c) Copyright 2005, 2006, 2007 Software Garden, Inc.
All Rights Reserved.

Portions (c) Copyright 2007 Socialtext, Inc.
All Rights Reserved.

Portions (c) Copyright 2008 Tony Bowden

=head1 LICENCE

The contents of this file are subject to the Artistic License 2.0;
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
  http://www.perlfoundation.org/artistic_license_2_0


