##---------------------------------------------------------------------------##
##  File:
##	$Id: Config.pm,v 1.5 2002/03/06 22:57:38 ehood Exp $
##  Description:
##	POD at end of file.
##---------------------------------------------------------------------------##
##  Copyright (C) 2002	Earl Hood <earl@earlhood.com>
##
##  This program is free software; you can redistribute it and/or modify
##  it under the terms of the GNU General Public License as published by
##  the Free Software Foundation; either version 2 of the License, or
##  (at your option) any later version.
##  
##  This program is distributed in the hope that it will be useful,
##  but WITHOUT ANY WARRANTY; without even the implied warranty of
##  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
##  GNU General Public License for more details.
##  
##  You should have received a copy of the GNU General Public License
##  along with this program; if not, write to the Free Software
##  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
##  02111-1307, USA
##---------------------------------------------------------------------------##

package MHArc::Config;

sub load {
    my $self	= { };
    my $mod	= shift;	# Name of module
    my $fname	= shift;	# Filename to read configuration from
    my $class	= ref($mod) || $mod;

    bless $self, $class;
    $self->read_filename($fname);
}

sub read_filename {
  my $self	= shift;
  my $filename	= shift;

  my $fh	= undef;
  my $fh_close	= 0;

  local(*FILE);
  if ($filename eq '-') {
    $fh = \*STDIN;
  } else {
    $filename .= '.dist'  unless (-e $filename);
    open(FILE, $filename) ||
	die qq/ERROR: Unable to open "$filename": $!\n/;
    $fh = \*FILE;
    $fh_close = 1;
  }

  while (defined($line = <$fh>)) {
    next unless $line =~ /\S/;
    next if     $line =~ /^\s*#/;
    chomp $line;
    ($key, $value) = split(/=/, $line, 2);

    if ($value =~ s/^'//) {
      $value =~ s/'$//;
    } else {
      $value =~ s/^"//; $value =~ s/"$//;
      $value = _expand_vars($self, $value);
    }
    $self->{$key} = $value;
  }

  close($fh)  if $fh_close;
  $self;
}

sub dump_config {
  my $self = shift;
  my $fh   = shift;

  foreach my $key (sort keys %$self) {
    print $fh $key, '=', $self->{$key}, "\n";
  }
}

sub _expand_vars {
  my $map     = shift;
  my $str     = shift;

  $str =~ s/(^|[^\$])\$(\{[^}]+\}|[\w]+)/$1 . _var_lookup($map, $2);/ge;
  $str;
}

sub _var_lookup {
  my $map     = shift;
  my $key     = shift;
  $key =~ s/[{}]//g;
  defined($map->{$key}) ? $map->{$key} :
      defined($ENV{$key}) ? $ENV{$key} : "";
}

#my $config = MHArc::Config->load('-');
#foreach (sort keys %$config) {
#  print "$_=", $config->{$_}, "\n";
#}

#==========================================================================
1;
__END__

=head1 NAME

MHArc::Config - Load mail archive configuration file

=head1 SYNOPSIS

  $conf = MHArc::Config->load($filename);
  print $conf->{'HTML_DIR'};

=head1 DESCRIPTION

This module will load in the archive configuration file.  The
archive configuration file defines variables in Bourne shell syntax format.

B<NOTE:> Only a subset of the Bourne shell syntax is supported, so do
not get fancy with the file.

The C<load> static method will create a new configuration instance
that is a bless hash reference.  The variables defined in the file
will be the hash keys.

B<NOTE:> If the filename specified does not exist, then the C<load()>
method will check for the filename with a C<.dist> extension.  It
is recommended to not rely on the C<.dist> version since it will
get overwritten on software updates.

=head1 VERSION

C<$Id>

=head1 AUTHOR

Earl Hood, earl@earlhood.com