package Algebra::Config;

use strict;

require Exporter;

use vars       qw($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);

@ISA = qw(Exporter);
@EXPORT= qw( get_config_var get_data_dir get_algebra_root );
@EXPORT_OK = qw( get_config_var );

$VERSION = 2000.0426;

use vars qw( $algebra_data_dir );

sub get_algebra_root {
	my $algebra_root = $ENV{'ALGEBRA_ROOT'} 
		|| die "Webmaster has to define ALGEBRA_ROOT environment variable!";
	return $algebra_root;

}

sub get_config_var {
	my ($category, $variable) = @_;
	my $algebra_root = get_algebra_root;
	my $config_file = "$algebra_root/etc/$category";
	die "Config file '$config_file' does not exist or is not readable."
		unless -r $config_file;
	open( CONFIG, $config_file );
	while( $_ = <CONFIG> ) {
		chomp;
		next if( /^\s*#/ );
		next if( /^\s*$/ );
		my( $key, $value ) = split( /\s*=\s*/, $_ );
		return $value if( $key eq $variable );
	}

	return undef;
}

$algebra_data_dir = get_config_var( "general", "algebra_data_dir" )
			|| $ENV{'ALGEBRA_ROOT'};

sub get_data_dir {
	my ($category, $variable) = @_;

	my $dir = get_config_var( $category, $variable );
	if( !($dir =~ /^\// ) ) {
		$dir = $algebra_data_dir . "/$dir";
	}
	return $dir;
}


1;