package Greenstone::Config;

use strict;
use warnings;
use utf8; 
use Greenstone::Helpers;

# Formats an array
sub replacement_array {
    die "Array handling must be defined by implementation";
}

# Determines the value to replace a variable with
sub replacement {
    my ($self, $var) = @_;
    my $val = $self->{config}->{$var};
    die "'$var' was not defined!" unless (defined $val);
    if (ref $val eq 'ARRAY') {
        return $self->replacement_array ($val);
    } else {
        return $val;
    }
}

# Substitutes variables with their value
sub subst {
    my $self = shift;
    for (@_) {
        s/@([\w]+)@/$self->replacement($1)/ge;
    }
    return @_;
}

# Reads a config file into the config hashmap
sub readconf {
    my ($self, $conf) = @_;
    $self->{config} = {} unless exists $self->{config};
    open CONF, '<', $conf
        or die "Failed to open '$conf' for reading: $!";
    my $var;
    while (my $line = <CONF>) {
        if (empty $line or comment $line) {
            $var = undef;
        } elsif (defined $var and $line =~ /^\s/) {
            trim $line;
            $self->subst ($line);
            escape $line;
            push @{$self->{config}->{$var}}, $line;
        } else {
            ($var, my $val) = trim (split ":", $line, 2);
            defined $var and defined $val or die "Invalid variable assignment: '$line'";
            if (empty $val) {
                $self->{config}->{$var} = [];
            } else {
                $self->subst ($val);
                escape $val;
                $self->{config}->{$var} = $val;
            }
        }
    }
    close CONF;
}

1;