#!/usr/bin/env perl

use strict;
use warnings;
use Carp;

while(1) {
    my $town = getTown('towns.dat');

    print "\nYou selected:\n";
    print 'ID: ', $town->{id}, "\n";
    print 'Short name: ', $town->{short}, "\n";
    print 'Long name: ', $town->{long}, "\n";
    print "\n";
}

sub getTown {
    my ($fname) = @_;

    my $towns = loadFile($fname);

    while(1) {
        print "Select town: ";
        my $input = <>;
        chomp $input;
        if(defined($towns->{$input})) {
            return $towns->{$input};
        }
        print "Unknown town!\n";
    }
}

sub loadFile {
    my ($fname) = @_;

    open(my $ifh, '<', $fname) or croak($!);
    my %towns;
    while((my $line = <$ifh>)) {
        chomp $line;

        # Skip comments and empty lines
        next if($line eq '' || $line =~ /^\#/);

        print "# $line #\n";

        my ($id, $short, $long) = split/\:/, $line;

        $towns{$short} = {
            id => $id,
            short => $short,
            long => $long,
        };
    }
    close $ifh;

    return \%towns;
}