#!/usr/bin/env perl

use strict;
use warnings;
use autodie;

use File::Copy;
use Tie::File;

my $master_ext = '.master';
my $used_ext = '.used';
my $year_file_base = 'pm_year_make_model_file_years';
my $make_file_base = 'pm_year_make_model_file_makes';
my $model_file_base = 'pm_year_make_model_file_models';
my $temp_file = 'pm_year_make_model_temp_file';

my $used_years = "$year_file_base$used_ext";
my $used_makes = "$make_file_base$used_ext";
my $used_models = "$model_file_base$used_ext";

if (! -e $temp_file) {
    copy("$year_file_base$master_ext", $used_years);
    copy("$make_file_base$master_ext", $used_makes);
    copy("$model_file_base$master_ext", $used_models);
}

tie my @years, 'Tie::File', $used_years;
tie my @makes, 'Tie::File', $used_makes;
tie my @models, 'Tie::File', $used_models;

my $year = select_item('year', \@years);
my $make = select_item('make', \@makes);
my $model = select_item('model', \@models);

untie @years;
untie @makes;
untie @models;

open my $fh, '>>', $temp_file;
print $fh "$year $make $model\n";
close $fh;

print "Temp file contents:\n";
system cat => $temp_file;

sub select_item {
    my ($item, $records_ref) = @_;
    my %item_index_for =
        map { $records_ref->[$_] => $_ }
        grep { $records_ref->[$_] !~ /^#/ } 0 .. $#$records_ref;

    print "Available ${item}s:\n";
    print "$_\n" for sort keys %item_index_for;
    print "Select $item: ";
    chomp(my $selection = <STDIN>);
    substr($records_ref->[$item_index_for{$selection}], 0, 0) = '#';
    return $selection;
}