#!perl -wT
# musiclist.cgi -- spits out my CD collection as HTML; 2nd attempt

use strict;
use CGI;

# some security, as per the CGI.pm POD
$CGI::POST_MAX = 1024 * 0;	# no posts
$CGI::DISABLE_UPLOADS = 1;	# no uploads

####################

my ($infile, @data, $description,
	$artist, $category, $year, $title, $notes, $numFields,
	%groupBy, $q, $key);

$description = <<END_DESCRIPTION;
About a year ago I thought it would be cool to make a dynamically sortable list
of all the CD's, cassettes, and LP's in my collection. I got as far as entering
the information about my CD's, which consists of the following: title, group or
artist, copyright year, what "category" the CD falls into, and notes.
END_DESCRIPTION

$infile = 'music.txt';
@data = ();

# columns/indices of fields of input file
($artist, $category, $year, $title, $notes) = (0, 1, 2, 3, 4);
$numFields = 5;

# mapping table; index of sort key must be first element in array
%groupBy = (
	artist =>   [ $artist,   $category, $year,     $title, $notes ],
	category => [ $category, $artist,   $year,     $title, $notes ],
	year =>     [ $year,     $artist,   $category, $title, $notes ],
	title =>    [ $title,    $artist,   $category, $year,  $notes ],
);

####################

$q = new CGI;

$key = $1 if $q->param('groupKey') =~ /^(\w+)$/;

print $q->header,
	$q->start_html("My CD's"),
	$q->h1("My CD's");

if( $key  && exists $groupBy{$key} ) {
	my %groups;

	print $q->hr,
		$q->p("Here is my collection of CD's, grouped by ", $key, ".");

	open IN, "<$infile" or die "Error opening input file: $!";
	while( <IN> ) {
		next if /^#|^$/;	# skip commented and empty lines
		chomp;
		push @data, [ split ',', $_, $numFields ];
	}
	close IN;

	# change this if mapping table (%groupBy) changes
	for ( @data ) {
		my @fields = @{ $groupBy{$key} };

		push @{ $groups{ @{ $_ }[ $fields[0] ] } }, [
			@{ $_ }[ $fields[1] ],
			@{ $_ }[ $fields[2] ],
			@{ $_ }[ $fields[3] ],
			@{ $_ }[ $fields[4] ],
		];
	}

	for ( sort keys %groups ) {
		my @entries;

		for ( @{ $groups{$_} } ) {
			push(@entries, join(", ", @{ $_ }));
		}
		print $q->p($q->b($_)),
			$q->ul($q->li(\@entries));
	}
}
else {
	print $q->p($description);
}

print $q->hr,
	$q->startform("GET", "musiclist.cgi", $CGI::URL_ENCODED),
		$q->p('Group by:'),
		$q->radio_group(
			-name => 'groupKey',
			-values => [ 'category', 'artist', 'year', 'title' ],
			-labels => {
				category => 'Category',
				artist => 'Artist, group, or composer',
				year => 'Copyright year',
				title => 'CD title',
			},
			-linebreak => 'true'
		),
		$q->br,
		$q->submit,
		$q->reset;
	$q->endform,
	$q->hr,
	$q->end_html;

##</code><code>##

	while( <IN> ) {
		next if /^#|^$/;

		chomp;
		my @record = split ',', $_, $numFields;
		push @{ $groups{ $record[ $fields[0] ] } }, [
			$record[ $fields[1] ],
			$record[ $fields[2] ],
			$record[ $fields[3] ],
			$record[ $fields[4] ],
		];
	}
	close IN;