package App::ArchLinux::PackagerTools::CPAN;
use strictures;

use autodie;
use CPAN::DistnameInfo;
use CPANPLUS::Backend;
use Carp;
use Function::Parameters;
use IO::Zlib;
use Log::Any qw($log);
use Syntax::Keyword::Try;
use version;

=head1 NAME

App::ArchLinux::PackagerTools::CPAN - Methods to interact with CPAN

=head1 SYNOPSIS

use App::ArchLinux::PackagerTools::CPAN;

# synopsis...

=head1 DESCRIPTION

# longer description...

=head1 METHODS

=head2 new

 App::ArchLinux::PackagerTools::CPAN->new();

Returns a new instance.

=cut

method new($class: $deps = {}) {
	$deps->{cpanplus_backend} //= CPANPLUS::Backend->new();
	return $class->new_no_defaults($deps);
}

method new_no_defaults($class: $deps = {}) {
	my $self = {};
	bless $self, $class;
	$self->{deps} = $deps;
	$self->{dist_lc_map} = {};
	$self->{dists} = {};
	$self->_build_dist_index();
	return $self;
}

=head2 Public Methods

=head3 is_newer_version_available

Return 1 if a newer version of the distribution is available, 0 otherwise.

=cut

method is_newer_version_available($dist_name, $version) {
	my $dist = $self->get_dist($dist_name);
	# TODO compare versions rather than not-equal check
	my $dist_version = version->parse($dist->{version});
	if ($dist_version > version->parse($version)) {
		return 1;
	} else {
		return 0;
	}
}

method _build_dist_index() {
	$self->{deps}->{cpanplus_backend}->reload_indices();
	# TODO download pacakges list ourselves instead of using cpanplus for it? We may need cpanplus for other features later so keeping it is probably also fine.

	my $packages_file = "$ENV{HOME}/.cpanplus/02packages.details.txt.gz";
	my $fh = IO::Zlib->new($packages_file, 'r');
	my %seen;
	my $line_number = 0;
	while (<$fh>) {
		# skip meta info (first 9 lines)
		next if $line_number++ < 9;

		#$log->tracef("Parsing line: %s", $_);
		my ($module_name, $module_version, $file) = split /\s+/;

		next if $seen{$file}++ > 0;

		my $dist = CPAN::DistnameInfo->new($file);
		if (!defined $dist->{dist}) {
			$log->debugf("Failed to parse file: %s", $file);
			next;
		}

		my $dist_name = $dist->{dist};
		my $dist_name_lc = lc($dist_name);

		my $dist_version;
		try {
			$dist_version = version->parse($dist->{version});
		} catch {
			$log->debugf("Skipping dist with invalid version: %s", $@);
			$log->debugf("Skipped dist is: %s", $dist);
			next;
		}

		my $index_dist;
		my $index_version = version->parse($self->{dists}->{$dist_name}->{version});
		my $index_name = $self->{dist_lc_map}->{$dist_name_lc};
		$index_dist = $self->{dists}->{$index_name} if defined $index_name;

		if (!defined($index_dist)
			|| (defined($index_dist) && $index_name eq $dist_name && $dist_version > $index_version)
		) {
			$self->{dist_lc_map}->{$dist_name_lc} = $dist_name;
			$self->{dists}->{$dist_name} = {
				dist_name => $dist_name,
				version => $dist->{version},
			};
		} else {
			if ($dist_name ne $index_name && $dist_version < $index_version) {
				confess $log->errorf("Key '%s' already exists in lc_map. This requires a manual exception to map correctly.\nExisting: %s\nCurrent: %s", $dist_name_lc, $index_dist, {$dist->%{qw(dist version)}});
			}
		}
	}
}

method search_dist($name) {
	$name =~ s/::/-/g;
	$log->tracef("Searching for CPAN distribution matching '%s'", $name);

	my $index_name = $self->{dist_lc_map}->{lc($name)};
	if (defined $index_name) {
		return $self->{dists}->{$index_name};
	}

	return;
}

method get_dist($dist_name) {
	$dist_name =~ s/::/-/g;
	$log->tracef("Getting CPAN data for distribution '%s'", $dist_name);

	my $index_name = $self->{dist_lc_map}->{lc($dist_name)};
	if (defined $index_name) {
		return $self->{dists}->{$index_name};
	}

	croak $log->errorf("Failed to find distribution with name %s", $dist_name);
}

1;

__END__