# ABSTRACT: Write records to an 02packages.details.txt file

package Pinto::IndexWriter;

use Moose;
use MooseX::StrictConstructor;
use MooseX::MarkAsMethods ( autoclean => 1 );

use IO::Zlib;
use Module::CoreList;
use Path::Class qw(file);
use HTTP::Date qw(time2str);

use Pinto::Types qw(File);
use Pinto::Util qw(debug throw);

#------------------------------------------------------------------------------

our $VERSION = '0.09999'; # VERSION

#------------------------------------------------------------------------------

has stack => (
    is       => 'ro',
    isa      => 'Pinto::Schema::Result::Stack',
    required => 1,
);

has index_file => (
    is      => 'ro',
    isa     => File,
    default => sub { $_[0]->stack->modules_dir->file('02packages.details.txt.gz') },
    lazy    => 1,
);

#------------------------------------------------------------------------------

sub write_index {
    my ($self) = @_;

    my $index_file = $self->index_file;
    my $stack      = $self->stack;

    debug("Writing index for stack $stack at $index_file");

    my $handle = IO::Zlib->new( $index_file->stringify, 'wb' )
        or throw "Cannot open $index_file: $!";

    my @records = $self->_get_index_records($stack);
    my $count   = scalar @records;

    debug("Index for stack $stack has $count records");

    $self->_write_header( $handle, $index_file, $count );
    $self->_write_records( $handle, @records );
    close $handle;

    return $self;
}

#------------------------------------------------------------------------------

sub _write_header {
    my ( $self, $fh, $filename, $line_count ) = @_;

    my $base = $filename->basename;
    my $uri  = 'file://' . $filename->absolute->as_foreign('Unix');

    my $writer  = ref $self;
    my $version = $self->VERSION || 'UNKNOWN';
    my $date    = time2str(time);

    print {$fh} <<"END_PACKAGE_HEADER";
File:         $base
URL:          $uri
Description:  Package names found in directory \$CPAN/authors/id/
Columns:      package name, version, path
Intended-For: Automated fetch routines, namespace documentation.
Written-By:   $writer version $version
Line-Count:   $line_count
Last-Updated: $date

END_PACKAGE_HEADER

    return $self;
}

#------------------------------------------------------------------------------

sub _write_records {
    my ( $self, $fh, @records ) = @_;

    for my $record (@records) {
        my ( $name, $version, $author, $archive ) = @{$record};
        my $path = join '/', substr( $author, 0, 1 ), substr( $author, 0, 2 ), $author, $archive;
        my $width = 38 - length $version;
        $width = length $name if $width < length $name;
        printf {$fh} "%-${width}s %s  %s\n", $name, $version, $path;
    }

    return $self;
}

#------------------------------------------------------------------------------

sub _get_index_records {
    my ( $self, $stack ) = @_;

    # The index is rewritten after almost every action, so we want
    # this to be as fast as possible (especially during an Add or
    # Remove action).  Therefore, we use a cursor to get raw data and
    # skip all the DBIC extras.

    # Yes, slurping all the records at once consumes a lot of memory,
    # but I want them to be sorted the way perl sorts them, not the
    # way sqlite sorts them.  That way, the index file looks more
    # like one produced by PAUSE.  Also, this is about twice as fast
    # as using an iterator to read each record lazily.

    my @joins   = qw(package distribution);
    my @selects = qw(package.name package.version distribution.author distribution.archive);

    my $attrs = { join => \@joins, select => \@selects };
    my $rs = $stack->head->search_related( 'registrations', {}, $attrs );
    my %stack_records = map { ($_->[0] => $_)  } $rs->cursor->all;

    # Now, we merge the stuff from the stack with core modules.  If
    # the stack has a newer version of a core module (dual-life) then
    # it should be the one that appears in the index.  Then finally
    # we sort them.

    my %fake_records = $self->_get_fake_records;
    my %merged_records = (%fake_records, %stack_records);
    return map { $merged_records{$_} } sort keys %merged_records;

}

#------------------------------------------------------------------------------

sub _get_fake_records {
    my ($self) = @_;

    # We generate artificial records for all the (non-deprecated) core modules
    # that are in the target perl.  That way, the index appears to have perl
    # itself (just like the real CPAN) and installers can handle requests to
    # install a core module.

    my $tpv = $self->stack->target_perl_version;
    my $tpv_normal = $tpv->normal; $tpv_normal =~ s/^v//;
    my @fake = ("FAKE", "perl-$tpv_normal.tar.gz");

    my $core_versions = $Module::CoreList::version{$tpv->numify + 0};
    my $deprecated_modules = $Module::CoreList::deprecated{$tpv->numify + 0};

    my $fake_records = {};
    for my $module (keys %{ $core_versions }) {
        next if $deprecated_modules && exists $deprecated_modules->{ $module };
        $fake_records->{$module} = [$module, $core_versions->{$module} || 0, @fake];
    }

    return %{ $fake_records };
}

#------------------------------------------------------------------------------

__PACKAGE__->meta->make_immutable;

#------------------------------------------------------------------------------

1;

__END__

=pod

=encoding UTF-8

=for :stopwords Jeffrey Ryan Thalhammer

=head1 NAME

Pinto::IndexWriter - Write records to an 02packages.details.txt file

=head1 VERSION

version 0.09999

=head1 AUTHOR

Jeffrey Ryan Thalhammer <jeff@stratopan.com>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2015 by Jeffrey Ryan Thalhammer.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut