#!/usr/bin/perl
# © 2021 Cyril Brulebois <kibi@debian.org>
#
# Generate ready-to-use .patterns files so that one can use grep to
# perform hardware to firmware-package lookups in the installer
# (see MODALIAS= lines in `udevadm info --export-db`), see the
# hw-detect component.
#
# Parameters: dists/<suite>/*/dep11/Components-<arch>.yml.(gz|xz)
#
# We're limiting ourselves to packages announcing Type: firmware, and
# they need to include such information in their metadata, e.g.
# src:firmware-nonfree; the --test option can be used until such
# packages appear in the archive.
#
# See: https://salsa.debian.org/kernel-team/firmware-nonfree/-/merge_requests/19

use strict;
use warnings;

use File::Path qw(make_path);
use File::Slurp;
use Getopt::Long;
use YAML::XS;


# XXX: Drop support for --test once we have the required metadata in
# the archive.
my $output_dir = '.';
my $test;
my $verbose;
GetOptions( "output-dir=s" => \$output_dir,
            "test"         => \$test,
            "verbose"      => \$verbose )
    or die "Error in command line arguments";


sub format_alias {
    return map { $a = $_; $a =~ s/[*]/.*/g; "^$a\$\n" } @_;
}


sub process_components {
    my $input = shift;
    my $content;
    print STDERR "processing $input\n"
        if $verbose;

    if ($input =~ /\.gz$/) {
        $content = `zcat $input`;
    }
    elsif ($input =~ /\.xz$/) {
        $content = `xzcat $input`;
    }
    else {
        die "only gz and xz suffixes are supported";
    }

    my @packages;
    foreach my $array (Load $content) {
        # XXX: Drop the condition once we have the required metadata
        # in the archive.
        if (! $test) {
            next if not defined $array->{Type};
            next if $array->{Type} ne 'firmware';
        }
        next if not defined $array->{Provides};
        next if not defined $array->{Provides}->{modaliases};

        print STDERR "found modaliases entries for firmware package ", $array->{Package}, "\n"
            if $verbose;

        my $patterns_file = $output_dir . "/" . $array->{Package} . ".patterns";
        printf STDERR "writing %d entries to %s\n",
            (scalar @{ $array->{Provides}->{modaliases} }),
            $patterns_file;

        # For each alias, anchor the pattern on the left (^) and on
        # the right ($), and replace each '*' with '.*':
        write_file($patterns_file,
                   format_alias( @{ $array->{Provides}->{modaliases} } ));
        push @packages, $array->{Package};
    }
    return @packages;
}


# Prepare output directory:
if (! -d $output_dir) {
    print STDERR "creating output directory $output_dir\n"
        if $verbose;
    make_path($output_dir, { verbose => $verbose });
}

write_file("$output_dir/README.txt",
           "These files help Debian Installer detect helpful firmware packages (via hw-detect).\n");

# Generate a .patterns file for each firmware package found in
# Components-* files:
my @all_packages;
foreach my $component (@ARGV) {
    my @packages = process_components($component);
    push @all_packages, @packages;
}
@all_packages = sort @all_packages;
print STDERR "all firmware packages found across all components: @all_packages\n"
    if $verbose;