#!/usr/bin/perl

use strict;
use warnings;

use File::Copy;
use Getopt::Long;

my $dir = ".";
my $rpmrelease;
my $patches="";

GetOptions(
	"patches=s" => \$patches,
	"release=s" => \$rpmrelease
) or die "Usage: $0 [--release <release>] [--patches <dir>]\n";

# flavor -> [supported archs]
my %flavor_archs = parse_config_conf();
# subset to include in kernel-syms
my %syms_flavor_archs = parse_config_conf("syms");

my %all_archs = parse_config_conf("needs_updating");
my @all_archs;
	for my $flavor (keys(%all_archs)) {
		push(@all_archs, arch2rpm(@{$all_archs{$flavor}}));
	}
@all_archs = sort(uniq(@all_archs));
my $all_archs = join(" ", @all_archs);

# template name -> template body
my %templates = read_spec_templates();

my @kmps = read_kmps();

# config.sh variables
my %vars = parse_config_sh();
my ($srcversion, $variant, $obs_build_variant) =
	($vars{'SRCVERSION'}, $vars{'VARIANT'}, $vars{'OBS_BUILD_VARIANT'});
$obs_build_variant = ($obs_build_variant ? $variant : "" );
my $compress_modules = 'none';
my $compress_vmlinux = 'gz';
if (defined($vars{'COMPRESS_MODULES'})) {
	$compress_modules = $vars{'COMPRESS_MODULES'};
}
if (defined($vars{'COMPRESS_VMLINUX'})) {
	$compress_vmlinux = $vars{'COMPRESS_VMLINUX'};
}
sub detect_false {
my $arg = $_[0];
	return "" if not $arg;
	return $arg =~ /^(0+|no|none)$/i ? "" : $arg;
}
my $build_dtbs = detect_false $vars{'BUILD_DTBS'};
my $multibuild = detect_false $vars{'MULTIBUILD'};
my $livepatch = detect_false $vars{'LIVEPATCH'};
my $livepatch_rt = detect_false $vars{'LIVEPATCH_RT'};
sub to_bool {
	return detect_false($_[0]) ? 1 : 0 ;
}
my $sb_efi_only = to_bool  $vars{'SB_EFI_ONLY'};
my $split_base = to_bool $vars{'SPLIT_BASE'};
my $split_optional = to_bool $vars{'SPLIT_OPTIONAL'};
my $supported_modules_check = to_bool $vars{'SUPPORTED_MODULES_CHECK'};
my $build_pdf = to_bool $vars{'BUILD_PDF'};
my $build_html = to_bool $vars{'BUILD_HTML'};

if (!defined ($rpmrelease)) {
	$rpmrelease = $vars{'RELEASE'} || 0;
}

# package name -> [summary, description, extra kmp deps]
my %binary_descriptions = parse_descriptions();

# arch -> flavor -> [obsoleted packages]
my %obsolete_packages = parse_old_flavors();

$patches="--patches $patches" if $patches;
my $patchversion = `$dir/compute-PATCHVERSION.sh $patches`;
chomp $patchversion;
my $rpmversion = $patchversion;
# stuff the -rcX tag into the rpm version if possible;
$rpmversion =~ s/\.0-rc/~rc/;
$rpmversion =~ s/-rc\d+//;
$rpmversion =~ s/-/./g;

$rpmrelease =~ s/-/./g;

my $sources = join("\n", $templates{source} =~ /^Source\d+:[^\n]*/msg);
# Do not include the signature and keyring as source in the binary packages
# The sources are not really included anyway, and for non-upstream tarballs these files do not exist
$sources = join("\n", grep { $_ !~ /[.](?:keyring|tar[.]sign)\s*$/ } $sources =~ /^[^\n]*/msg);
# Find all SourceN: foo.tar.(bz2|xz) lines and generate the NoSource:
# lines and the %setup line
my @tarballs = ($sources =~ /^Source(\d+):[^\n]*\.tar\.(?:bz2|xz)/msg);
my $nosource = $sources;
$nosource =~ s/^Source(\d+):.*?$/NoSource:       $1/mg;

# Source0 (the linux tarball) is unpacked manually
@tarballs = grep { $_ > 0 } @tarballs;
my $unpack_patches = join(" ", map { "-a $_" } @tarballs);
# List of scripts to automatically chmod +x before build
my $scripts = join(",", grep { is_script($_) }
			($sources =~ /\nSource\d+:\s*([^\s]*)/mg));

my $tarball_url;
if ($srcversion =~ /^(\d+)(?:\.\d+)*(-rc\d+)?$/) {
	$tarball_url = "https://www.kernel.org/pub/linux/kernel/v$1.x/";
	$tarball_url = "" if $2; # kernel.org has no tarballs for rc kernels
	# rc tarballs only available from git as https://git.kernel.org/torvalds/t/linux-*.gz
} else {
	# kernel.org has no tarballs for  linux-next or vanilla snapshots
	$tarball_url = "";
}

my $commit = get_commit();
my $commit_full = get_commit(1);

my %macros = (
	VARIANT => $variant,
	OBS_BUILD_VARIANT => $obs_build_variant . "%{nil}",
	SRCVERSION => $srcversion,
	PATCHVERSION => $patchversion,
	RPMVERSION => $rpmversion,
	TARBALL_URL => $tarball_url,
	RELEASE => $rpmrelease,
	COMMIT => $commit,
	COMMIT_FULL => $commit_full,
	SOURCES => $sources . "\n# These files are found in the kernel-source package:\n" . $nosource,
	UNPACK_PATCHES => $unpack_patches,
	SCRIPTS => $scripts,
	LIVEPATCH => $livepatch,
	LIVEPATCH_RT => $livepatch_rt,
	SB_EFI_ONLY => $sb_efi_only,
	SPLIT_BASE => $split_base,
	SPLIT_OPTIONAL => $split_optional,
	SUPPORTED_MODULES_CHECK => $supported_modules_check,
	BUILD_PDF => $build_pdf,
	BUILD_HTML => $build_html,
	YEAR => (localtime time)[5] + 1900,
	COMPRESS_MODULES => $compress_modules,
	COMPRESS_VMLINUX => $compress_vmlinux,
);

# binary spec files
my $kmp_definitions = "";
my @kmp_definitions;
for my $kmp (@kmps) {
	my ($summary, $description, $deps);
	if (!exists($binary_descriptions{$kmp})) {
		print STDERR "warning: no description for $kmp found\n";
		($summary = $kmp) =~ s/-kmp$//;
		$summary .= " kernel modules";
		$description = "$summary.";
		$deps = "";
	} else {
		$summary = $binary_descriptions{$kmp}->[0];
		$description = $binary_descriptions{$kmp}->[1];
		$deps = $binary_descriptions{$kmp}->[2];
	}
	push(@kmp_definitions, expand_template("kmp",
		KMP_NAME => $kmp,
		KMP_SUMMARY => $summary,
		KMP_DESCRIPTION => $description,
		KMP_DEPS => $deps));
}
$kmp_definitions = join("\n", @kmp_definitions);

for my $flavor (sort keys(%flavor_archs)) {
	my ($summary, $description);
	if (!exists($binary_descriptions{"kernel-$flavor"})) {
		print STDERR "warning: no description for kernel-$flavor found\n";
		$summary = "The Linux Kernel";
		$description = "The Linux Kernel.";
	} else {
		$summary = $binary_descriptions{"kernel-$flavor"}->[0];
		$description = $binary_descriptions{"kernel-$flavor"}->[1];
	}

	my %obsolete_macros;
	for my $subpac ("", "-base", "-extra", "-devel", "-hmac", "-optional") {
		(my $macro = "PROVIDES_OBSOLETES" . uc($subpac)) =~ s/-/_/;
		$obsolete_macros{$macro} =
			provides_obsoletes($flavor, $subpac, @{$flavor_archs{$flavor}});
	}

	do_spec('binary', "kernel-$flavor.spec", %macros,
		FLAVOR => $flavor,
		SUMMARY => $summary,
		DESCRIPTION => $description,
		ARCHS => join(" ", arch2rpm(@{$flavor_archs{$flavor}})),
		COMMON_DEPS => $templates{common_deps},
		KMPS => join(" ", @kmps),
		KMP_DEFINITIONS => $kmp_definitions,
		%obsolete_macros
	);
}
# kernel-source.spec
do_spec('source', "kernel-source$variant.spec", %macros);

if ($variant eq "") {
	# kernel-docs.spec
	do_spec('docs', "kernel-docs$variant.spec", %macros);
}

# kernel-syms.spec
{
	my $requires = "";
	my %syms_archs;
	my $syms_archs;
	for my $flavor (sort keys(%syms_flavor_archs)) {
		next if $flavor eq "vanilla";
		my @archs = arch2rpm(@{$syms_flavor_archs{$flavor}});
		$syms_archs{$_} = 1 for @archs;
		$requires .= "%ifarch @archs\n";
		$requires .= "Requires:       kernel-$flavor-devel = \%version-\%source_rel\n";
		$requires .= "%endif\n";
	}
	chomp $requires;
	$syms_archs = join(" ", sort(keys(%syms_archs)));
	if (keys(%syms_archs)) {
		do_spec('syms', "kernel-syms$variant.spec", %macros,
			REQUIRES => $requires,
			ARCHS => $syms_archs);
	}
}

# kernel-obs-*.spec
if (!$variant || $obs_build_variant) {
	my @default_archs;
	my $flavor = $obs_build_variant;
	if ($flavor) {
		$flavor =~ s/^-//;
	} else {
		$flavor = 'default';
	}

	@default_archs = arch2rpm(@{$flavor_archs{$flavor}});
	# No kernel-obs-* for 32bit ppc and x86
	@default_archs = grep { $_ ne "ppc" && $_ ne '%ix86' } @default_archs;
	my $default_archs = join(" ", @default_archs);
	do_spec('obs-build', "kernel-obs-build.spec", %macros,
		ARCHS => $default_archs);
	do_spec('obs-qa', "kernel-obs-qa.spec", %macros,
		ARCHS => $default_archs);
}

# dtb-*.spec
if ((!$variant || $obs_build_variant) && $build_dtbs) {
	do_spec('dtb', "dtb.spec.in", %macros);
	print "./mkspec-dtb $all_archs\n";
	system("./mkspec-dtb $all_archs\n");
	unlink("$dir/dtb.spec.in");
	if ($?) {
		exit(($? >> 8) || ($? & 127 + 128) || 1);
	}
}

copy_changes();

# _constraints
{
	my @packages = map { "<package>kernel-$_</package>" } sort keys(%flavor_archs);
	my $packages = join("\n", @packages);
	do_spec('constraints', "_constraints",
		BINARY_PACKAGES_XML => $packages);
}

exit 0;



sub parse_config_conf {
	my @symbols = @_;
	my $symbols = join(' ', @symbols);
	my %res;

	for my $arch (split(/\s+/, `$dir/arch-symbols --list`)) {
		my @flavors = `$dir/guards $arch $symbols < $dir/config.conf`;
		next if @flavors == 0;
		chomp @flavors;
		@flavors = map { s/.*\///; $_ } @flavors;
		for my $flavor (@flavors) {
			$res{$flavor} ||= [];
			push(@{$res{$flavor}}, $arch);
		}
	}
	for my $flavor (keys(%res)) {
		$res{$flavor} = [sort @{$res{$flavor}}];
	}
	return %res;
}

sub read_spec_templates {
	my %res;

	for my $template (qw(binary source syms docs obs-build obs-qa)) {
		xopen(my $fh, '<', "$dir/kernel-$template.spec.in");
		local $/ = undef;
		$res{$template} = <$fh>;
		close($fh);
		next unless $template eq "binary";
		if ($res{$template} =~ /^# BEGIN COMMON DEPS\n?(.*)^# END COMMON DEPS/ms) {
			$res{common_deps} = $1;
		} else {
			print STDERR "warning: Expected # BEGIN COMMON DEPS in kernel-binary.spec.in\n";
			$res{common_deps} = "";
		}
		if ($res{$template} =~ s/^# BEGIN KMP\n?(.*)^# END KMP/\@KMP_DEFINITIONS\@/ms) {
			$res{kmp} = $1;
		} else {
			print STDERR "warning: Expected # BEGIN KMP in kernel-binary.spec.in\n";
			$res{kmp} = "";
		}
	}
	{
		xopen(my $fh, '<', "$dir/constraints.in");
		local $/ = undef;
		$res{constraints} = <$fh>;
		close($fh);
		xopen($fh, '<', "$dir/dtb.spec.in.in");
		$res{dtb} = <$fh>;
		close($fh);
	}
	return %res;
}

# return a hash of config.sh variables
sub parse_config_sh {
	my %res;

	xopen(my $fh, '<', "$dir/config.sh");
	while (<$fh>) {
		chomp;
		if (/^\s*([A-Z_]+)=(.*)/) {
			my ($key, $val) = ($1, $2);
			$val =~ s/^"(.*)"$/$1/;
			$res{$key} = $val;
		}
	}
	close($fh);
	return %res;
}

sub parse_descriptions {
	my %res;
	my $current;
	my $blank = "";
	# 0 - expect summary, 1 - eating blank lines, 2 - reading description
	my $state = 0;

	xopen(my $fh, '<', "$dir/package-descriptions");
	while (<$fh>) {
		next if /^\s*#/;

		if (/^==+\s+([^\s]+)\s+==+\s*$/) {
			my $package = $1;
			if ($current) {
				chomp $current->[1];
			}
			$current = ["", "", ""];
			$res{$package} = $current;
			$state = 0;
			next;
		}
		if (/^$/) {
			if ($state == 0) {
				$state++;
			} elsif ($state == 2) {
				$blank .= $_;
			}
			next;
		}
		# non-blank line and not === package ===
		if ($state == 0) {
			chomp;
			if (s/^Requires: *//) {
				# foo-kmp is a shorthand for another kmp
				# from the same specfile
				s/-kmp/-kmp-%build_flavor = %version-%release/g;
				s/^/Requires:       /;
				if ($current->[2]) {
					$current->[2] .= "\n";
				}
				$current->[2] .= $_;
			} else {
				# The Summary: keyword is optional
				s/^Summary: *//;
				if ($current->[0]) {
					print STDERR "warning: multi-line summary\n";
				}
				$current->[0] = $_;
			}
		} elsif ($state == 1) {
			$current->[1] = $_;
			$blank = "";
			$state++;
		} else {
			$current->[1] .= $blank;
			$blank = "";
			$current->[1] .= $_;
		}
	}
	if ($current) {
		chomp $current->[1];
	}
	close($fh);
	return %res;
}

sub read_kmps {
	my %res;

	open(my $fh, '-|', "$dir/guards", "--list", "--with-guards",
		"-c", "$dir/supported.conf") or die "Error running guards: $!\n";
	while (<$fh>) {
		my @guards = split(' ');
		pop(@guards);
		for my $g (@guards) {
			if ($g =~ /^(?:\+|-!)(.*-kmp)$/) {
				$res{$1} = 1;
			}
		}
	}
	close($fh) or die "Error running guards: $!\n";
	return sort(keys(%res));
}

sub parse_old_flavors{
	my %res;


	xopen(my $fh, '<', "$dir/old-flavors");
	while (<$fh>) {
		chomp;
		next if /^\s*(#|$)/;
		if (!m:^\s*(\w+)/([\w-]+)\s+([\w-]+)\s+([\w.-]+)\s*$:) {
			print STDERR "$dir/old-flavors:$.: expected arch/flavor <old flavor> <old version>\n";
			next;
		}
		my ($arch, $flavor, $old_flavor, $old_version) = ($1, $2, $3, $4);
		$res{$arch} ||= {};
		$res{$arch}{$flavor} ||= [];
		push(@{$res{$arch}{$flavor}},
			["kernel-$old_flavor", $old_version]);
	}
	close($fh);
	return %res;
}

sub is_script {
	my $script = shift;

	return undef if $script =~ /\.(tar\.(gz|bz2)|in|conf)$/;
	return undef if $script =~ /^README/;
	return 1 if $script =~ /\.pl$/;
	open(my $fh, '<', $script) or return undef;
	sysread($fh, my $shebang, 2);
	close($fh);
	return 1 if $shebang eq "#!";
	return undef;
}

sub arch2rpm {
	if (wantarray) {
		return map { _arch2rpm($_) } @_;
	}
	return _arch2rpm($_[0]);
}
sub _arch2rpm {
	my $arch = shift;
	return "\%ix86" if $arch eq "i386";
	return "aarch64" if $arch eq "arm64";
	return $arch;
}

sub provides_obsoletes {
	my $flavor = shift;
	my $subpac = shift;
	my @archs = @_;
	my $res = "";

	for my $arch (@archs) {
		my @packs = @{$obsolete_packages{$arch}{$flavor} || []};
		my $printed;

		next if (!@packs);
		my $rpmarch = arch2rpm($arch);
		chomp $rpmarch;
		for my $pack (@packs) {
			my $name = $pack->[0] . $subpac;
			my $version = $pack->[1];
			if (!$printed) {
				$res .= "\%ifarch $rpmarch\n";
				$printed = 1;
			}
			$res .= "Provides:       $name = $version\n";
			$res .= "Obsoletes:      $name <= $version\n";
		}
		$res .= "\%endif\n" if $printed;
	}
	chomp $res;
	return $res;
}

sub get_commit {
	my ($commit, $fh, $full);

	$full = $_[0] // 0;

	if (!open($fh, '<', "source-timestamp")) {
		print STDERR "warning: source-timestamp: $!\n";
		print STDERR "warning: Cannot determine commit id\n";
		return "0000000";
	}
	while (<$fh>) {
		if ($full ? /^GIT Revision: ([0-9a-f]{40})/ : /^GIT Revision: ([0-9a-f]{7})/) {
			$commit = $1;
		}
	}
	close($fh);
	if (!$commit) {
		print STDERR "warning: Commit id missing in source-timestamp file\n";
		return "0000000";
	}
	return $commit;
}

sub expand_template {
	my $template = shift;
	my %macros = @_;

	my $text = $templates{$template};
	my $prev_text;
	do {
		$prev_text = $text;
		for my $m (keys %macros) {
			if ($macros{$m} eq "") {
				# Do not generate empty lines
				$text =~ s/^\@$m\@\n//mg;
			}
			$text =~ s/\@$m\@/$macros{$m}/g;
		}
	} while ($prev_text ne $text);
	return $text;
}

sub do_spec {
	my $template = shift;
	my $specfile = shift;
	my %macros = @_;

	my $text = expand_template($template, %macros);
	print "$specfile\n";
	xopen(my $fh, '>', "$dir/$specfile");
	print $fh $text;
	close($fh);
}

sub copy_changes {

	opendir(my $dh, $dir) or die "$dir: $!\n";
	xopen(my $fh, '>', "$dir/_multibuild") if $multibuild;
	print $fh "<multibuild>\n" if $fh;

	while (my $name = readdir $dh) {
		next unless $name =~ /\.spec$/;
		next if $name eq "kernel-source$variant.spec";

		$name =~ s/\.spec$//;
		copy("$dir/kernel-source$variant.changes", "$dir/$name.changes");
		print $fh "\t<package>$name</package>\n" if $fh;
	}
	print $fh "</multibuild>\n" if $fh;
	close($fh) if $fh;
	closedir($dh);
}

sub xopen {
        open($_[0], $_[1], $_[2]) or die "$_[2]: $!\n";
}

sub uniq {
	my %seen;
	return grep { !$seen{$_}++ } @_;
}