#!/usr/bin/perl -w

use strict;

use File::Basename qq(basename);

use Git;

use Storable qw(store);

use Term::ANSIColor qw(colored);

if (@ARGV < 2) {

	print "Usage: $0 suse_machine|-d stable_version\n";

	exit 1;

}

my $machine = shift;

my $dump_only = $machine eq '-d';

my $stable_ver = shift;

my $old_version;

my $new_version;

my $bsc;

my %bsc_map = (

	'other' => '1012628',

);

if ($stable_ver =~ /^v?(([3-9]\.[0-9]+)\.([0-9]+))$/) {

	$new_version = $1;

	$old_version = $2;

	$bsc = $bsc_map{$old_version};

	if ($3 ne 1) {

		$old_version .= '.' . ($3 - 1);

	}

} else {

	die "cannot understand stable version $stable_ver";

}

if (!defined $bsc) {

	print colored("Kernel version not found in the map, assuming Tumbleweed\n", 'red');

	$bsc = $bsc_map{'other'};

}

my $patchpar = '/dev/shm';

my $patchdir = "patches-$new_version";

my $patchpath = "$patchpar/$patchdir";

my $idsfile = "$patchpath/ids";

if (!$dump_only && !mkdir $patchpath) {

	die "$patchpath already exists";

}

my $range = "v$old_version..v$new_version";

my $repo = Git->repository();

my @revs = $repo->command('rev-list', '--reverse', $range);

my %ids;

my $digits = length scalar @revs;

my $counter = 1;

my @to_delete;

my $sha_re = qr/[0-9a-f]{40}/;

$digits = 3 if ($digits < 3);

print "References: bsc#$bsc $new_version\n" if ($dump_only);

foreach my $rev (@revs) {

	my ($filename, @commit_log) = $repo->command('show', '--no-patch',

		'--format=%f%n%B', $rev);

	my $cont = 0;

	my @shas;

	my @unmatched_shas;

	foreach (@commit_log) {

		if ($cont) {

			if (/^\s+($sha_re)\s*[\])]$/) {

				push @shas, $1;

				$cont = 0;

				next;

			}

		}

		if (/^[Cc]ommit ($sha_re) upstream\.?$/ ||

			/^[\[(]\s*[Uu]pstream commit ($sha_re)\s*[\])]$/ ||

			/^[uU]pstream commit ($sha_re)\.$/ ||

			/^This is a backport of ($sha_re)$/) {

			push @shas, $1;

		} elsif (/^\(cherry picked from commit ($sha_re)\)$/) {

			# if this is not the first SHA, it's likely DRM crap

			push(@shas, $1) if (!scalar @shas);

		} elsif (/^[\[(]\s*[Uu]pstream commits ($sha_re)\s+and\s*$/) {

			push @shas, $1;

			$cont = 1;

		} elsif (/^(Fixes:|This reverts commit) $sha_re(?: \(".*)?\.?$/ ||

			/^Link: .*lkml/) {

			# ignore

		} elsif (/\b$sha_re\b/) {

			push @unmatched_shas, $_;

		}

	}

	if ($dump_only) {

		print "$rev";

		if (scalar @shas) {

			print "=", join ' ', @shas;

		} else {

			print ' STABLE-ONLY patch: "', $commit_log[0], '"';

		}

		print "\n";

		next;

	}

	# better than nothing

	if (!scalar @shas) {

		push @shas, $rev;

	}

	my @patch = $repo->command('format-patch', '--stdout',

		'--signoff', '--no-renames',

		'-1', $rev,

		'--add-header', "References: bsc#$bsc",

		'--add-header', "Patch-mainline: $new_version",

		(map { ('--add-header', "Git-commit: $_") } @shas));

	# drop From

	shift(@patch) =~ /^From/ or die "From line is not the first one?";

	my $newname = sprintf("${new_version}-%0${digits}d-%s", $counter,

		$filename);

	# 57 is what git-format-patch uses

	$newname =~ s/^(.{1,57}).*$/$1.patch/;

	my $newpath = "$patchpath/$newname";

	open(PATCH, ">$newpath") or die "cannot output to $newpath";

	print PATCH join "\n", @patch;

	print PATCH "\n";

	close PATCH;

	$ids{$newname} = [ @shas ];

	$rev =~ /.{12}/;

	print colored($&, "yellow"), " -> $newname\n";

	foreach (@shas) {

		/.{12}/;

		print "\tUpstream SHA: ", colored("$&\n", "yellow");

	}

	foreach (@unmatched_shas) {

		print colored("\tUNMATCHED SHA:", 'bold red'), " $_\n";

	}

	push @to_delete, $newpath;

	$counter++;

}

exit 0 if ($dump_only);

store(\%ids, $idsfile) or die "cannot write $idsfile";

push @to_delete, $idsfile;

if ($machine ne 'localhost') {

	system("tar -cC $patchpar $patchdir|ssh -C $machine -o StrictHostKeyChecking=no 'tar -xC $patchpar'") == 0 ||

		die "ssh didn't start";

	unlink(@to_delete) or print STDERR "cannot delete some temp files\n";

	rmdir("$patchpath") or print STDERR "cannot remove $patchpath\n";

}

print "Written patches and ids to $machine:$patchpath\n";

0;