#!/usr/bin/perl

use strict;
use Getopt::Long;

my @generated_files = qw( proto.h configure config.h.in rsync.1 rsyncd.conf.5 );

my($no_cvs, $failures_only, $minor_updates, $prepare_source);
my @auto_cmds;

&Getopt::Long::Configure('bundling');
GetOptions(
    'no-cvs|n' => \$no_cvs,
    'failures-only|f' => \$failures_only,
    'minor-updates|u' => \$minor_updates,
    'prepare-source|p' => \$prepare_source,
    'auto-cmd|a=s' => sub { push(@auto_cmds, $_[1]) },
) or &usage;

$" = '|';
my $auto_regex = @auto_cmds ? qr/^(@auto_cmds)$/i : qr/^never$/;
my $interesting_fuzz = $minor_updates ? '\d' : '[2-9]';
$" = ' ';

chdir('patches') if -d 'patches';

if (!-f 'verify-patches') {
    die <<EOT;
Please run this script from the root of the rsync dir or
from inside the patches subdir.
EOT
}

$ENV{'LC_COLLATE'} = 'C';
$| = 1;
my $CONF_OPTS = '--cache-file=../config.cache';

my($has_dependencies, @new, @rejects);

END {
    &restore_cvsdir;
    system "rsync -a --del cvsdir/ workdir/" if -d 'cvsdir';
};

my $root;
open(IN, '../CVS/Root') or die $!;
chomp($root = <IN>);
close IN;

mkdir('tmp', 0777) unless -d 'tmp';
chdir('tmp') or die "Unable to chdir to 'tmp'";
symlink('..', 'patches') unless -d 'patches';

mkdir('workdir') unless -d 'workdir';
open(OUT, '>exclude') or die $!;
print OUT join("\n", 'CVS', @generated_files), "\n";
close OUT;

unless ($no_cvs) {
    print "Using CVS to update the tmp/cvsdir copy of the source.\n";
    system qq|cvs -qd "$root" co -P -d cvsdir rsync|;
}

@ARGV = glob('patches/*.diff') unless @ARGV;

DIFF:
foreach my $diff (@ARGV) {
    next unless $diff =~ /\.diff$/;
    next if $diff =~ /gzip-rsyncable[-_a-z]*\.diff$/;
    $diff =~ s#^(patches|\.\.)/##;

    my $conf_opts;
    open(IN, "patches/$diff") or die $!;
    while (<IN>) {
	last if /^--- /;
	if (m#^\s+patch -p1 <patches/(\S+.diff)# && $1 ne $diff) {
	    my $dep = $1;
	    $has_dependencies = 1;
	    print "\nApplying dependency patch $dep...\n";
	    if (system("patch -d cvsdir -p1 -b -Vt <patches/$dep") != 0) {
		print "Unable to cleanly apply dependency patch -- skipping $diff\n";
		system "rm -f cvsdir/*.rej cvsdir/*/*.rej";
		&restore_cvsdir;
		next DIFF;
	    }
	    sleep(1) if $prepare_source; # Ensure later diffs get later times.
	}
	if (!defined($conf_opts) && s#^\s+\./configure\s+##) {
	    chomp($conf_opts = $_);
	    $conf_opts =~ s/\s*\(.*?\)//;
	}
    }
    close IN;
    $conf_opts = '' unless defined $conf_opts;

    my $default = apply_patch($diff);

    if ($prepare_source) {
	print "\nPreparing the source...\n";
	chdir('workdir') or die $!;
	system "./prepare-source";
	chdir('..') or die $!;
    }

    if ($default =~ s/^D,// || $default eq 'N') {
	my $def = generate_new_patch($diff);
	$default = 'U,N' if $default eq 'N' && $def eq 'E';
	$default = 'N' if !$minor_updates && $default eq 'U,N';
    }

    my $first_time = 1;
    PROMPT:
    while (1) {
	print "\n----------- $diff ------------\n",
	    "\nFix rejects, Diff create, Edit both diffs, Update patch,\n",
	    "Apply patch again, !(CMD), Build rsync, Next, Quit: [$default] ";
	my $ans = $default;
	if ($first_time && $default =~ /$auto_regex/) {
	    print $default, "\n";
	} else {
	    my $input = <STDIN>;
	    chomp $input;
	    if ($input =~ s/^(-a|--auto-cmd=?)\s*//) {
		push(@auto_cmds, $input eq '' ? $default : $input);
		$" = '|';
		$auto_regex = qr/^(@auto_cmds)$/i;
		$" = ' ';
		next;
	    }
	    $ans = $input if $input ne '';
	}
	$first_time = 0;
	while ($ans =~ s/^\s*(!|\w)((?<!!)[^;,]*|[^;]*)[;,]?//) {
	    my $cmd = "\U$1\E";
	    if ($cmd eq '!') {
		$cmd = $2 || $ENV{'SHELL'};
		chdir('workdir') or die $!;
		system $cmd;
		chdir('..') or die $!;
		$default = 'D';
		next;
	    }
	    if ($cmd eq 'A') {
		$default = apply_patch($diff);
		next;
	    }
	    if ($cmd eq 'B') {
		chdir('workdir') or die $!;
		my $cmd = "./prepare-source && ./configure $CONF_OPTS $conf_opts && make";
		print "Running: $cmd\n";
		system $cmd;
		chdir('..') or die $!;
		$default = '!make test';
		next;
	    }
	    if ($cmd eq 'D') {
		$default = generate_new_patch($diff);
		next;
	    }
	    if ($cmd eq 'E') {
		chdir('workdir') or die $!;
		system "vim -d ../patches/$diff ../new.patch";
		chdir('..') or die $!;
		$default = 'U,A,D';
		next;
	    }
	    if ($cmd eq 'F') {
		chdir('workdir') or die $!;
		system "vim @rejects";
		chdir('..') or die $!;
		$default = 'D,E';
		next;
	    }
	    if ($cmd eq 'N') {
		last PROMPT;
	    }
	    if ($cmd eq 'Q') {
		exit;
	    }
	    if ($cmd eq 'U') {
		system "cp -p new.patch patches/$diff";
		print "\nUpdated $diff from new.patch\n";
		$default = 'A';
		next;
	    }
	}
    }

    &restore_cvsdir;
}

exit;


sub apply_patch
{
    my($diff) = @_;

    undef @new;
    system "rsync -a --delete --exclude='*~' cvsdir/ workdir/";
    print "\nApplying patch $diff...\n";
    undef @rejects;
    my($saw_offset, $saw_fuzz);
    open(IN, "patch -d workdir -p1 --no-backup-if-mismatch <patches/$diff |") or die $!;
    while (<IN>) {
	print $_;
	chomp;
	if (s/^patching file //) {
	    push(@new, $_) unless -f "cvsdir/$_";
	} elsif (s/.* saving rejects to file //) {
	    push(@rejects, $_);
	} elsif (/^Hunk #\d+ succeeded at \d+( with fuzz $interesting_fuzz)?/o) {
	    $saw_fuzz ||= defined $1;
	    $saw_offset = 1;
	}
    }
    close IN;
    return 'F,D,E' if @rejects;
    return 'D,E' if $saw_fuzz && !$failures_only;
    return 'D,U,N' if $saw_offset && !$failures_only;
    'N';
}

sub filter_diff
{
    my($cmd) = @_;
    open(IN, '-|', $cmd) or die $!;
    while (<IN>) {
	next if /^(diff -|Index: |Only in )/;
	s#^\Q--- cvsdir/\E([^\t]+).*#--- old/$1#;
	s#^\Q+++ workdir/\E([^\t]+).*#+++ new/$1#;
	print OUT $_;
    }
    close IN;
}

sub generate_new_patch
{
    my($diff) = @_;

    foreach (@new) {
	system "touch -r workdir/$_ cvsdir/$_";
    }
    open(IN, "patches/$diff") or die $!;
    open(OUT, '>new.patch') or die $!;
    while (<IN>) {
	last if /^--- /;
	print OUT $_;
    }
    close IN;
    &filter_diff('diff --exclude-from=exclude -dupr cvsdir workdir');
    if ($prepare_source) {
	# These are not included in the diff above so that patch will give
	# generated files a later timestamp than the source files.
	foreach my $fn (@generated_files) {
	    &filter_diff("diff -dup cvsdir/$fn workdir");
	}
    }
    close OUT;
    foreach (@new) {
	unlink("cvsdir/$_");
    }
    print "\nDiffing... ";
    if (system("diff patches/$diff new.patch >/dev/null") == 0) {
	print "new patch is identical to old.\n";
	return 'N';
    }
    print "New patch DIFFERS from old.\n";
    'E';
}

sub restore_cvsdir
{
    return unless $has_dependencies;
    $has_dependencies = 0;

    chdir('cvsdir') or die $!;
    foreach (glob('*.~[1-9]~'), glob('*/*.~[1-9]~')) {
	my $fn;
	($fn = $_) =~ s/\.~1~$//;
	if ($fn eq $_) {
	    unlink($_);
	} elsif (-r $_) {
	    rename($_, $fn);
	} else {
	    unlink($_);
	    unlink($fn);
	}
    }
    chdir('..') or die $!;
}

sub usage
{
    die <<EOT;
Usage: $0 [OPTS] [DIFF-FILE...]
 -a, --auto-cmd=REGEX  If default_cmd =~ /^(REGEX)\$/, enter it automatically
 -f, --failures-only   Suggest skipping patches that don't have failing hunks
 -n, --no-cvs          Don't update tmp/cvsdir at the start of the run
 -p, --prepare-source  Run ./prepare-source and include generated files in diff
 -u, --minor-updates   Suggest 'U' for even minor changes in the diff
EOT
}