package Git::SVN::Editor;
use vars qw/@ISA $_rmdir $_cp_similarity $_find_copies_harder $_rename_limit/;
use strict;
use warnings;
use SVN::Core;
use SVN::Delta;
use Carp qw/croak/;
use IO::File;
use Git qw/command command_oneline command_noisy command_output_pipe
           command_input_pipe command_close_pipe
           command_bidi_pipe command_close_bidi_pipe/;
BEGIN {
        @ISA = qw(SVN::Delta::Editor);
}

sub new {
        my ($class, $opts) = @_;
        foreach (qw/svn_path r ra tree_a tree_b log editor_cb/) {
                die "$_ required!\n" unless (defined $opts->{$_});
        }

        my $pool = SVN::Pool->new;
        my $mods = generate_diff($opts->{tree_a}, $opts->{tree_b});
        my $types = check_diff_paths($opts->{ra}, $opts->{svn_path},
                                     $opts->{r}, $mods);

        # $opts->{ra} functions should not be used after this:
        my @ce  = $opts->{ra}->get_commit_editor($opts->{log},
                                                $opts->{editor_cb}, $pool);
        my $self = SVN::Delta::Editor->new(@ce, $pool);
        bless $self, $class;
        foreach (qw/svn_path r tree_a tree_b/) {
                $self->{$_} = $opts->{$_};
        }
        $self->{url} = $opts->{ra}->{url};
        $self->{mods} = $mods;
        $self->{types} = $types;
        $self->{pool} = $pool;
        $self->{bat} = { '' => $self->open_root($self->{r}, $self->{pool}) };
        $self->{rm} = { };
        $self->{path_prefix} = length $self->{svn_path} ?
                               "$self->{svn_path}/" : '';
        $self->{config} = $opts->{config};
        $self->{mergeinfo} = $opts->{mergeinfo};
        return $self;
}

sub generate_diff {
        my ($tree_a, $tree_b) = @_;
        my @diff_tree = qw(diff-tree -z -r);
        if ($_cp_similarity) {
                push @diff_tree, "-C$_cp_similarity";
        } else {
                push @diff_tree, '-C';
        }
        push @diff_tree, '--find-copies-harder' if $_find_copies_harder;
        push @diff_tree, "-l$_rename_limit" if defined $_rename_limit;
        push @diff_tree, $tree_a, $tree_b;
        my ($diff_fh, $ctx) = command_output_pipe(@diff_tree);
        local $/ = "\0";
        my $state = 'meta';
        my @mods;
        while (<$diff_fh>) {
                chomp $_; # this gets rid of the trailing "\0"
                if ($state eq 'meta' && /^:(\d{6})\s(\d{6})\s
                                        ($::sha1)\s($::sha1)\s
                                        ([MTCRAD])\d*$/xo) {
                        push @mods, {   mode_a => $1, mode_b => $2,
                                        sha1_a => $3, sha1_b => $4,
                                        chg => $5 };
                        if ($5 =~ /^(?:C|R)$/) {
                                $state = 'file_a';
                        } else {
                                $state = 'file_b';
                        }
                } elsif ($state eq 'file_a') {
                        my $x = $mods[$#mods] or croak "Empty array\n";
                        if ($x->{chg} !~ /^(?:C|R)$/) {
                                croak "Error parsing $_, $x->{chg}\n";
                        }
                        $x->{file_a} = $_;
                        $state = 'file_b';
                } elsif ($state eq 'file_b') {
                        my $x = $mods[$#mods] or croak "Empty array\n";
                        if (exists $x->{file_a} && $x->{chg} !~ /^(?:C|R)$/) {
                                croak "Error parsing $_, $x->{chg}\n";
                        }
                        if (!exists $x->{file_a} && $x->{chg} =~ /^(?:C|R)$/) {
                                croak "Error parsing $_, $x->{chg}\n";
                        }
                        $x->{file_b} = $_;
                        $state = 'meta';
                } else {
                        croak "Error parsing $_\n";
                }
        }
        command_close_pipe($diff_fh, $ctx);
        \@mods;
}

sub check_diff_paths {
        my ($ra, $pfx, $rev, $mods) = @_;
        my %types;
        $pfx .= '/' if length $pfx;

        sub type_diff_paths {
                my ($ra, $types, $path, $rev) = @_;
                my @p = split m#/+#, $path;
                my $c = shift @p;
                unless (defined $types->{$c}) {
                        $types->{$c} = $ra->check_path($c, $rev);
                }
                while (@p) {
                        $c .= '/' . shift @p;
                        next if defined $types->{$c};
                        $types->{$c} = $ra->check_path($c, $rev);
                }
        }

        foreach my $m (@$mods) {
                foreach my $f (qw/file_a file_b/) {
                        next unless defined $m->{$f};
                        my ($dir) = ($m->{$f} =~ m#^(.*?)/?(?:[^/]+)$#);
                        if (length $pfx.$dir && ! defined $types{$dir}) {
                                type_diff_paths($ra, \%types, $pfx.$dir, $rev);
                        }
                }
        }
        \%types;
}

sub split_path {
        return ($_[0] =~ m#^(.*?)/?([^/]+)$#);
}

sub repo_path {
        my ($self, $path) = @_;
        if (my $enc = $self->{pathnameencoding}) {
                require Encode;
                Encode::from_to($path, $enc, 'UTF-8');
        }
        $self->{path_prefix}.(defined $path ? $path : '');
}

sub url_path {
        my ($self, $path) = @_;
        if ($self->{url} =~ m#^https?://#) {
                # characters are taken from subversion/libsvn_subr/path.c
                $path =~ s#([^~a-zA-Z0-9_./!$&'()*+,-])#sprintf("%%%02X",ord($1))#eg;
        }
        $self->{url} . '/' . $self->repo_path($path);
}

sub rmdirs {
        my ($self) = @_;
        my $rm = $self->{rm};
        delete $rm->{''}; # we never delete the url we're tracking
        return unless %$rm;

        foreach (keys %$rm) {
                my @d = split m#/#, $_;
                my $c = shift @d;
                $rm->{$c} = 1;
                while (@d) {
                        $c .= '/' . shift @d;
                        $rm->{$c} = 1;
                }
        }
        delete $rm->{$self->{svn_path}};
        delete $rm->{''}; # we never delete the url we're tracking
        return unless %$rm;

        my ($fh, $ctx) = command_output_pipe(qw/ls-tree --name-only -r -z/,
                                             $self->{tree_b});
        local $/ = "\0";
        while (<$fh>) {
                chomp;
                my @dn = split m#/#, $_;
                while (pop @dn) {
                        delete $rm->{join '/', @dn};
                }
                unless (%$rm) {
                        close $fh;
                        return;
                }
        }
        command_close_pipe($fh, $ctx);

        my ($r, $p, $bat) = ($self->{r}, $self->{pool}, $self->{bat});
        foreach my $d (sort { $b =~ tr#/#/# <=> $a =~ tr#/#/# } keys %$rm) {
                $self->close_directory($bat->{$d}, $p);
                my ($dn) = ($d =~ m#^(.*?)/?(?:[^/]+)$#);
                print "\tD+\t$d/\n" unless $::_q;
                $self->SUPER::delete_entry($d, $r, $bat->{$dn}, $p);
                delete $bat->{$d};
        }
}

sub open_or_add_dir {
        my ($self, $full_path, $baton, $deletions) = @_;
        my $t = $self->{types}->{$full_path};
        if (!defined $t) {
                die "$full_path not known in r$self->{r} or we have a bug!\n";
        }
        {
                no warnings 'once';
                # SVN::Node::none and SVN::Node::file are used only once,
                # so we're shutting up Perl's warnings about them.
                if ($t == $SVN::Node::none || defined($deletions->{$full_path})) {
                        return $self->add_directory($full_path, $baton,
                            undef, -1, $self->{pool});
                } elsif ($t == $SVN::Node::dir) {
                        return $self->open_directory($full_path, $baton,
                            $self->{r}, $self->{pool});
                } # no warnings 'once'
                print STDERR "$full_path already exists in repository at ",
                    "r$self->{r} and it is not a directory (",
                    ($t == $SVN::Node::file ? 'file' : 'unknown'),"/$t)\n";
        } # no warnings 'once'
        exit 1;
}

sub ensure_path {
        my ($self, $path, $deletions) = @_;
        my $bat = $self->{bat};
        my $repo_path = $self->repo_path($path);
        return $bat->{''} unless (length $repo_path);

        my @p = split m#/+#, $repo_path;
        my $c = shift @p;
        $bat->{$c} ||= $self->open_or_add_dir($c, $bat->{''}, $deletions);
        while (@p) {
                my $c0 = $c;
                $c .= '/' . shift @p;
                $bat->{$c} ||= $self->open_or_add_dir($c, $bat->{$c0}, $deletions);
        }
        return $bat->{$c};
}

# Subroutine to convert a globbing pattern to a regular expression.
# From perl cookbook.
sub glob2pat {
        my $globstr = shift;
        my %patmap = ('*' => '.*', '?' => '.', '[' => '[', ']' => ']');
        $globstr =~ s{(.)} { $patmap{$1} || "\Q$1" }ge;
        return '^' . $globstr . '$';
}

sub check_autoprop {
        my ($self, $pattern, $properties, $file, $fbat) = @_;
        # Convert the globbing pattern to a regular expression.
        my $regex = glob2pat($pattern);
        # Check if the pattern matches the file name.
        if($file =~ m/($regex)/) {
                # Parse the list of properties to set.
                my @props = split(/;/, $properties);
                foreach my $prop (@props) {
                        # Parse 'name=value' syntax and set the property.
                        if ($prop =~ /([^=]+)=(.*)/) {
                                my ($n,$v) = ($1,$2);
                                for ($n, $v) {
                                        s/^\s+//; s/\s+$//;
                                }
                                $self->change_file_prop($fbat, $n, $v);
                        }
                }
        }
}

sub apply_autoprops {
        my ($self, $file, $fbat) = @_;
        my $conf_t = ${$self->{config}}{'config'};
        no warnings 'once';
        # Check [miscellany]/enable-auto-props in svn configuration.
        if (SVN::_Core::svn_config_get_bool(
                $conf_t,
                $SVN::_Core::SVN_CONFIG_SECTION_MISCELLANY,
                $SVN::_Core::SVN_CONFIG_OPTION_ENABLE_AUTO_PROPS,
                0)) {
                # Auto-props are enabled.  Enumerate them to look for matches.
                my $callback = sub {
                        $self->check_autoprop($_[0], $_[1], $file, $fbat);
                };
                SVN::_Core::svn_config_enumerate(
                        $conf_t,
                        $SVN::_Core::SVN_CONFIG_SECTION_AUTO_PROPS,
                        $callback);
        }
}

sub check_attr {
        my ($attr,$path) = @_;
        my $val = command_oneline("check-attr", $attr, "--", $path);
        if ($val) { $val =~ s/^[^:]*:\s*[^:]*:\s*(.*)\s*$/$1/; }
        return $val;
}

sub apply_manualprops {
        my ($self, $file, $fbat) = @_;
        my $pending_properties = check_attr( "svn-properties", $file );
        if ($pending_properties eq "") { return; }
        # Parse the list of properties to set.
        my @props = split(/;/, $pending_properties);
        # TODO: get existing properties to compare to
        # - this fails for add so currently not done
        # my $existing_props = ::get_svnprops($file);
        my $existing_props = {};
        # TODO: caching svn properties or storing them in .gitattributes
        # would make that faster
        foreach my $prop (@props) {
                # Parse 'name=value' syntax and set the property.
                if ($prop =~ /([^=]+)=(.*)/) {
                        my ($n,$v) = ($1,$2);
                        for ($n, $v) {
                                s/^\s+//; s/\s+$//;
                        }
                        my $existing = $existing_props->{$n};
                        if (!defined($existing) || $existing ne $v) {
                            $self->change_file_prop($fbat, $n, $v);
                        }
                }
        }
}

sub A {
        my ($self, $m, $deletions) = @_;
        my ($dir, $file) = split_path($m->{file_b});
        my $pbat = $self->ensure_path($dir, $deletions);
        my $fbat = $self->add_file($self->repo_path($m->{file_b}), $pbat,
                                        undef, -1);
        print "\tA\t$m->{file_b}\n" unless $::_q;
        $self->apply_autoprops($file, $fbat);
        $self->apply_manualprops($m->{file_b}, $fbat);
        $self->chg_file($fbat, $m);
        $self->close_file($fbat,undef,$self->{pool});
}

sub C {
        my ($self, $m, $deletions) = @_;
        my ($dir, $file) = split_path($m->{file_b});
        my $pbat = $self->ensure_path($dir, $deletions);
        # workaround for a bug in svn serf backend (v1.8.5 and below):
        # store third argument to ->add_file() in a local variable, to make it
        # have the same lifetime as $fbat
        my $upa = $self->url_path($m->{file_a});
        my $fbat = $self->add_file($self->repo_path($m->{file_b}), $pbat,
                                $upa, $self->{r});
        print "\tC\t$m->{file_a} => $m->{file_b}\n" unless $::_q;
        $self->apply_manualprops($m->{file_b}, $fbat);
        $self->chg_file($fbat, $m);
        $self->close_file($fbat,undef,$self->{pool});
}

sub delete_entry {
        my ($self, $path, $pbat) = @_;
        my $rpath = $self->repo_path($path);
        my ($dir, $file) = split_path($rpath);
        $self->{rm}->{$dir} = 1;
        $self->SUPER::delete_entry($rpath, $self->{r}, $pbat, $self->{pool});
}

sub R {
        my ($self, $m, $deletions) = @_;
        my ($dir, $file) = split_path($m->{file_b});
        my $pbat = $self->ensure_path($dir, $deletions);
        # workaround for a bug in svn serf backend, see comment in C() above
        my $upa = $self->url_path($m->{file_a});
        my $fbat = $self->add_file($self->repo_path($m->{file_b}), $pbat,
                                $upa, $self->{r});
        print "\tR\t$m->{file_a} => $m->{file_b}\n" unless $::_q;
        $self->apply_autoprops($file, $fbat);
        $self->apply_manualprops($m->{file_b}, $fbat);
        $self->chg_file($fbat, $m);
        $self->close_file($fbat,undef,$self->{pool});

        ($dir, $file) = split_path($m->{file_a});
        $pbat = $self->ensure_path($dir, $deletions);
        $self->delete_entry($m->{file_a}, $pbat);
}

sub M {
        my ($self, $m, $deletions) = @_;
        my ($dir, $file) = split_path($m->{file_b});
        my $pbat = $self->ensure_path($dir, $deletions);
        my $fbat = $self->open_file($self->repo_path($m->{file_b}),
                                $pbat,$self->{r},$self->{pool});
        print "\t$m->{chg}\t$m->{file_b}\n" unless $::_q;
        $self->apply_manualprops($m->{file_b}, $fbat);
        $self->chg_file($fbat, $m);
        $self->close_file($fbat,undef,$self->{pool});
}

sub T {
        my ($self, $m, $deletions) = @_;

        # Work around subversion issue 4091: toggling the "is a
        # symlink" property requires removing and re-adding a
        # file or else "svn up" on affected clients trips an
        # assertion and aborts.
        if (($m->{mode_b} =~ /^120/ && $m->{mode_a} !~ /^120/) ||
            ($m->{mode_b} !~ /^120/ && $m->{mode_a} =~ /^120/)) {
                $self->D({
                        mode_a => $m->{mode_a}, mode_b => '000000',
                        sha1_a => $m->{sha1_a}, sha1_b => '0' x 40,
                        chg => 'D', file_b => $m->{file_b}
                }, $deletions);
                $self->A({
                        mode_a => '000000', mode_b => $m->{mode_b},
                        sha1_a => '0' x 40, sha1_b => $m->{sha1_b},
                        chg => 'A', file_b => $m->{file_b}
                }, $deletions);
                return;
        }

        $self->M($m, $deletions);
}

sub change_file_prop {
        my ($self, $fbat, $pname, $pval) = @_;
        $self->SUPER::change_file_prop($fbat, $pname, $pval, $self->{pool});
}

sub change_dir_prop {
        my ($self, $pbat, $pname, $pval) = @_;
        $self->SUPER::change_dir_prop($pbat, $pname, $pval, $self->{pool});
}

sub _chg_file_get_blob ($$$$) {
        my ($self, $fbat, $m, $which) = @_;
        my $fh = $::_repository->temp_acquire("git_blob_$which");
        if ($m->{"mode_$which"} =~ /^120/) {
                print $fh 'link ' or croak $!;
                $self->change_file_prop($fbat,'svn:special','*');
        } elsif ($m->{mode_a} =~ /^120/ && $m->{"mode_$which"} !~ /^120/) {
                $self->change_file_prop($fbat,'svn:special',undef);
        }
        my $blob = $m->{"sha1_$which"};
        return ($fh,) if ($blob =~ /^0{40}$/);
        my $size = $::_repository->cat_blob($blob, $fh);
        croak "Failed to read object $blob" if ($size < 0);
        $fh->flush == 0 or croak $!;
        seek $fh, 0, 0 or croak $!;

        my $exp = ::md5sum($fh);
        seek $fh, 0, 0 or croak $!;
        return ($fh, $exp);
}

sub chg_file {
        my ($self, $fbat, $m) = @_;
        if ($m->{mode_b} =~ /755$/ && $m->{mode_a} !~ /755$/) {
                $self->change_file_prop($fbat,'svn:executable','*');
        } elsif ($m->{mode_b} !~ /755$/ && $m->{mode_a} =~ /755$/) {
                $self->change_file_prop($fbat,'svn:executable',undef);
        }
        my ($fh_a, $exp_a) = _chg_file_get_blob $self, $fbat, $m, 'a';
        my ($fh_b, $exp_b) = _chg_file_get_blob $self, $fbat, $m, 'b';
        my $pool = SVN::Pool->new;
        my $atd = $self->apply_textdelta($fbat, $exp_a, $pool);
        if (-s $fh_a) {
                my $txstream = SVN::TxDelta::new ($fh_a, $fh_b, $pool);
                my $res = SVN::TxDelta::send_txstream($txstream, @$atd, $pool);
                if (defined $res) {
                        die "Unexpected result from send_txstream: $res\n",
                            "(SVN::Core::VERSION: $SVN::Core::VERSION)\n";
                }
        } else {
                my $got = SVN::TxDelta::send_stream($fh_b, @$atd, $pool);
                die "Checksum mismatch\nexpected: $exp_b\ngot: $got\n"
                    if ($got ne $exp_b);
        }
        Git::temp_release($fh_b, 1);
        Git::temp_release($fh_a, 1);
        $pool->clear;
}

sub D {
        my ($self, $m, $deletions) = @_;
        my ($dir, $file) = split_path($m->{file_b});
        my $pbat = $self->ensure_path($dir, $deletions);
        print "\tD\t$m->{file_b}\n" unless $::_q;
        $self->delete_entry($m->{file_b}, $pbat);
}

sub close_edit {
        my ($self) = @_;
        my ($p,$bat) = ($self->{pool}, $self->{bat});
        foreach (sort { $b =~ tr#/#/# <=> $a =~ tr#/#/# } keys %$bat) {
                next if $_ eq '';
                $self->close_directory($bat->{$_}, $p);
        }
        $self->close_directory($bat->{''}, $p);
        $self->SUPER::close_edit($p);
        $p->clear;
}

sub abort_edit {
        my ($self) = @_;
        $self->SUPER::abort_edit($self->{pool});
}

sub DESTROY {
        my $self = shift;
        $self->SUPER::DESTROY(@_);
        $self->{pool}->clear;
}

# this drives the editor
sub apply_diff {
        my ($self) = @_;
        my $mods = $self->{mods};
        my %o = ( D => 0, C => 1, R => 2, A => 3, M => 4, T => 5 );
        my %deletions;

        foreach my $m (@$mods) {
                if ($m->{chg} eq "D") {
                        $deletions{$m->{file_b}} = 1;
                }
        }

        foreach my $m (sort { $o{$a->{chg}} <=> $o{$b->{chg}} } @$mods) {
                my $f = $m->{chg};
                if (defined $o{$f}) {
                        $self->$f($m, \%deletions);
                } else {
                        fatal("Invalid change type: $f");
                }
        }

        if (defined($self->{mergeinfo})) {
                $self->change_dir_prop($self->{bat}{''}, "svn:mergeinfo",
                                       $self->{mergeinfo});
        }
        $self->rmdirs if $_rmdir;
        if (@$mods == 0 && !defined($self->{mergeinfo})) {
                $self->abort_edit;
        } else {
                $self->close_edit;
        }
        return scalar @$mods;
}

1;
__END__

=head1 NAME

Git::SVN::Editor - commit driver for "git svn set-tree" and dcommit

=head1 SYNOPSIS

        use Git::SVN::Editor;
        use Git::SVN::Ra;

        my $ra = Git::SVN::Ra->new($url);
        my %opts = (
                r => 19,
                log => "log message",
                ra => $ra,
                config => SVN::Core::config_get_config($svn_config_dir),
                tree_a => "$commit^",
                tree_b => "$commit",
                editor_cb => sub { print "Committed r$_[0]\n"; },
                mergeinfo => "/branches/foo:1-10",
                svn_path => "trunk"
        );
        Git::SVN::Editor->new(\%opts)->apply_diff or print "No changes\n";

        my $re = Git::SVN::Editor::glob2pat("trunk/*");
        if ($branchname =~ /$re/) {
                print "matched!\n";
        }

=head1 DESCRIPTION

This module is an implementation detail of the "git svn" command.
Do not use it unless you are developing git-svn.

This module adapts the C<SVN::Delta::Editor> object returned by
C<SVN::Delta::get_commit_editor> and drives it to convey the
difference between two git tree objects to a remote Subversion
repository.

The interface will change as git-svn evolves.

=head1 DEPENDENCIES

Subversion perl bindings,
the core L<Carp> and L<IO::File> modules,
and git's L<Git> helper module.

C<Git::SVN::Editor> has not been tested using callers other than
B<git-svn> itself.

=head1 SEE ALSO

L<SVN::Delta>,
L<Git::SVN::Fetcher>.

=head1 INCOMPATIBILITIES

None reported.

=head1 BUGS

None.