package Git::SVN::Ra;
use vars qw/@ISA $config_dir $_ignore_refs_regex $_log_window_size/;
use strict;
use warnings;
use Memoize;
use SVN::Client;
use Git::SVN::Utils qw(
        canonicalize_url
        canonicalize_path
        add_path_to_url
);

use SVN::Ra;
BEGIN {
        @ISA = qw(SVN::Ra);
}

my ($ra_invalid, $can_do_switch, %ignored_err, $RA);

BEGIN {
        # enforce temporary pool usage for some simple functions
        no strict 'refs';
        for my $f (qw/rev_proplist get_latest_revnum get_uuid get_repos_root
                      get_file/) {
                my $SUPER = "SUPER::$f";
                *$f = sub {
                        my $self = shift;
                        my $pool = SVN::Pool->new;
                        my @ret = $self->$SUPER(@_,$pool);
                        $pool->clear;
                        wantarray ? @ret : $ret[0];
                };
        }
}

# serf has a bug that leads to a coredump upon termination if the
# remote access object is left around (not fixed yet in serf 1.3.1).
# Explicitly free it to work around the issue.
END {
        $RA = undef;
        $ra_invalid = 1;
}

sub _auth_providers () {
        my @rv = (
          SVN::Client::get_simple_provider(),
          SVN::Client::get_ssl_server_trust_file_provider(),
          SVN::Client::get_simple_prompt_provider(
            \&Git::SVN::Prompt::simple, 2),
          SVN::Client::get_ssl_client_cert_file_provider(),
          SVN::Client::get_ssl_client_cert_prompt_provider(
            \&Git::SVN::Prompt::ssl_client_cert, 2),
          SVN::Client::get_ssl_client_cert_pw_file_provider(),
          SVN::Client::get_ssl_client_cert_pw_prompt_provider(
            \&Git::SVN::Prompt::ssl_client_cert_pw, 2),
          SVN::Client::get_username_provider(),
          SVN::Client::get_ssl_server_trust_prompt_provider(
            \&Git::SVN::Prompt::ssl_server_trust),
          SVN::Client::get_username_prompt_provider(
            \&Git::SVN::Prompt::username, 2)
        );

        # earlier 1.6.x versions would segfault, and <= 1.5.x didn't have
        # this function
        if (::compare_svn_version('1.6.15') >= 0) {
                my $config = SVN::Core::config_get_config($config_dir);
                my ($p, @a);
                # config_get_config returns all config files from
                # ~/.subversion, auth_get_platform_specific_client_providers
                # just wants the config "file".
                @a = ($config->{'config'}, undef);
                $p = SVN::Core::auth_get_platform_specific_client_providers(@a);
                # Insert the return value from
                # auth_get_platform_specific_providers
                unshift @rv, @$p;
        }
        \@rv;
}

sub prepare_config_once {
        SVN::_Core::svn_config_ensure($config_dir, undef);
        my ($baton, $callbacks) = SVN::Core::auth_open_helper(_auth_providers);
        my $config = SVN::Core::config_get_config($config_dir);
        my $dont_store_passwords = 1;
        my $conf_t = $config->{'config'};

        no warnings 'once';
        # The usage of $SVN::_Core::SVN_CONFIG_* variables
        # produces warnings that variables are used only once.
        # I had not found the better way to shut them up, so
        # the warnings of type 'once' are disabled in this block.
        if (SVN::_Core::svn_config_get_bool($conf_t,
            $SVN::_Core::SVN_CONFIG_SECTION_AUTH,
            $SVN::_Core::SVN_CONFIG_OPTION_STORE_PASSWORDS,
            1) == 0) {
                SVN::_Core::svn_auth_set_parameter($baton,
                    $SVN::_Core::SVN_AUTH_PARAM_DONT_STORE_PASSWORDS,
                    bless (\$dont_store_passwords, "_p_void"));
        }
        if (SVN::_Core::svn_config_get_bool($conf_t,
            $SVN::_Core::SVN_CONFIG_SECTION_AUTH,
            $SVN::_Core::SVN_CONFIG_OPTION_STORE_AUTH_CREDS,
            1) == 0) {
                $Git::SVN::Prompt::_no_auth_cache = 1;
        }

        return ($config, $baton, $callbacks);
} # no warnings 'once'

INIT {
        Memoize::memoize '_auth_providers';
        Memoize::memoize 'prepare_config_once';
}

sub new {
        my ($class, $url) = @_;
        $url = canonicalize_url($url);
        return $RA if ($RA && $RA->url eq $url);

        ::_req_svn();

        $RA = undef;
        my ($config, $baton, $callbacks) = prepare_config_once();
        my $self = SVN::Ra->new(url => $url, auth => $baton,
                              config => $config,
                              pool => SVN::Pool->new,
                              auth_provider_callbacks => $callbacks);
        $RA = bless $self, $class;

        # Make sure its canonicalized
        $self->url($url);
        $self->{svn_path} = $url;
        $self->{repos_root} = $self->get_repos_root;
        $self->{svn_path} =~ s#^\Q$self->{repos_root}\E(/|$)##;
        $self->{cache} = { check_path => { r => 0, data => {} },
                           get_dir => { r => 0, data => {} } };

        return $RA;
}

sub url {
        my $self = shift;

        if (@_) {
                my $url = shift;
                $self->{url} = canonicalize_url($url);
                return;
        }

        return $self->{url};
}

sub check_path {
        my ($self, $path, $r) = @_;
        my $cache = $self->{cache}->{check_path};
        if ($r == $cache->{r} && exists $cache->{data}->{$path}) {
                return $cache->{data}->{$path};
        }
        my $pool = SVN::Pool->new;
        my $t = $self->SUPER::check_path($path, $r, $pool);
        $pool->clear;
        if ($r != $cache->{r}) {
                %{$cache->{data}} = ();
                $cache->{r} = $r;
        }
        $cache->{data}->{$path} = $t;
}

sub get_dir {
        my ($self, $dir, $r) = @_;
        my $cache = $self->{cache}->{get_dir};
        if ($r == $cache->{r}) {
                if (my $x = $cache->{data}->{$dir}) {
                        return wantarray ? @$x : $x->[0];
                }
        }
        my $pool = SVN::Pool->new;
        my ($d, undef, $props) = $self->SUPER::get_dir($dir, $r, $pool);
        my %dirents = map { $_ => { kind => $d->{$_}->kind } } keys %$d;
        $pool->clear;
        if ($r != $cache->{r}) {
                %{$cache->{data}} = ();
                $cache->{r} = $r;
        }
        $cache->{data}->{$dir} = [ \%dirents, $r, $props ];
        wantarray ? (\%dirents, $r, $props) : \%dirents;
}

# get_log(paths, start, end, limit,
#         discover_changed_paths, strict_node_history, receiver)
sub get_log {
        my ($self, @args) = @_;
        my $pool = SVN::Pool->new;

        # svn_log_changed_path_t objects passed to get_log are likely to be
        # overwritten even if only the refs are copied to an external variable,
        # so we should dup the structures in their entirety.  Using an
        # externally passed pool (instead of our temporary and quickly cleared
        # pool in Git::SVN::Ra) does not help matters at all...
        my $receiver = pop @args;
        my $prefix = "/".$self->{svn_path};
        $prefix =~ s#/+($)##;
        my $prefix_regex = qr#^\Q$prefix\E#;
        push(@args, sub {
                my ($paths) = $_[0];
                return &$receiver(@_) unless $paths;
                $_[0] = ();
                foreach my $p (keys %$paths) {
                        my $i = $paths->{$p};
                        # Make path relative to our url, not repos_root
                        $p =~ s/$prefix_regex//;
                        my %s = map { $_ => $i->$_; }
                                qw/copyfrom_path copyfrom_rev action/;
                        if ($s{'copyfrom_path'}) {
                                $s{'copyfrom_path'} =~ s/$prefix_regex//;
                                $s{'copyfrom_path'} = canonicalize_path($s{'copyfrom_path'});
                        }
                        $_[0]{$p} = \%s;
                }
                &$receiver(@_);
        });


        # the limit parameter was not supported in SVN 1.1.x, so we
        # drop it.  Therefore, the receiver callback passed to it
        # is made aware of this limitation by being wrapped if
        # the limit passed to is being wrapped.
        if (::compare_svn_version('1.2.0') <= 0) {
                my $limit = splice(@args, 3, 1);
                if ($limit > 0) {
                        my $receiver = pop @args;
                        push(@args, sub { &$receiver(@_) if (--$limit >= 0) });
                }
        }
        my $ret = $self->SUPER::get_log(@args, $pool);
        $pool->clear;
        $ret;
}

sub trees_match {
        my ($self, $url1, $rev1, $url2, $rev2) = @_;
        my $ctx = SVN::Client->new(auth => _auth_providers);
        my $out = IO::File->new_tmpfile;

        # older SVN (1.1.x) doesn't take $pool as the last parameter for
        # $ctx->diff(), so we'll create a default one
        my $pool = SVN::Pool->new_default_sub;

        $ra_invalid = 1; # this will open a new SVN::Ra connection to $url1
        $ctx->diff([], $url1, $rev1, $url2, $rev2, 1, 1, 0, $out, $out);
        $out->flush;
        my $ret = (($out->stat)[7] == 0);
        close $out or croak $!;

        $ret;
}

sub get_commit_editor {
        my ($self, $log, $cb, $pool) = @_;

        my @lock = (::compare_svn_version('1.2.0') >= 0) ? (undef, 0) : ();
        $self->SUPER::get_commit_editor($log, $cb, @lock, $pool);
}

sub gs_do_update {
        my ($self, $rev_a, $rev_b, $gs, $editor) = @_;
        my $new = ($rev_a == $rev_b);
        my $path = $gs->path;

        if ($new && -e $gs->{index}) {
                unlink $gs->{index} or die
                  "Couldn't unlink index: $gs->{index}: $!\n";
        }
        my $pool = SVN::Pool->new;
        $editor->set_path_strip($path);
        my (@pc) = split m#/#, $path;
        my $reporter = $self->do_update($rev_b, (@pc ? shift @pc : ''),
                                        1, $editor, $pool);
        my @lock = (::compare_svn_version('1.2.0') >= 0) ? (undef) : ();

        # Since we can't rely on svn_ra_reparent being available, we'll
        # just have to do some magic with set_path to make it so
        # we only want a partial path.
        my $sp = '';
        my $final = join('/', @pc);
        while (@pc) {
                $reporter->set_path($sp, $rev_b, 0, @lock, $pool);
                $sp .= '/' if length $sp;
                $sp .= shift @pc;
        }
        die "BUG: '$sp' != '$final'\n" if ($sp ne $final);

        $reporter->set_path($sp, $rev_a, $new, @lock, $pool);

        $reporter->finish_report($pool);
        $pool->clear;
        $editor->{git_commit_ok};
}

# this requires SVN 1.4.3 or later (do_switch didn't work before 1.4.3, and
# svn_ra_reparent didn't work before 1.4)
sub gs_do_switch {
        my ($self, $rev_a, $rev_b, $gs, $url_b, $editor) = @_;
        my $path = $gs->path;
        my $pool = SVN::Pool->new;

        my $old_url = $self->url;
        my $full_url = add_path_to_url( $self->url, $path );
        my ($ra, $reparented);

        if ($old_url =~ m#^svn(\+\w+)?://# ||
            ($full_url =~ m#^https?://# &&
             canonicalize_url($full_url) ne $full_url)) {
                $_[0] = undef;
                $self = undef;
                $RA = undef;
                $ra = Git::SVN::Ra->new($full_url);
                $ra_invalid = 1;
        } elsif ($old_url ne $full_url) {
                SVN::_Ra::svn_ra_reparent(
                        $self->{session},
                        canonicalize_url($full_url),
                        $pool
                );
                $self->url($full_url);
                $reparented = 1;
        }

        $ra ||= $self;
        $url_b = canonicalize_url($url_b);
        my $reporter = $ra->do_switch($rev_b, '', 1, $url_b, $editor, $pool);
        my @lock = (::compare_svn_version('1.2.0') >= 0) ? (undef) : ();
        $reporter->set_path('', $rev_a, 0, @lock, $pool);
        $reporter->finish_report($pool);

        if ($reparented) {
                SVN::_Ra::svn_ra_reparent($self->{session}, $old_url, $pool);
                $self->url($old_url);
        }

        $pool->clear;
        $editor->{git_commit_ok};
}

sub longest_common_path {
        my ($gsv, $globs) = @_;
        my %common;
        my $common_max = scalar @$gsv;

        foreach my $gs (@$gsv) {
                my @tmp = split m#/#, $gs->path;
                my $p = '';
                foreach (@tmp) {
                        $p .= length($p) ? "/$_" : $_;
                        $common{$p} ||= 0;
                        $common{$p}++;
                }
        }
        $globs ||= [];
        $common_max += scalar @$globs;
        foreach my $glob (@$globs) {
                my @tmp = split m#/#, $glob->{path}->{left};
                my $p = '';
                foreach (@tmp) {
                        $p .= length($p) ? "/$_" : $_;
                        $common{$p} ||= 0;
                        $common{$p}++;
                }
        }

        my $longest_path = '';
        foreach (sort {length $b <=> length $a} keys %common) {
                if ($common{$_} == $common_max) {
                        $longest_path = $_;
                        last;
                }
        }
        $longest_path;
}

sub gs_fetch_loop_common {
        my ($self, $base, $head, $gsv, $globs) = @_;
        return if ($base > $head);
        my $gpool = SVN::Pool->new_default;
        my $ra_url = $self->url;
        my $reload_ra = sub {
                $_[0] = undef;
                $self = undef;
                $RA = undef;
                $gpool->clear;
                $self = Git::SVN::Ra->new($ra_url);
                $ra_invalid = undef;
        };
        my $inc = $_log_window_size;
        my ($min, $max) = ($base, $head < $base + $inc ? $head : $base + $inc);
        my $longest_path = longest_common_path($gsv, $globs);
        my $find_trailing_edge;
        while (1) {
                my %revs;
                my $err;
                my $err_handler = $SVN::Error::handler;
                $SVN::Error::handler = sub {
                        ($err) = @_;
                        skip_unknown_revs($err);
                };
                sub _cb {
                        my ($paths, $r, $author, $date, $log) = @_;
                        [ $paths,
                          { author => $author, date => $date, log => $log } ];
                }
                $self->get_log([$longest_path], $min, $max, 0, 1, 1,
                               sub { $revs{$_[1]} = _cb(@_) });
                if ($err) {
                        print "Checked through r$max\r";
                } else {
                        $find_trailing_edge = 1;
                }
                if ($err and $find_trailing_edge) {
                        print STDERR "Path '$longest_path' ",
                                     "was probably deleted:\n",
                                     $err->expanded_message,
                                     "\nWill attempt to follow ",
                                     "revisions r$min .. r$max ",
                                     "committed before the deletion\n";
                        my $hi = $max;
                        while (--$hi >= $min) {
                                my $ok;
                                $self->get_log([$longest_path], $min, $hi,
                                               0, 1, 1, sub {
                                               $ok = $_[1];
                                               $revs{$_[1]} = _cb(@_) });
                                if ($ok) {
                                        print STDERR "r$min .. r$ok OK\n";
                                        last;
                                }
                        }
                        $find_trailing_edge = 0;
                }
                $SVN::Error::handler = $err_handler;

                my %exists = map { $_->path => $_ } @$gsv;
                foreach my $r (sort {$a <=> $b} keys %revs) {
                        my ($paths, $logged) = @{delete $revs{$r}};

                        foreach my $gs ($self->match_globs(\%exists, $paths,
                                                           $globs, $r)) {
                                if ($gs->rev_map_max >= $r) {
                                        next;
                                }
                                next unless $gs->match_paths($paths, $r);
                                $gs->{logged_rev_props} = $logged;
                                if (my $last_commit = $gs->last_commit) {
                                        $gs->assert_index_clean($last_commit);
                                }
                                my $log_entry = $gs->do_fetch($paths, $r);
                                if ($log_entry) {
                                        $gs->do_git_commit($log_entry);
                                }
                                $Git::SVN::INDEX_FILES{$gs->{index}} = 1;
                        }
                        foreach my $g (@$globs) {
                                my $k = "svn-remote.$g->{remote}." .
                                        "$g->{t}-maxRev";
                                Git::SVN::tmp_config($k, $r);
                        }
                        $reload_ra->() if $ra_invalid;
                }
                # pre-fill the .rev_db since it'll eventually get filled in
                # with '0' x40 if something new gets committed
                foreach my $gs (@$gsv) {
                        next if $gs->rev_map_max >= $max;
                        next if defined $gs->rev_map_get($max);
                        $gs->rev_map_set($max, 0 x40);
                }
                foreach my $g (@$globs) {
                        my $k = "svn-remote.$g->{remote}.$g->{t}-maxRev";
                        Git::SVN::tmp_config($k, $max);
                }
                last if $max >= $head;
                $min = $max + 1;
                $max += $inc;
                $max = $head if ($max > $head);

                $reload_ra->();
        }
        Git::SVN::gc();
}

sub get_dir_globbed {
        my ($self, $left, $depth, $r) = @_;

        my @x = eval { $self->get_dir($left, $r) };
        return unless scalar @x == 3;
        my $dirents = $x[0];
        my @finalents;
        foreach my $de (keys %$dirents) {
                next if $dirents->{$de}->{kind} != $SVN::Node::dir;
                if ($depth > 1) {
                        my @args = ("$left/$de", $depth - 1, $r);
                        foreach my $dir ($self->get_dir_globbed(@args)) {
                                push @finalents, "$de/$dir";
                        }
                } else {
                        push @finalents, $de;
                }
        }
        @finalents;
}

# return value: 0 -- don't ignore, 1 -- ignore
sub is_ref_ignored {
        my ($g, $p) = @_;
        my $refname = $g->{ref}->full_path($p);
        return 1 if defined($g->{ignore_refs_regex}) &&
                    $refname =~ m!$g->{ignore_refs_regex}!;
        return 0 unless defined($_ignore_refs_regex);
        return 1 if $refname =~ m!$_ignore_refs_regex!o;
        return 0;
}

sub match_globs {
        my ($self, $exists, $paths, $globs, $r) = @_;

        sub get_dir_check {
                my ($self, $exists, $g, $r) = @_;

                my @dirs = $self->get_dir_globbed($g->{path}->{left},
                                                  $g->{path}->{depth},
                                                  $r);

                foreach my $de (@dirs) {
                        my $p = $g->{path}->full_path($de);
                        next if $exists->{$p};
                        next if (length $g->{path}->{right} &&
                                 ($self->check_path($p, $r) !=
                                  $SVN::Node::dir));
                        next unless $p =~ /$g->{path}->{regex}/;
                        $exists->{$p} = Git::SVN->init($self->url, $p, undef,
                                         $g->{ref}->full_path($de), 1);
                }
        }
        foreach my $g (@$globs) {
                if (my $path = $paths->{"/$g->{path}->{left}"}) {
                        if ($path->{action} =~ /^[AR]$/) {
                                get_dir_check($self, $exists, $g, $r);
                        }
                }
                foreach (keys %$paths) {
                        if (/$g->{path}->{left_regex}/ &&
                            !/$g->{path}->{regex}/) {
                                next if $paths->{$_}->{action} !~ /^[AR]$/;
                                get_dir_check($self, $exists, $g, $r);
                        }
                        next unless /$g->{path}->{regex}/;
                        my $p = $1;
                        my $pathname = $g->{path}->full_path($p);
                        next if is_ref_ignored($g, $p);
                        next if $exists->{$pathname};
                        next if ($self->check_path($pathname, $r) !=
                                 $SVN::Node::dir);
                        $exists->{$pathname} = Git::SVN->init(
                                              $self->url, $pathname, undef,
                                              $g->{ref}->full_path($p), 1);
                }
                my $c = '';
                foreach (split m#/#, $g->{path}->{left}) {
                        $c .= "/$_";
                        next unless ($paths->{$c} &&
                                     ($paths->{$c}->{action} =~ /^[AR]$/));
                        get_dir_check($self, $exists, $g, $r);
                }
        }
        values %$exists;
}

sub minimize_url {
        my ($self) = @_;
        return $self->url if ($self->url eq $self->{repos_root});
        my $url = $self->{repos_root};
        my @components = split(m!/!, $self->{svn_path});
        my $c = '';
        do {
                $url = add_path_to_url($url, $c);
                eval {
                        my $ra = (ref $self)->new($url);
                        my $latest = $ra->get_latest_revnum;
                        $ra->get_log("", $latest, 0, 1, 0, 1, sub {});
                };
        } while ($@ && ($c = shift @components));

        return canonicalize_url($url);
}

sub can_do_switch {
        my $self = shift;
        unless (defined $can_do_switch) {
                my $pool = SVN::Pool->new;
                my $rep = eval {
                        $self->do_switch(1, '', 0, $self->url,
                                         SVN::Delta::Editor->new, $pool);
                };
                if ($@) {
                        $can_do_switch = 0;
                } else {
                        $rep->abort_report($pool);
                        $can_do_switch = 1;
                }
                $pool->clear;
        }
        $can_do_switch;
}

sub skip_unknown_revs {
        my ($err) = @_;
        my $errno = $err->apr_err();
        # Maybe the branch we're tracking didn't
        # exist when the repo started, so it's
        # not an error if it doesn't, just continue
        #
        # Wonderfully consistent library, eh?
        # 160013 - svn:// and file://
        # 175002 - http(s)://
        # 175007 - http(s):// (this repo required authorization, too...)
        #   More codes may be discovered later...
        if ($errno == 175007 || $errno == 175002 || $errno == 160013) {
                my $err_key = $err->expanded_message;
                # revision numbers change every time, filter them out
                $err_key =~ s/\d+/\0/g;
                $err_key = "$errno\0$err_key";
                unless ($ignored_err{$err_key}) {
                        warn "W: Ignoring error from SVN, path probably ",
                             "does not exist: ($errno): ",
                             $err->expanded_message,"\n";
                        warn "W: Do not be alarmed at the above message ",
                             "git-svn is just searching aggressively for ",
                             "old history.\n",
                             "This may take a while on large repositories\n";
                        $ignored_err{$err_key} = 1;
                }
                return;
        }
        die "Error from SVN, ($errno): ", $err->expanded_message,"\n";
}

1;
__END__

=head1 NAME

Git::SVN::Ra - Subversion remote access functions for git-svn

=head1 SYNOPSIS

    use Git::SVN::Ra;

    my $ra = Git::SVN::Ra->new($branchurl);
    my ($dirents, $fetched_revnum, $props) =
        $ra->get_dir('.', $SVN::Core::INVALID_REVNUM);

=head1 DESCRIPTION

This is a wrapper around the L<SVN::Ra> module for use by B<git-svn>.
It fills in some default parameters (such as the authentication
scheme), smooths over incompatibilities between libsvn versions, adds
caching, and implements some functions specific to B<git-svn>.

Do not use it unless you are developing git-svn.  The interface will
change as git-svn evolves.

=head1 DEPENDENCIES

Subversion perl bindings,
L<Git::SVN>.

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

=head1 SEE ALSO

L<SVN::Ra>.

=head1 INCOMPATIBILITIES

None reported.

=head1 BUGS

None.