package Local::Util::Git;

# Copyright (C) 2019 Sean Whitton
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or (at
# your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.


# Probably best if this module has no non-core dependencies.

use strict;
use warnings;

use Exporter 'import';

our @EXPORT_OK = qw(unpushed_tags);

sub unpushed_tags {
    my ($dir) = shift;

    my $git = "git";
    $git .= " -C $dir" if defined $dir;

    # allow skipping this check on a whole repo
    chomp(my $ignore =
          `$git config --get --type=bool spwhitton.unpushed-tags.ignore`);
    return () if $ignore eq 'true';

    # archive/debian/foo tags are pushed only to dgit repos in split
    # brain mode.  Also, it is highly unlikely they don't get pushed
    # there, so we aren't going to check.  We probably don't want to
    # ls-remote dgit-repos because that's not really a supported API
    # (note that dgit doesn't create an origin remote pointing to
    # dgit-repos anymore)
    #
    # We also ignore a debian/foo tag where the corresponding
    # archive/debian/foo tag exists, because that means the former has
    # been pushed to dgit repos
    chomp(my @all_tags = `$git tag`);
    die "failed to get git tags" unless ($? == 0);
    my @tags;
    my %dgit_archive_tags;
    for (@all_tags) {
        if (m|^archive/debian/|) {
            $dgit_archive_tags{$_} = undef;
        } else {
            push @tags, $_;
        }
    }
    @tags
      = grep { !(m|^debian/| and exists $dgit_archive_tags{"archive/$_"}) }
      @tags;

    chomp(my @remotes = `$git remote`);
    die "failed to get git remotes" unless ($? == 0);
    @remotes = grep !/\A(dgit|develacc)\z/, @remotes;

    my %pushed_tags;
    foreach my $remote (@remotes) {
        # allow skipping remotes which don't like 'ls-remote'
        # TODO replace with an spwhitton.unpushed-tags.skip-remotes key ?
        # chomp(my $ignore =
        #       `$git config --get --type=bool remote.$remote.unpushed-tags-ignore`);
        # next if $ignore eq 'true';

        # remotes without URIs are probably git-annex special remotes; skip them
        `$git config --local --get remote.$remote.url`;
        next unless $? == 0;

        chomp(my @ls_remote = `$git ls-remote --tags $remote`);
        die "failed to list git remote $remote" unless ($? == 0);
        $pushed_tags{$_} = undef
          for map { m|^[0-9a-f]+\s+refs/tags/([^^]+)|; $1 // () } @ls_remote;
    }

    return grep { ! exists $pushed_tags{$_} } @tags;
}

1;