#!/usr/bin/perl
# ------------------------------------------------------------------------------
# (C) British Crown Copyright 2006-16 Met Office.
#
# This file is part of FCM, tools for managing and building source code.
#
# FCM 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.
#
# FCM 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 FCM. If not, see <http://www.gnu.org/licenses/>.
# ------------------------------------------------------------------------------

use strict;
use warnings;

use FindBin;
use lib "$FindBin::Bin/../lib";
use File::Basename qw{basename};
use File::Spec;

use FCM::Admin::Config;
use FCM::Admin::Runner;
use FCM::Admin::System qw{
    distribute_wc
    filter_projects
    get_projects_from_svn_live
    install_svn_hook
};
use FCM::Admin::Util qw{
    run_mkpath
    run_rmtree
    run_svn_info
    run_svn_update
    write_file
};
use Getopt::Long qw{GetOptions};
use Pod::Usage qw{pod2usage};
use Text::ParseWords qw{shellwords};

# ------------------------------------------------------------------------------
my $CONFIG = FCM::Admin::Config->instance();
my %PATTERN_OF = (
    q{}      => qr{.*}xms,
    SRC_HOOK => qr{svn-hooks/}xms,
);

if (!caller()) {
    main(@ARGV);
}

# ------------------------------------------------------------------------------
# The main logic.
sub main {
    local(@ARGV) = @_;
    my %option;
    my $result = GetOptions(
        \%option,
        q{help|usage|h},
        q{force},
    );
    if (!$result) {
        pod2usage(1);
    }
    if (exists($option{help})) {
        pod2usage(q{-verbose} => 1);
    }
    create_lock() || return;
    my $RUNNER = FCM::Admin::Runner->instance();
    my $is_force = $option{'force'};
    UPDATE:
    while (1) {
        my @updates;
        for my $source_key (shellwords($CONFIG->get_mirror_keys())) {
            my $method = "get_$source_key";
            push(@updates, run_svn_update($CONFIG->$method()));
        }
        if (!$is_force && !@updates) {
            last UPDATE;
        }
        if ($is_force || grep {$_ =~ $PATTERN_OF{'SRC_HOOK'}} @updates) {
            $RUNNER->run(
                '(re-)installing hook scripts',
                sub {
                    for my $project (get_projects_from_svn_live()) {
                        install_svn_hook($project);
                    }
                    return 1;
                }
            );
        }
        if ($is_force || grep {$_ =~ $PATTERN_OF{q{}}} @updates) {
            $RUNNER->run(
                'distributing FCM to standard locations', \&distribute_wc);
        }
        $is_force = 0;
    }
}

# ------------------------------------------------------------------------------
# Creates a lock. Returns true on success. Removes lock when program finishes.
our $LOCK;
sub create_lock {
    my $home = (getpwuid($<))[7];
    $LOCK = File::Spec->catfile($home, sprintf(".%s.lock", basename($0)));
    if (-e $LOCK) {
        $LOCK = undef;
        return;
    }
    return run_mkpath($LOCK);
    END {
        if ($LOCK) {
            run_rmtree($LOCK);
        }
    }
}

__END__

=head1 NAME

fcm-commit-update

=head1 SYNOPSIS

    fcm-commit-update

=head1 DESCRIPTION

This program performs the post-commit update for the FCM system. It runs
continuously until no more update is available. It prevent another copy from
running by creating a lock. If another copy detects a lock, it exits without
doing anything.

=head1 OPTIONS

=over 4

=item --force

Force an update.

=back

=head1 ARGUMENTS

=over 4

=item REPOS-NAME

The name of the repository invoking this program.

=item LOG-DIR-PATH

The path to the log directory.

=back

=head1 COPYRIGHT

E<169> Crown copyright Met Office. All rights reserved.

=cut
