#!/usr/bin/perl
# ------------------------------------------------------------------------------
# (C) Crown copyright Met Office. All rights reserved.
# For further details please refer to the file COPYRIGHT.txt
# which you should have received as part of this distribution.
# ------------------------------------------------------------------------------

use strict;
use warnings;

use FindBin;
use lib "$FindBin::Bin/../lib";
use File::Basename qw{basename};
use File::Spec;
use Pod::Usage qw{pod2usage};

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_html2pdf
    run_mkpath
    run_rmtree
    run_svn_info
    run_svn_update
    write_file
};

# ------------------------------------------------------------------------------
my $CONFIG = FCM::Admin::Config->instance();
my %PATTERN_OF = (
    q{}             => qr{.*}xms,
    DOC_COLLAB      => qr{doc/collaboration/}xms,
    DOC_STD_FORTRAN => qr{doc/standards/fortran_standard\.html}xms,
    DOC_STD_PERL    => qr{doc/standards/perl_standard\.html}xms,
    DOC_UG          => qr{doc/user_guide/}xms,
    SRC             => qr{(?:bin|etc|lib|man)/}xms,
    SRC_HOOK        => qr{svn-hooks/}xms,
);

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

# ------------------------------------------------------------------------------
# The main logic.
sub main {
    if (@_ != 2) {
        my $message = sprintf(qq{Expect 2 arguments, %d given}, scalar(@_));
        pod2usage({q{-exitval} => 1, q{-message} => $message});
    }
    my ($repos_name, $log_dir_path) = @_;
    create_lock($repos_name, $log_dir_path) || return;
    my $RUNNER = FCM::Admin::Runner->instance();
    UPDATE:
    while (1) {
        my @updates_in_fcm   = run_svn_update($CONFIG->get_fcm_wc());
        my @updates_in_admin = run_svn_update($CONFIG->get_fcm_admin_wc());
        if (!@updates_in_fcm && !@updates_in_admin) {
            last UPDATE;
        }
        for my $task ((
            {
                name => '(re-)installing hook scripts',
                main => sub {
                    for my $project (get_projects_from_svn_live()) {
                        install_svn_hook($project);
                    }
                    return 1;
                },
                want => get_pattern_grepper('SRC_HOOK', 1), # in "Admin"
            },
            {
                name => 'updating FCM release number file',
                main => sub {
                    my $root = $CONFIG->get_fcm_wc();
                    write_file(
                        File::Spec->catfile($root, qw{etc fcm_rev}),
                        run_svn_info($root)->last_changed_rev(),
                    );
                },
                want => get_pattern_grepper(q{}),
            },
            {
                name => 'generating PDF for the user guide',
                main => get_fcm_html2pdf('user_guide', 'user-guide'),
                want => get_pattern_grepper('DOC_UG'),
            },
            {
                name => 'generating PDF for the collaboration guide',
                main => get_fcm_html2pdf('collaboration', 'collaboration'),
                want => get_pattern_grepper('DOC_COLLAB'),
            },
            {
                name => 'generating PDF for the FCM Fortran Standard document',
                main => get_fcm_html2pdf(
                    'standards', 'fortran-standard', 'fortran_standard',
                ),
                want => get_pattern_grepper('DOC_STD_FORTRAN'),
            },
            {
                name => 'generating PDF for the FCM Perl Standard document',
                main => get_fcm_html2pdf(
                    'standards', 'perl-standard', 'perl_standard',
                ),
                want => get_pattern_grepper('DOC_STD_PERL'),
            },
            {
                name => 'distributing FCM to standard locations',
                main => \&distribute_wc,
                want => get_pattern_grepper('SRC'),
            },
        )) {
            if ($task->{want}->(\@updates_in_fcm, \@updates_in_admin)) {
                $RUNNER->run($task->{name}, $task->{main});
            }
        }
    }
}

# ------------------------------------------------------------------------------
# Returns a wrapper of run_html2pdf, base on the relative $path in the doc/
# sub-directory of the central FCM working copy pointing to the container
# directory of the input and output.
sub get_fcm_html2pdf {
    my ($path, $name_of_output, $name_of_input) = @_;
    my $container = File::Spec->catfile($CONFIG->get_fcm_wc(), 'doc', $path);
    my $input = File::Spec->catfile(
        $container, ($name_of_input ? $name_of_input : 'index') . '.html',
    );
    my $output = File::Spec->catfile($container, "fcm-$name_of_output.pdf");
    return sub {run_html2pdf($input, $output)};
}

# ------------------------------------------------------------------------------
# Returns a function that "grep" for a known pattern ($pattern_key). The
# returned function expects a list reference in the $index'th (default = 0)
# element of its argument list.
sub get_pattern_grepper {
    my ($pattern_key, $index) = @_;
    if (!defined($index)) {
        $index = 0;
    }
    return sub {grep({$_ =~ $PATTERN_OF{$pattern_key}} @{$_[$index]})};
}

# ------------------------------------------------------------------------------
# Creates a lock. Returns true on success. Removes lock when program finishes.
sub create_lock {
    my ($repos_name, $log_dir_path) = @_;
    my $lock = File::Spec->catfile($log_dir_path, $repos_name . '.lock');
    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 REPOS-NAME LOG-DIR-PATH

=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 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