package Developer::Dashboard::UpdateManager;
$Developer::Dashboard::UpdateManager::VERSION = '0.94';
use strict;
use warnings;

use Capture::Tiny qw(capture);
use Cwd qw(cwd);
use File::Basename qw(dirname);
use File::Spec;
use FindBin qw($Bin);

# new(%args)
# Constructs the updater coordinator.
# Input: config, files, paths, and runner objects.
# Output: Developer::Dashboard::UpdateManager object.
sub new {
    my ( $class, %args ) = @_;
    my $config = $args{config} || die 'Missing config';
    my $files  = $args{files}  || die 'Missing file registry';
    my $paths  = $args{paths}  || die 'Missing path registry';
    my $runner = $args{runner} || die 'Missing collector runner';

    return bless {
        config => $config,
        files  => $files,
        paths  => $paths,
        runner => $runner,
    }, $class;
}

# updates_dir()
# Returns the directory containing updater scripts.
# Input: none.
# Output: directory path string.
sub updates_dir {
    my ($self) = @_;
    return File::Spec->catdir( cwd(), 'updates' );
}

# run()
# Executes update scripts in order while stopping and restarting managed collectors.
# Input: none.
# Output: array reference of update step result hashes.
sub run {
    my ($self) = @_;

    my @running = $self->_running_collectors;
    $self->_stop_collectors(@running);

    my @results;
    my $dir = $self->updates_dir;

    opendir my $dh, $dir or die "Unable to open updates directory $dir: $!";
    for my $file ( sort readdir $dh ) {
        next if $file eq '.' || $file eq '..';
        next if !-f File::Spec->catfile( $dir, $file );

        my $path = File::Spec->catfile( $dir, $file );
        my @cmd;

        if ( $file =~ /\.pl$/ ) {
            @cmd = ( $^X, $path );
        }
        elsif ( $file =~ /\.sh$/ ) {
            @cmd = ( 'sh', $path );
        }
        else {
            next;
        }

        print "-" x 40, "\n";
        print ">> Run Update: $file...\n";
        print "-" x 40, "\n";
        print ">> @cmd\n";
        print "-" x 40, "\n";

        my ( $stdout, $stderr, $exit_code ) = capture {
            system @cmd;
            return $? >> 8;
        };
        my $output = $stdout . $stderr;

        print $output if defined $output && $output ne '';
        print "\n>> Finished.\n\n";

        push @results, {
            file      => $file,
            exit_code => $exit_code,
            output    => $output,
        };
    }
    closedir $dh;

    $self->_restart_collectors(@running);

    return \@results;
}

# _running_collectors()
# Returns the list of currently running managed collectors.
# Input: none.
# Output: list of collector name strings.
sub _running_collectors {
    my ($self) = @_;
    return map { $_->{name} } $self->{runner}->running_loops;
}

# _stop_collectors(@names)
# Stops the named managed collectors.
# Input: list of collector name strings.
# Output: none.
sub _stop_collectors {
    my ( $self, @names ) = @_;
    for my $name (@names) {
        eval { $self->{runner}->stop_loop($name) };
    }
}

# _restart_collectors(@wanted)
# Restarts configured collectors that were previously running and are still desired.
# Input: list of collector name strings.
# Output: none.
sub _restart_collectors {
    my ( $self, @names ) = @_;
    return if !@names;

    my %wanted = map { $_ => 1 } @names;
    my @jobs = @{ $self->{config}->collectors };

    for my $job (@jobs) {
        next if ref($job) ne 'HASH';
        next if !$wanted{ $job->{name} };
        eval { $self->{runner}->start_loop($job) };
    }
}

1;

__END__

=head1 NAME

Developer::Dashboard::UpdateManager - managed update runner

=head1 SYNOPSIS

  my $updater = Developer::Dashboard::UpdateManager->new(...);
  my $steps = $updater->run;

=head1 DESCRIPTION

This module executes repository update scripts while coordinating managed
collector shutdown and restart around the update process.

=head1 METHODS

=head2 new, updates_dir, run

Construct and execute dashboard updates.

=cut
