package Test::Stream::Plugin::Grab;
use strict;
use warnings;

use Test::Stream::Sync;
use Test::Stream::DebugInfo;
use Test::Stream::Hub::Interceptor;

use Test::Stream::Exporter;
default_export grab => sub { __PACKAGE__->new };
no Test::Stream::Exporter;

my $STACK = Test::Stream::Sync->stack;

use Test::Stream::HashBase(
    accessors => [qw/hub finished _events term_size/],
);

sub init {
    my $self = shift;

    my $ipc;
    if ($INC{'Test/Stream/IPC.pm'}) {
        my ($driver) = Test::Stream::IPC->drivers;
        $ipc = $driver->new;
    }

    $self->{+HUB} = Test::Stream::Hub::Interceptor->new(
        ipc => $ipc,
        no_ending => 1,
    );

    my @events;
    $self->{+HUB}->listen(sub { push @events => $_[1] });

    $self->{+_EVENTS} = \@events;

    $STACK->top(); # Make sure there is a top hub before we begin.
    $STACK->push($self->{+HUB});

    $self->{+TERM_SIZE} = $ENV{TS_TERM_SIZE};
    $ENV{TS_TERM_SIZE} = 80;
}

sub flush {
    my $self = shift;
    my $out = [@{$self->{+_EVENTS}}];
    @{$self->{+_EVENTS}} = ();
    return $out;
}

sub events {
    my $self = shift;
    # Copy
    return [@{$self->{+_EVENTS}}];
}

sub finish {
    my ($self) = @_; # Do not shift;
    $_[0] = undef;

    if (defined $self->{+TERM_SIZE}) {
        $ENV{TS_TERM_SIZE} = $self->{+TERM_SIZE};
    }
    else {
        delete $ENV{TS_TERM_SIZE};
    }

    my $hub = $self->{+HUB};

    $self->{+FINISHED} = 1;
    $STACK->pop($hub);

    my $dbg = Test::Stream::DebugInfo->new(
        frame => [caller(0)],
    );
    $hub->finalize($dbg, 1)
        if !$hub->no_ending
        && !$hub->state->ended;

    return $self->flush;
}

sub DESTROY {
    my $self = shift;
    return if $self->{+FINISHED};
    $STACK->pop($self->{+HUB});
}

1;

__END__

=pod

=encoding UTF-8

=head1 NAME

Test::Stream::Plugin::Grab - Object used to temporarily intercept all events.

=head1 DESCRIPTION

Once created this object will intercept and stash all events sent to the shared
L<Test::Stream::Hub> object. Once the object is destroyed events will once
again be sent to the shared hub.

=head1 SYNOPSIS

    use Test::Stream qw/-V1 Grab/;

    my $grab = grab();

    # Generate some events, they are intercepted.
    ok(1, "pass");
    ok(0, "fail");

    my $events_a = $grab->flush;

    # Generate some more events, they are intercepted.
    ok(1, "pass");
    ok(0, "fail");

    # Same as flush, except it destroys the grab object.
    my $events_b = $grab->finish;

After calling C<finish()> the grab object is destroyed and C<$grab> is set to
undef. C<$events_a> is an arrayref with the first 2 events. C<$events_b> is an
arrayref with the second 2 events.

=head1 EXPORTS

=item $grab = grab()

This lets you intercept all events for a section of code without adding
anything to your call stack. This is useful for things that are sensitive to
changes in the stack depth.

    my $grab = grab();
        ok(1, 'foo');
        ok(0, 'bar');

    # $grab is magically undef after this.
    my $events = $grab->finish;

    is(@$events, 2, "grabbed 2 events.");

When you call C<finish()> the C<$grab> object will automagically undef itself,
but only for the reference used in the method call. If you have other
references to the C<$grab> object they will not be undef'd.

If the C<$grab> object is destroyed without calling C<finish()>, it will
automatically clean up after itself and restore the parent hub.

    {
        my $grab = grab();
        # Things are grabbed
    }
    # Things are back to normal

By default the hub used has C<no_ending> set to true. This will prevent the hub
from enforcing that you issued a plan and ran at least 1 test. You can turn
enforcement back one like this:

    $grab->hub->set_no_ending(0);

With C<no_ending> turned off, C<finish> will run the post-test checks to
enforce the plan and that tests were run. In many cases this will result in
additional events in your events array.

=head1 METHODS

=over 4

=item $grab = $class->new()

Create a new grab object, immediately starts intercepting events.

=item $ar = $grab->flush()

Get an arrayref of all the events so far, clearing the grab objects internal
list.

=item $ar = $grab->events()

Get an arrayref of all events so far, does not clear the internal list.

=item $ar = $grab->finish()

Get an arrayref of all the events, then destroy the grab object.

=item $hub = $grab->hub()

Get the hub that is used by the grab event.

=back

=head1 ENDING BEHAVIOR

By default the hub used has C<no_ending> set to true. This will prevent the hub
from enforcing that you issued a plan and ran at least 1 test. You can turn
enforcement back one like this:

    $grab->hub->set_no_ending(0);

With C<no_ending> turned off, C<finish> will run the post-test checks to
enforce the plan and that tests were run. In many cases this will result in
additional events in your events array.

=head1 SEE ALSO

L<Test::Stream::Plugin::Intercept> - Accomplish the same thing, but using
blocks instead.

=head1 SOURCE

The source code repository for Test::Stream can be found at
F<http://github.com/Test-More/Test-Stream/>.

=head1 MAINTAINERS

=over 4

=item Chad Granum E<lt>exodist@cpan.orgE<gt>

=back

=head1 AUTHORS

=over 4

=item Chad Granum E<lt>exodist@cpan.orgE<gt>

=back

=head1 COPYRIGHT

Copyright 2015 Chad Granum E<lt>exodist7@gmail.comE<gt>.

This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

See F<http://www.perl.com/perl/misc/Artistic.html>

=cut
