use warnings;
use strict;

=head1 NAME

BarnOwl::Module::ShellFilter

=head1 DESCRIPTION

filter text through a shell command

=cut

package BarnOwl::Module::ShellFilter;
use POSIX;
use BarnOwl::Editwin qw(move_to_line_start move_to_line_end move_to_buffer_start move_to_buffer_end replace_region delete_prev_char set_mark get_region);
use IPC::Open2;

our $VERSION = 0.2;

sub shell_filter {
	shift;
	# warning leftover from Digraphs:
	# There exist things that, if you do them inside save_excursion, cause a segfault?
	move_to_buffer_start();
	set_mark();
	move_to_buffer_end();
	my $input_text = get_region();

	# psychotic haxx from random corners of Google to try to make sure shell
	# commands that hang don't bring BarnOwl down with them:
	# http://www.perlmonks.org/?node_id=309205
	my $output_text;
	my $diestr;
	eval {
		local $SIG{ALRM} = sub { die "timed out" };
		alarm(8); # time out in 8 seconds
		my $pid = open2(my $child_out, my $child_in, @_);
		print $child_in $input_text;
		close $child_in;

		# weird idiom to read all output:
		$output_text = do { local $/ = undef; <$child_out> };
		close $child_out;
		waitpid( $pid, 0 );
		my $child_exit_status = $? >> 8;
		die "exited with status $child_exit_status" if $child_exit_status;
		$diestr = $@ if $@; # string from dying
		alarm(0);
	};
	$diestr = $@ if $@; # string from dying
	alarm(0);
	if (!defined($diestr) && defined($output_text)) {
		replace_region($output_text);
	} else {
		BarnOwl::message("shell-filter error: $diestr");
	}
}

BarnOwl::new_command('shell-filter' => \&shell_filter, {
		summary => "Filter text through a shell command",
		usage   => "shell-filter CMD",
		description => "Filter text through a shell command",
	});

1;