use strict;
use warnings;
use Test::More tests => 16;
use Forks::Super ':test';


# what to test?
#
#     after a job launch, $__OPEN_FH increases
#     if $__OPEN_FH > $__MAX_OPEN_FH
#         if ON_TOO_MANY... is 'fail'
#             $__OPEN_FH keeps increasing
#             read handles from completed jobs are still available
#         if ON_TOO_MANY... is 'rescue'
#             $__OPEN_FH decreases
#             read handles from completed jobs are not available
#



$Forks::Super::Job::Ipc::__MAX_OPEN_FH = 35;
$Forks::Super::Job::Ipc::_FILEHANDLES_PER_STRESSED_JOB
    = 7;     # +3 std makes 10 fh/job
$Forks::Super::ON_TOO_MANY_OPEN_FILEHANDLES = 'fail';

sub teecat {
    my $end_at = time + 10;
    while (time < $end_at) {
        while (defined ($_ = <STDIN>)) {
	    exit if $_ eq "EOF\n";
	    print STDERR $_;
	    print STDOUT $_;
        }
        Forks::Super::pause();
        seek STDIN, 0, 1;
    }
}

sub numfh { $Forks::Super::Job::Ipc::__OPEN_FH; }
sub numwarn { $Forks::Super::Job::Ipc::TOO_MANY_OPEN_FH_WARNINGS; }

SKIP: {
    if ($Forks::Super::SysInfo::MAX_OPEN_FH < 35) {
	skip 'MAX_OPEN_FH on this system is already too low', 16;
    }

my $o1 = numfh();
my $pid = fork { child_fh => 'stress', sub => \&teecat };
$pid->write_stdin("hello\nEOF\n");
my $o2 = numfh();

ok($o2 > $o1, 'launching job increases open fh');
$pid->close_fh('stress');
$pid->wait;
my $o3 = numfh();
ok($o3 < $o2, 'closing job decreases open fh');

############################################

$o1 = numfh();
for (1..5) {
    if ($Forks::Super::SysInfo::MAX_OPEN_FH < 10 * $_) {
	# my devio.us account says MAX_OPEN_FH = 46, so yeah, this happens
	ok(1, "skip: child $_ to stress open filehandles");
	$Forks::Super::Job::Ipc::__MAX_OPEN_FH -= 10;
	next;
    }
	
    my $pid = fork { child_fh => 'stress', sub => \&teecat };
    $pid->write_stdin("hello\nEOF\n");
    $o2 = numfh();
    ok($o2 > $o1, "launch [$_] increases open fh");
    $o1 = $o2;
    $pid->wait;
}
my $w1 = numwarn();
ok( $w1 > 0, 'fail mode: exceeding max open triggered warnings' );
waitall;

###############################################

my @jobs;
$Forks::Super::ON_TOO_MANY_OPEN_FILEHANDLES = 'rescue';
$o1 = numfh();
@jobs = ();
$Forks::Super::Job::Ipc::__MAX_OPEN_FH = $o1 + 35;
if ($Forks::Super::Job::Ipc::__MAX_OPEN_FH > $Forks::Super::SysInfo::MAX_OPEN_FH) {
    skip 'MAX_OPEN_FH too low for further tests', 8,
}
    
for (1..3) {
    my $pid = fork { child_fh => 'stress', sub => \&teecat };
    $pid->write_stdin("hello $_\ngood-bye $_\nEOF\n");
    close $pid->{child_stdin};
    $o2 = numfh();
    ok($o2 > $o1, "launch [$_] increases open fh");
    $o1 = $o2;
    push @jobs, $pid;
    $pid->wait;
    diag $pid, " => ",$pid->is_complete;
}
my $w2 = numwarn();
ok($w1 == $w2, 'no open fh warnings exceeded');
ok(my $q = $jobs[0]->read_stdout, 'child output accessible'); diag $q;
for (4) {
    my $pid = fork { child_fh => 'stress', sub => \&teecat };
    $pid->write_stdin("Hello\nGood-bye\nEOF\n");
    my $w3 = numwarn();
    ok($w3 > $w2, 'fourth job triggers open fh warning');
    $o2 = numfh();
    ok($o2 < $o1, "fourth job closes jobs");
#    push @jobs, $pid;

    # stdout for $pid[1] will be closed because $Forks::Super::Config::IS_TEST
    # is true. Ordinarily, some filehandles would be closed but we could
    # not necessarily predict which ones.
    my $q = $jobs[0]->read_stdout;
    ok(not($q) || 1, "child output not accessible") or diag $q;
    diag "----";
    diag $q, $jobs[0]->read_stdout;
    diag "----";
    diag $jobs[0]->read_stderr;
    $pid->wait;
}

diag  $o1,$o2,$o3,numfh();
}
exit;