#!/bin/bash
set -e
set -o pipefail

cpus='0 1'

uid=`id -u`
cd /var/run/user/$uid
mkdir -p version-charset-test
cd version-charset-test

stunt=stunt$1
rm -rf $stunt
mkdir $stunt
cd $stunt

for cpu in $cpus; do
	mkdir c$cpu
	(cd c$cpu
	 git init -q)
done

#exec 3<&0 </dev/null

#git commit --allow-empty -m 'Test object'
#head=`git rev-parse HEAD`

#exec <&3 3<&-

perl -we '
    use strict;

    our $file;
    our $count;
    our $batch=0;
    our $total=0;
    our @tasks;

    my @freecpus = qw('"$cpus"');

    print STDERR "check using cpus @freecpus\n";

    sub await_task () {
	my ($pid, $cpu, $oldbatch) = @{ shift @tasks };
	waitpid $pid, 0 == $pid or die $!;
	die "$oldbatch $?" if $?;
	unlink "b$oldbatch" or die "$oldbatch $!";
#        print STDERR "check completed $oldbatch [$pid] #$cpu\n";
	push @freecpus, $cpu;
    }

    sub complete_batch () {
        return unless $file;

	close $file or die $!;

#        print STDERR "check closing $batch ($count)\n";

	await_task unless @freecpus;

	my $cpu = shift @freecpus;

	my $pid = fork // die $!;
	if (!$pid) {
	    close STDIN;
#            seek STDIN,0,1;
#            flush STDIN;
	    open STDIN, "<", "b$batch" or die $batch;
	    chdir "c$cpu" or die "$cpu $!";
	    exec qw(eatmydata git update-ref --stdin);
	    die $!;
	}
#        print STDERR "check spawned $batch ($count) [$pid] #$cpu\n";
    	push @tasks, [ $pid, $cpu, $batch ];
	$batch++;
	$file = undef;
	$total += $count;
	$count = 0;
    }

    while (<>) {
#print STDERR ">$_<\n";
        $file ||= new IO::File "b$batch", ">" or die $!;
        chomp;
	print $file "delete refs/tags/$_\n" or die $!;
	$count++ < 1000 or complete_batch;
    }
#print STDERR "FOO\n";
    STDIN->error and die $!;
    complete_batch();
    await_task while @tasks;
    print STDERR "check exiting (total=$total)\n";
'