#! /usr/bin/env bash
#
# Usage: btest-bg-run <tag> <cmdline>
#
# Creates a new empty working directory <tag> within the current directory
# and spawns <cmdline> in there in the background. It also records
# a set of meta information that btest-bg-wait will read.

# Sleep this many seconds after creating the process and before
# returning from btest-bg-run.
BTEST_BG_RUN_SLEEP=${BTEST_BG_RUN_SLEEP:-1}

if [ "$#" -le 1 ]; then
    echo "usage: $(basename "$0") <tag> <cmdline>"
    exit 1
fi

cwd=$(pwd)
cd "$(dirname "$0")" || exit 1
helper=$(pwd)/btest-bg-run-helper
setsid=$(pwd)/btest-setsid
cd "$cwd" || exit 1

dir=$1
shift

if [ -e "$dir" ]; then
    echo "directory '$dir' already exists" >&2
    exit 1
fi

echo "$dir" >>.bgprocs
mkdir "$dir"
cd "$dir" || exit 1

echo "$@" >.cmdline

$setsid "$helper" "$@" >.stdout 2>.stderr &

sleep "$BTEST_BG_RUN_SLEEP"