#!/usr/bin/env bash
set -e

usage() {
    echo "usage: lxc-wait -n CONTAINER" >&2
    exit 1
}

args="$(getopt -o +n: --long help,name: -- "$@")"
eval "set -- $args"
while true; do
    case "$1" in
        --help) usage;;
        -n|--name) CONTAINER_NAME="$2"; shift; shift;;
        --) shift; break;;
        *) usage;;
    esac
done

if [ -z "$CONTAINER_NAME" ] || [ "$#" -gt 0 ]; then
    usage
fi

if [ "$EUID" -ne 0 ]; then
    echo "error: this script must be run as root" >&2
    exit 1
fi

# We poll.
for _ in {1..60}; do
    echo "lxc-wait: $CONTAINER_NAME: polling for boot..." >&2
    runlevel="$(lxc-attach --clear-env -n "$CONTAINER_NAME" -- runlevel 2>/dev/null)" \
        || { sleep 1; continue; }
    if [ "$runlevel" != "${0%[0-9]}" ]; then
        echo "lxc-wait: $CONTAINER_NAME: booted!" >&2
        exit 0
    fi
    sleep 1
done

echo "error: timeout waiting for container to boot" >&2
exit 1