#!/usr/bin/env sh

TIMEOUT=15
INTERVAL=1
QUIET=0

echoerr() {
    if [ "$QUIET" -ne 1 ]; then printf "%s\n" "$*" 1>&2; fi
}

usage() {
    exitcode="$1"
    cat << USAGE >&2
Usage:
  $cmdname host:port [-t timeout] [-- command args]
  -q | --quiet                        Do not output any status messages
  -t TIMEOUT | --timeout=timeout      Timeout in seconds, zero for no timeout
  -i INTERVAL | --interval=interval   Time in seconds between retries
  -- COMMAND ARGS                     Execute command with args after the test finishes
USAGE
    exit "$exitcode"
}

wait_for() {
    local t=$TIMEOUT

    while [ $t -gt 0 ] ||  [ $TIMEOUT -eq 0 ]; do
        nc -z "$HOST" "$PORT" > /dev/null 2>&1

        result=$?
        if [ $result -eq 0 ] ; then
            if [ $# -gt 0 ] ; then
                exec "$@"
            fi
            echoerr "$HOST":"$PORT" is available
            exit 0
        fi
        echoerr "$HOST":"$PORT" is not available
        sleep $INTERVAL
        t=$((t-$INTERVAL))
    done

    echoerr "Operation timed out"
    exit 1
}

while getopts "qt:i:" arg; do
    case "$arg" in
        *:*)
            HOST=$(printf "%s\n" "$1"| cut -d : -f 1)
            PORT=$(printf "%s\n" "$1"| cut -d : -f 2)
            shift 1
            ;;
        -q) # quiet.
            QUIET=1
            shift 1
            ;;
        -t) # timeout. Requires passed value.
            TIMEOUT="$2"
            if [ "$TIMEOUT" = "" ]; then break; fi
            shift 2
            ;;
        -i) # interval. Requires passed value.
            INTERVAL="$2"
            if [ "$INTERVAL" = "" ]; then break; fi
            shift 2
            ;;
        -h) # help.
            usage 0
            ;;
        *)
            echoerr "Unknown argument: $1"
            usage 1
            ;;
    esac
done

if [ "$HOST" = "" -o "$PORT" = "" ]; then
    echoerr "Error: Host and port need to be provided."
    usage 2
fi

wait_for "$@"