#! /bin/sh

set -e
export PATH=/usr/bin:/usr/sbin:/sbin:/bin

frontend=noninteractive

findcommandinroot() {
    ROOT="$1/"
    shift
    while [ "$#" -ge 1 ]; do
        P="$PATH"
        while [ "$P" ]; do
            D=${P%%:*}
            P=${P#*:}
            if [ "$D" = "$P" ]; then
                P=
            fi
            if [ -z "$D" ]; then
                D=.
            fi
            if [ -x "$ROOT$D/$1" ]; then
                echo "$D/$1"
                return 0
            fi
        done
        shift
    done
    return 1
}

runcommandinroot() {
    C=$(findcommandinroot "$1" "$2")
    ROOT="$1"
    shift
    shift
    [ -n "$C" ] && chroot "$ROOT" "$C" "$@"
}

root="$1"
package="$2"

version=$(runcommandinroot "$root" dpkg-query -W --showformat='${Version}' "$package" 2>/dev/null) || version=""

if [ -z "$version" ]; then
    echo >&2 "$0: package '$package' is not installed"
    exit 0
fi

unset DEBIAN_HAS_FRONTEND
unset DEBIAN_FRONTEND
unset DEBCONF_REDIR
runcommandinroot "$root" dpkg-reconfigure -fnoninteractive --no-reload "$package"

exit 0