#!/bin/sh

FORCE="n"
RUN=""

working_dir=""

APPNAME=$(basename "${0}")

if [ "$EUID" != "0" ]; then
    echo "This script must be run as root."
    exit 1
fi

usage ()
{
    echo "usage ${APPNAME} [options] working-dir package [package [package..]]"
    echo " options:"
    echo "    -r <app>      run 'app' within the context of the chroot"
    echo "    -f            force overwrite of files in the working-dir"
    echo "    -h            this message."
    exit 1
}

while getopts 'r:fh' arg; do
    case "${arg}" in
        r) RUN="$OPTARG" ;;
        f) FORCE="y" ;;
        h|?) usage ;;
        *) echo "invalid argument '${arg}'"; usage ;;
    esac
done
shift $(($OPTIND - 1))

if [ "$RUN" == "" -a $# -lt 2 ]; then
    echo "you must specify a directory and one or more packages"
    usage
elif [ $# -lt 1 ]; then
    echo "you must specify a directory"
    usage
fi

working_dir="$(readlink -f ${1})"
shift 1

[ "${working_dir}" = "" ] && echo "error: please specify a working directory" && usage

# {{{ functions 

function chroot_mount ()
{
    echo "mounting sysfs : /sys"
    [ -e "${working_dir}/sys" ] || mkdir "${working_dir}/sys"
    mount -t sysfs sysfs "${working_dir}/sys"

    echo "mounting procfs : /proc"
    [ -e "${working_dir}/proc" ] || mkdir "${working_dir}/proc"
    mount -t proc proc "${working_dir}/proc"

    echo "binding device nodes : /dev"
    [ -e "${working_dir}/dev" ] || mkdir "${working_dir}/dev"
    mount -o bind /dev "${working_dir}/dev"

    echo "binding pacman cache : /var/cache/pacman"
    [ -e "${working_dir}/var/cache/pacman" ] || mkdir -p "${working_dir}/var/cache/pacman"
    mount -o bind /var/cache/pacman "${working_dir}/var/cache/pacman"

    trap 'chroot_umount' 0 1 2 15
}

function chroot_umount ()
{
    echo "cleaning up mounts"
    umount "${working_dir}/proc"
    umount "${working_dir}/sys"
    umount "${working_dir}/dev"
    umount "${working_dir}/var/cache/pacman"
}
# }}}

if [ "$RUN" != "" ]; then
# run chroot {{{
    if [ "$EUID" != "0" ]; then
        echo "Running a chroot requires root privileges, aborting"
        exit 1
    fi

    #Sanity check
    if [ ! -f "${working_dir}/.arch-chroot" ]; then
        echo "'${working_dir}' does not appear to be a Arch chroot"
        echo "  please build the image using mkarchchroot"
        exit 1
    fi

    chroot_mount

    echo "starting chroot ($RUN)"
    chroot "${working_dir}" "${RUN}"

# }}}
else
# {{{ build chroot
    if [ -e "${working_dir}" -a "${FORCE}" = "n" ]; then
        echo "Working dir '${working_dir}' already exists - try using -f"
        exit 1
    fi

    mkdir -p "${working_dir}"

    chroot_mount

    pacargs="--noconfirm -v " #--noprogressbar -v
    pacargs="$pacargs --root=${working_dir}"
    # pacman takes these as relative to the given root
    pacargs="$pacargs --dbpath=/var/lib/pacman"
    pacargs="$pacargs --cachedir=/var/cache/pacman/pkg"

    if [ $# -eq 0 ]; then
        echo "no packages to install"
    else
        echo "installing packages:"
        for i in $@; do echo -e "\t$i"; done

        op="-Sy"
        if [ "$FORCE" == "y" ]; then
            op="${op}f"
        fi
        if ! pacman ${op} ${pacargs} $@; then
            echo "error: failed to instal all packages"
            exit 1
        fi
    fi

    if [ -d "${working_dir}/lib/modules" ]; then
        echo "running ldconfig"
        ldconfig -r "${working_dir}"
    fi

    echo "generating default locales"
    sed -i "s|^#\(.*$LANG\)|\1|g" /etc/locale.gen
    locale-gen

    if [ ! -e "${working_dir}/.arch-chroot" ]; then
        date +%s > "${working_dir}/.arch-chroot"
    fi
# }}}
fi

# vim:ft=sh:ts=4:sw=4:et: