#!/bin/sh

set -e

STATE="$1"
FILES="$2"

prev_files_tar="$FILES"/tmp/prev_files.tar
update_files_tar="$FILES"/files/update.tar
dest_dir_file="$FILES"/files/dest_dir

case "$STATE" in

    NeedsArtifactReboot)
        echo "No"
        ;;

    SupportsRollback)
        echo "Yes"
        ;;

    ArtifactInstall)
        dest_dir=$(cat $dest_dir_file)
        test -z "$dest_dir" && \
            echo "Fatal error: dest_dir is undefined." && exit 1
        test "$dest_dir" = "/" && \
            echo "Error: destination dir is '/', install not supported." && exit 1
        mkdir -p $dest_dir
        if ! tar -cf ${prev_files_tar} -C ${dest_dir} .
        then
            ret=$?
            # Make sure there is no half-backup lying around.
            rm -f ${prev_files_tar}
            exit $ret
        fi
        rm -rf ${dest_dir}
        mkdir -p ${dest_dir}
        tar -xf ${update_files_tar} -C ${dest_dir}
        ;;

    ArtifactRollback)
        test -f $prev_files_tar || exit 0
        dest_dir=$(cat $dest_dir_file)
        test -z "$dest_dir" && \
            echo "Fatal error: dest_dir is undefined." && exit 1
        test "$dest_dir" = "/" && \
            echo "Info: destination dir is '/', not performing rollback." && exit 0
        rm -rf ${dest_dir}
        mkdir -p ${dest_dir}
        tar -xf ${prev_files_tar} -C ${dest_dir}
        ;;
esac

exit 0