##
# systrunk checkout <version> [[<remote>] <path>]
#
# Reset a worktree to the state at <version>.  If <path> is given,
# checkout also initializes a new worktree at the CWD.  If <remote>
# is given, the path is assumed to be located on a remote machine
# and is contacted over SSH.  While resetting to the state at
# <version>, all local uncommitted changes are lost.
#
# After checkout, BASE and TRAC will be set to <version>.
##
function systr_checkout
{
    # check arguments #
    if [ $# -lt 2 ]; then
        echo "Missing required parameters"
        exit
    fi

    # init worktree #
    if [ $# -gt 2 ]; then
        init_wktree $@
    fi

    # perform checkout #
    read remote <.systr/remote
    read path   <.systr/path
    version=$2

    if [[ "$version" == "NULL" ]]; then
        echo "Checking out NULL :: Checkout not performed"
        exit
    fi

    commit=$(get_commit "$version")
    symref=$(get_symref "$version")

    echo "$commit" >.systr/BASE
    echo "$symref" >.systr/TRAC

    if [[ "$commit" == "NULL" ]]; then
        echo "Nothing to checkout"
        exit
    fi

    echo "Checking out files..."

    # local repository #
    if [[ "$remote" == "" ]]; then
        rsync -az --info=progress2 --info=stats2 \
            --delete --exclude='*.systr' \
            "$path/$commit/" .

    # remote repository #
    else
        rsync -az -e ssh --info=progress2 --info=stats2 \
            --delete --exclude='*.systr' \
            "$remote:$path/$commit/" .

    fi
}