if [[ -z "$ZSHRC_UPDATE_ASYNC_CHILD" && -z "$ZSHRC_UPDATE_SYNC" ]]; then
    _zshrc_start_async_update() {
        if (( $+functions[add-zsh-hook] )); then
            add-zsh-hook -d precmd _zshrc_start_async_update 2>/dev/null
        fi
        (
            export ZSHRC_UPDATE_ASYNC_CHILD=1
            export SCR
            export PATH="$SCR/bin:$PATH"
            exec zsh -f "$SCR/includes/init/update.sh"
        ) &!
        unset -f _zshrc_start_async_update 2>/dev/null
    }

    if [[ -o interactive ]]; then
        autoload -Uz add-zsh-hook
        add-zsh-hook -d precmd _zshrc_start_async_update 2>/dev/null
        add-zsh-hook precmd _zshrc_start_async_update
    else
        _zshrc_start_async_update
    fi

    return 0 2>/dev/null || exit 0
fi

old_pwd="$PWD"
cd "$SCR" || { cd "$old_pwd" 2>/dev/null; return 0 2>/dev/null || exit 0; }
export PATH="$SCR/bin:$PATH"

prefix="&7[&3zshrc&7]"
remote_ref="${ZSHRC_UPDATE_REF:-origin/master}"
lock_dir="$SCR/.git/zshrc-update.lock"

if ! mkdir "$lock_dir" 2>/dev/null; then
    cd "$old_pwd" 2>/dev/null
    return 0 2>/dev/null || exit 0
fi
_zshrc_update_cleanup() {
    rmdir "$lock_dir" 2>/dev/null
    cd "$old_pwd" 2>/dev/null
}
trap _zshrc_update_cleanup EXIT INT TERM

_zshrc_stash_created=0
_zshrc_stash_if_needed() {
    if ! git diff --quiet --ignore-submodules -- \
        || ! git diff --cached --quiet --ignore-submodules -- \
        || [[ -n "$(git ls-files --others --exclude-standard)" ]]; then
        if git stash push -u -m "zshrc auto-update before applying $remote_ref" >/dev/null; then
            _zshrc_stash_created=1
        fi
    fi
}

_zshrc_restore_stash() {
    if [[ "$_zshrc_stash_created" == "1" ]]; then
        git stash pop >/dev/null || color "$prefix &cUpdated, but saved local changes need manual conflict resolution."
    fi
}

# Check for updates
if git fetch origin --quiet && git rev-parse --verify --quiet "$remote_ref" >/dev/null; then

    # Handle rewritten or force-pushed history. This keeps auto-update working
    # after repository cleanup that removes old large objects.
    if ! git merge-base --is-ancestor HEAD "$remote_ref" 2>/dev/null; then
        color "$prefix &cRepo history changed. Resetting local zshrc to $remote_ref..."

        _zshrc_stash_if_needed
        if git reset --hard "$remote_ref" && git submodule update --init --recursive --depth 1; then
            _zshrc_restore_stash
            color "$prefix &aUpdated after history rewrite! Open a new shell to use the latest zshrc."
        else
            color "$prefix &cUpdate failed!"
        fi
    else
        reslog=$(git log HEAD.."$remote_ref" --oneline)
        if [[ "${reslog}" != "" ]] ; then

            # Has updates
            color "$prefix &cYour zshrc is outdated. Automatically updating..."

            # Try to fast-forward without invoking git pull's merge/rebase behavior.
            _zshrc_stash_if_needed
            if git merge --ff-only "$remote_ref" && git submodule update --init --recursive --depth 1; then
                _zshrc_restore_stash
                color "$prefix &aUpdated! Open a new shell to use the latest zshrc."
            else
                color "$prefix &cUpdate failed!"
            fi
        fi
    fi
elif [[ -n "$ZSHRC_UPDATE_VERBOSE" ]]; then
    color "$prefix &cUpdate check failed!"
fi

unset -f _zshrc_stash_if_needed _zshrc_restore_stash 2>/dev/null
_zshrc_update_cleanup
trap - EXIT INT TERM
unset -f _zshrc_update_cleanup 2>/dev/null
unset _zshrc_stash_created remote_ref reslog lock_dir old_pwd