if [ "$PREVIOUS_SESSION_ID" != "" ]; then
    # Spawned as a new window/terminal for an existing remote session (by the
    # niri/hyprland keybind). Inherit that session's working directory: find a
    # live shell whose SSH_SESSION_ID (carried in its environment) matches and
    # cd to its cwd. Then drop the hint so child shells don't keep jumping back.
    _best_pid=0
    _prev_cwd=""
    for _environ in /proc/[0-9]*/environ; do
        _pid=${_environ%/environ}
        _pid=${_pid#/proc/}
        # cat (not a < redirect) so unreadable/ptrace-protected environ files
        # fail quietly into the pipe instead of raising a shell error.
        if cat "$_environ" 2>/dev/null | tr '\0' '\n' | grep -Fxq "SSH_SESSION_ID=$PREVIOUS_SESSION_ID"; then
            [ "$(cat /proc/$_pid/comm 2>/dev/null)" = zsh ] || continue
            _c=$(readlink -e /proc/$_pid/cwd 2>/dev/null) || continue
            if [ -n "$_c" ] && [ "$_pid" -gt "$_best_pid" ]; then
                _best_pid=$_pid
                _prev_cwd=$_c
            fi
        fi
    done
    [ -n "$_prev_cwd" ] && cd "$_prev_cwd"
    unset _best_pid _prev_cwd _environ _pid _c PREVIOUS_SESSION_ID
fi

function run_waypipe() {
    if [ -z "$1" ]; then
        echo "usage: run_waypipe <host>" >&2
        return 1
    fi
    local SSH_SESSION_ID=$RANDOM REMOTE_PATH
    # Map the current path relative to $HOME so it resolves to the remote user's
    # home even when the username differs (the remote shell expands $HOME).
    if [[ "$PWD" == "$HOME" || "$PWD" == "$HOME"/* ]]; then
        REMOTE_PATH="\$HOME${PWD#$HOME}"
    else
        REMOTE_PATH="$PWD"
    fi
    # cd into the mirrored path before the interactive shell starts, so the cwd
    # is never carried in an inherited env var (which would leak to every child
    # shell and override the cwd of new zellij panes). SSH_SESSION_ID stays in
    # the environment on purpose: it is the token the WM keybind above uses to
    # locate this session's shells later.
    waypipe -n ssh -t "$1" "cd \"$REMOTE_PATH\" 2>/dev/null; exec env SSH_SESSION_ID=$SSH_SESSION_ID zsh --login"
}

alias s='run_waypipe'