#!/bin/sh
# this script is based on some assumptions that are made in the context
# of my gentoo/swaywm setup

set -e
[ -n "$DEBUG" ] && set -x

usage() {
	printf "usage: %s USER [ARGS...]\n" "$(basename "$0")"
	printf "\n"
	printf "enter the desktop session of USER and run COMMAND.\n"
	exit 1
}

case "$1" in
-h) usage && exit 0 ;;
esac

user="${1}"
[ -z "${user}" ] && usage
shift

[ "${1}" = "--" ] && shift

marker_bins="
	oguri
	kanshi
	waybar
	wlsunset
	pipewire
	swayidle
"
pid=
for bin in ${marker_bins}; do
	pid=$(pgrep --uid "$(id -u "${user}")" --exact "${bin}") || true
	kill -0 "${pid}" && break
done
if [ -z "$pid" ]; then exit 1; fi

grep -zE '^(SWAY|I3|WAYLAND|DBUS|XDG|PATH|BEMENU|HOME)' /proc/"${pid}"/environ | tr '\0' '\n' | sed -e "s/'/'\\\''/g" -e "s/=\(.*\)/='\1'/g" >/dev/shm/"gui_enter_env.${pid}"
[ -n "$DEBUG" ] && cat /dev/shm/"gui_enter_env.${pid}"
cmdline="set -aeu ; . /dev/shm/gui_enter_env.${pid} ; "
for i; do cmdline="${cmdline} '${i}'"; done
exec doas -nu "${user}" -- env -i sh -c "${cmdline}"