#!/bin/sh
# The nRF9151 station's X session: the front end, full screen under matchbox-wm.
# The station image selects this as x-session-manager, so /etc/X11/Xsession runs
# it in place of a desktop session.
#
# The front end's own output, and every command it runs, goes to
# /tmp/nrf-station-ui.log. It is started again if it ever exits; the console
# beside the session keeps working either way.

LOG=/tmp/nrf-station-ui.log

# A session without a display has nothing to run; a stray call (with --version,
# say) must not start the front end's restart loop.
[ -n "${DISPLAY:-}" ] || { echo "nrf-station-session: no DISPLAY; this is an X session" >&2; exit 1; }

# BRINTOS-WORKAROUND: brintos/linux#153 remove -- programs started together can take each other's staged libraries; staging the window manager's and the front end's once, one after the other, before either starts leaves nothing to race on.
# No DISPLAY, so a program that does not know --version refuses rather than runs.
env -u DISPLAY /usr/bin/matchbox-window-manager --version </dev/null >/dev/null 2>&1
env -u DISPLAY /usr/bin/nrf-station-ui --version </dev/null >/dev/null 2>&1

up() { read -r u _ < /proc/uptime; echo "${u%.*}"; }

(
	fast=0
	while [ "$fast" -lt 3 ]; do
		t0=$(up)
		/usr/bin/nrf-station-ui --announce /dev/console
		echo "nrf-station-ui exited with status $? at uptime $(up) s"
		if [ $(( $(up) - t0 )) -lt 10 ]; then fast=$((fast + 1)); else fast=0; fi
	done
	echo "nrf-station-ui: stopped restarting it after three quick exits" | tee /dev/console
) >>"$LOG" 2>&1 &

# The image ships no fontconfig cache and its root is read-only, so the window
# manager's font setup would rescan every font and never finish: it gets one
# font and a cache it can write.
FC=/tmp/nrf-station-fc
mkdir -p "$FC/fonts" "$FC/cache"
ln -sf /usr/share/fonts/X11/misc/6x13-ISO8859-1.pcf.gz "$FC/fonts/"
cat > "$FC/fonts.conf" <<EOF
<?xml version="1.0"?><!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig><dir>$FC/fonts</dir><cachedir>$FC/cache</cachedir></fontconfig>
EOF
FONTCONFIG_FILE="$FC/fonts.conf" exec matchbox-window-manager -use_titlebar no -use_cursor yes