#! /usr/bin/bash

set -e

die() {
	echo >&2 "!! $*"
	exit 1
}

CONF_FILE="/etc/lightdm/lightdm.conf.d/10-chimeraos-session.conf"
SENTINEL_FILE="steamos-session-select"
RETURN_SESSION_FILE="chimeraos-session-return"

# For sanity this shipped file must be present, to ensure we're still on a normal-looking Chimeraos setup.
CHECK_FILE="/etc/lightdm/lightdm.conf.d/10-chimeraos-session.conf"

session="${1:-gamescope-session-steam-plus}"
session_type="wayland"

session_launcher="gamescope-session-steam-plus"
create_sentinel=""

if [[ "$2" == "--sentinel-created" ]]; then
	SENTINEL_CREATED=1
	session_type="wayland"
fi

# Update config sentinel
if [[ -z $SENTINEL_CREATED ]]; then
	[[ $EUID == 0 ]] && die "Running $0 as root is not allowed"

	[[ -n ${HOME+x} ]] || die "No \$HOME variable"
	config_dir="${XDG_CONF_DIR:-"$HOME/.config"}"
	session_type=$(
		cd "$HOME"
		mkdir -p "$config_dir"
		cd "$config_dir"
		if [[ -f "steamos-session-type" ]]; then
			cp steamos-session-type "$SENTINEL_FILE"
		else
			echo "wayland" >"$SENTINEL_FILE"
		fi
		cat "$SENTINEL_FILE"
	)

	return_session=$(grep autologin-session $CONF_FILE | cut -d = -f 2)
	return_session=$(
		cd "$HOME"
		mkdir -p "$config_dir"
		cd "$config_dir"
		echo "$return_session" >"$RETURN_SESSION_FILE"
		cat "$RETURN_SESSION_FILE"
	)

	# clear steam game desktop shortcut clutter
	DATA_HOME=${XDG_DATA_HOME:-$HOME/.local/share}
	grep -r --files-with-matches "Exec=steam steam://rungameid/" "${DATA_HOME}"/applications/ | tr '\n' '\0' | xargs -0 -I {} rm {} || true

	# If we were executed as a session user and then re-execute as root below, we don't want to set root's sentinel too
	export SENTINEL_CREATED=1
fi

# We use "plasma" as "desktop" to hook up to SteamOS's scripts
case "$session" in
plasma-wayland-persistent)
	session_launcher="gnome-session"
	;;
plasma-x11-persistent)
	session_launcher="gnome-session"
	;;
desktop | plasma)
	session_launcher="gnome-session-oneshot"
	create_sentinel=1
	if (systemctl -q is-active inputplumber.service); then
		sudo systemctl restart inputplumber || true
	fi
	;;
opengamepadui | gamescope-session-opengamepadui)
	session_launcher="gamescope-session-opengamepadui"
	create_sentinel=1
	;;
steam-plus | gamescope-session-steam-plus)
	session_launcher="gamescope-session-steam-plus"
	create_sentinel=1
	;;
steam | gamescope-session-steam)
	session_launcher="gamescope-session-steam"
	create_sentinel=1
	;;
*)
	echo >&2 "!! Unrecognized session '$session'"
	exit 1
	;;
esac

echo "Updated user selected session to $session_launcher"

# Become root
if [[ $EUID != 0 ]]; then
	exec pkexec "$(realpath $0)" "$session" --sentinel-created
	exit 1
fi

{
	echo "[Seat:*]"
	echo "autologin-session=$session_launcher"
} >"$CONF_FILE"

echo "Updated system autologin session to $session_launcher"
systemctl reset-failed lightdm
systemctl restart lightdm
echo "Restarted LightDM"
