#!/bin/sh
#
# SecuBox Zigbee2MQTT manager
# Handles prerequisite checks, Docker installation, container lifecycle,
# and configuration generation using UCI.

CONFIG="zigbee2mqtt"
CONTAINER="secbx-zigbee2mqtt"
OPKG_UPDATED=0

usage() {
	cat <<'EOF'
Usage: zigbee2mqttctl <command>

Commands:
  install         Run prerequisite checks, install Docker packages, prepare data dir
  check           Validate kernel modules, cgroups, storage, and serial access
  update          Pull the latest Zigbee2MQTT image and restart the service
  status          Show container and service status
  logs            Show Docker logs (pass -f to follow)
  service-run     Internal: invoked by procd to run the container
  service-stop    Stop the running container
  help            Show this message
EOF
}

require_root() {
	if [ "$(id -u)" -ne 0 ]; then
		echo "This command requires root privileges." >&2
		exit 1
	fi
}

uci_get() {
	uci -q get "${CONFIG}.main.$1"
}

defaults() {
	serial_port="$(uci_get serial_port || echo /dev/ttyACM0)"
	mqtt_host="$(uci_get mqtt_host || echo mqtt://127.0.0.1:1883)"
	mqtt_user="$(uci_get mqtt_username || printf '')"
	mqtt_pass="$(uci_get mqtt_password || printf '')"
	base_topic="$(uci_get base_topic || echo zigbee2mqtt)"
	frontend_port="$(uci_get frontend_port || echo 8080)"
	channel="$(uci_get channel || echo 11)"
	image="$(uci_get image || echo ghcr.io/koenkk/zigbee2mqtt:latest)"
	data_path="$(uci_get data_path || echo /srv/zigbee2mqtt)"
	timezone="$(uci_get timezone || echo UTC)"
}

ensure_dir() {
	local path="$1"
	[ -d "$path" ] || mkdir -p "$path"
}

ensure_packages() {
	local pkgs="$*"
	require_root
	for pkg in $pkgs; do
		if ! opkg status "$pkg" >/dev/null 2>&1; then
			if [ "$OPKG_UPDATED" -eq 0 ]; then
				opkg update || return 1
				OPKG_UPDATED=1
			fi
			opkg install "$pkg" || return 1
		fi
	done
	return 0
}

check_storage() {
	local target="$1"
	local free_kb
	free_kb=$(df -Pk "${target:-/overlay}" | awk 'NR==2 {print $4}')
	[ -z "$free_kb" ] && free_kb=0
	if [ "$free_kb" -lt 102400 ]; then
		echo "[WARN] Less than 100MB free on ${target:-overlay}. Docker images may fail." >&2
	fi
}

check_cgroups() {
	if [ ! -d /sys/fs/cgroup ]; then
		echo "[ERROR] /sys/fs/cgroup missing. Enable cgroups in the kernel." >&2
		return 1
	fi
	return 0
}

check_serial() {
	local port="$1"
	if [ ! -c "$port" ]; then
		echo "[WARN] Serial device $port not found. Plug the Zigbee coordinator first." >&2
	fi
}

check_prereqs() {
	defaults
	check_storage "$data_path"
	check_cgroups || return 1
	check_serial "$serial_port"
	ensure_packages kmod-usb-acm || return 1
	return 0
}

ensure_docker() {
	ensure_packages containerd docker dockerd || return 1
	/etc/init.d/dockerd enable >/dev/null 2>&1
	/etc/init.d/dockerd start >/dev/null 2>&1
}

generate_configuration() {
	defaults
	ensure_dir "$data_path/data"
	cat > "$data_path/data/configuration.yaml" <<EOF
homeassistant: true
permit_join: false
mqtt:
  base_topic: "${base_topic}"
  server: "${mqtt_host}"
  user: "${mqtt_user}"
  password: "${mqtt_pass}"
serial:
  port: "${serial_port}"
advanced:
  channel: ${channel}
frontend:
  port: ${frontend_port}
EOF
	chmod 600 "$data_path/data/configuration.yaml"
}

pull_image() {
	defaults
	docker pull "$image"
}

stop_container() {
	docker stop "$CONTAINER" >/dev/null 2>&1 || true
	docker rm "$CONTAINER" >/dev/null 2>&1 || true
}

cmd_install() {
	require_root
	check_prereqs || exit 1
	ensure_docker || exit 1
	ensure_dir "$data_path"
	generate_configuration
	pull_image
	/etc/init.d/zigbee2mqtt enable
	echo "Zigbee2MQTT prerequisites installed. Enable with: /etc/init.d/zigbee2mqtt start"
}

cmd_check() {
	check_prereqs
	echo "Prerequisite check completed."
}

cmd_update() {
	require_root
	defaults
	pull_image || exit 1
	if /etc/init.d/zigbee2mqtt enabled >/dev/null 2>&1; then
		/etc/init.d/zigbee2mqtt restart
	else
		echo "Image updated. Restart manually to apply."
	fi
}

cmd_status() {
	docker ps -a --filter "name=$CONTAINER"
}

cmd_logs() {
	docker logs "$@" "$CONTAINER"
}

cmd_service_run() {
	require_root
	check_prereqs || exit 1
	ensure_docker || exit 1
	generate_configuration
	stop_container
	defaults
	exec docker run --rm \
		--name "$CONTAINER" \
		--device "$serial_port" \
		-p "${frontend_port}:8080" \
		-v "$data_path/data:/app/data" \
		-e TZ="$timezone" \
		"$image"
}

cmd_service_stop() {
	require_root
	stop_container
}

case "$1" in
	install) shift; cmd_install "$@";;
	check) shift; cmd_check "$@";;
	update) shift; cmd_update "$@";;
	status) shift; cmd_status "$@";;
	logs) shift; cmd_logs "$@";;
	service-run) shift; cmd_service_run "$@";;
	service-stop) shift; cmd_service_stop "$@";;
	help|--help|-h|"") usage;;
	*) echo "Unknown command: $1" >&2; usage >&2; exit 1;;
esac