#!/bin/sh /etc/rc.common

# In recent (relevant) versions of shellcheck busybox is a valid shell type
# shellcheck shell=busybox

# shellcheck disable=SC2034
START=82
STOP=28
USE_PROCD=1

# IPKG_INSTROOT is intentionally only set when building an image and
# is intentionally empty on a live OpenWrt device

# Shellcheck source paths intentionally point to the location of files of
# the scripts in the development environment (where shellcheck is used), not
# on the live OpenWrt device

# shellcheck source=net/nut/files/functions.sh.functions
. "${IPKG_INSTROOT}"/lib/functions.sh || {
	# Before our sourcing error logging definitions are sourced
	logger -t nut-monitor[$$] "Unable to source 'functions.sh' in 'nut-monitor'. Bailing"
	exit 1
}

# 'shellcheck' complains about nut-common.sh due to a case pattern it does not understand, even
# though it is correctly POSIX compliant
# shellcheck disable=SC1094
# shellcheck source=net/nut/files/nut-common.sh.functions
. "${IPKG_INSTROOT}"/lib/functions/nut/nut-common.sh || {
	# Before our sourcing error logging definitions are sourced
	logger -t nut-monitor[$$] "Unable to source 'nut-common.sh' in 'nut-monitor'. Bailing"
	exit 1
}

# shellcheck source=/dev/null
. "${IPKG_INSTROOT}"/usr/share/libubox/jshn.sh || {
	log_source_error "jshn.sh" "nut-monitor" "nut-monitor"
	exit 1
}

# shellcheck source=net/nut/files/nut-service.sh.functions
. "${IPKG_INSTROOT}"/lib/functions/nut/nut-service.sh || {
	log_source_error "nut-service.sh" "nut-monitor" "nut-monitor"
	exit 1
}

# /lib/functions/network.sh exists on live OpenWrt systems (base-files), but
# not our development environment. We do not run the script in a development
# environment as it depends on cross-compiled binaries and files being in
# location and having live target names.
# shellcheck disable=SC1091
# shellcheck source=/dev/null
. "${IPKG_INSTROOT}"/lib/functions/network.sh || {
	log_source_error "network.sh" "nut-monitor" "nut-monitor"
	exit 1
}

# defines NUT_EVENT_TYPES PIDFILE UPSMON_C
# shellcheck source=net/nut/files/nut-monitor-config.sh.functions
. "${IPKG_INSTROOT}"/lib/functions/nut/nut-monitor-config.sh || {
	log_source_error "nut-monitor-config.sh" "nut-monitor" "nut-monitor"
	exit 1
}

restore_umask_on_exit

service_preconditions() {
	local action="$1"
	# action can be one of start, stop, or reload

	case "$action" in
	start | reload)
		# NUT_KILLPOWER is an external sentinel that indicates a forced shutdown
		if [ -f "$NUT_KILLPOWER" ]; then
			return 1
		fi

		config_load nut_monitor || {
			log_config_load_error "nut_monitor" "nut-monitor" "nut-monitor"
			exit 1
		}

		if have_section_named "upsmon" "upsmon"; then
			# Find the RUNAS user for upsmon
			RUNAS="$(find_runas "upsmon" "nut_monitor" "nutmon")" || {
				log_error_exit "Failed to determine RUNAS user" "nut-monitor" "nut-monitor"
			}
		else
			# If we do not have a 'upsmon' section in nut_monitor, use defaults
			log_msg "No upsmon section so no RUNAS user, falling back to nutmon" "nut-monitor" "nut-monitor" "notice"
			RUNAS=nutmon
		fi

		build_config || return 1
		check_interface_up "upsmon" || return 1
		return 0
		;;
	*)
		return 0
		;;
	esac
}

start_monitor_instance() {
	procd_open_instance upsmon
	procd_set_param respawn
	procd_set_param stderr 1
	procd_set_param stdout 1
	procd_set_param env NUT_QUIET_INIT_UPSNOTIFY=true
	procd_set_param env NUT_DEBUG_SYSLOG="stderr"
	procd_set_param reload_signal HUP
	procd_set_param command /usr/sbin/upsmon
	procd_append_param command -FF
	# upsmon needs root for some actions (like
	# shutting down the system), but forks
	# and drops root for most of its operation
	procd_append_param command -u "$RUNAS"
	procd_close_instance
}

perform_instance_action() {
	local active_upsmon_action="$1"
	shift || true
	local active_upsmon_signal="$1"
	shift || true
	local action_command="$1"
	shift || true
	local action_arg="$1"
	shift || true
	local active_upsmon_secondary_command="$1"
	shift || true

	# If nut-monitor is running but has no instances (even upsmon)
	if service_active_no_instances "nut-monitor"; then
		log_msg "nut-monitor active with no instances" "nut-monitor" "nut-monitor" "info"
		if [ -n "$action_command" ]; then
			"$action_command" "$action_arg"
		fi
	# The only possible instance of nut-monitor in this package is a single
	# upsmon instance. Therefore we do not need to check for other instances
	elif procd_running nut-monitor upsmon; then
		# If nut-monitor has an active upsmon instance
		signal_instance "upsmon" \
			"upsmon" \
			"$active_upsmon_action" \
			"$active_upsmon_signal" "$PIDFILE" "" \
			"nut-monitor" \
			"$active_upsmon_secondary_command" \
			"$@"
	fi
}

manage_service() {
	local action="$1"

	# We only support one instance of upsmon, and its UCI
	# section must be named 'upsmon'

	service_preconditions "$action" || return 1
	case "$action" in
	start)
		start_monitor_instance
		;;
	reload)
		# We need to use rpc_procd to start an instance from service_reload
		perform_instance_action "reload" "HUP" "rc_procd" "start_monitor_instance"
		;;
	stop)
		# Note that the middle procd_kill is *without* upsmon which stops the procd
		# service entirely, not just the instances (so reload triggers will have
		# no effect until the service is started again).
		perform_instance_action "stop" "TERM" "procd_kill" "nut-monitor" "procd_kill" "nut-monitor" "upsmon"
		rm -f "$UPSMON_C"
		;;
	stop-instance)
		# Stop the upsmon instance but leave nut-monitor procd service active
		perform_instance_action "stop" "TERM" "" "" "procd_kill" "nut-monitor" "upsmon"
		rm -f "$UPSMON_C"
		;;
	*)
		# Do not abort on unknown $action, but log it.
		log_error "Unknown action: '$action'" "nut-monitor" nut-monitor
		;;
	esac
}

stop_and_cleanup_on_error() {
	manage_service stop-instance
	rm -f "$UPSMON_C.new"
}

start_service() {
	manage_service start || stop_and_cleanup_on_error
}

reload_service() {
	manage_service reload || stop_and_cleanup_on_error
}

stop_service() {
	manage_service stop
}

service_triggers() {
	local val interface_reload_delay

	# No config, or error loading config is fatal
	config_load nut_monitor || {
		log_config_load_error "nut_monitor" "nut-monitor" "nut-monitor"
		exit 1
	}

	config_get interface_reload_delay upsmon interface_reload_delay $DEFAULT_PROCD_INTERFACE_RELOAD_DELAY
	if ! check_unsigned_int "$interface_reload_delay" || [ -z "$interface_reload_delay" ]; then
		log_msg "interface_reload_delay must be an unsigned integer" nut-monitor nut-monitor warn
		interface_reload_delay="$DEFAULT_PROCD_INTERFACE_RELOAD_DELAY"
	fi

	# We do not pass a variadic instance name as the nut-monitor initscript does
	# not need an additional instance name argument, only the initscript name
	add_interface_triggers "upsmon" "$interface_reload_delay" "nut-monitor" || {
		log_error "Failed to add interface triggers" nut-monitor nut-monitor
	}
	procd_add_reload_trigger "nut_monitor"
}