#!/bin/sh
# Script is sourced not executed, but shebang helps tools recognize this as
# a shell script.

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

# uci-defaults script to migrate old uci config for notifications and monitor sections,
# to the new. Applied during install or on first boot after install, if setting on install
# fails

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

# Only run this uci-defaults script on a live OpenWrt device
[ -z "${IPKG_INSTROOT}" ] || exit 0

# Loads needed OpenWrt functions
# shellcheck source=net/nut/files/functions.sh.functions
. /lib/functions.sh || {
	# As the uci-defaults environment in which this runs does not have logging
	# available, nor is stderr captured or displayed on the console, these messages
	# exist only to assist when debugging manual runs of the script.
	printf "'%s': ERROR: '%s'\n" nut-monitor-migrate "Unable to source 'functions.sh' in 'nut-monitor-migrate' uci-default script. Bailing"
	exit 1
}

# Adds notification flag (value) to 'notify_flags' from caller
# shellcheck disable=SC2329,SC2317
get_notify_flags() {
	local value="$1"

	append notify_flags "$value" "+"
}

# shellcheck disable=SC2329,SC2317
convert_flags() {
	local notify_flags="$1"
	local working_flags=""
	local flag_val

	# In input flags can be in any order. If any of the input flags are IGNORE,
	# the output should only contain IGNORE. If the input contains only SYSLOG
	# or only EXEC, use as is. If the input contains both SYSLOG and EXEC (in
	# any order) the output must be SYSLOG+EXEC
	for flag_val in IGNORE SYSLOG EXEC; do
		# If the notify_flags contains $flag_val
		case "$notify_flags" in
		"$flag_val"+* | *+"$flag_val" | "$flag_val")
			case "$flag_val" in
			IGNORE)
				working_flags="IGNORE"
				printf "%s" "$working_flags"
				return
				;;
			SYSLOG)
				# If working flags exists, it already has a non SYSLOG value
				# SYSLOG must come first in the final flags, so append
				# old working_flags to SYSLOG with delimiter '+', and make
				# that the new working_flags
				if [ "$working_flags" = "EXEC" ]; then
					working_flags="${flag_val}+${working_flags}"
				else
					working_flags="$flag_val"
				fi
				;;
			EXEC)
				# append to an empty variable just returns the value to be
				# appended without a delimiter, so we do not need to check
				# for already having a value in 'working_flags'
				append working_flags "$flag_val" "+"
				;;
			esac
			;;
		esac
	done
	printf "%s" "$working_flags"
}

# As the uci-defaults environment in which this runs does not have logging
# available, nor is stderr captured or displayed on the console, these messages
# exist only to assist when debugging manual runs of the script.
# shellcheck disable=SC2329,SC2317
log_migration_error() {
	local reason="$1"

	printf "'%s': ERROR: '%s'\n" "nut-monitor-migrate" "$reason" >&2
}

# shellcheck disable=SC2329,SC2317
get_notification_flags() {
	local uci_option="$1"
	local cfg="$2"
	local notify_flags=""
	# accumulates flags in notify_flags via get_notify_flags
	config_list_foreach "$cfg" "$uci_option" get_notify_flags
	convert_flags "$notify_flags"
}

# shellcheck disable=SC2329,SC2317
process_upsmon_section() {
	local cfg="$1"
	local notify_type flag_name notify_msg notify_section val
	local notification_name notify_flags_as_var upsmon_final_flags
	# List of notification messages options in existing (to be converted)
	# UCI config for nut_monitor
	local nut_notify_message_types="onlinemsg onbattmsg lowbattmsg fsdmsg commokmsg"
	append nut_notify_message_types "commbadmsg shutdownmsg replbattmsg"
	append nut_notify_message_types "nocommmsmsg nocommmsg noparentmsg"
	local nocomm_exists="false"

	# Get hotsync (typo) value if present
	config_get val "$cfg" hotsync
	# Get hostsync value, only using hotsync as default if hostsync does not exist
	config_get val "$cfg" hostsync "$val"

	if [ -n "$val" ]; then
		if ! uci -q set nut_monitor."$cfg".hostsync="$val"; then
			log_migration_error "Failed to set hostsync value"
		fi
	fi

	# Remove invalid hotsync option unconditionally
	uci -q delete nut_monitor."$cfg".hotsync || true

	if uci -q get nut_monitor.NOCOMM; then
		nocomm_exists="true"
	fi

	# We need word-splitting to iterate over nut_notify_message_types
	# This is a local variable defined by us, so it is safe to do this.
	# We still disable globbing of the word-split
	set -f
	for notify_type in $nut_notify_message_types; do
		# Transform <prefix>msg into <prefix>notify (flag_name) and <PREFIX> (notification_name)
		flag_name="${notify_type/msg/notify}"
		notification_name="${notify_type/msg/}"
		# busybox ash does not support case transformation via variable  parameter substitution,
		# so we use tr.
		notification_name="$(printf '%s' "$notification_name" | tr '[:lower:]' '[:upper:]')"
		# Transform wrong NOCOMMS to NOCOMM (typo in nocommsmsg which should
		# have been nocommmsg in previous script), preferring NOCOMM (correct
		# version) if both exist
		if [ "$notification_name" = "NOCOMMMS" ]; then
			notification_name="NOCOMM"
		fi
		if [ "$notification_name" = "NOCOMM" ]; then
			if [ "$nocomm_exists" = "true" ]; then
				# Do not delete or overwrite pre-existing NOCOMM section
				continue
			fi
			if uci -q get nut_monitor."$notification_name"; then
				uci -q delete nut_monitor."$notification_name" || {
					log_migration_error "Failed to remove duplicate NOCOMM section"
					# We don't want to prevent other sections from being processed
					# if this one fails, so do not error exit, but keep going.
					continue
				}
				printf "'%s': WARN: '%s'\n" "nut-monitor-migrate" "Removed duplicate NOCOMM section, likely from NOCOMMS typo" >&2
			fi
		fi
		config_get notify_msg "$cfg" "$notify_type"
		config_get notify_flags_as_var "$cfg" "$flag_name"
		if [ -n "$notify_msg" ] || [ -n "$notify_flags_as_var" ]; then
			notify_section="$(uci -q add nut_monitor notifications)"
			if [ -z "$notify_section" ]; then
				log_migration_error "Failed to add notifications section"
				# We don't want to prevent other sections from being processed
				# if this one fails, so do not error exit, but keep going.
				continue
			fi
			if ! uci -q rename nut_monitor."$notify_section"="$notification_name"; then
				log_migration_error "Failed to rename '$notify_section' to '$notification_name'"
				# We don't want to prevent other sections from being processed
				# if this one fails, so do not error exit, but keep going.
				continue
			fi
		fi
		if [ -n "$notify_msg" ]; then
			if ! uci -q set nut_monitor."$notification_name".message="$notify_msg"; then
				log_migration_error "Failed to add message for '$notification_name'"
				continue
			fi
		fi
		upsmon_final_flags="$(get_notification_flags "$flag_name" "$cfg")"
		if [ -n "$upsmon_final_flags" ]; then
			if ! uci -q set nut_monitor."$notification_name".flag="$upsmon_final_flags"; then
				log_migration_error "Failed to add flag(s) to '$notification_name'"
				continue
			fi
		fi

		# Keep going even if deleting old flag fails. It won't be used
		# anyway, and partial success is better than none.
		if [ -n "$cfg" ] && [ -n "$notify_flags_as_var" ] && ! uci -q delete nut_monitor."$cfg"."$flag_name"; then
			log_migration_error "Failed to delete old flag '$flag_name' from '$cfg'"
		fi
		# Keep going even if deleting old notification message fails. It
		# won't be used anyway, and partial success is better than none.
		if [ -n "$cfg" ] && [ -n "$notify_msg" ] && ! uci -q delete nut_monitor."$cfg"."$notify_type"; then
			log_migration_error "Failed to delete old notification type '$notify_type' from '$cfg'"
		fi
	done
	set +f
	upsmon_final_flags="$(get_notification_flags "defaultnotify" "$cfg")"
	if [ -n "$upsmon_final_flags" ]; then
		if ! uci -q set nut_monitor."$cfg".defaultnotify="$upsmon_final_flags"; then
			log_migration_error "Failed to update defaultnotify for '$cfg'"
		fi
	fi
}

# shellcheck disable=SC2329,SC2317
process_primary_secondary() {
	local cfg="$1"
	local monitor_type="$2"
	local upsname hostname port powervalue username password section

	section="$(uci -q add nut_monitor monitor)" || {
		log_migration_error "Failed to add monitor section to replace '$cfg'"
		# Do not error exit as we do not want to stop other sections from being
		# processed
		return 0
	}

	if [ -n "$section" ]; then
		{
			uci -q set nut_monitor."$section".type="$monitor_type" || return 1

			# Empty values are allowed and should remain as such in the new
			# section.
			config_get upsname "$cfg" upsname
			config_get hostname "$cfg" hostname
			config_get port "$cfg" port
			config_get powervalue "$cfg" powervalue
			config_get username "$cfg" username
			config_get password "$cfg" password

			uci -q set nut_monitor."$section".upsname="$upsname" || return 1
			uci -q set nut_monitor."$section".hostname="$hostname" || return 1
			uci -q set nut_monitor."$section".port="$port" || return 1
			uci -q set nut_monitor."$section".powervalue="$powervalue" || return 1
			uci -q set nut_monitor."$section".username="$username" || return 1
			uci -q set nut_monitor."$section".password="$password" || return 1

			# Delete the old section with name config (of type primary
			# or secondary)
			uci -q delete nut_monitor."$cfg" || return 1
			# Rename the nut_monitor section '$section' we created, above, with
			# the name of the old section. This requires that the old section
			# with the same name has already been removed.
			# In the event of delete failure, the new section is present, but
			# with the name assigned when the new section was created.
			uci -q rename nut_monitor."$section"="$cfg" || return 1
			return 0
		} || {
			log_migration_error "Error converting primary/secondary section '$cfg'"
			# Do not error exit as we do not want to stop other sections from
			# being processed
			return 0
		}
	else
		log_migration_error "Name of monitor section to replace '$cfg' was empty"
		# Do not error exit as we do not want to stop other sections from being
		# processed
		return 0

	fi
}

config_load nut_monitor || {
	echo "nut-monitor-migrate: FATAL: Failed to load nut_monitor"
	exit 1
}
config_foreach process_upsmon_section upsmon
config_foreach process_primary_secondary master primary
config_foreach process_primary_secondary slave secondary

uci commit nut_monitor

exit 0