#!/bin/sh
# Copyright (C) 2016 Velocloud Inc
# Copyright (C) 2016 Aleksander Morgado <aleksander@aleksander.es>

################################################################################

. /lib/functions.sh
. /lib/netifd/netifd-proto.sh

################################################################################
# Runtime state

MODEMMANAGER_RUNDIR="/var/run/modemmanager"
MODEMMANAGER_PID_FILE="${MODEMMANAGER_RUNDIR}/modemmanager.pid"
MODEMMANAGER_CDCWDM_CACHE="${MODEMMANAGER_RUNDIR}/cdcwdm.cache"
MODEMMANAGER_SYSFS_CACHE="${MODEMMANAGER_RUNDIR}/sysfs.cache"
MODEMMANAGER_EVENTS_CACHE="${MODEMMANAGER_RUNDIR}/events.cache"

################################################################################
# Common logging

mm_log() {
	logger -t "ModemManager" "hotplug: $*"
}

################################################################################
# Receives as input argument the full sysfs path of the device
# Returns the physical device sysfs path
#
# NOTE: this method only works when the device exists, i.e. it cannot be used
# on removal hotplug events

mm_find_physdev_sysfs_path() {
	local tmp_path="$1"

	while true; do
		tmp_path=$(dirname "${tmp_path}")

		# avoid infinite loops iterating
		[ -z "${tmp_path}" ] || [ "${tmp_path}" = "/" ] && return

		# the physical device will be that with a idVendor and idProduct pair of files
		[ -f "${tmp_path}"/idVendor ] && [ -f "${tmp_path}"/idProduct ] && {
			tmp_path=$(readlink -f "$tmp_path")
			echo "${tmp_path}"
			return
		}
	done
}

################################################################################

# Returns the cdc-wdm name retrieved from sysfs
mm_track_cdcwdm() {
	local wwan="$1"
	local cdcwdm

	cdcwdm=$(ls "/sys/class/net/${wwan}/device/usbmisc/")
	[ -n "${cdcwdm}" ] || return

	# We have to cache it for later, as we won't be able to get the
	# associated cdc-wdm device on a remove event
	echo "${wwan} ${cdcwdm}" >> "${MODEMMANAGER_CDCWDM_CACHE}"

	echo "${cdcwdm}"
}

# Returns the cdc-wdm name retrieved from the cache
mm_untrack_cdcwdm() {
	local wwan="$1"
	local cdcwdm

	# Look for the cached associated cdc-wdm device
	[ -f "${MODEMMANAGER_CDCWDM_CACHE}" ] || return

	cdcwdm=$(awk -v wwan="${wwan}" '!/^#/ && $0 ~ wwan { print $2 }' "${MODEMMANAGER_CDCWDM_CACHE}")
	[ -n "${cdcwdm}" ] || return

	# Remove from cache
	sed -i "/${wwan} ${cdcwdm}/d" "${MODEMMANAGER_CDCWDM_CACHE}"

	echo "${cdcwdm}"
}

################################################################################
# ModemManager needs some time from the ports being added until a modem object
# is exposed in DBus. With the logic here we do an explicit wait of N seconds
# for ModemManager to expose the new modem object, making sure that the wait is
# unique per device (i.e. per physical device sysfs path).

# Gets the modem wait status as retrieved from the cache
mm_get_modem_wait_status() {
	local sysfspath="$1"

	# If no sysfs cache file, we're done
	[ -f "${MODEMMANAGER_SYSFS_CACHE}" ] || return

	# Get status of the sysfs path
	awk -v sysfspath="${sysfspath}" '!/^#/ && $0 ~ sysfspath { print $2 }' "${MODEMMANAGER_SYSFS_CACHE}"
}

# Clear the modem wait status from the cache, if any
mm_clear_modem_wait_status() {
	local sysfspath="$1"

	local escaped_sysfspath

	[ -f "${MODEMMANAGER_SYSFS_CACHE}" ] && {
		# escape '/', '\' and '&' for sed...
		escaped_sysfspath=$(echo "$sysfspath" | sed -e 's/[\/&]/\\&/g')
		sed -i "/${escaped_sysfspath}/d" "${MODEMMANAGER_SYSFS_CACHE}"
	}
}

# Sets the modem wait status in the cache
mm_set_modem_wait_status() {
	local sysfspath="$1"
	local status="$2"

	# Remove sysfs line before adding the new one with the new state
	mm_clear_modem_wait_status "${sysfspath}"

	# Add the new status
	echo "${sysfspath} ${status}" >> "${MODEMMANAGER_SYSFS_CACHE}"
}

# Callback for config_foreach()
mm_get_modem_config_foreach_cb() {
	local cfg="$1"
	local sysfspath="$2"

	local proto
	config_get proto "${cfg}" proto
	[ "${proto}" = modemmanager ] || return 0

	local dev
	dev=$(uci_get network "${cfg}" device)
	[ "${dev}" = "${sysfspath}" ] || return 0

	echo "${cfg}"
}

# Returns the name of the interface configured for this device
mm_get_modem_config() {
	local sysfspath="$1"

	# Look for configuration for the given sysfs path
	config_load network
	config_foreach mm_get_modem_config_foreach_cb interface "${sysfspath}"
}

# Wait for a modem in the specified sysfspath
mm_wait_for_modem() {
	local cfg="$1"
	local sysfspath="$2"

	# TODO: config max wait
	local n=45
	local step=5

	while [ $n -ge 0 ]; do
		[ -d "${sysfspath}" ] || {
			mm_log "error: ignoring modem detection request: no device at ${sysfspath}"
			proto_set_available "${cfg}" 0
			return 1
		}

		# Check if the modem exists at the given sysfs path
		if ! mmcli -m "${sysfspath}" > /dev/null 2>&1
		then
			mm_log "error: modem not detected at sysfs path"
		else
			mm_log "modem exported successfully at ${sysfspath}"
			mm_log "setting interface '${cfg}' as available"
			proto_set_available "${cfg}" 1
			return 0
		fi

		sleep $step
		n=$((n-step))
	done

	mm_log "error: timed out waiting for the modem to get exported at ${sysfspath}"
	proto_set_available "${cfg}" 0
	return 2
}

mm_report_modem_wait() {
	local sysfspath=$1

	local parent_sysfspath status

	parent_sysfspath=$(mm_find_physdev_sysfs_path "$sysfspath")
	[ -n "${parent_sysfspath}" ] || {
		mm_log "error: parent device sysfspath not found"
		return
	}

	status=$(mm_get_modem_wait_status "${parent_sysfspath}")
	case "${status}" in
		"")
			local cfg

			cfg=$(mm_get_modem_config "${parent_sysfspath}")
			if [ -n "${cfg}" ]; then
				mm_log "interface '${cfg}' is set to configure device '${parent_sysfspath}'"
				mm_log "now waiting for modem at sysfs path ${parent_sysfspath}"
				mm_set_modem_wait_status "${parent_sysfspath}" "processed"
				# Launch subshell for the explicit wait
				( mm_wait_for_modem "${cfg}" "${parent_sysfspath}" ) > /dev/null 2>&1 &
			else
				mm_log "no need to wait for modem at sysfs path ${parent_sysfspath}"
				mm_set_modem_wait_status "${parent_sysfspath}" "ignored"
			fi
			;;
		"processed")
			mm_log "already waiting for modem at sysfs path ${parent_sysfspath}"
			;;
		"ignored")
			;;
		*)
			mm_log "error: unknown status read for device at sysfs path ${parent_sysfspath}"
			;;
	esac
}

################################################################################
# Cleanup interfaces

mm_cleanup_interface_cb() {
	local cfg="$1"

	local proto
	config_get proto "${cfg}" proto
	[ "${proto}" = modemmanager ] || return 0

	proto_set_available "${cfg}" 0
}

mm_cleanup_interfaces() {
	config_load network
	config_foreach mm_cleanup_interface_cb interface
}

mm_cleanup_interface_by_sysfspath() {
	local dev="$1"

	local cfg
	cfg=$(mm_get_modem_config "$dev")
	[ -n "${cfg}" ] || return

	mm_log "setting interface '$cfg' as unavailable"
	proto_set_available "${cfg}" 0
}

################################################################################
# Event reporting

# Receives as input the action, the device name and the subsystem
mm_report_event() {
	local action="$1"
	local name="$2"
	local subsystem="$3"
	local sysfspath="$4"

	# Track/untrack events in cache
	case "${action}" in
		"add")
			# On add events, store event details in cache (if not exists yet)
			grep -qs "${name},${subsystem}" "${MODEMMANAGER_EVENTS_CACHE}" || \
				echo "${action},${name},${subsystem},${sysfspath}" >> "${MODEMMANAGER_EVENTS_CACHE}"
			;;
		"remove")
			# On remove events, remove old events from cache (match by subsystem+name)
			sed -i "/${name},${subsystem}/d" "${MODEMMANAGER_EVENTS_CACHE}"
			;;
	esac

	# Report the event
	mm_log "event reported: action=${action}, name=${name}, subsystem=${subsystem}"
	mmcli --report-kernel-event="action=${action},name=${name},subsystem=${subsystem}" 1>/dev/null 2>&1 &

	# Wait for added modem if a sysfspath is given
	[ -n "${sysfspath}" ] && [ "$action" = "add" ] && mm_report_modem_wait "${sysfspath}"
}

mm_report_event_from_cache_line() {
	local event_line="$1"

	local action name subsystem sysfspath
	action=$(echo "${event_line}" | awk -F ',' '{ print $1 }')
	name=$(echo "${event_line}" | awk -F ',' '{ print $2 }')
	subsystem=$(echo "${event_line}" | awk -F ',' '{ print $3 }')
	sysfspath=$(echo "${event_line}" | awk -F ',' '{ print $4 }')

	mm_log "cached event found: action=${action}, name=${name}, subsystem=${subsystem}, sysfspath=${sysfspath}"
	mm_report_event "${action}" "${name}" "${subsystem}" "${sysfspath}"
}

mm_report_events_from_cache() {
	# Remove the sysfs cache
	rm -f "${MODEMMANAGER_SYSFS_CACHE}"

	local n=10
	local step=1
	local mmrunning=0

	# Wait for ModemManager to be available in the bus
	while [ $n -ge 0 ]; do
		sleep $step
		mm_log "checking if ModemManager is available..."

		if ! mmcli -L >/dev/null 2>&1
		then
			mm_log "ModemManager not yet available"
		else
			mmrunning=1
			break
		fi
		n=$((n-step))
	done

	[ ${mmrunning} -eq 1 ] || {
		mm_log "error: couldn't report initial kernel events: ModemManager not running"
		return
	}

	# Report cached kernel events
	while IFS= read -r event_line; do
		mm_report_event_from_cache_line "${event_line}"
	done < ${MODEMMANAGER_EVENTS_CACHE}
}