#!/bin/sh
# vim: set noexpandtab tabstop=4 shiftwidth=4 softtabstop=4 :

name=$0
basename="$(basename $0)"

_log() {
	logger -p daemon.info -t "${basename}" "$@"
}

_ping_server() {
	local host=$1
	ret=$(ping \
	    -w "$OMR_TRACKER_TIMEOUT" \
	    -c 1 \
	    -q \
	    "${host}"
	) && echo "$ret" | grep -sq " 0% packet loss" && {
		server_ping=true
	}
}

_get_ip() {
	uci -q set openmptcprouter.omr=router
	if [ "$(uci -q get openmptcprouter.settings.external_check)" != "0" ]; then
		check_ipv4_website="$(uci -q get openmptcprouter.settings.check_ipv4_website)"
		[ -z "$check_ipv4_website" ] && check_ipv4_website="http://ip.openmptcprouter.com"
		check_ipv6_website="$(uci -q get openmptcprouter.settings.check_ipv6_website)"
		[ -z "$check_ipv6_website" ] && check_ipv6_website="http://ipv6.openmptcprouter.com"
		uci -q set openmptcprouter.omr.detected_public_ipv4="$(wget -4 -qO- -T 3 $check_ipv4_website)"
		uci -q set openmptcprouter.omr.detected_ss_ipv4="$(curl -s -4 --socks5 "${proxy}" --max-time 3 $check_ipv4_website)"
		if [ "$(uci -q get openmptcprouter.settings.disable_ipv6)" != "1" ]; then
			uci -q set openmptcprouter.omr.detected_public_ipv6="$(wget -6 -qO- -T 3 $check_ipv6_website)"
		#	uci -q set openmptcprouter.omr.detected_ss_ipv6=$(curl -s -6 --socks5 ":::1111" --max-time 3 http://ip.openmptcprouter.com)
		fi
	fi
	uci -q commit openmptcprouter
}

timeout=${OMR_TRACKER_TIMEOUT:-5}
interval=${OMR_TRACKER_INTERVAL:-10}
retry=${OMR_TRACKER_TRIES:-4}
proxy=${OMR_TRACKER_PROXY:-127.0.0.1:1111}
hosts=${OMR_TRACKER_HOSTS:-1.1.1.1 1.0.0.1}

nodns=0

last=0
nocontact=""
uci -q set openmptcprouter.omr=router
uci -q delete openmptcprouter.omr.shadowsocks=""
_get_ip

while true; do
	host="${hosts%% *}"
	[ "$host" = "$hosts" ] || {
		hosts="${hosts#* } $host"
	}
	if [ "$(curl -s -I -w %{http_code} --socks5 ${proxy} --max-time ${timeout} $host -o /dev/null)" != "000" ]; then
		nocontact=""
		[ "${last}" -ge "${retry}" ] || [ "$(uci -q get openmptcprouter.omr.shadowsocks)" = "" ] && {
			_log "Shadowsocks is up (can contact via http ${host})"
			uci -q set openmptcprouter.omr.shadowsocks="up"
			uci -q commit openmptcprouter.omr
		}
		if [ -z "$(iptables -t nat -L -n | grep ss_rules_forward)" ] && [ "$(uci -q get shadowsocks-libev.ss_rules.disabled)" != "1" ]; then
			_log "Reload Shadowsocks rules"
			/etc/init.d/shadowsocks-libev rules_up 2> /dev/null
			_get_ip
		fi
		[ "$(uci -q get openmptcprouter.omr.detected_public_ipv4)" = "" ] || ([ "$(uci -q get openmptcprouter.settings.disable_ipv6)" != "1" ] && [ "$(uci -q get openmptcprouter.omr.detected_public_ipv6)" = "" ]) && _get_ip
		last=0
	else
		last=$((last + 1 ))
		[ -z "$nocontact" ] && nocontact="$host" || nocontact="$nocontact, $host"
		[ "${last}" -ge "${retry}" ] && {
			if [ -n "$(iptables -t nat -L -n | grep ss_rules_forward)" ]; then
				_log "Shadowsocks is down (can't contact via http ${nocontact})"
				uci -q set openmptcprouter.omr.shadowsocks="down"
				uci -q commit openmptcprouter.omr
				/etc/init.d/shadowsocks-libev rules_down 2> /dev/null
				_get_ip
				server_ping=false
				server="$(uci -q get shadowsocks-libev.sss0.server)"
				_ping_server $server
				if [ "$server_ping" = false ]; then
					_log "Server ($server) seems down, no answer to ping"
				fi
			fi
		}
	fi
	sleep "${interval}"
done