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

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

if [ -f /usr/sbin/iptables-legacy ]; then
	IPTABLES="/usr/sbin/iptables-legacy"
	IPTABLESSAVE="/usr/sbin/iptables-legacy-save"
else
	IPTABLES="/usr/sbin/iptables"
	IPTABLESSAVE="/usr/sbin/iptables-save"
fi



_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 "$check_ipv6_website" ] && check_ipv6_website="http://ipv6.openmptcprouter.com"
		public_ipv4="$(curl -s -4 -m 3 $check_ipv4_website)"
		uci -q set openmptcprouter.omr.detected_public_ipv4="${public_ipv4}"
		[ -n "$public_ipv4" ] && {
			uci -q set upnpd.config.external_ip="${public_ipv4}"
			uci -q commit upnpd
		}
		if [ "$(uci -q get openmptcprouter.omr.shadowsocks)" != "down" ]; then
			uci -q set openmptcprouter.omr.detected_ss_ipv4="$(curl -s -4 --socks5 "${proxy}" --max-time 3 $check_ipv4_website)"
		else
			uci -q del openmptcprouter.omr.detected_ss_ipv4
		fi
		if [ "$(uci -q get openmptcprouter.settings.disable_ipv6)" != "1" ]; then
			uci -q set openmptcprouter.omr.detected_public_ipv6="$(curl -s -6 -m 3 $check_ipv6_website)"
		else
			uci -q del openmptcprouter.omr.detected_public_ipv6
		#	uci -q set openmptcprouter.omr.detected_ss_ipv6=$(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=${OMR_TRACKER_HOSTS:-1.1.1.1 1.0.0.1}
wait_test=${OMR_TRACKER_WAIT_TEST:-0}
server=${OMR_TRACKER_SERVER:-sss0}
type=${OMR_TRACKER_SS_TYPE:-libev}
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.ss_${server})" = "" ] && {
			_log "Shadowsocks ${server} is up (can contact via http ${host})"
			OMR_TRACKER_STATUS_MSG="Shadowsocks ${server} is up (can contact via http ${host})"
			uci -q set openmptcprouter.omr.ss_${server}="up"
			uci -q commit openmptcprouter.omr
			mail_alert="$(uci -q get omr-tracker.proxy.mail_alert)"
			#[ -z "$mail_alert" ] && mail_alert="$(uci -q get omr-tracker.defaults.mail_alert)"
			[ "$mail_alert" = "1" ] && [ -n "$(uci -q get mail.default.to)" ] && {
				OMR_SYSNAME="$(uci -q get system.@system[0].hostname)"
				if [ "$(uci -q get omr-tracker.defaults.mail_up_subject)" != "" ] && [ "$(uci -q get omr-tracker.defaults.mail_up_message)" != "" ]; then
					mail_subject="$(uci -q get omr-tracker.defaults.mail_up_subject)"
					mail_subject=`echo $mail_subject | sed -e "s/%SYSNAME%/$OMR_SYSNAME/g" -e "s/%INTERFACE%/Shadowsocks Proxy/g" -e "s/%DEVICE%/Shadowsocks Proxy/g" -e "s/%MESSAGE%/$OMR_TRACKER_STATUS_MSG/g"`
					mail_message="$(uci -q get omr-tracker.defaults.mail_up_message)"
					mail_message=`echo $mail_message | sed -e "s/%SYSNAME%/$OMR_SYSNAME/g" -e "s/%INTERFACE%/Shadowsocks Proxy/g" -e "s/%DEVICE%/Shadowsocks Proxy/g" -e "s/%MESSAGE%/$OMR_TRACKER_STATUS_MSG/g"`
					echo -e "Subject: ${mail_subject}\n\n${mail_message}" | sendmail $(uci -q get mail.default.to)
				else
					echo -e "Subject: $OMR_SYSNAME: Shadowsocks Proxy is UP." | sendmail $(uci -q get mail.default.to)
				fi
			}
			script_alert_up="$(uci -q get omr-tracker.proxy.script_alert_up)"
			[ -n "$script_alert_up" ] && eval $script_alert_up
		}
		if [ -z "$($IPTABLESSAVE 2>/dev/null | grep :ssr)" ]; then
			if [ "$type" = "libev" ] && [ "$(uci -q get shadowsocks-libev.ss_rules.disabled)" != "1" ]; then
				_log "Reload Shadowsocks rules"
				/etc/init.d/shadowsocks-libev rules_up 2> /dev/null
				_get_ip
			elif [ "$type" = "rust" ] && [ "$(uci -q get shadowsocks-rust.ss_rules.disabled)" != "1" ]; then
				_log "Reload Shadowsocks Rust rules"
				/etc/init.d/shadowsocks-rust rules_up 2> /dev/null
				_get_ip
			fi
		fi
		[ "$(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 -w -t nat -L -n 2>/dev/null | grep ssr)" ]; then
				_log "Shadowsocks ${server} is down (can't contact via http ${nocontact})"
				OMR_TRACKER_STATUS_MSG="Shadowsocks ${server} is down (can't contact via http ${nocontact})"
				uci -q set openmptcprouter.omr.ss_${server}="down"
				uci -q commit openmptcprouter.omr
				if [ "$(uci show openmptcprouter.omr | grep ss_ | grep up)" = "" ]; then
					[ "$type" = "libev" ] && /etc/init.d/shadowsocks-libev rules_down 2> /dev/null
					[ "$type" = "rust" ] && /etc/init.d/shadowsocks-rust rules_down 2> /dev/null
				fi
				_get_ip
				server_ping=false
				if [ "$type" = "libev" ]; then
					serverip="$(uci -q get shadowsocks-libev.${server}.server)"
					disabled="$(uci -q get shadowsocks-libev.${server}.disabled)"
				elif [ "$type" = "rust" ]; then
					serverip="$(uci -q get shadowsocks-rust.${server}.server)"
					disabled="$(uci -q get shadowsocks-rust.${server}.disabled)"
				fi
				_ping_server $serverip
				if [ "$server_ping" = false ]; then
					_log "Server $server ($serverip) seems down, no answer to ping"
					OMR_TRACKER_STATUS_MSG="${OMR_TRACKER_STATUS_MSG} - Server $server ($serverip) seems down, no answer to ping"
				fi
				mail_alert="$(uci -q get omr-tracker.proxy.mail_alert)"
				#[ -z "$mail_alert" ] && mail_alert="$(uci -q get omr-tracker.defaults.mail_alert)"
				[ "$mail_alert" = "1" ] && [ -n "$(uci -q get mail.default.to)" ] && {
					OMR_SYSNAME="$(uci -q get system.@system[0].hostname)"
					if [ "$(uci -q get omr-tracker.defaults.mail_down_subject)" != "" ] && [ "$(uci -q get omr-tracker.defaults.mail_down_message)" != "" ]; then
						mail_subject="$(uci -q get omr-tracker.defaults.mail_down_subject)"
						mail_subject=`echo $mail_subject | sed -e "s/%SYSNAME%/$OMR_SYSNAME/g" -e "s/%INTERFACE%/Shadowsocks Proxy/g" -e "s/%DEVICE%/Shadowsocks Proxy/g" -e "s/%MESSAGE%/$OMR_TRACKER_STATUS_MSG/g"`
						mail_message="$(uci -q get omr-tracker.defaults.mail_down_message)"
						mail_message=`echo $mail_message | sed -e "s/%SYSNAME%/$OMR_SYSNAME/g" -e "s/%INTERFACE%/Shadowsocks Proxy/g" -e "s/%DEVICE%/Shadowsocks Proxy/g" -e "s/%MESSAGE%/$OMR_TRACKER_STATUS_MSG/g"`
						echo -e "Subject: ${mail_subject}\n\n${mail_message}" | sendmail $(uci -q get mail.default.to)
					else
						echo -e "Subject: $OMR_SYSNAME: Shadowsocks Proxy is down\n\nConnection failure of ShadowSocks proxy detected. The reason is \"$OMR_TRACKER_STATUS_MSG\"." | sendmail $(uci -q get mail.default.to)
					fi
				}
				script_alert_down="$(uci -q get omr-tracker.proxy.script_alert_down)"
				[ -n "$script_alert_down" ] && eval $script_alert_down

				if [ "$disabled" != "1" ]; then
					if [ "$type" = "libev" ] && [ "$(pgrep ss-redir)" = "" ] && [ "$(uci -q get shadowsocks-libev.${server}.key)" != "" ]; then
						_log "Can't find shadowsocks, restart it..."
						/etc/init.d/shadowsocks-libev restart
						sleep 5
					fi
					if [ "$type" = "rust" ] && [ "$(pgrep ss-redir)" = "" ] && [ "$(uci -q get shadowsocks-libev.${server}.key)" != "" ]; then
						_log "Can't find shadowsocks rust, restart it..."
						/etc/init.d/shadowsocks-rust restart
						sleep 5
					fi
				fi
				sleep $wait_test
			fi
		}
	fi
	sleep "${interval}"
done