#!/bin/bash

set -e

id=$(date +%s)_$$

fail () {
	printf >&2 "%s\n" "modrelays-probe: error: $1"
	exit 16
}

record-probing () {
	# implicitly uses newsgroup, id, domain
	# prints working dir filename
	local probeid=$1

	probeid=${probeid//[^=-.,_0-9A-Za-z]/%/}
	case $probeid in
	.*|*/*) fail "yikes, sanitisation bug!" ;;
	esac

	local newtd="monitoring/modrelays.probes/$probeid"
	mkdir -p $newtd
	printf "%s" $newtd
}

record-outcome () {
	local probeid=$1
	local outcome=$2
	local message=$3
	local td=`record-probing "$probeid"`
	printf "%s\n" >"$td"/"$outcome"
}

record-success () { record-outcome "$1" ok '' }
record-tempfail () { record-outcome "$1" tempfail "$2" }
record-permfail () { record-outcome "$1" permfail "$2" }

probe-addr () {
	local mx=$1
	local addr=$2

	local td=`record-probing "mx=$mx,addr=$addr"`

	set +e
	swaks	--to "${GROUP//./-/}@$domain" \
		--server $addr \
		--tls-optional-strict \
		--header 'Subject: test modrelays probe test' \
		--header \
	"X-WebSTUMP-Relay-Probe: $GROUP $id $domain $mx $addr" \
		-n >$td/swaks.log 2>$td/swaks.err
	rc=$?
	set -e

	case $rc in
	0) return ;; # record-success done by receiver
	esac
	local permfail=''

	local rhs
	local prefix
	local expect_no_5xx='initial connection'
	while read <$td/swaks.log prefix rhs; do
		case "$prefix" in
		'<'*)
			case "$rhs" in
			5*)
				if [ "x$expect_no_5xx" != x ] && \
				   [ "x$permfail" = x ]; then
					permfail="$rhs ($expect_no_5xx)" ;;
				fi
				;;
			esac
			;;
		*'>')
			case "$rhs" in
			EHLO*|STARTTLS*) expect_no_5xx='' ;;
			*) expect_no_5xx="after $rhs" ;;
			esac
			;;
		*)
	done

	if [ "x$permfail" = x ]; then
		record-tempfail "mx=$mx,addr=$addr" "see swaks.log / swaks.err"
	else
		record-permfail "mx=$mx,addr=$addr" "$permfail"
	fi
}

probe-domain () {
	local domain=$1
	local td=`record-probing dns`
	
	set +e
	adnshost -Fi -Tn +Do +Dt -t mx $domain >$td/dns
	rc=$?
	set -e

	case $rc in
	0)
		# have a list of MX's
		exec <$td/dns
		local pref
		local mx
		local statustype
		local rhs
		while read pref mx statustype rhs; do
			case $statustype in
			0)
				# have a list of relays
				case $rhs in
				*" ( "*")") ;;
				*)
					record-permfail "mx=$mx" \
						"dns format $rhs"
					continue
				;;
				rhs=${rhs%%* (}
				rhs=${rhs# )}
				local addr
				for addr in $rhs; do
					case $addr in
					INET|INET6) continue ;;
					esac
					probe-addr $mx $addr
				done
				;;
			[123])
				# temporary errors
				record-tempfail "mx=$mx" "dns $rc $rhs"
				;;
			*)
				# yikes
				record-permfail "mx=$mx" "dns $rc $rhs"
				;;
			esac
		done
		record-success dns
		return
		;;
	6)
		permfail, try A
		set +e
		adnshost -Fi -Tn +Do +Dt -t a $domain >$td
		rc=$?
		set -e
		;;
	esac

	case $rc in
	0)
		# have a list of A's (dealt with MXs above)
		exec <$td/dns
		local addr
		while read addr; do
			probe-addr '<no-mx>' $addr
		done
		record-success dns
		return
		;;
	[123])
		local emsg
		read <$td/dns emsg
		record-tempfail dns "dns <no-mx> $emsg"
		;;
	*)
		local emsg
		read <$td/dns emsg
		record-permfail dns "dns <no-mx> $emsg"
		;;
	esac
}

no_args () {
	case $1 in
	0) return ;;
	*) fail

mode_all () {
	no_args $#
	for domain in $MODRELAYS; do
		probe $domain
	done
}

mode_auto () {
	no_args $#
	xxx do something to cause sleeping
	mode_all
}

mode_relay () {
	relay="$1"
	probe "$relay"
}

mode=$1; shift||:

"mode_$mode" "$@"