#!/bin/bash

set -e

. settings

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

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

record-probing () {
	# implicitly uses newsgroup, id, domain
	# caller must "local td", which will be set
	local probeid=$1

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

	td="probes/probes/$probeid"
	mkdir -p $td
}

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

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'
	exec <$td/swaks.log
	while read prefix rhs; do
		case "$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
			;;
		*)
		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 statustypenum rhs; do
			case $statustypenum in
			0)
				# have a list of relays
				case $rhs in
				*" ( "*")") ;;
				*)
					record-permfail "mx=$mx" \
						"dns format $rhs"
					continue
					;;
				esac
				rhs=${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 $statustype $rhs"
				;;
			*)
				# yikes
				record-permfail "mx=$mx" \
					"dns $rc $statustype $rhs"
				;;
			esac
		done
		record-success dns
		return
		;;
	6)
		# permfail, try A
		set +e
		adnshost -Fi -Tn +Do +Dt -t a $domain >$td/dns
		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 'NONE' $addr
		done
		record-success dns
		return
		;;
	[123])
		local emsg
		read <$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 "no arguments to $mode allowed" ;;
	esac
}

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

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

mode_domain () {
	for domain in "$@"; do
		probe-domain $domain
	done
}

mode=$1; shift||:

"mode_$mode" "$@"