#!/bin/sh

. ./dns-functions.sh

ReverseDomain="$1"
ReverseZone="${ReverseDomain%*.}"
ForwardZones="$2"
ReverseZoneFile="$3""db.""$(echo "$ReverseZone" | awk -F. '{ printf $(NF-2);for(i=NF-3;i>0;--i) printf "."$i}')"
TempDir="/tmp/""$ReverseZone"
TTL="${4%% *}"
ReReExMi="${4#* }"
View="$5"

GetIPEntries() {
	if [ -z "$RZoneIsIPv6" ]; then
		IPPattern="[aA]\s\+\([0-9\.]\+\)"
	else
		IPPattern="[aA]\{4\}\s\+\([0-9a-f:]\+\)"
	fi
	
	sed -ne "s/^\s*\(\S\+\)\s\+\([0-9]*\s\)\?\s*[Ii][Nn]\s\+""$IPPattern"".*/\1\/\3/p" "$TempDir/$ForwardZoneFile"
}

ReverseEntry() {
	if [ -z "$RZoneIsIPv6" ]; then
		echo "$(GetReverseDomains "$1""/32")"
	else
		echo "$(GetReverseDomains "$1""/128")"
	fi
}

if [ -z "${ReverseDomain##*.in-addr.arpa.}" ]; then
	RZoneIsIPv6=""
elif [ -z "${ReverseDomain##*.ip6.arpa.}" ]; then
	RZoneIsIPv6=1
else
	echo "No valid ReverseDomain" 1>&2
	exit 1
fi

mkdir -p "$TempDir"

for ForwardZone in $ForwardZones; do
	ZoneName="${ForwardZone%%/*}"
	ZoneFile="${ForwardZone#*/}"
	named-checkzone -f text -i local -o "$TempDir/$ZoneName" -D "$ZoneName" "$ZoneFile" >/dev/null 2>&1
	Serial="$(GetZoneFileSerial "$TempDir/$ZoneName")"
	NewReverseSerial=$((Serial + NewReverseSerial))
	ZoneRevNS="$(sed -ne 's/^\s*\S\+\s\+\([0-9]*\s\)\?\s*[Ii][Nn]\s\+[Nn][Ss]\s\+\(\S\+\)\s*.*;\s*Reverse:\s*\([^;]*\)$/\2\/\3/p' "$ZoneFile")"
	ZoneRevNS="$(echo "$ZoneRevNS" | sed -e 's/\(.*[^\.]\)\//\1\.'"$ZoneName"'\.\//' )"
	SubNSEntries="$SubNSEntries""$ZoneRevNS"
done

if [ -f "$ReverseZoneFile" ]; then
	OldSerial=$(GetZoneFileSerial "$ReverseZoneFile")
else
	OldSerial=0
fi

if [ $NewReverseSerial -gt $OldSerial ]; then
	echo "$ReverseDomain $TTL IN SOA $DNSSCRIPT_SERVER_NAME""."" $DNSSCRIPT_CONTACT_EMAIL $NewReverseSerial $ReReExMi" > "$TempDir/$ReverseZone"
	echo "$ReverseDomain $TTL IN NS $DNSSCRIPT_SERVER_NAME"".""" >> "$TempDir/$ReverseZone"
	
	echo "$SubNSEntries" | while read -r SubNSEntry; do
		for SubReverseDomain in ${SubNSEntry#*/}; do
			if [ -n "$SubReverseDomain" ] && [ -z "${SubReverseDomain##*$ReverseDomain}" ]; then
				echo "$SubReverseDomain $TTL IN NS ${SubNSEntry%/*}" >> "$TempDir/$ReverseZone"
			fi
		done
	done
	
	for ForwardZoneFile in $(ls $TempDir); do
		IPEntries="$(GetIPEntries)"
		
		for IPEntry in $IPEntries; do
			IP="${IPEntry#*/}"
			# IP syntax checked by named-checkzone
			IP="$(ReverseEntry "$IP")"
			if [ -z "${IP##*$ReverseDomain}" ]; then
				Host="${IPEntry%/*}"
				echo "$IP $TTL IN PTR $Host" >> "$TempDir/$ReverseZone"
			fi
		done
	done
	
	named-checkzone -o "$ReverseZoneFile" "$ReverseDomain" "$TempDir/$ReverseZone" >/dev/null 2>&1
	ReloadZone "$ReverseDomain" "$View"
fi

rm -r "$TempDir"