#!/bin/sh
# Created on 2025-12-07 12:22 UTC
# Author: Dominic Reich (OE7DRT) <quick.hat4396@qtztsjosmprqmgtunjyf.com>

# Get my outgoing ipv4 address via ifconfig.me and compare it with the recent ip saved in ~/.my-ipv4
# Update dns with the actual ipv4 if it changed

# set default value for CHECK
# override this when starting the script like `CHECK=true update-ip.sh`
: "${CHECK:=false}"

if [ "${CHECK}x" = "truex" ]
then
        # currently abort if jq is not installed
        # might enter another routine to still display the record at the end
        command -v jq > /dev/null 2>&1 || { echo >&2 "jq not found"; exit 1; }

        # jq may be placed somewhere in /usr/local so first get the real path
        JQ=$(command -v jq)
fi

# specify file names
IPFILE4="${HOME}/.my-ipv4"
IPFILE6="${HOME}/.my-ipv6"

# Auth token (Hetzner new dns console as of Dec 2025)
API_URL="https://api.hetzner.cloud/v1/zones/"
AUTH_TOKEN=""

# Domain settings (zone id, rrset name, rrset type)
ZONE_ID="domain.local"
RR_NAME="@"
RR_TYPE4="A"
RR_TYPE6="AAAA"
RR_COMMENT4=""
RR_COMMENT6=""

# remote ipv4
IPREMOTE4=$(curl -4 -sgkL https://ifconfig.me/ip 2>/dev/null)
IPREMOTE6=$(curl -6 -sgkL https://ifconfig.me/ip 2>/dev/null)
# echo "DBG: got ip ${IPREMOTE4}"

# check if remote ips contain valid data
# TODO:
#       get info about useful regex on ipv4 and ipv6 addresses

# check if old IP4 is saved in file
if [ -w "${IPFILE4}" -a -f "${IPFILE4}" ]
then
        SAVEDIP4=$(cat ${IPFILE4})
        # echo "DBG: saved ip is ${SAVEDIP4}"
else
        # no existing ipv4 file, create one and add new ipv4 into it
        /bin/echo -n "${IPREMOTE4}" > ${IPFILE4}
        # echo "DBG: saved ip ${IPREMOTE4} to file ${IPFILE4}"
fi

#check for IP6
if [ -w "${IPFILE6}" -a -f "${IPFILE6}" ]
then
        SAVEDIP6=$(cat ${IPFILE6})
        # echo "DBG: saved ip is ${SAVEDIP4}"
else
        # no existing ipv4 file, create one and add new ipv4 into it
        /bin/echo -n "${IPREMOTE6}" > ${IPFILE6}
        # echo "DBG: saved ip ${IPREMOTE4} to file ${IPFILE4}"
fi

# check if remote ip is identical as locally saved ip
if [ "${SAVEDIP4}x" = "${IPREMOTE4}x" ]
then
        # if remote ip is equal as locally saved (old) ip
        # echo "DBG: do nothing, ips are equal"
        echo >&2 "IPv4 identical. Nothing to do"
else
        # ips differ, update dns ip with remote ip and save into local ip file
        curl -s -g -X POST -H "Authorization: Bearer ${AUTH_TOKEN}" \
                -H "Content-Type: application/json" \
                -d '{"records":[{"value":"'${IPREMOTE4}'","comment":"'${RR_COMMENT4}'"}]}' \
                "${API_URL}${ZONE_ID}/rrsets/${RR_NAME}/${RR_TYPE4}/actions/set_records" > /dev/null
        /bin/echo -n "${IPREMOTE4}" > ${IPFILE4}
fi

if [ "${CHECK}x" = "truex" ]
then
        # finally check (output actual json record saved on dns server) remote ip
        curl -s -H "Authorization: Bearer ${AUTH_TOKEN}" \
                "${API_URL}${ZONE_ID}/rrsets/${RR_NAME}/${RR_TYPE4}" | ${JQ} "[.[] | .records]"
fi

# and repeat for ipv6
if [ "${SAVEDIP6}x" = "${IPREMOTE6}x" ]
then
        # if remote ip is equal as locally saved (old) ip
        # echo "DBG: do nothing, ips are equal"
        echo >&2 "IPv6 identical. Nothing to do"
else
        # ips differ, update dns ip with remote ip and save into local ip file
        curl -s -g -X POST -H "Authorization: Bearer ${AUTH_TOKEN}" \
                -H "Content-Type: application/json" \
                -d '{"records":[{"value":"'${IPREMOTE6}'","comment":"'${RR_COMMENT6}'"}]}' \
                "${API_URL}${ZONE_ID}/rrsets/${RR_NAME}/${RR_TYPE6}/actions/set_records" > /dev/null
        /bin/echo -n "${IPREMOTE6}" > ${IPFILE6}
fi

if [ "${CHECK}x" = "truex" ]
then
        # also check for ipv6
        curl -s -H "Authorization: Bearer ${AUTH_TOKEN}" \
                "${API_URL}${ZONE_ID}/rrsets/${RR_NAME}/${RR_TYPE6}" | ${JQ} "[.[] | .records]"
fi