#!/bin/bash

###
# Cloudflare API DDNS update script
# Heavily inspired by https://gist.github.com/lifehome/eb3f7d798f9bc6720cdc7d2be1238d4f
#
# Requirements: jq, curl
###

auth_token="XXXXXXXXXXXXXXX"          # Token generated from "My profile > API Tokens"
zone_identifier="XXXXXXX"             # Can be found in the "Overview" tab of your domain
record_name="my.hostname.example.com" # Which record you want to be synced

# DO NOT CHANGE LINES BELOW
#ip=$(curl -s https://ipv4.icanhazip.com/)
ip=$(curl -s https://ifconfig.me/ip)

# SCRIPT START
echo "[Cloudflare DDNS] Check Initiated"

# Seek for the record
record=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$zone_identifier/dns_records?name=$record_name" -H "Authorization: Bearer $auth_token" -H "Content-Type: application/json")

# Can't do anything without the record
if [[ $record == *"\"count\":0"* ]]; then
  >&2 echo -e "[Cloudflare DDNS] Record does not exist, perhaps create one first?"
  exit 1
fi

# Set existing IP address from the fetched record
old_ip=$(echo "$record" | jq -r ".result[0].content")

# Compare if they're the same
if [ $ip == $old_ip ]; then
  echo "[Cloudflare DDNS] IP address has not changed."
  exit 0
fi

# Set the record identifier from result
record_identifier=$(echo "$record" | jq -r ".result[0].id")

# The execution of update
update=$(curl -s -X PUT "https://api.cloudflare.com/client/v4/zones/$zone_identifier/dns_records/$record_identifier" -H "Authorization: Bearer $auth_token" -H "Content-Type: application/json" --data "{\"id\":\"$zone_identifier\",\"type\":\"A\",\"proxied\":false,\"name\":\"$record_name\",\"content\":\"$ip\"}")

# The moment of truth
case "$update" in
*"\"success\":false"*)
  >&2 echo -e "[Cloudflare DDNS] Update failed for $record_identifier. DUMPING RESULTS:\n$update"
  exit 1;;
*)
  echo "[Cloudflare DDNS] IPv4 context '$ip' has been synced to Cloudflare.";;
esac