#!/bin/bash
set -u

auth_email="${DDNS_AUTH_EMAIL:-}"                  # The email used to login 'https://dash.cloudflare.com'
auth_method="${DDNS_AUTH_METHOD:-token}"           # Set to "global" for Global API Key or "token" for Scoped API Token
auth_key="${DDNS_AUTH_KEY:-}"                      # Your API Token or Global API Key
zone_identifier="${DDNS_ZONE_IDENTIFIER:-}"        # Can be found in the "Overview" tab of your domain
record_name="${DDNS_RECORD_NAME:-}"                # Which record you want to be synced
proxy="${DDNS_PROXY:-false}"                       # Set the proxy to true or false

###########################################
## Validate variables have been set
###########################################
if [ -z "${auth_email}" ]; then
  logger "DDNS Updater: DDNS_AUTH_EMAIL was unset"
  exit 1
fi
if [ -z "${auth_method}" ]; then
  logger "DDNS Updater: DDNS_AUTH_METHOD was unset"
  exit 1
fi
if [ -z "${auth_key}" ]; then
  logger "DDNS Updater: DDNS_AUTH_KEY was unset"
  exit 1
fi
if [ -z "${zone_identifier}" ]; then
  logger "DDNS Updater: DDNS_ZONE_IDENTIFIER was unset"
  exit 1
fi
if [ -z "${record_name}" ]; then
  logger "DDNS Updater: DDNS_RECORD_NAME was unset"
  exit 1
fi
if [ -z "${proxy}" ]; then
  logger "DDNS Updater: DDNS_PROXY was unset"
  exit 1
fi

###########################################
## Check if we have a public IP
###########################################
ip=$(curl -s https://api.ipify.org || curl -s https://ipv4.icanhazip.com/)

if [ "${ip}" == "" ]; then 
  logger -s "DDNS Updater: No public IP found"
  exit 1
fi

###########################################
## Check and set the proper auth header
###########################################
if [ "${auth_method}" == "global" ]; then
  auth_header="X-Auth-Key:"
else
  auth_header="Authorization: Bearer"
fi

###########################################
## Seek for the A record
###########################################

logger "DDNS Updater: Check Initiated"
record=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$zone_identifier/dns_records?name=$record_name" -H "X-Auth-Email: $auth_email" -H "$auth_header $auth_key" -H "Content-Type: application/json")

###########################################
## Check if the domain has an A record
###########################################
if [[ $record == *"\"count\":0"* ]]; then
  logger -s "DDNS Updater: Record does not exist, perhaps create one first? (${ip} for ${record_name})"
  exit 1
fi

###########################################
## Get existing IP
###########################################
old_ip=$(echo "$record" | grep -Po '(?<="content":")[^"]*' | head -1)
# Compare if they're the same
if [[ $ip == "${old_ip}" ]]; then
  logger "DDNS Updater: IP ($ip) for ${record_name} has not changed."
  exit 0
fi

###########################################
## Set the record identifier from result
###########################################
record_identifier=$(echo "$record" | grep -Po '(?<="id":")[^"]*' | head -1)

###########################################
## Change the IP@Cloudflare using the API
###########################################
update=$(curl -s -X PUT "https://api.cloudflare.com/client/v4/zones/$zone_identifier/dns_records/$record_identifier" \
                     -H "X-Auth-Email: $auth_email" \
                     -H "$auth_header $auth_key" \
                     -H "Content-Type: application/json" \
              --data "{\"id\":\"$zone_identifier\",\"type\":\"A\",\"proxied\":${proxy},\"name\":\"$record_name\",\"content\":\"$ip\"}")

###########################################
## Report the status
###########################################
case "$update" in
*"\"success\":false"*)
  logger -s "DDNS Updater: $ip $record_name DDNS failed for $record_identifier ($ip). DUMPING RESULTS:\n$update"
  exit 1;;
*)
  logger "DDNS Updater: $ip $record_name DDNS updated."
  exit 0;;
esac