<?php

//
// This script updates the DNS type A on porkbun.com so it is always pointing to your public IP address.
//
// Dependencies:
//
// - PorkbunAPI.php
// - pb-dydns.json (it will be created automatically the 1st time)
//
// How to use it:
//
// - from command line:
//
// $ php /path/to/pb-dydns.php domain_name
//
// It will retrieve all DNS records for the specificied domain_name and update the A type ones
// with your public IP address.
//
//- as a cron job, to add it to:
//
// $ crontab -e
//
// Append this line as many times as domains you want to automatically update:
//
// */10 * * * *    php /path/to/pb-dydns.php domain_name > /dev/null
//
// And restart cron (I'm not sure if this is necessary):
//
// $ sudo systemctl restart cron
//
// Entries to a log file called "pb-dydns.log" will be added, to view it you can:
//
// $ cat /path/to/pb-dydns.log
//

require "PorkbunAPI.php";

// Make sure that pb-dydns.json exists:
$config_filename = __DIR__ . "/pb-dydns.json";

if (!file_exists($config_filename))
{
    echo "The config file $config_filename does not exist." . PHP_EOL;

	$config = json_encode(array
	(
		"url" => "https://porkbun.com/api/json/v3/",
		"apikey" => "",
		"secretapikey" => ""
	), JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);

	file_put_contents($config_filename, $config);

	echo "It has been created but you must edit it with your API key and secret." . PHP_EOL;
	echo "After that you can try again." . PHP_EOL;

	exit(1);
}

// Domain name must be provided as argument.
// There should be 2 arguments as $argc includes the script name itself:
if ($argc != 2)
{
	echo_to_cli("This script requires a domain name as argument:" . PHP_EOL);
	echo_to_cli("php $argv[0] domain_name" . PHP_EOL);

	exit(2);
}

// Take the arguments in individual variables:
$myDomain = $argv[1];

// Create an instance of PorkbunAPI:
$pbapi = new PorkbunAPI($config_filename);

// Test connection to Porkbun API in order to get the public IP:
$result = json_decode($pbapi->ping());
if ($result->status == "SUCCESS") $myIp = $result->yourIp;
else
{
	echo_to_cli("There was an error trying to ping Porkbun." . PHP_EOL);
	var_dump($result);
	exit(3);
}

echo_to_cli("Your public IP address is $myIp" . PHP_EOL);

// Retrieve all DNS records associated with user's domain:
$records = $pbapi->retrieve($myDomain);

// Discard those records that are not type "A":
$data = json_decode($records);
$filteredRecords = array_filter($data->records, function ($record)
{
	return $record->type == "A";
});

$log_filename = __DIR__ . "/pb-dydns.log";

// Update the records that passed the filter with the public IP:
foreach ($filteredRecords as $record)
{
	echo_to_cli("Porkbun's DNS for $record->name is pointing to $record->content... ");

	if ($record->content != $myIp)
	{
		echo_to_cli("Let's change that... ");
		$name = rtrim(strstr($record->name, $myDomain, true), ".");
		$result = json_decode($pbapi->edit($myDomain, $record->id, $myIp, $name));
		if ($result->status == "SUCCESS") echo_to_cli("Done!" . PHP_EOL);

		$now = date('Y-m-d H:i:s');
		$message = "$now: Updated DNS on $record->name from $record->content to $myIp" . PHP_EOL;
		file_put_contents($log_filename, $message, FILE_APPEND);
	}

	else
	{
		echo_to_cli("Nothing needs to be changed!" . PHP_EOL);
	}
}

?>