<?php

class RPZExport {

	private $__policies = array(
			'walled-garden' => array(
					'explanation' => 'returns the defined alternate location.',
					'action' => '$walled_garden',
					'setting_id' => 3,
			),
			'NXDOMAIN' => array(
					'explanation' => 'return NXDOMAIN (name does not exist) irrespective of actual result received.',
					'action' => '.',
					'setting_id' => 1,
			),
			'NODATA' => array(
					'explanation' => 'returns NODATA (name exists but no answers returned) irrespective of actual result received.',
					'action' => '*.',
					'setting_id' => 2,
			),
			'DROP' => array(
					'explanation' => 'timeout.',
					'action' => 'rpz-drop.',
					'setting_id' => 0,
			),
	);

	public function getPolicyById($id) {
		foreach ($this->__policies as $k => $v) {
			if ($id == $v['setting_id']) return $k;
		}
	}

	public function getIdByPolicy($policy) {
		return $this->__policies[$policy]['setting_id'];
	}

	public function explain($type, $policy) {
		$explanations = array(
			'ip' => '; The following list of IP addresses will ',
			'domain' => '; The following domain names and all of their sub-domains will ',
			'hostname' => '; The following hostnames will '
		);
		$policy_explanations = array(
			'walled-garden' => 'returns the defined alternate location.',
			'NXDOMAIN' => 'return NXDOMAIN (name does not exist) irrespective of actual result received.',
			'NODATA' => 'returns NODATA (name exists but no answers returned) irrespective of actual result received.',
			'DROP' => 'timeout.',
		);
		return $explanations[$type] . $this->__policies[$policy]['explanation'] . PHP_EOL;
	}

	public function buildHeader($rpzSettings) {
		$rpzSettings['serial'] = str_replace('$date', date('Ymd'), $rpzSettings['serial']);
		$header = '';
		$header .= '$TTL ' . $rpzSettings['ttl'] . ';' . PHP_EOL;
		$header .= '@               SOA ' . $rpzSettings['ns'] . ' ' . $rpzSettings['email'] . ' ('  . $rpzSettings['serial'] . ' ' . $rpzSettings['refresh'] . ' ' . $rpzSettings['retry'] . ' ' . $rpzSettings['expiry'] . ' ' . $rpzSettings['minimum_ttl'] . ')' . PHP_EOL;
		$header .= '                NS ' . $rpzSettings['ns'] . PHP_EOL . PHP_EOL;
		return $header;
	}

	public function export($items, $rpzSettings) {
		$result = $this->buildHeader($rpzSettings);
		$policy = $this->getPolicyById($rpzSettings['policy']);
		$action = $this->__policies[$policy]['action'];
		if ($policy == 'walled-garden') $action = str_replace('$walled_garden', $rpzSettings['walled_garden'], $action);

		if (isset($items['ip'])) {
			$result .= $this->explain('ip', $policy);
			foreach ($items['ip'] as $item) {
				$result .= $this->__convertIP($item, $action);
			}
			$result .= PHP_EOL;
		}

		if (isset($items['domain'])) {
			$result .= $this->explain('domain', $policy);
			foreach ($items['domain'] as $item) {
				$result .= $this->__convertdomain($item, $action);
			}
			$result .= PHP_EOL;
		}

		if (isset($items['hostname'])) {
			$result .= $this->explain('hostname', $policy);
			foreach ($items['hostname'] as $item) {
				$result .= $this->__converthostname($item, $action);
			}
			$result .= PHP_EOL;
		}
		return $result;
	}

	private function __convertdomain($input, $action) {
		return $input . ' CNAME ' . $action . PHP_EOL . '*.' . $input . ' CNAME ' . $action . PHP_EOL;
	}

	private function __converthostname($input, $action) {
		return $input . ' CNAME ' . $action . PHP_EOL;
	}

	private function __convertip($input, $action) {
		$type = filter_var($input, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) ? 'ipv6' : 'ipv4';
		if ($type == 'ipv6') $prefix = '128';
		else $prefix = '32';
		if (strpos($input, '/')) {
			list($input, $prefix) = explode('/', $input);
		}
		return $prefix . '.' . $this->{'__' . $type}($input) . '.rpz-ip CNAME ' . $action . PHP_EOL;
	}

	private function __ipv6($input) {
		return implode('.', array_reverse(preg_split('/:/', str_replace('::', ':zz:', $input), NULL, PREG_SPLIT_NO_EMPTY)));
	}

	private function __ipv4($input) {
		return implode('.', array_reverse(explode('.', $input)));

	}

}