<?php

use SilverStripe\ORM\FieldType\DBDatetime;
use SilverStripe\ORM\DataObject;
/**
 * Persists a token associated with a device for users who opted for the "Remember Me"
 * feature when logging in.
 * By default, logging out will discard all existing tokens for this user
 * The device ID is a temporary ID associated with the device when the user logged in
 * and chose to get the login state remembered on this device. When logging out, the ID
 * is discarded as well.
 *
 * @package framework
 * @subpackage security
 *
 * @property string $DeviceID
 * @property string $RememberLoginHash
 */

class RememberLoginHash extends DataObject {

	private static $db = array (
		'DeviceID' => 'Varchar(40)',
		'Hash' => 'Varchar(160)',
		'ExpiryDate' => 'Datetime'
	);

	private static $has_one = array (
		'Member' => 'Member',
	);

	private static $indexes = array(
		'DeviceID' => true,
		'Hash' => true
	);

	/**
	 * Determines if logging out on one device also clears existing login tokens
	 * on all other devices owned by the member.
	 * If set to false, there is no way for users to revoke a login, unless additional
	 * code (custom or with a module) is provided by the developer
	 *
	 * @config
	 * @var bool
	 */
	private static $logout_across_devices = true;

	/**
	 * Number of days the token will be valid for
	 *
	 * @config
	 * @var int
	 */
	private static $token_expiry_days = 90;

	/**
	 * Number of days the device ID will be valid for
	 *
	 * @config
	 * @var int
	 */
	private static $device_expiry_days = 365;

	/**
	 * If true, user can only use auto login on one device. A user can still login from multiple
	 * devices, but previous tokens from other devices will become invalid.
	 *
	 * @config
	 * @var bool
	 */
	private static $force_single_token = false;

	/**
	 * The token used for the hash
	 */
	private $token = null;

	public function getToken() {
		return $this->token;
	}

	public function setToken($token) {
		$this->token = $token;
	}

	/**
	 * Randomly generates a new ID used for the device
	 * @return string A device ID
	 */
	protected function getNewDeviceID(){
		$generator = new RandomGenerator();
		return $generator->randomToken('sha1');
	}

	/**
	 * Creates a new random token and hashes it using the
	 * member information
	 * @param Member The logged in user
	 * @return string The hash to be stored in the database
	 */
	public function getNewHash(Member $member){
		$generator = new RandomGenerator();
		$this->setToken($generator->randomToken('sha1'));
		return $member->encryptWithUserSettings($this->token);
	}

	/**
	 * Generates a new login hash associated with a device
	 * The device is assigned a globally unique device ID
	 * The returned login hash stores the hashed token in the
	 * database, for this device and this member
	 * @param Member The logged in user
	 * @return RememberLoginHash The generated login hash
	 */
	public static function generate(Member $member) {
		if(!$member->exists()) { return; }
		if (Config::inst()->get('RememberLoginHash', 'force_single_token') == true) {
			$rememberLoginHash = RememberLoginHash::get()->filter('MemberID', $member->ID)->removeAll();
		}
		$rememberLoginHash = RememberLoginHash::create();
		do {
			$deviceID = $rememberLoginHash->getNewDeviceID();
		} while (RememberLoginHash::get()->filter('DeviceID', $deviceID)->Count());

		$rememberLoginHash->DeviceID = $deviceID;
		$rememberLoginHash->Hash = $rememberLoginHash->getNewHash($member);
		$rememberLoginHash->MemberID = $member->ID;
		$now = DBDatetime::now();
		$expiryDate = new DateTime($now->Rfc2822());
		$tokenExpiryDays = Config::inst()->get('RememberLoginHash', 'token_expiry_days');
		$expiryDate->add(new DateInterval('P'.$tokenExpiryDays.'D'));
		$rememberLoginHash->ExpiryDate = $expiryDate->format('Y-m-d H:i:s');
		$rememberLoginHash->extend('onAfterGenerateToken');
		$rememberLoginHash->write();
		return $rememberLoginHash;
	}

	/**
	 * Generates a new hash for this member but keeps the device ID intact
	 * @param Member the logged in user
	 * @return RememberLoginHash
	 */
	public function renew() {
		$hash = $this->getNewHash($this->Member());
		$this->Hash = $hash;
		$this->extend('onAfterRenewToken');
		$this->write();
		return $this;
	}

	/**
	 * Deletes existing tokens for this member
	 * if logout_across_devices is true, all tokens are deleted, otherwise
	 * only the token for the provided device ID will be removed
	 */
	public static function clear(Member $member, $alcDevice = null) {
		if(!$member->exists()) { return; }
		$filter = array('MemberID'=>$member->ID);
		if ((Config::inst()->get('RememberLoginHash', 'logout_across_devices') == false) && $alcDevice) {
			$filter['DeviceID'] = $alcDevice;
		}
		RememberLoginHash::get()
			->filter($filter)
			->removeAll();
	}

}