<?php

namespace Franzz\Livetrail;
use Franzz\Objects\PhpObject;
use Franzz\Objects\Db;

class User extends PhpObject {

	//DB Tables
	public const USER_TABLE = 'users';

	//Clearance Levels
	public const CLEARANCE_USER = 0;
	public const CLEARANCE_ADMIN = 9;
	public const CLEARANCES = ['user'=>self::CLEARANCE_USER, 'admin'=>self::CLEARANCE_ADMIN];

	public const USER_SUBSCRIBED = 1;
	public const USER_UNSUBSCRIBED = 0;

	public const DEFAULT_USER = [
		'id'		=> 0,
		'id_user'	=> 0,
		'name'		=> '',
		'email'		=> '',
		'language'	=> '',
		'timezone'	=> '',
		'subscribed'=> self::USER_UNSUBSCRIBED,
		'clearance'	=> self::CLEARANCE_USER
	];

	//Session & Cookie
	private const SESSION_ID_USER = 'id_user';
	private const SESSION_ADMIN = 'admin_authenticated';
	private const COOKIE_TOKEN = 'login';
	private const COOKIE_DURATION = 60 * 60 * 24 * 365; //1 year

	/**
	 * Database Handle
	 * @var Db
	 */
	private $oDb;

	//User Info
	private $iUserId;
	private $asUserInfo;

	public function __construct(Db &$oDb) {
		parent::__construct(__CLASS__);
		$this->oDb = &$oDb;
		$this->setUserId(0);
		$this->checkSession();
	}

	public function getUserId() {
		return $this->iUserId;
	}

	public function setUserId($iUserId) {
		$this->iUserId = 0;
		$this->asUserInfo = self::DEFAULT_USER;

		if($iUserId > 0) {
			$asUser = $this->getUserById($iUserId);
			if(!empty($asUser)) {
				$this->iUserId = $iUserId;
				$this->asUserInfo = $asUser;
			}
		}
	}

	public function getUserInfo() {
		return $this->asUserInfo;
	}

	public function getUserById($iUserId) {
		$asUsersInfo = [];
		if($iUserId > 0) $asUsersInfo = $this->getUsersInfo($iUserId);
		return empty($asUsersInfo)?[]:array_shift($asUsersInfo);
	}

	public function getUsersInfo($iUserId=-1) {

		//Mapping between user fields and DB fields
		$asSelect = array_keys($this->asUserInfo);
		$asSelect[array_search('id', $asSelect)] = Db::getId(self::USER_TABLE).' AS id';

		$asInfo = [
			'select'	=> $asSelect,
			'from'		=> self::USER_TABLE
		];
		if($iUserId != -1) $asInfo['constraint'] = [Db::getId(self::USER_TABLE) => $iUserId];

		return $this->oDb->selectRows($asInfo);
	}

	public function getLang() {
		return $this->asUserInfo['language'];
	}

	private function addUser($sEmail, $sLang, $sTimezone, $sNickName='') {
		$bSuccess = false;
		$sLangId = '';

		$iUserId = $this->oDb->insertRow(
			self::USER_TABLE,
			['email'=>$sEmail, 'language'=>$sLang, 'timezone'=>$sTimezone]
		);

		if($iUserId == 0) $sLangId = 'error.commit_db';
		else $bSuccess = true;

		//Extra optional values
		if($bSuccess) {
			$this->updateNickname($sNickName);
			$this->updateGravatar($iUserId, $sEmail);
		}

		return Livetrail::getResult($bSuccess, $sLangId, [Db::getId(self::USER_TABLE) => $iUserId]);
	}

	public function setSubscription($bSubscribed) {
		if($this->getUserId() > 0) {
			$iSubscribed = $bSubscribed?1:0;
			$iUserId = $this->oDb->updateRow(self::USER_TABLE, $this->getUserId(), ['subscribed'=>$iSubscribed]);
			if(!$iUserId) return Livetrail::getResult(false, 'error.commit_db');
			$this->asUserInfo['subscribed'] = $iSubscribed;
			return Livetrail::getResult(true, $iSubscribed?'account.subscribed':'account.unsubscribed');
		}
	}

	public function getSubscribedUsersInfo() {
		$asSelect = array_keys($this->asUserInfo);
		$asSelect[array_search('id', $asSelect)] = Db::getId(self::USER_TABLE).' AS id';
		return $this->oDb->selectRows([
			'select'=>$asSelect,
			'from'=>self::USER_TABLE,
			'constraint'=>['subscribed'=>self::USER_SUBSCRIBED]
		]);
	}

	public function login($sEmail, $sPassword, $sLang, $sTimezone, $sNickName='') {
		$bSuccess = false;
		$bSubscribe = false;
		$sLangId = '';
		$sEmail = strtolower(trim($sEmail));
		
		//Check email value
		if(!filter_var($sEmail, FILTER_VALIDATE_EMAIL)) {
			$sLangId = 'account.invalid_email';
		}
		else {
			//Check Email presence in DB
			$asDBUser = $this->oDb->selectRow(
				self::USER_TABLE,
				['email' => $sEmail],
				[Db::getId(self::USER_TABLE), 'password', 'clearance']
			);
			$iUserId = $asDBUser[Db::getId(self::USER_TABLE)] ?? 0;
		
			//User exists
			if($iUserId > 0) {
				//Is Admin
				if($asDBUser['clearance'] >= self::CLEARANCE_ADMIN) {
					//Request a password
					if($sPassword === '') $sLangId = empty($asDBUser['password'])?'account.set_password':'account.password_required';
					
					//Set password
					elseif(empty($asDBUser['password'])) {
						if(!$this->oDb->updateRow(self::USER_TABLE, $iUserId, ['password' => password_hash($sPassword, PASSWORD_DEFAULT)])) $sLangId = 'error.commit_db';
						else {
							$sLangId = 'account.password_set';
							$bSuccess = true;
						}
					}

					//Check password
					elseif(password_verify($sPassword, $asDBUser['password'])) {
						$bSuccess = true;
						$sLangId = 'account.logged_in';
					}
					else $sLangId = 'account.invalid_credentials';
				}
				else {
					$bSuccess = true;
					$sLangId = 'account.logged_in';
				}
			}
			else {
				//Unknown user, create it
				$asAddResult = $this->addUser($sEmail, $sLang, $sTimezone, $sNickName);
				$bSuccess = $asAddResult['result'];
				$bSubscribe = $bSuccess;
				$sLangId = $bSuccess?'':$asAddResult['desc_lang_id'];
				$iUserId = $asAddResult['data'][Db::getId(self::USER_TABLE)] ?? 0;
			}
		}
		
		if($bSuccess) {
			$this->setUserId($iUserId);
			$this->setSession();
			$this->setTokenCookie();
		}

		return Livetrail::getResult($bSuccess, $sLangId, ['subscribe'=>$bSubscribe]);
	}

	public function logout() {
		if($this->getUserId() > 0) $this->oDb->updateRow(self::USER_TABLE, $this->getUserId(), ['token' => '', 'token_exp' => '0000-00-00 00:00:00']);
		$this->clearSession();
		$this->clearCookie();
		$this->setUserId(0);
		return Livetrail::getResult(true, 'account.logged_out');
	}

	public function updateNickname($sNickname) {
		if($this->getUserId() > 0 && $sNickname!='') $this->oDb->updateRow(self::USER_TABLE, $this->getUserId(), ['name'=>$sNickname]);
	}

	private function updateGravatar($iUserId, $sEmail) {
		$sImage = ($sEmail != '')?@file_get_contents('https://www.gravatar.com/avatar/'.md5($sEmail).'.png?d=404&s=24'):'';
		$this->oDb->updateRow(self::USER_TABLE, $iUserId, ['gravatar' => base64_encode($sImage)]);
	}

	public function checkUserClearance($iClearance) {
		return ($this->asUserInfo['clearance'] >= $iClearance);
	}

	public function setUserClearance($iUserId, $iClearance) {
		$bSuccess = false;
		$sLangId = '';
		$asLangParams = [];

		if(!$this->checkUserClearance(self::CLEARANCE_ADMIN)) $sLangId = 'error.no_auth';
		else {
			if(!in_array($iClearance, self::CLEARANCES)) {
				$sLangId = 'error.impossible_value';
				$asLangParams = [$iClearance, 'clearance'];
			}
			else {
				$iUserId = $this->oDb->updateRow(self::USER_TABLE, $iUserId, ['clearance'=>$iClearance]);
				if(!$iUserId) $sLangId = 'error.commit_db';
				else $bSuccess = true;
			}
		}

		return Livetrail::getResult($bSuccess, $sLangId, [], $asLangParams);
	}

	/* Session */

	private function checkSession() {
		$iUserId = (int) ($_SESSION[self::SESSION_ID_USER] ?? 0);
		if($iUserId > 0) {
			$this->setUserId($iUserId);
			if($this->checkUserClearance(self::CLEARANCE_ADMIN) && empty($_SESSION[self::SESSION_ADMIN])) $this->logout();
		}
		else $this->checkTokenCookie();
	}

	private function setSession() {
		session_regenerate_id(true);
		$_SESSION[self::SESSION_ID_USER] = $this->getUserId();
		$_SESSION[self::SESSION_ADMIN] = $this->checkUserClearance(self::CLEARANCE_ADMIN);
	}

	private function clearSession() {
		unset($_SESSION[self::SESSION_ID_USER], $_SESSION[self::SESSION_ADMIN]);
	}

	/* Cookie */

	private function checkTokenCookie() {
		$sCookieValue = $this->getCookie();

		//Check cookie structure
		$asToken = explode(':', $sCookieValue, 3);
		$iUserId = $asToken[0];
		if(count($asToken) !== 3 || !ctype_digit($iUserId) || !ctype_digit($asToken[1]) || !preg_match('/^[a-f0-9]{64}$/', $asToken[2])) {
			if($sCookieValue !== '') $this->clearCookie();
			return;
		}

		//Get user info
		$asUser = $this->oDb->selectRow(
			self::USER_TABLE,
			$iUserId,
			['clearance', 'token', 'token_exp']
		);

		//Check token value
		if(!empty($asUser)
			&& $asUser['clearance'] == $asToken[1]
			&& time() <= strtotime($asUser['token_exp'])
			&& hash_equals($asUser['token'], hash('sha256', $sCookieValue))
		) {
			$this->setUserId($iUserId);
			$this->setSession();
		}
		else $this->clearCookie();
	}

	private function setTokenCookie() {
		$sToken = bin2hex(random_bytes(32));
		$iClearance = $this->asUserInfo['clearance'];
		$sCookieValue = implode(':', [$this->getUserId(), $iClearance, $sToken]);

		$this->oDb->updateRow(
			self::USER_TABLE,
			$this->getUserId(),
			[
				'token'		=> hash('sha256', $sCookieValue),
				'token_exp'	=> date(Db::TIMESTAMP_FORMAT, time() + self::COOKIE_DURATION)
			]
		);

		$this->setCookie($sCookieValue, time() + self::COOKIE_DURATION);
	}

	private function getCookie() {
		return $_COOKIE[self::COOKIE_TOKEN] ?? '';
	}

	private function setCookie($sValue, $iExpires) {
		setcookie(
			self::COOKIE_TOKEN,
			$sValue,
			[
				'expires'	=> $iExpires,
				'path'		=> '/',
				'secure'	=> (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off') || (($_SERVER['HTTP_X_FORWARDED_PROTO'] ?? '') === 'https'),
				'httponly'	=> true,
				'samesite'	=> 'Lax'
			]
		);
	}

	private function clearCookie() {
		$this->setCookie('', time() - 3600);
		unset($_COOKIE[self::COOKIE_TOKEN]);
	}
}