<?php

namespace App\Auth;

use Illuminate\Contracts\Auth\Guard;
use Illuminate\Http\Request;

/**
 * Xenforo authentification bridge.
 */
class XenForoGuard implements Guard
{

    /**
     * Authenticated user.
     * @var XenForoUser|null
     */
    private ?XenForoUser $user = null;

    public function __construct(private readonly Request $request) {}

    /**
     * Check if user is logged in.
     * @return bool
     */
    public function check(): bool
    {
        return $this->user() !== null;
    }

    /**
     * Check if user is a guest.
     * @return bool
     */
    public function guest(): bool
    {
        return ! $this->check();
    }

    /**
     * Get user ID.
     * @return mixed
     */
    public function id(): mixed
    {
        return $this->user()?->getAuthIdentifier();
    }

    /**
     * If user is defined.
     * @return bool
     */
    public function hasUser(): bool
    {
        return $this->user !== null;
    }

    /**
     * Login user.
     * @return XenForoUser|null
     */
    public function user(): ?XenForoUser
    {
        if ($this->hasUser())
            return $this->user;

        $user = $this->getFromSession();
        if( $user )
            return $user;

        $user = $this->getFromCookie();
        if( $user )
            return $user;

        return null;
    }

    private function getFromSession(): ?XenForoUser
    {
        $sessionId = $this->request->cookie('xf_session');
        if(!$sessionId)
            return null;

        $xfSession = \DB::connection('xenforo')
            ->table('session')
            ->where('session_id', $sessionId)
            ->value('session_data');

        if(!$xfSession)
            return null;

        $sessionData = unserialize($xfSession);

        if (!$sessionData || !isset($sessionData['userId']) || !$sessionData['userId'])
            return null;

        $xfUser = \DB::connection('xenforo')
            ->table('user')
            ->where('user_id', $sessionData['userId'])
            ->first();

        if(!$xfUser)
            return null;

        return $this->user = new XenForoUser($xfUser);
    }

    private function isCorrectCookieKey(string $key, $record): bool
    {
        $known = $record->remember_key;
        if( !$known )
            return false;

        $check = hash('sha256', $key, true);
        return hash_equals($known, $check);
    }

    private function getFromCookie(): ?XenForoUser
    {
        $cookie = $this->request->cookie('xf_user');
        if(!$cookie)
            return null;

        $parts = explode(',', $cookie);
        if( count( $parts ) !== 2 )
            return null;

        [$userId, $key] = $parts;
        $userId = (int) $userId;

        if( !$userId || !$key )
            return null;

        $remembers = \DB::connection('xenforo')
                        ->table('user_remember')
                        ->where('user_id', $userId)
                        ->get();

        if( !$remembers )
            return null;

        $valid = false;

        foreach( $remembers as $remember )
        {
            if( $this->isCorrectCookieKey($key, $remember) && $remember->expiry_date >= time() ){
                $valid = true;
                break;
            }
        }

        if( !$valid )
            return null;

        $xfUser = \DB::connection('xenforo')
            ->table('user')
            ->where('user_id', $userId)
            ->first();

        if(!$xfUser)
            return null;

        return $this->user = new XenForoUser($xfUser);
    }

    /**
     * Unused.
     *
     * @param array $credentials
     *
     * @return bool
     */
    public function validate(array $credentials = []): bool
    {
        return false;
    }

    public function setUser(mixed $user): void
    {
        $this->user = $user;
    }

    /**
     * Unused.
     * @return void
     */
    public function logout(): void
    {
        redirect('/');
    }

}