<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use Psy\Exception\ErrorException;

class HomeController extends Controller
{
    private $apiVersion = '5.78';

    private function getUserInformation(Request $request, $token) {
        $url = 'https://api.vk.com/method/users.get';

        $params = [
            'uid'          => $request->session()->get('user_id'),
            'access_token' => $token,
            'fields'       => 'first_name,last_name',
            'version'      => $this->apiVersion
        ];

        $userInfo = json_decode(file_get_contents($url . '?' . urldecode(http_build_query($params))), true);

        if(isset($userInfo['error'])){
            throw new ErrorException('Превышено количество запросов в секунду или сервис недоступен. Попробуйте позже.');
        } else {
            return $userInfo['response'][0];
        }
    }

    private function getFriends(Request $request, $token, $count) {
        $url = 'https://api.vk.com/method/friends.get';

        $params = [
            'access_token' => $token,
            'order'        => 'random',
            'count'        => $count,
            'offset'       => 3,
            'fields'       => 'first_name,last_name',
            'version'      => $this->apiVersion
        ];

        $friends = json_decode(file_get_contents($url . '?' . urldecode(http_build_query($params))), true);

        if(isset($friends['error'])){
            throw new ErrorException('Превышено количество запросов в секунду или сервис недоступен. Попробуйте позже.');
        } else {
            return $friends['response'];
        }
    }

    private  function getFiveValidFriends(Request $request, $token){
        $friends = $this->getFriends($request, $token, 10);
        $validFriends = [];
        while(count($validFriends)<5){
            $validFriends = array_filter($friends, function($friend){
                return isset($friend['deactivated']) ? false : true;
            });
            if(count($validFriends)<5){
                $friends = $this->getFriends($request, $token, 10);
            }
        }

        return array_slice($validFriends, 0, 5);
    }

    public function index(Request $request) {
        $clientId = 6605907;
        $clientSecret = 'секретный ключ';
        $redirectUri = 'http://u3835.red.elastictech.org/';
        $display = 'page';
        $scope = 'friends';
        $responseType = 'code';

        $url = 'https://oauth.vk.com/authorize';

        $queryParams = [
            'client_id'     => $clientId,
            'redirect_uri'  => $redirectUri,
            'display'       => $display,
            'scope'         => $scope,
            'response_type' => $responseType
        ];

        $query = $url . '?' . urldecode(http_build_query($queryParams));

        if($request->session()->has('token')){
            $token = $request->session()->get('token');
            try {
                return view('auth', [
                    'user_info' => $this->getUserInformation($request, $token),
                    'friends' => $this->getFiveValidFriends($request, $token)
                ]);
            } catch (ErrorException $ex){
                return view('welcome', [
                'error'             => 'Ошбика доступа',
                'error_description' => $ex->getRawMessage(),
                'query'             => '/',
                'button'            => 'Попробовать снова'
            ]);
            }
        } else if ($request->has('code')) {
            $url = 'https://oauth.vk.com/access_token';
            $code = $request->input('code');

            $params = [
                'client_id'     => $clientId,
                'redirect_uri'  => $redirectUri,
                'client_secret' => $clientSecret,
                'code'          => $code
            ];

            $query = $url . '?' . urldecode(http_build_query($params));
            $resp = @json_decode(file_get_contents($query), true);
            if($resp == false){
                return view('welcome', [
                    'error'             => 'Ошибка авторизации',
                    'error_description' => 'Ошибка получения токена. Неверный код.',
                    'query'             => $query,
                    'button'            => 'Авторизация'
                ]);
            } else {
                $request->session()->put('token', $resp['access_token']);
                $request->session()->put('user_id', $resp['user_id']);
                return redirect('/');
            }
        } else if ($request->has("error")){
            return view('welcome', [
                'error'             => 'Ошибка авторизации',
                'error_description' => $request->input("error_description"),
                'query'             => $query,
                'button'            => 'Авторизация'
            ]);
        } else {
            return view('welcome', [
                'query'  => $query,
                'button' => 'Авторизация'
            ]);
        }
    }


    public function logout(Request $request){
        $request->session()->flush();
        return redirect('/');
    }
}