<?php namespace Zoomyboy\Social\FormWidgets;

use \Session;
use Backend\Classes\FormWidgetBase;
use GuzzleHttp\Client;
use Zoomyboy\Social\Models\Page;
use Zoomyboy\Social\Models\Setting;

/**
 * FacebookLogin Form Widget
 */
class FacebookLogin extends FormWidgetBase
{
    /**
     * @inheritDoc
     */
    protected $defaultAlias = 'zoomyboy_social_facebook_login';

    /**
     * @inheritDoc
     */
    public function init()
    {
        if (request()->has('code') && request()->query('state') == Session::get('facebook_auth_state')) {
            $this->authenticate();
            $this->storePages();
        }
    }

    public function authenticate(): void
    {
        $client = $this->client();
        $response = $client->get('/v11.0/oauth/access_token', ['query' => [
             'client_id' => Setting::get('facebook_client_id'),
             'redirect_uri' => $this->redirectUri(),
             'client_secret' => Setting::get('facebook_client_secret'),
             'code' => request()->query('code')
        ]]);
        $accessToken = json_decode((string) $response->getBody())->access_token;

        $response = $client->get('/v11.0/oauth/access_token', ['query' => [
            'grant_type' => 'fb_exchange_token',
            'client_id' => Setting::get('facebook_client_id'),
            'client_secret' => Setting::get('facebook_client_secret'),
            'fb_exchange_token' => $accessToken,
        ]]);
        $accessToken = json_decode((string) $response->getBody())->access_token;

        Setting::set('facebook_access_token', $accessToken);
    }

    public function storePages(): void
    {
        $client = $this->client($auth = true);

        $response = $client->get('/me');
        $userId = json_decode((string) $response->getBody())->id;

        $response = $client->get('/v11.0/'.$userId.'/accounts');
        $response = json_decode((string) $response->getBody());

        foreach ($response->data as $page) {
            Page::updateOrCreate(
                ['remote_id' => $page->id],
                ['type' => 'facebook', 'remote_id' => $page->id, 'access_token' => $page->access_token, 'name' => $page->name],
            );
        }
    }

    public function render()
    {
        $this->prepareVars();
        return $this->makePartial('facebooklogin');
    }

    public function redirectUri(): string
    {
        return env('FACEBOOK_REDIRECT_URI', url()->current());
    }

    /**
     * Prepares the form widget view data
     */
    public function prepareVars()
    {
        $state = str_random('20');
        Session::put('facebook_auth_state', $state);
        $this->vars['name'] = $this->formField->getName();
        $this->vars['value'] = $this->getLoadValue();
        $this->vars['model'] = $this->model;
        $this->vars['client_id'] = Setting::get('facebook_client_id');
        $this->vars['redirect_url'] = $this->redirectUri();;
        $this->vars['state'] = $state;
    }

    public function loadAssets()
    {
        $this->addCss('css/facebooklogin.css', 'zoomyboy.social');
        $this->addJs('js/facebooklogin.js', 'zoomyboy.social');
    }

    public function getSaveValue($value)
    {
        return $value;
    }

    private function client(bool $auth = false): Client
    {
        $query = $auth
            ? ['access_token' => Setting::get('facebook_access_token')]
            : [];

        return new Client([
            'base_uri' => 'https://graph.facebook.com',
            'query' => $query,
        ]);
    }

}