<?php
namespace app\components;

use app\models\Auth;
use app\models\User;
use Yii;
use yii\authclient\ClientInterface;
use yii\helpers\ArrayHelper;

/**
 * AuthHandler handles successful authentication via Yii auth component
 */
class AuthHandler
{
    /**
     * @var ClientInterface
     */
    private $client;

    public function __construct(ClientInterface $client)
    {
        $this->client = $client;
    }

    public function handle()
    {
        $attributes = $this->client->getUserAttributes();

        /* @var Auth $auth */
        $auth = Auth::find()->where([
            'source' => $this->client->getId(),
            'source_id' => $id,
        ])->one();

        if (Yii::$app->user->isGuest) {
            if ($auth) { // login
                /* @var User $user */
                $user = $auth->user;
                $this->updateUserInfo($user);
                Yii::$app->user->login($user, Yii::$app->params['user.rememberMeDuration']);
            } else { // signup
               $this->signupUser($attributes);
            }
        } else { // user already logged in
            $this->authLoggedInUser($attributes, $auth);
        }
    }


    private function signupUser($attributes)
    {
        $id = ArrayHelper::getValue($attributes, 'id');
        $email = ArrayHelper::getValue($attributes, 'email');
        $nickname = ArrayHelper::getValue($attributes, 'login');

        if ($email !== null && User::find()->where(['email' => $email])->exists()) {
            $this->setFlash('error', "User with the same email as in {client} account already exists but isn't linked to it. Login using email first to link it.",
                ['client' => $this->client->getTitle()]
            );
        } else {
            $password = Yii::$app->security->generateRandomString(6);
            $user = new User([
                'username' => $nickname,
                'github' => $nickname,
                'email' => $email,
                'password' => $password,
            ]);
            $user->generateAuthKey();
            $user->generatePasswordResetToken();

            $transaction = User::getDb()->beginTransaction();

            if ($user->save()) {
                $auth = new Auth([
                    'user_id' => $user->id,
                    'source' => $this->client->getId(),
                    'source_id' => (string)$id,
                ]);
                if ($auth->save()) {
                    $transaction->commit();
                    Yii::$app->user->login($user, Yii::$app->params['user.rememberMeDuration']);
                } else {
                    $this->setFlash('error', 'Unable to save {client} account: {errors}.', [
                            'client' => $this->client->getTitle(),
                            'errors' => json_encode($auth->getErrors()),
                        ]
                    );
                }
            } else {
                $this->setFlash('error', 'Unable to save user: {errors}.', [
                        'client' => $this->client->getTitle(),
                        'errors' => json_encode($user->getErrors()),
                    ]
                );
            }
        }
    }

    private function authLoggedInUser($attributes, $auth)
    {
        if (!$auth) { // add auth provider

            $id = ArrayHelper::getValue($attributes, 'id');

            $auth = new Auth([
                'user_id' => Yii::$app->user->id,
                'source' => $this->client->getId(),
                'source_id' => (string)$id,
            ]);
            if ($auth->save()) {
                /** @var User $user */
                $user = $auth->user;
                $this->updateUserInfo($user);

                $this->setFlash('success', 'Linked {client} account.',
                    ['client' => $this->client->getTitle()]
                );
            } else {
                $this->setFlash('error', 'Unable to link {client} account: {errors}', [
                        'client' => $this->client->getTitle(),
                        'errors' => json_encode($auth->getErrors()),
                    ]
                );
            }
        } else { // there's existing auth
            $this->setFlash('error', 'Unable to link {client} account. There is another user using it.',
                ['client' => $this->client->getTitle()]
            );
        }
    }

    /**
     * @param User $user
     */
    private function updateUserInfo(User $user)
    {
        $attributes = $this->client->getUserAttributes();
        $github = ArrayHelper::getValue($attributes, 'login');
        if ($user->github === null && $github) {
            $user->github = $github;
            $user->save();
        }
    }

    private function setFlash($status, $message, $data)
    {
        Yii::$app->getSession()->setFlash($status, [
            Yii::t('app', $message, $data),
        ]);
    }
}