Pony.fm/app/Library/Notifications/RecipientFinder.php

<?php

/**
 * Pony.fm - A community for pony fan music.
 * Copyright (C) 2016 Peter Deltchev
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

namespace Poniverse\Ponyfm\Library\Notifications;


use Illuminate\Foundation\Bus\DispatchesJobs;
use Poniverse\Ponyfm\Contracts\Favouritable;
use Poniverse\Ponyfm\Contracts\NotificationHandler;
use Poniverse\Ponyfm\Jobs\SendNotifications;
use Poniverse\Ponyfm\Library\Notifications\Drivers\PonyfmDriver;
use Poniverse\Ponyfm\Models\Comment;
use Poniverse\Ponyfm\Models\Playlist;
use Poniverse\Ponyfm\Models\Track;
use Poniverse\Ponyfm\Models\User;

/**
 * Class RecipientFinder
 * @package Poniverse\Ponyfm\Library\Notifications
 * 
 * This class returns a list of users who are to receive a particular notification.
 * It is instantiated on a per-driver basis.
 */
class RecipientFinder implements NotificationHandler {
    /**
     * @var string class name of a notification driver
     */
    private $notificationDriver;
    
    public function __construct(string $notificationDriver) {
        $this->notificationDriver = $notificationDriver;
    }

    private function fail() {
        throw new \InvalidArgumentException("Unknown notification driver given: {$this->notificationDriver}");
    }

    /**
     * @inheritdoc
     */
    public function publishedNewTrack(Track $track) {
        switch ($this->notificationDriver) {
            case PonyfmDriver::class:
                return $track->user->followers;
            default:
                return $this->fail();
        }
    }

    /**
     * @inheritdoc
     */
    public function publishedNewPlaylist(Playlist $playlist) {
        switch ($this->notificationDriver) {
            case PonyfmDriver::class:
                return $playlist->user->followers;
            default:
                return $this->fail();
        }
    }

    /**
     * @inheritdoc
     */
    public function newFollower(User $userBeingFollowed, User $follower) {
        switch ($this->notificationDriver) {
            case PonyfmDriver::class:
                return [$userBeingFollowed];
            default:
                return $this->fail();
        }
    }

    /**
     * @inheritdoc
     */
    public function newComment(Comment $comment) {
        switch ($this->notificationDriver) {
            case PonyfmDriver::class:
                return
                    $comment->user->id === $comment->resource->user->id
                        ? []
                        : [$comment->resource->user];
            default:
                return $this->fail();
        }
    }

    /**
     * @inheritdoc
     */
    public function newFavourite(Favouritable $entityBeingFavourited, User $favouriter) {
        switch ($this->notificationDriver) {
            case PonyfmDriver::class:
                return
                    $favouriter->id === $entityBeingFavourited->user->id
                        ? []
                        : [$entityBeingFavourited->user];
            default:
                return $this->fail();
        }
    }
}