//trigger event

// Event
class UserEarnedExperience
{
    public $user;

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

// Listener
class AwardAchivements
{
    public function handle(UserEarnedExperience $event)
    {
        $achivementIdsToAwward = app('achievements')->filter(function ($achievement) use ($event) {
            return $achievement->qualified($event->user);
        })->map(function ($achievement) {
            return $achievement->modelKey();
        });

        $event->user->achievements()->sync($achivementIdsToAwward);
    }
}

class FirstThousandPoints extends AchievementType
{
    public $name = 'First Thousand Points';
    public $description = 'Achieved by getting to 1000 points';
    public $icon = 'thousand-points.svg';
    public $level = 'beginer';

    public function qualified($user)
    {
        return $user->points >= 1000;
    }
}
class StartYourEngines extends AchievementType
{
    public $name = 'Start your engines';
    public $description = 'Achieved by completing at least one lesson';
    public $icon = 'start-your-engines.svg';
    public $level = 'beginer';

    public function qualified($user)
    {
        return $user->completions()->count() >= 1;
    }
}

abstract class AchievementType
{
    // we might take a different approach to populate the database
    // Achievement is the Model with many2many relationship with User
    public function __construct()
    {
        $this->model = Achievement::firstOrCreate([
            'name' => $this->name,
            'description' => $this->description,
            'icon' => $this->icon,
            'level' => $this->level
        ]);
    }

    public function modelKey()
    {
        return $this->model->getKey();
    }
}

class AchievementServiceProvider extends ServiceProvider
{
    protected $achievements = [
      FirstThousandPointsAchievement::class,
      StartYourEngines::class
    ];

    public function register()
    {
        $this->app->singleton('achievement', function () {
            // caching because instead of hitting database every time on every user we hit only once
            // now when we hit this it looks up for achievement classes in cache
            // dont forget to clear cache when creating new achievement
            return cache()->rememberForever('achievements', function () {
                return collect($this->achievements)->map(function ($achievement) {
                    return new $achievement;
                });
            });
        });
    }
}