Какая здесь должна быть переменная?

<?php 
 
namespace medeyacom\blog\models; 
 
use common\components\behaviors\StatusBehavior; 
use Yii; 
use yii\behaviors\TimestampBehavior; 
use yii\db\ActiveRecord; 
use yii\db\Expression; 
use yii\helpers\ArrayHelper; 
use yii\helpers\Url; 
use yii\web\UploadedFile; 
use common\models\User; 
use common\models\ImageManager; 
 
/** 
 * This is the model class for table "blog". 
 * 
 * @property integer $id 
 * @property string $title 
 * @property string $text 
 * @property string $image 
 * @property string $url 
 * @property string $date_create 
 * @property string $date_update 
 * @property integer $status_id 
 * @property integer $sort 
 */ 
class Blog extends ActiveRecord 
{ 
    const STATUS_LIST = ['off','on']; 
    const IMAGES_SIZE = [ 
        ['50','50'], 
        ['800',null], 
    ]; 
    public $tags_array; 
    public $file; 
 
    /** 
     * @inheritdoc 
     */ 
    public static function tableName() 
    { 
        return 'blog'; 
    } 
 
    public function behaviors() 
    { 
        return [ 
            'timestampBehavior'=>[ 
                'class' => TimestampBehavior::className(), 
                'createdAtAttribute' => 'date_create', 
                'updatedAtAttribute' => 'date_update', 
                'value' => new Expression('NOW()'), 
            ], 
            'statusBehavior'=>[ 
                'class' => StatusBehavior::className(), 
                'statusList' => self::STATUS_LIST, 
            ] 
        ]; 
    } 
 
    /** 
     * @inheritdoc 
     */ 
    public function rules() 
    { 
        return [ 
            [['title', 'url'], 'required'], 
            [['text'], 'string'], 
            [['url'], 'unique'], 
            [['status_id', 'sort'], 'integer'], 
            [['sort'], 'integer', 'max'=>99, 'min'=>1], 
            [['title', 'url'], 'string', 'max' => 150], 
            [['image'], 'string', 'max' => 100], 
            [['file'], 'image'], 
            [['tags_array','date_create','date_update'], 'safe'], 
        ]; 
    } 
 
    /** 
     * @inheritdoc 
     */ 
    public function attributeLabels() 
    { 
        return [ 
            'id' => 'ID', 
            'title' => 'Заголовок', 
            'text' => 'Текст', 
            'url' => 'ЧПУ', 
            'status_id' => 'Статус', 
            'sort' => 'Сортировка', 
            'tags_array' => 'Тэги', 
            'image' => 'Картинка', 
            'file' => 'Картинка', 
            'tagsAsString' => 'Тэги', 
            'author.username' => 'Имя Автора', 
            'author.email' => 'Почта Автора', 
            'date_update' => 'Обновлено', 
            'date_create' => 'Создано', 
        ]; 
    } 
 
 
    public function getAuthor(){ 
        return $this->hasOne(User::className(),['id'=>'user_id']); 
    } 
    public function getImages() 
    { 
        return $this->hasMany(ImageManager::className(), ['item_id' => 'id'])->andWhere(['class'=>self::tableName()])->orderBy('sort'); 
    } 
    public function getImagesLinks() 
    { 
        return ArrayHelper::getColumn($this->images,'imageUrl'); 
    } 
    public function getImagesLinksData() 
    { 
        return ArrayHelper::toArray($this->images,[ 
                ImageManager::className() => [ 
                    'caption'=>'name', 
                    'key'=>'id', 
                ]] 
        ); 
    } 
    public function getBlogTag(){ 
        return $this->hasMany(BlogTag::className(),['blog_id'=>'id']); 
    } 
 
    public function getTags() 
    { 
        return $this->hasMany(Tag::className(), ['id' => 'tag_id'])->via('blogTag'); 
    } 
 
    public function getTagsAsString() 
    { 
        $arr = \yii\helpers\ArrayHelper::map($this->tags,'id','name'); 
        return implode(', ',$arr); 
    } 
 
    public function getSmallImage() 
    { 
        if($this->image){ 
            $path = str_replace('admin.','',Url::home(true)).'uploads/images/blog/50x50/'.$this->image; 
        }else{ 
            $path = str_replace('admin.','',Url::home(true)).'uploads/images/ss.jpg'; 
        } 
        return $path; 
    } 
 
 
    public function afterFind() 
    { 
        parent::afterFind(); 
        $this->tags_array = $this->tags; 
    } 
 
    public function beforeSave($insert) 
    { 
        if($file = UploadedFile::getInstance($this, 'file')){ 
            $dir = Yii::getAlias('@images').'/blog/'; 
            if(file_exists($dir.$this->image)){ 
                unlink($dir.$this->image); 
            } 
            if(file_exists($dir.'50x50/'.$this->image)){ 
                unlink($dir.'50x50/'.$this->image); 
            } 
            if(file_exists($dir.'800x/'.$this->image)){ 
                unlink($dir.'800x/'.$this->image); 
            } 
            $this->image = strtotime('now').'_'.Yii::$app->getSecurity()->generateRandomString(6)  . '.' . $file->extension; 
            $file->saveAs($dir.$this->image); 
            $imag = Yii::$app->image->load($dir.$this->image); 
            $imag->background('#fff',0); 
            $imag->resize('50','50', Yii\image\drivers\Image::INVERSE); 
            $imag->crop('50','50'); 
            $imag->save($dir.'50x50/'.$this->image, 90); 
            $imag = Yii::$app->image->load($dir.$this->image); 
            $imag->background('#fff',0); 
            $imag->resize('800',null, Yii\image\drivers\Image::INVERSE); 
            $imag->save($dir.'800x/'.$this->image, 90); 
        } 
        return parent::beforeSave($insert); 
    } 
 
    public function afterSave($insert, $changedAttributes) 
    { 
        parent::afterSave($insert, $changedAttributes); 
        $arr = \yii\helpers\ArrayHelper::map($this->tags,'id','id'); 
        foreach ($this->tags_array as $one){ 
            if(!in_array($one,$arr)){ 
                $model = new BlogTag(); 
                $model->blog_id = $this->id; 
                $model->tag_id = $one; 
                $model->save(); 
            } 
            if(isset($arr[$one])){ 
                unset($arr[$one]); 
            } 
        } 
        BlogTag::deleteAll(['tag_id'=>$arr]); 
    } 
 
    public function beforeDelete() 
        { 
            if (parent::beforeDelete()) { 
                $dir = Yii::getAlias('@images').'/blog/'; 
                 if (file_exists($filename) && is_writable($filename)) 
                unlink($filename); 
                else throw new Exception('Файла нет или нет прав на его удаление'); 
                if(file_exists($dir.$this->image)){ 
                    unlink($dir.$this->image); 
                } 
                foreach (self::IMAGES_SIZE as $size){ 
                    $size_dir = $size[0].'x'; 
                    if($size[1] !== null) 
                        $size_dir .= $size[1]; 
                    if(file_exists($dir.$this->image)){ 
                        unlink($dir.$size_dir.'/'.$this->image); 
                    } 
                } 
                BlogTag::deleteAll(['blog_id'=>$this->id]); 
                return true; 
            } else { 
                return false; 
            } 
        } 
}