Add multiply categories, tags and relation

render_file_links.php

public static function render_file_links( $attrs ) {
		$files = array();

		$post_args = array(
			'post_type'      => models\File::$cpt,
			'post_status'    => 'publish',
			'posts_per_page' => isset( $attrs['limit'] ) && 0 < $attrs['limit'] ? $attrs['limit'] : - 1
		);

		if ( isset( $attrs['category'] ) && ! empty( $attrs['category'] ) ) {
			$relation = isset( $attrs['category-relation'] ) && in_array( strtoupper( $attrs['category-relation'] ), array(
				'IN',
				'AND'
			) ) ? strtoupper( $attrs['category-relation'] ) : 'IN';
			if ( strpos( $attrs['category'], ',' ) !== false ) {
				$terms = explode( ',', trim( $attrs['category'] ) );
			} else {
				$terms = trim( $attrs['category'] );
			}
			if ( ! is_numeric( $attrs['category'] ) ) { // Category is a slug or name
				$post_args = \array_merge(
					array(
						'tax_query' => array(
							'relation' => 'OR',
							array(
								'relation' => $relation,
								'taxonomy' => models\File::$file_category_ctax,
								'field'    => 'name',
								'terms'    => $terms,
								'operator' => $relation
							),
							array(
								'taxonomy' => models\File::$file_category_ctax,
								'field'    => 'slug',
								'terms'    => $terms,
								'operator' => $relation
							)
						)
					),
					$post_args );
			} else { // Category is an ID
				$post_args = \array_merge(
					array(
						'tax_query' => array(
							array(
								'taxonomy' => models\File::$file_category_ctax,
								'field'    => 'term_id',
								'terms'    => $terms,
								'operator' => $relation
							)
						)
					),
					$post_args
				);
			}
		} elseif ( isset( $attrs['tag'] ) && ! empty( $attrs['tag'] ) ) {
			$relation = isset( $attrs['tag-relation'] ) && in_array( strtoupper( $attrs['tag-relation'] ), array(
				'IN',
				'AND'
			) ) ? strtoupper( $attrs['tag-relation'] ) : 'IN';
			if ( strpos( $attrs['tag'], ',' ) !== false ) {
				$terms = explode( ',', trim( $attrs['tag'] ) );
			} else {
				$terms = trim( $attrs['tag'] );
			}
			if ( ! is_numeric( $attrs['tag'] ) ) {
				$post_args = \array_merge(
					array(
						'tax_query' => array(
							'relation' => 'OR',
							array(
								'taxonomy' => models\File::$file_tag_ctax,
								'field'    => 'name',
								'terms'    => $terms,
								'operator' => $relation
							),
							array(
								'taxonomy' => models\File::$file_tag_ctax,
								'field'    => 'slug',
								'terms'    => $terms,
								'operator' => $relation
							)
						)
					),
					$post_args );
			} else { // Tag is an ID
				$post_args = \array_merge(
					array(
						'tax_query' => array(
							array(
								'taxonomy' => models\File::$file_tag_ctax,
								'field'    => 'term_id',
								'terms'    => $terms,
								'operator' => $relation
							),
						)
					),
					$post_args
				);
			}
		}

		if ( isset( $attrs['class'] ) ) {
			$link_class = $attrs['class'];
		}

		$file_posts = \get_posts( $post_args );

		foreach ( $file_posts as $post ) {
			$files[] = new models\File( $post->ID );
		}

		\ob_start();
		require( base\VIEWS_PATH . '/files/file_links.php' );

		return \ob_get_clean();
	}