main_file_name ) ) {
			return;
		}

		$content = self::get_asset_file_content( $ext );

		// If no premium elements exist on the page, then don't generate files
		if ( empty( $content ) ) {
			return;
		}

		if ( 'css' === $ext && is_rtl() ) {
			$rtl_file_name = Helper_Functions::get_safe_path( PREMIUM_ASSETS_PATH . '/pa-frontend-rtl-' . self::$post_id . '.min.css' );
		}

		if ( ! file_exists( PREMIUM_ASSETS_PATH ) ) {
			wp_mkdir_p( PREMIUM_ASSETS_PATH );
		}

		if ( 'css' === $ext ) {

			if ( is_rtl() ) {
				// Make sure to delete the file before creating the new one.
                file_put_contents( $rtl_file_name, '@charset "UTF-8";' . $content['rtl'] );  // phpcs:ignore
			} else {
                file_put_contents( $main_file_name, '@charset "UTF-8";' . $content['main'] ); // phpcs:ignore
			}
		} else {
			file_put_contents( $main_file_name, $content );  // phpcs:ignore
		}
	}


	/**
	 * Clear cached file.
	 * Delete file if it exists.
	 *
	 * @access public
	 * @since 4.6.1
	 *
	 * @param string $file_name  file name.
	 */
	public static function clear_cached_file( $file_name ) {

		if ( file_exists( $file_name ) ) {
			unlink( $file_name );
		}
	}

	/**
	 * Remove files
	 *
	 * @since 4.6.1
	 */
	public static function remove_files() {

		$ext = array( 'css', 'js' );

		foreach ( $ext as $e ) {

			$path = PREMIUM_ASSETS_PATH . '/pa-frontend-' . self::$post_id . '.min.' . $e;

			if ( 'css' === $e ) {
				$rtl_path = PREMIUM_ASSETS_PATH . '/pa-frontend-rtl-' . self::$post_id . '.min.' . $e;
				self::clear_cached_file( $rtl_path );
			}

			self::clear_cached_file( $path );
		}

	}

	/**
	 * Get Asset File Content.
	 *
	 * Collects pa/papro widgets assets.
	 *
	 * @access public
	 * @since 4.6.1
	 *
	 * @param string $ext js|css.
	 *
	 * @return string|array $content
	 */
	public static function get_asset_file_content( $ext ) {

		// Get the cached elements of the current post/page.
		$pa_elements = get_option( 'pa_elements_' . self::$post_id, array() );

		if ( empty( $pa_elements ) ) {
			return '';
		}

		$content = '';

		if ( 'css' === $ext ) {
			$rtl_content = '';
		}

		$pa_elements = self::prepare_pa_elements( $pa_elements, $ext );

		foreach ( $pa_elements as $element ) {

			$path = self::get_file_path( $element, $ext );

			if ( ! $path ) {
				continue;
			}

			$content .= self::get_file_content( $path );

			if ( 'css' === $ext && is_rtl() ) {
				$rtl_path     = self::get_file_path( $element, $ext, '-rtl' );
				$rtl_content .= self::get_file_content( $rtl_path );
			}
		}

		if ( 'css' === $ext ) {

			$content = array(
				'main' => $content,
				'rtl'  => $rtl_content,
			);

			// Fix: at-rule or selector expected css error.
			$content = str_replace( '@charset "UTF-8";', '', $content );
		}

		return $content;
	}

	/**
	 * Prepare PA Elements.
	 *
	 * @access public
	 * @since 4.6.1
	 *
	 * @param array  $elements  post elements.
	 * @param string $ext  js|css.
	 *
	 * @return array
	 */
	public static function prepare_pa_elements( $elements, $ext ) {

		if ( 'css' === $ext ) {
			$common_assets = self::has_free_elements( $elements ) ? array( 'common' ) : array();
			$common_assets = self::has_pro_elements( $elements ) ? array_merge( $common_assets, array( 'common-pro' ) ) : $common_assets;

			$elements = array_merge( $elements, $common_assets );

		} else {
			$indep_elements = array(
				'social-common',
				'premium-hscroll',
				'premium-lottie',
				'premium-vscroll',
				'premium-nav-menu',
				'premium-addon-maps',
				'premium-woo-products-pro',
				'premium-addon-testimonials',
				'premium-addon-pricing-table',
				'premium-addon-image-separator',
			);

			$elements = array_diff( $elements, $indep_elements );
		}

		return $elements;
	}

	/**
	 * Get File Content.
	 *
	 * @param string $path file path.
	 *
	 * @return string
	 */
	public static function get_file_content( $path ) {

		$file_content = rplg_urlopen( $path );

		if ( isset( $file_content['code'] ) ) {
			if ( in_array( $file_content['code'], array( 404, 401 ), true ) ) {
				return '';
			}
		}

		return self::clean_content( $file_content['data'] );
	}

	/**
	 * Clean Content
	 * Removes Page Html if it's returned as result.
	 *
	 * @param string $content file content.
	 *
	 * @return string
	 */
	public static function clean_content( $content ) {

		if ( strpos( $content, '<!DOCTYPE html>' ) ) {
			$content = explode( '<!DOCTYPE html>', $content )[0];
		}

		if ( strpos( $content, '<!doctype html>' ) ) {
			$content = explode( '<!doctype html>', $content )[0];
		}

		return $content;
	}

	/**
	 * Get File Path.
	 * Construct file path.
	 *
	 * @param string $element  pa element name.
	 * @param string $ext      file extension ( js|css).
	 * @param string $dir      post dir (-rtl|'').
	 *
	 * @return string file path.
	 */
	public static function get_file_path( $element, $ext, $dir = '' ) {

		$is_pro = self::is_pro_widget( $element );

		$papro_activated = apply_filters( 'papro_activated', false ) && version_compare( PREMIUM_PRO_ADDONS_VERSION, '2.7.1', '>' );

		if ( ! $papro_activated && $is_pro ) {
			return false;
		}

		$element = str_replace( '-addon', '', $element );

		$path = $is_pro ? PREMIUM_PRO_ADDONS_URL : PREMIUM_ADDONS_URL;

		return $path . 'assets/frontend/min-' . $ext . '/' . $element . $dir . '.min.' . $ext;
	}

	/**
	 * Is Pro Widget.
	 * Checks if the widget is pro.
	 *
	 * @access public
	 * @since 4.6.1
	 *
	 * @param string $widget  widget name.
	 *
	 * @return bool
	 */
	public static function is_pro_widget( $widget ) {

		$pro_names = array_merge( array( 'common-pro', 'premium-reviews', 'premium-woo-products-pro', 'social-common' ), self::get_pro_widgets_names() );

		return in_array( $widget, $pro_names, true );
	}

	/**
	 * Has Pro Elements.
	 * Check if the post has pa pro elements.
	 *
	 * @access public
	 * @since 4.6.1
	 *
	 * @param array $post_elems post elements.
	 *
	 * @return boolean
	 */
	public static function has_pro_elements( $post_elems ) {

		$papro_elems = self::get_pro_widgets_names();
		$has_pro     = array_intersect( $post_elems, $papro_elems ) ? true : false;

		return $has_pro;
	}

	/**
	 * Has Free Elements.
	 * Check if the post has pa elements.
	 *
	 * @access public
	 * @since 4.6.1
	 *
	 * @param array $post_elems post elements.
	 *
	 * @return boolean
	 */
	public static function has_free_elements( $post_elems ) {

		$pa_elems = Admin_Helper::get_free_widgets_names();
		$has_free = array_intersect( $post_elems, $pa_elems ) ? true : false;

		return $has_free;
	}

	/**
	 * Get Pro Widgets Names.
	 *
	 * @access public
	 * @since 4.6.1
	 *
	 * @return array
	 */
	public static function get_pro_widgets_names() {

		$pro_elems = Admin_Helper::get_pro_elements();
		$pro_names = array();

		foreach ( $pro_elems as $element ) {
			if ( isset( $element['name'] ) ) {
				array_push( $pro_names, $element['name'] );
			}
		}

		return $pro_names;
	}

	/**
	 * Creates and returns an instance of the class.
	 *
	 * @since  4.6.1
	 * @access public
	 *
	 * @return object
	 */
	public static function get_instance() {

		if ( ! isset( self::$instance ) ) {

			self::$instance = new self();

		}

		return self::$instance;
	}
}