<?php
// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class Gtm_Webfont_Loader {
	private static $instance;
	protected $fonts = [];

	/*
		GDPR flag for fetching font files from server side
	*/
	public $gdpr = false;

	public static function get_instance() {
		if ( ! self::$instance ) {
			self::$instance = new self();

		}

		return self::$instance;
	}

	protected function __construct() {
		// Use priority=9 to support late wp_enqueue_style
		add_action( 'wp_footer', [$this, 'get_style'], 9 );

		// Allow override GDPR flag
		$gdpr_option = (bool) get_option( 'gtm_typography_enable_local_fonts', false );
		$this->gdpr  = DEFINED( 'GTM_ALLOW_WEBFONT_GDPR' ) ? GTM_ALLOW_WEBFONT_GDPR : $gdpr_option;

		// Add preconnect if can load fonts from google site directly
		if ( ! $this->gdpr ) {
			add_filter( 'wp_resource_hints', [$this, 'resource_hints'], 10, 2 );
		}
	}

	public function resource_hints( $urls, $relation_type ) {
		if ( 'preconnect' === $relation_type ) {
			// Hint for google font css
			$urls[] = [
				'href' => 'https://fonts.googleapis.com',
				'crossorigin',
			];
			// Hint for actual font files
			$urls[] = [
				'href' => 'https://fonts.gstatic.com',
				'crossorigin',
			];
		}

		return $urls;
	}

	public function add( $family, $weights = 400 ) {
		if ( ! is_array( $weights ) ) {
			$weights = [$weights];
		}

		$this->fonts[$family] = array_unique( array_merge( $this->fonts[$family] ?? [], $weights ) );
	}

	protected function the_css() {
		foreach ( $this->fonts as $family => $weights ) {
			// Gfont requires sorted value
			natsort( $weights );

			$url = gtm_generate_web_font_url( $family, $weights );

			if ( $this->gdpr ) {
				// Download and cached on server side
				$downloader = new Gtm_Webfont_Downloader();
				$contents   = $downloader->get_styles( $url );

				if ( $contents ) {
					echo wp_strip_all_tags( $contents ); // phpcs:ignore WordPress.Security.EscapeOutput
				}
			} else {
				// Add direct link to google font's website
				$style_slug = gtm_generate_web_font_handle( $family, $weights );
				wp_enqueue_style( $style_slug, $url );

			}
		}
	}

	public function get_style() {
		echo '<style>';
		$this->the_css();
		echo '</style>';

	}
}