<?php
/**
 * Lazy Loading check.
 *
 * @package advanced-analytics
 *
 * @since 4.9.0
 */

declare(strict_types=1);

namespace ADVAN\Checks\Speed;

use ADVAN\Checks\Abstract_Check;
use ADVAN\Helpers\Plugin_Theme_Helper;

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

if ( ! class_exists( 'ADVAN\Checks\Speed\Lazy_Loading_Check' ) ) {

	/**
	 * Checks if images and iframes use lazy loading.
	 *
	 * @since 4.9.0
	 */
	class Lazy_Loading_Check extends Abstract_Check {

		/**
		 * Check identifier.
		 *
		 * @var string Check identifier.
		 *
		 * @since 4.9.0
		 */
		protected static string $id = 'lazy-loading';

		/**
		 * Check category.
		 *
		 * @var string Check category.
		 *
		 * @since 4.9.0
		 */
		protected static string $category = 'speed';

		/**
		 * Check weight (1-10).
		 *
		 * @var int Check weight.
		 *
		 * @since 4.9.0
		 */
		protected static int $weight = 6;

		/**
		 * Check title (translatable).
		 *
		 * @return string Check title.
		 *
		 * @since 4.9.0
		 */
		public static function get_title(): string {
			return \__( 'Lazy Loading', '0-day-analytics' );
		}

		/**
		 * Check description (translatable).
		 *
		 * @return string Check description.
		 *
		 * @since 4.9.0
		 */
		public static function get_description(): string {
			return \__( 'Checks if images and iframes use lazy loading.', '0-day-analytics' );
		}

		/**
		 * Run the check.
		 *
		 * @return array Check result.
		 *
		 * @since 4.9.0
		 */
		public static function run(): array {
			// WordPress 5.5+ has native lazy loading.
			global $wp_version;
			$native_lazy_loading = version_compare( $wp_version, '5.5', '>=' );

			// Check if lazy loading is disabled.
			$lazy_loading_disabled = has_filter( 'wp_lazy_loading_enabled', '__return_false' );

			// Lazy loading plugins.
			$lazy_plugins = array(
				'a3-lazy-load/a3-lazy-load.php'         => 'a3 Lazy Load',
				'lazy-load/lazy-load.php'               => 'Lazy Load',
				'rocket-lazy-load/rocket-lazy-load.php' => 'Rocket Lazy Load',
			);

			$active_plugin = null;
			foreach ( $lazy_plugins as $plugin_path => $plugin_name ) {
				if ( Plugin_Theme_Helper::is_plugin_active( $plugin_path ) ) {
					$active_plugin = $plugin_name;
					break;
				}
			}

			$details = array(
				'native_supported'  => $native_lazy_loading,
				'native_disabled'   => $lazy_loading_disabled,
				'active_plugin'     => $active_plugin,
				'wordpress_version' => $wp_version,
			);

			if ( $lazy_loading_disabled ) {
				return static::warning(
					\__( 'Native lazy loading has been disabled on your site. Images load immediately even if they\'re not visible, which slows down initial page load.', '0-day-analytics' ),
					\__( 'Check your theme or plugin code for the filter "wp_lazy_loading_enabled" and remove it, or configure your lazy loading plugin to work properly.', '0-day-analytics' ),
					$details
				);
			}

			if ( $active_plugin ) {
				return static::pass(
					sprintf(
					/* translators: %s: plugin name */
						\__( 'Lazy loading is enabled via %s. Images and videos load only when visitors scroll to them, speeding up initial page load.', '0-day-analytics' ),
						$active_plugin
					),
					$details
				);
			}

			if ( $native_lazy_loading ) {
				return static::pass(
					\__( 'WordPress native lazy loading is active. Images load only when visitors scroll near them, which speeds up initial page load.', '0-day-analytics' ),
					$details
				);
			}

			return static::warning(
				\__( 'Lazy loading is not available. Your WordPress version is too old to support native lazy loading. Images load immediately, slowing down your pages.', '0-day-analytics' ),
				\__( 'Update WordPress to version 5.5 or higher for native lazy loading, or install a lazy loading plugin.', '0-day-analytics' ),
				$details
			);
		}
	}
}