<?php
/**
 * Performance analytics center.
 *
 * @package AceloraSiteAccelerator
 */

namespace Acelora\SiteAccelerator\Modules;

use Acelora\SiteAccelerator\Includes\Filesystem;
use Acelora\SiteAccelerator\Includes\Logger;
use Acelora\SiteAccelerator\Includes\Settings;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Builds dashboard metrics and recommendations.
 */
class Analytics {

	/**
	 * Settings.
	 *
	 * @var Settings
	 */
	private $settings;

	/**
	 * Logger.
	 *
	 * @var Logger
	 */
	private $logger;

	/**
	 * Filesystem.
	 *
	 * @var Filesystem
	 */
	private $filesystem;

	/**
	 * Constructor.
	 *
	 * @param Settings   $settings   Settings.
	 * @param Logger     $logger     Logger.
	 * @param Filesystem $filesystem Filesystem.
	 */
	public function __construct( Settings $settings, Logger $logger, Filesystem $filesystem ) {
		$this->settings   = $settings;
		$this->logger     = $logger;
		$this->filesystem = $filesystem;
	}

	/**
	 * Register hooks.
	 *
	 * @return void
	 */
	public function register() {}

	/**
	 * Dashboard metrics.
	 *
	 * @return array
	 */
	public function metrics() {
		$cache = $this->filesystem->directory_stats( $this->filesystem->page_cache_dir() );
		$asset = $this->filesystem->directory_stats( $this->filesystem->asset_cache_dir() );
		$image = wp_parse_args(
			get_option( Image_Optimizer::STATS_OPTION, array() ),
			array(
				'optimized_images' => 0,
				'saved_bytes'      => 0,
				'webp_files'       => 0,
			)
		);

		$logs      = $this->logger->recent( 200 );
		$hits      = 0;
		$misses    = 0;
		$purges    = 0;
		$errors    = 0;
		$last_logs = array_slice( $logs, 0, 10 );

		foreach ( $logs as $log ) {
			$message = isset( $log['message'] ) ? strtolower( $log['message'] ) : '';
			$level   = isset( $log['level'] ) ? strtolower( $log['level'] ) : '';

			if ( false !== strpos( $message, 'cache hit' ) ) {
				$hits++;
			}

			if ( false !== strpos( $message, 'cache miss' ) ) {
				$misses++;
			}

			if ( false !== strpos( $message, 'purged' ) ) {
				$purges++;
			}

			if ( 'error' === $level ) {
				$errors++;
			}
		}

		return array(
			'cache_files'      => $cache['files'],
			'cache_size'       => $cache['bytes'],
			'asset_files'      => $asset['files'],
			'asset_size'       => $asset['bytes'],
			'image_stats'      => $image,
			'cache_hits'       => $hits,
			'cache_misses'     => $misses,
			'cache_purges'     => $purges,
			'errors'           => $errors,
			'optimization_score' => $this->score(),
			'recommendations'  => $this->recommendations(),
			'logs'             => $last_logs,
		);
	}

	/**
	 * Optimization score estimate.
	 *
	 * @return int
	 */
	private function score() {
		$checks = array(
			$this->settings->get( 'cache.enabled', 1 ),
			$this->settings->get( 'preload.enabled', 1 ),
			$this->settings->get( 'browser.enabled', 1 ),
			$this->settings->get( 'css.minify', 1 ),
			$this->settings->get( 'js.defer', 1 ),
			$this->settings->get( 'images.webp', 1 ),
			$this->settings->get( 'lazy.images', 1 ),
			$this->settings->get( 'compression.enabled', 1 ),
			$this->settings->get( 'automation.enabled', 1 ),
			$this->settings->get( 'logging.enabled', 1 ),
		);

		return (int) round( ( array_sum( array_map( 'absint', $checks ) ) / count( $checks ) ) * 100 );
	}

	/**
	 * Recommendations and warnings.
	 *
	 * @return array
	 */
	private function recommendations() {
		$items = array();

		if ( ! $this->settings->get( 'cache.enabled', 1 ) ) {
			$items[] = __( 'Enable intelligent page caching to reduce PHP execution and database load.', 'acelora-site-accelerator' );
		}

		if ( ! $this->settings->get( 'preload.enabled', 1 ) ) {
			$items[] = __( 'Enable URL warmup so important URLs are requested after purges.', 'acelora-site-accelerator' );
		}

		if ( ! $this->settings->get( 'images.webp', 1 ) ) {
			$items[] = __( 'Enable WebP generation to reduce image transfer size for modern browsers.', 'acelora-site-accelerator' );
		}

		if ( ! $this->settings->get( 'cdn.enabled', 0 ) ) {
			$items[] = __( 'Connect a CDN for static assets if your visitors are geographically distributed.', 'acelora-site-accelerator' );
		}

		if ( ! extension_loaded( 'zlib' ) ) {
			$items[] = __( 'The PHP zlib extension is not loaded. Server-level GZIP should be verified.', 'acelora-site-accelerator' );
		}

		return $items;
	}
}