<?php
/**
 * AKSRT 访问量统计系统
 *
 * 追踪每日访客数和浏览量，为网站统计小工具提供数据支持。
 *
 * @package AKSRT
 */

defined('ABSPATH') || exit;

class AKSRT_Stats_Tracker {

	private static $instance = null;

	/**
	 * 单例模式
	 */
	public static function get_instance(): self {
		if (null === self::$instance) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * 初始化：挂钩到 wp_head
	 */
	public static function init(): void {
		add_action('wp_head', [self::get_instance(), 'track_visit'], 1);
	}

	/**
	 * 追踪访问
	 */
	public function track_visit(): void {
		// 排除管理员、爬虫、AJAX请求
		if (is_admin() || wp_doing_ajax()) {
			return;
		}

		if (is_user_logged_in() && current_user_can('manage_options')) {
			return;
		}

		$today = current_time('Y-m-d');
		$option_key = 'aksrt_daily_stats_' . $today;

		// 检查是否已统计过该访客
		$visitor_cookie = 'aksrt_visitor_' . $today;
		$is_unique = empty($_COOKIE[$visitor_cookie]);

		// 获取或初始化今日统计
		$stats = get_option($option_key, ['visitors' => 0, 'pageviews' => 0]);

		if (!is_array($stats)) {
			$stats = ['visitors' => 0, 'pageviews' => 0];
		}

		// 更新统计
		$stats['pageviews']++;
		if ($is_unique) {
			$stats['visitors']++;
			setcookie($visitor_cookie, '1', time() + DAY_IN_SECONDS, COOKIEPATH, COOKIE_DOMAIN);
		}

		update_option($option_key, $stats, false);

		// 每月1日清理旧数据
		if ((int) date('j') === 1 && (int) date('H') === 0 && (int) date('i') < 5) {
			$this->cleanup_old_stats();
		}
	}

	/**
	 * 清理30天前的统计数据
	 */
	private function cleanup_old_stats(): void {
		global $wpdb;

		$threshold = date('Y-m-d', strtotime('-30 days'));
		$wpdb->query($wpdb->prepare(
			"DELETE FROM {$wpdb->options} WHERE option_name LIKE %s AND option_name < %s",
			$wpdb->esc_like('aksrt_daily_stats_') . '%',
			'aksrt_daily_stats_' . $threshold
		));
	}

	/**
	 * 获取今日统计
	 */
	public static function get_today_stats(): array {
		$today = current_time('Y-m-d');
		$stats = get_option('aksrt_daily_stats_' . $today, ['visitors' => 0, 'pageviews' => 0]);

		if (!is_array($stats)) {
			return ['visitors' => 0, 'pageviews' => 0];
		}

		return [
			'visitors'  => absint($stats['visitors'] ?? 0),
			'pageviews' => absint($stats['pageviews'] ?? 0),
		];
	}

	/**
	 * 获取指定日期统计
	 */
	public static function get_daily_stats(string $date): array {
		$stats = get_option('aksrt_daily_stats_' . $date, ['visitors' => 0, 'pageviews' => 0]);

		if (!is_array($stats)) {
			return ['visitors' => 0, 'pageviews' => 0];
		}

		return [
			'visitors'  => absint($stats['visitors'] ?? 0),
			'pageviews' => absint($stats['pageviews'] ?? 0),
		];
	}

	/**
	 * 获取最近N天统计
	 */
	public static function get_period_stats(int $days = 30): array {
		$total = ['visitors' => 0, 'pageviews' => 0];
		for ($i = 0; $i < $days; $i++) {
			$date = date('Y-m-d', strtotime("-{$i} days"));
			$stats = self::get_daily_stats($date);
			$total['visitors'] += $stats['visitors'];
			$total['pageviews'] += $stats['pageviews'];
		}
		return $total;
	}

	/**
	 * 获取总浏览量（所有文章）
	 */
	public static function get_total_views(): int {
		global $wpdb;
		$total = $wpdb->get_var(
			"SELECT SUM(CAST(meta_value AS UNSIGNED)) FROM {$wpdb->postmeta} WHERE meta_key = 'aksrt_post_views'"
		);
		return max(0, (int) $total);
	}
}