<?php
/**
 * 日志分析器类
 * 
 * 用于分析日志数据，生成统计报告和趋势分析
 */

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

/**
 * 日志分析器类
 */
class Yoone_Log_Analyzer {
    
    /**
     * 分析最近的日志
     * 
     * @param int $days 分析天数
     * @return array 分析结果
     */
    public static function analyze_recent_logs($days = 7) {
        $logs = Yoone_Logger::get_recent_logs(1000);
        $cutoff_date = date('Y-m-d H:i:s', strtotime("-{$days} days"));
        
        $analysis = array(
            'total_logs' => 0,
            'error_count' => 0,
            'warning_count' => 0,
            'info_count' => 0,
            'debug_count' => 0,
            'daily_stats' => array(),
            'hourly_stats' => array(),
            'top_errors' => array(),
            'subscription_stats' => array(),
            'payment_stats' => array(),
            'performance_issues' => array()
        );
        
        foreach ($logs as $log_line) {
            $parsed_log = self::parse_log_line($log_line);
            
            if (!$parsed_log || $parsed_log['timestamp'] < $cutoff_date) {
                continue;
            }
            
            $analysis['total_logs']++;
            
            // 统计日志级别
            $level = $parsed_log['level'];
            if (isset($analysis[$level . '_count'])) {
                $analysis[$level . '_count']++;
            }
            
            // 按日统计
            $date = date('Y-m-d', strtotime($parsed_log['timestamp']));
            if (!isset($analysis['daily_stats'][$date])) {
                $analysis['daily_stats'][$date] = array(
                    'total' => 0,
                    'error' => 0,
                    'warning' => 0,
                    'info' => 0,
                    'debug' => 0
                );
            }
            $analysis['daily_stats'][$date]['total']++;
            $analysis['daily_stats'][$date][$level]++;
            
            // 按小时统计
            $hour = date('H', strtotime($parsed_log['timestamp']));
            if (!isset($analysis['hourly_stats'][$hour])) {
                $analysis['hourly_stats'][$hour] = 0;
            }
            $analysis['hourly_stats'][$hour]++;
            
            // 收集错误信息
            if ($level === 'error') {
                $error_key = md5($parsed_log['message']);
                if (!isset($analysis['top_errors'][$error_key])) {
                    $analysis['top_errors'][$error_key] = array(
                        'message' => $parsed_log['message'],
                        'count' => 0,
                        'first_seen' => $parsed_log['timestamp'],
                        'last_seen' => $parsed_log['timestamp']
                    );
                }
                $analysis['top_errors'][$error_key]['count']++;
                $analysis['top_errors'][$error_key]['last_seen'] = $parsed_log['timestamp'];
            }
            
            // 订阅相关统计
            if (strpos($parsed_log['message'], 'subscription') !== false) {
                $analysis['subscription_stats']['total'] = ($analysis['subscription_stats']['total'] ?? 0) + 1;
                
                if (strpos($parsed_log['message'], 'created') !== false) {
                    $analysis['subscription_stats']['created'] = ($analysis['subscription_stats']['created'] ?? 0) + 1;
                } elseif (strpos($parsed_log['message'], 'cancelled') !== false) {
                    $analysis['subscription_stats']['cancelled'] = ($analysis['subscription_stats']['cancelled'] ?? 0) + 1;
                } elseif (strpos($parsed_log['message'], 'renewed') !== false) {
                    $analysis['subscription_stats']['renewed'] = ($analysis['subscription_stats']['renewed'] ?? 0) + 1;
                }
            }
            
            // 支付相关统计
            if (strpos($parsed_log['message'], 'payment') !== false) {
                $analysis['payment_stats']['total'] = ($analysis['payment_stats']['total'] ?? 0) + 1;
                
                if (strpos($parsed_log['message'], 'success') !== false) {
                    $analysis['payment_stats']['success'] = ($analysis['payment_stats']['success'] ?? 0) + 1;
                } elseif (strpos($parsed_log['message'], 'failed') !== false) {
                    $analysis['payment_stats']['failed'] = ($analysis['payment_stats']['failed'] ?? 0) + 1;
                }
            }
            
            // 性能问题检测
            if (strpos($parsed_log['message'], 'timeout') !== false || 
                strpos($parsed_log['message'], 'slow') !== false ||
                strpos($parsed_log['message'], 'memory') !== false) {
                $analysis['performance_issues'][] = array(
                    'timestamp' => $parsed_log['timestamp'],
                    'message' => $parsed_log['message'],
                    'level' => $level
                );
            }
        }
        
        // 排序错误统计
        uasort($analysis['top_errors'], function($a, $b) {
            return $b['count'] - $a['count'];
        });
        
        // 只保留前10个错误
        $analysis['top_errors'] = array_slice($analysis['top_errors'], 0, 10, true);
        
        return $analysis;
    }
    
    /**
     * 生成健康报告
     * 
     * @return array 健康报告
     */
    public static function generate_health_report() {
        $analysis = self::analyze_recent_logs(7);
        
        $health_score = 100;
        $issues = array();
        $recommendations = array();
        
        // 错误率检查
        $error_rate = $analysis['total_logs'] > 0 ? ($analysis['error_count'] / $analysis['total_logs']) * 100 : 0;
        if ($error_rate > 10) {
            $health_score -= 30;
            $issues[] = sprintf(__('错误率过高: %.1f%%', 'yoone-subscriptions'), $error_rate);
            $recommendations[] = __('检查并修复频繁出现的错误', 'yoone-subscriptions');
        } elseif ($error_rate > 5) {
            $health_score -= 15;
            $issues[] = sprintf(__('错误率较高: %.1f%%', 'yoone-subscriptions'), $error_rate);
        }
        
        // 警告率检查
        $warning_rate = $analysis['total_logs'] > 0 ? ($analysis['warning_count'] / $analysis['total_logs']) * 100 : 0;
        if ($warning_rate > 20) {
            $health_score -= 20;
            $issues[] = sprintf(__('警告率过高: %.1f%%', 'yoone-subscriptions'), $warning_rate);
            $recommendations[] = __('关注警告信息，预防潜在问题', 'yoone-subscriptions');
        }
        
        // 支付失败率检查
        if (isset($analysis['payment_stats']['total']) && $analysis['payment_stats']['total'] > 0) {
            $payment_failure_rate = (($analysis['payment_stats']['failed'] ?? 0) / $analysis['payment_stats']['total']) * 100;
            if ($payment_failure_rate > 15) {
                $health_score -= 25;
                $issues[] = sprintf(__('支付失败率过高: %.1f%%', 'yoone-subscriptions'), $payment_failure_rate);
                $recommendations[] = __('检查支付网关配置和网络连接', 'yoone-subscriptions');
            }
        }
        
        // 性能问题检查
        if (count($analysis['performance_issues']) > 5) {
            $health_score -= 20;
            $issues[] = sprintf(__('发现 %d 个性能问题', 'yoone-subscriptions'), count($analysis['performance_issues']));
            $recommendations[] = __('优化代码性能，检查服务器资源', 'yoone-subscriptions');
        }
        
        // 频繁错误检查
        foreach ($analysis['top_errors'] as $error) {
            if ($error['count'] > 10) {
                $health_score -= 10;
                $issues[] = sprintf(__('频繁错误: %s (出现 %d 次)', 'yoone-subscriptions'), 
                    substr($error['message'], 0, 50) . '...', $error['count']);
                break;
            }
        }
        
        // 确保分数不低于0
        $health_score = max(0, $health_score);
        
        // 健康等级
        if ($health_score >= 90) {
            $health_level = 'excellent';
            $health_text = __('优秀', 'yoone-subscriptions');
        } elseif ($health_score >= 70) {
            $health_level = 'good';
            $health_text = __('良好', 'yoone-subscriptions');
        } elseif ($health_score >= 50) {
            $health_level = 'fair';
            $health_text = __('一般', 'yoone-subscriptions');
        } else {
            $health_level = 'poor';
            $health_text = __('较差', 'yoone-subscriptions');
        }
        
        return array(
            'score' => $health_score,
            'level' => $health_level,
            'text' => $health_text,
            'issues' => $issues,
            'recommendations' => $recommendations,
            'analysis' => $analysis
        );
    }
    
    /**
     * 获取趋势数据
     * 
     * @param int $days 天数
     * @return array 趋势数据
     */
    public static function get_trend_data($days = 30) {
        $analysis = self::analyze_recent_logs($days);
        
        $trends = array(
            'daily_errors' => array(),
            'daily_warnings' => array(),
            'daily_total' => array(),
            'subscription_activity' => array(),
            'payment_activity' => array()
        );
        
        // 填充每日数据
        for ($i = $days - 1; $i >= 0; $i--) {
            $date = date('Y-m-d', strtotime("-{$i} days"));
            
            $trends['daily_errors'][$date] = $analysis['daily_stats'][$date]['error'] ?? 0;
            $trends['daily_warnings'][$date] = $analysis['daily_stats'][$date]['warning'] ?? 0;
            $trends['daily_total'][$date] = $analysis['daily_stats'][$date]['total'] ?? 0;
        }
        
        return $trends;
    }
    
    /**
     * 检测异常模式
     * 
     * @return array 异常模式
     */
    public static function detect_anomalies() {
        $analysis = self::analyze_recent_logs(7);
        $anomalies = array();
        
        // 检测错误激增
        $daily_errors = array();
        foreach ($analysis['daily_stats'] as $date => $stats) {
            $daily_errors[] = $stats['error'];
        }
        
        if (count($daily_errors) >= 3) {
            $avg_errors = array_sum($daily_errors) / count($daily_errors);
            $latest_errors = end($daily_errors);
            
            if ($latest_errors > $avg_errors * 2 && $latest_errors > 5) {
                $anomalies[] = array(
                    'type' => 'error_spike',
                    'severity' => 'high',
                    'message' => sprintf(__('今日错误数量异常增加: %d (平均: %.1f)', 'yoone-subscriptions'), 
                        $latest_errors, $avg_errors),
                    'timestamp' => current_time('mysql')
                );
            }
        }
        
        // 检测重复错误
        foreach ($analysis['top_errors'] as $error) {
            if ($error['count'] > 20) {
                $anomalies[] = array(
                    'type' => 'repeated_error',
                    'severity' => 'medium',
                    'message' => sprintf(__('重复错误: %s (出现 %d 次)', 'yoone-subscriptions'), 
                        substr($error['message'], 0, 100), $error['count']),
                    'timestamp' => $error['last_seen']
                );
            }
        }
        
        // 检测支付问题
        if (isset($analysis['payment_stats']['failed']) && $analysis['payment_stats']['failed'] > 10) {
            $anomalies[] = array(
                'type' => 'payment_issues',
                'severity' => 'high',
                'message' => sprintf(__('支付失败次数过多: %d', 'yoone-subscriptions'), 
                    $analysis['payment_stats']['failed']),
                'timestamp' => current_time('mysql')
            );
        }
        
        return $anomalies;
    }
    
    /**
     * 生成报告摘要
     * 
     * @param array $analysis 分析数据
     * @return string 报告摘要
     */
    public static function generate_summary($analysis) {
        $summary = array();
        
        $summary[] = sprintf(__('总计 %d 条日志记录', 'yoone-subscriptions'), $analysis['total_logs']);
        
        if ($analysis['error_count'] > 0) {
            $summary[] = sprintf(__('%d 个错误', 'yoone-subscriptions'), $analysis['error_count']);
        }
        
        if ($analysis['warning_count'] > 0) {
            $summary[] = sprintf(__('%d 个警告', 'yoone-subscriptions'), $analysis['warning_count']);
        }
        
        if (isset($analysis['subscription_stats']['total'])) {
            $summary[] = sprintf(__('%d 个订阅相关事件', 'yoone-subscriptions'), 
                $analysis['subscription_stats']['total']);
        }
        
        if (isset($analysis['payment_stats']['total'])) {
            $summary[] = sprintf(__('%d 个支付相关事件', 'yoone-subscriptions'), 
                $analysis['payment_stats']['total']);
        }
        
        return implode('，', $summary);
    }
    
    /**
     * 解析日志行
     * 
     * @param string $log_line 日志行
     * @return array|false 解析结果
     */
    private static function parse_log_line($log_line) {
        // 匹配WooCommerce日志格式
        if (preg_match('/^(\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}[+-]\d{2}:\d{2})\s+(\w+)\s+(.+)$/', $log_line, $matches)) {
            return array(
                'timestamp' => $matches[1],
                'level' => strtolower($matches[2]),
                'message' => $matches[3]
            );
        }
        
        return false;
    }
    
    /**
     * 导出分析报告
     * 
     * @param string $format 格式 (json|csv|html)
     * @param int $days 分析天数
     * @return string 报告内容
     */
    public static function export_report($format = 'json', $days = 7) {
        $health_report = self::generate_health_report();
        $trends = self::get_trend_data($days);
        $anomalies = self::detect_anomalies();
        
        $report_data = array(
            'generated_at' => current_time('mysql'),
            'period_days' => $days,
            'health' => $health_report,
            'trends' => $trends,
            'anomalies' => $anomalies
        );
        
        switch ($format) {
            case 'json':
                return json_encode($report_data, JSON_PRETTY_PRINT);
                
            case 'csv':
                return self::convert_to_csv($report_data);
                
            case 'html':
                return self::convert_to_html($report_data);
                
            default:
                return json_encode($report_data);
        }
    }
    
    /**
     * 转换为CSV格式
     * 
     * @param array $data 数据
     * @return string CSV内容
     */
    private static function convert_to_csv($data) {
        $csv = "Yoone Subscriptions Log Analysis Report\n";
        $csv .= "Generated: " . $data['generated_at'] . "\n";
        $csv .= "Period: " . $data['period_days'] . " days\n\n";
        
        $csv .= "Health Score," . $data['health']['score'] . "\n";
        $csv .= "Health Level," . $data['health']['text'] . "\n\n";
        
        if (!empty($data['health']['issues'])) {
            $csv .= "Issues:\n";
            foreach ($data['health']['issues'] as $issue) {
                $csv .= "," . $issue . "\n";
            }
            $csv .= "\n";
        }
        
        if (!empty($data['anomalies'])) {
            $csv .= "Anomalies:\n";
            $csv .= "Type,Severity,Message,Timestamp\n";
            foreach ($data['anomalies'] as $anomaly) {
                $csv .= $anomaly['type'] . "," . $anomaly['severity'] . "," . 
                       $anomaly['message'] . "," . $anomaly['timestamp'] . "\n";
            }
        }
        
        return $csv;
    }
    
    /**
     * 转换为HTML格式
     * 
     * @param array $data 数据
     * @return string HTML内容
     */
    private static function convert_to_html($data) {
        $html = '<html><head><title>Yoone Subscriptions Log Analysis Report</title>';
        $html .= '<style>body{font-family:Arial,sans-serif;margin:20px;}';
        $html .= '.health-score{font-size:24px;font-weight:bold;margin:20px 0;}';
        $html .= '.excellent{color:#28a745;}.good{color:#17a2b8;}.fair{color:#ffc107;}.poor{color:#dc3545;}';
        $html .= 'table{border-collapse:collapse;width:100%;margin:20px 0;}';
        $html .= 'th,td{border:1px solid #ddd;padding:8px;text-align:left;}';
        $html .= 'th{background-color:#f2f2f2;}</style></head><body>';
        
        $html .= '<h1>Yoone Subscriptions 日志分析报告</h1>';
        $html .= '<p>生成时间: ' . $data['generated_at'] . '</p>';
        $html .= '<p>分析周期: ' . $data['period_days'] . ' 天</p>';
        
        $html .= '<div class="health-score ' . $data['health']['level'] . '">';
        $html .= '健康评分: ' . $data['health']['score'] . '/100 (' . $data['health']['text'] . ')';
        $html .= '</div>';
        
        if (!empty($data['health']['issues'])) {
            $html .= '<h2>发现的问题</h2><ul>';
            foreach ($data['health']['issues'] as $issue) {
                $html .= '<li>' . htmlspecialchars($issue) . '</li>';
            }
            $html .= '</ul>';
        }
        
        if (!empty($data['health']['recommendations'])) {
            $html .= '<h2>建议</h2><ul>';
            foreach ($data['health']['recommendations'] as $rec) {
                $html .= '<li>' . htmlspecialchars($rec) . '</li>';
            }
            $html .= '</ul>';
        }
        
        if (!empty($data['anomalies'])) {
            $html .= '<h2>异常检测</h2><table>';
            $html .= '<tr><th>类型</th><th>严重程度</th><th>描述</th><th>时间</th></tr>';
            foreach ($data['anomalies'] as $anomaly) {
                $html .= '<tr>';
                $html .= '<td>' . htmlspecialchars($anomaly['type']) . '</td>';
                $html .= '<td>' . htmlspecialchars($anomaly['severity']) . '</td>';
                $html .= '<td>' . htmlspecialchars($anomaly['message']) . '</td>';
                $html .= '<td>' . htmlspecialchars($anomaly['timestamp']) . '</td>';
                $html .= '</tr>';
            }
            $html .= '</table>';
        }
        
        $html .= '</body></html>';
        
        return $html;
    }
}