<?php
namespace app\common\service;

use think\Db;
use think\Cache;

class RuleCheckService
{
    // 缓存前缀
    const CACHE_PREFIX = 'risk_control:rule:';
    // 缓存时间（秒）
    const CACHE_TIME = 3600;
    
    /**
     * 检查频率规则
     * @param array $detail 规则详情
     * @param array $eventData 事件数据
     * @return bool
     */
    public function checkFrequencyRule(array $detail, array $eventData)
    {
        $cacheKey = self::CACHE_PREFIX . 'frequency:' . $detail['rule_id'] . ':' . $eventData[$detail['object_type']];
        
        // 获取时间窗口内的记录数
        $count = $this->getFrequencyCount($detail, $eventData, $cacheKey);
        
        // 根据逻辑类型判断
        switch ($detail['logic_type']) {
            case 'gt': // 大于
                return $count > $detail['logic_value'];
            case 'gte': // 大于等于
                return $count >= $detail['logic_value'];
            case 'lt': // 小于
                return $count < $detail['logic_value'];
            case 'lte': // 小于等于
                return $count <= $detail['logic_value'];
            case 'eq': // 等于
                return $count == $detail['logic_value'];
            default:
                return false;
        }
    }
    
    /**
     * 获取频率计数
     * @param array $detail
     * @param array $eventData
     * @param string $cacheKey
     * @return int
     */
    private function getFrequencyCount(array $detail, array $eventData, string $cacheKey)
    {
        // 先查缓存
        $count = Cache::get($cacheKey);
        if ($count !== false) {
            return $count;
        }
        
        // 计算时间窗口
        $endTime = $eventData['timestamp'];
        $startTime = $endTime - $detail['time_window'];
        
        // 查询数据库
        $count = Db::name('fk_exception_records')
            ->where([
                'rule_id' => $detail['rule_id'],
                'object_type' => $detail['object_type'],
                'object_value' => $eventData[$detail['object_type']]
            ])
            ->where('create_time', 'between', [$startTime, $endTime])
            ->count();
            
        // 设置缓存
        Cache::set($cacheKey, $count, min($detail['time_window'], self::CACHE_TIME));
        
        return $count;
    }
    
    /**
     * 检查统计规则
     * @param array $detail
     * @param array $eventData
     * @return bool
     */
    public function checkStatisticsRule(array $detail, array $eventData)
    {
        $cacheKey = self::CACHE_PREFIX . 'statistics:' . $detail['rule_id'] . ':' . $eventData[$detail['object_type']];
        
        // 获取统计数据
        $statistics = $this->getStatisticsData($detail, $eventData, $cacheKey);
        
        // 根据逻辑类型判断
        switch ($detail['logic_type']) {
            case 'gt': // 大于
                return $statistics > $detail['logic_value'];
            case 'gte': // 大于等于
                return $statistics >= $detail['logic_value'];
            case 'lt': // 小于
                return $statistics < $detail['logic_value'];
            case 'lte': // 小于等于
                return $statistics <= $detail['logic_value'];
            case 'eq': // 等于
                return $statistics == $detail['logic_value'];
            default:
                return false;
        }
    }
    
    /**
     * 获取统计数据
     * @param array $detail
     * @param array $eventData
     * @param string $cacheKey
     * @return float
     */
    private function getStatisticsData(array $detail, array $eventData, string $cacheKey)
    {
        // 先查缓存
        $data = Cache::get($cacheKey);
        if ($data !== false) {
            return $data;
        }
        
        // 计算时间窗口
        $endTime = $eventData['timestamp'];
        $startTime = $endTime - $detail['time_window'];
        
        // 查询数据库
        $query = Db::name('fk_exception_records')
            ->where([
                'rule_id' => $detail['rule_id'],
                'object_type' => $detail['object_type'],
                'object_value' => $eventData[$detail['object_type']]
            ])
            ->where('create_time', 'between', [$startTime, $endTime]);
            
        // 根据统计类型计算
        switch ($detail['statistics_type']) {
            case 'avg': // 平均值
                $data = $query->avg('exception_level');
                break;
            case 'sum': // 总和
                $data = $query->sum('exception_level');
                break;
            case 'max': // 最大值
                $data = $query->max('exception_level');
                break;
            case 'min': // 最小值
                $data = $query->min('exception_level');
                break;
            default:
                $data = 0;
        }
        
        // 设置缓存
        Cache::set($cacheKey, $data, min($detail['time_window'], self::CACHE_TIME));
        
        return $data;
    }
}