// 预警检查服务 - 定时任务调用
const { v4: uuidv4 } = require('uuid');
const notificationService = require('./notification');

// 模拟数据库
const db = {
  alertRules: [
    // 示例规则，实际从数据库读取
    {
      id: 'rule-1',
      name: '日销售额低于警戒线',
      cubeName: 'Orders',
      measureName: 'Orders.totalAmount',
      dimension: 'Orders.orderDate',
      condition: 'lt',
      threshold: 100000,
      timeGranularity: 'day',
      timeRange: 'Today',
      notifyChannels: ['wechat', 'dingtalk'],
      severity: 'high',
      status: 'active',
    },
    {
      id: 'rule-2',
      name: '订单取消率超标',
      cubeName: 'Orders',
      measureName: 'Orders.cancelRate',
      dimension: 'Orders.orderDate',
      condition: 'gt',
      threshold: 0.05,
      timeGranularity: 'day',
      timeRange: 'Last 7 days',
      notifyChannels: ['dingtalk'],
      severity: 'critical',
      status: 'active',
    },
  ],
  alertRecords: [],
  notificationChannels: [],
};

class AlertChecker {
  constructor() {
    this.cubejsApi = null;
  }

  // 设置 Cube.js API 实例
  setCubeJsApi(api) {
    this.cubejsApi = api;
  }

  // 获取所有启用的规则
  async getActiveRules() {
    return db.alertRules.filter(r => r.status === 'active');
  }

  // 检查所有规则
  async checkAllRules() {
    const rules = await this.getActiveRules();
    const results = [];

    for (const rule of rules) {
      const result = await this.checkRule(rule);
      results.push(result);
    }

    console.log(`🔔 预警检查完成: ${results.filter(r => r.triggered).length} 条触发`);
    return results;
  }

  // 检查单条规则
  async checkRule(rule) {
    try {
      const query = this.buildQuery(rule);
      const currentValue = await this.executeQuery(query);

      const isTriggered = this.evaluateCondition(currentValue, rule.condition, rule.threshold);

      if (isTriggered) {
        await this.triggerAlert(rule, currentValue);
      }

      return {
        ruleId: rule.id,
        ruleName: rule.name,
        triggered: isTriggered,
        value: currentValue,
        threshold: rule.threshold,
        checkedAt: new Date().toISOString(),
      };
    } catch (error) {
      console.error(`⚠️ 规则检查失败 [${rule.name}]:`, error.message);
      return {
        ruleId: rule.id,
        ruleName: rule.name,
        error: error.message,
        checkedAt: new Date().toISOString(),
      };
    }
  }

  // 构建查询
  buildQuery(rule) {
    return {
      measures: [rule.measureName],
      timeDimensions: [
        {
          dimension: rule.dimension,
          granularity: rule.timeGranularity,
          dateRange: rule.timeRange,
        },
      ],
      filters: rule.dimensionFilter || [],
      limit: 1,
    };
  }

  // 执行查询（模拟，实际调用 Cube.js API）
  async executeQuery(query) {
    // 如果没有设置 Cube.js API，返回模拟数据用于测试
    if (!this.cubejsApi) {
      // 模拟查询结果
      return Math.random() * 200000; // 随机生成一个值用于测试
    }

    try {
      const result = await this.cubejsApi.load(query);
      const data = result.data || [];
      if (data.length > 0) {
        const firstRow = data[0];
        // 获取 measures 中的第一个指标值
        const measureKey = Object.keys(firstRow).find(k => k.startsWith(query.measures[0].split('.')[0]));
        return firstRow[measureKey] || 0;
      }
      return 0;
    } catch (error) {
      throw new Error(`查询失败: ${error.message}`);
    }
  }

  // 条件判断
  evaluateCondition(value, condition, threshold) {
    switch (condition) {
      case 'gt':
        return value > threshold;
      case 'lt':
        return value < threshold;
      case 'eq':
        return value === threshold;
      case 'gte':
        return value >= threshold;
      case 'lte':
        return value <= threshold;
      default:
        return false;
    }
  }

  // 触发预警
  async triggerAlert(rule, currentValue) {
    // 检查是否已触发（避免重复通知）
    const recentRecord = db.alertRecords.find(r => {
      return (
        r.ruleId === rule.id &&
        r.status === 'triggered' &&
        new Date() - new Date(r.triggeredAt) < 30 * 60 * 1000 // 30分钟内不重复
      );
    });

    if (recentRecord) {
      console.log(`⏭️ 跳过重复预警 [${rule.name}]`);
      return;
    }

    // 获取订阅用户
    const subscribers = await this.getSubscribers(rule.id);

    // 发送通知
    const message = notificationService.formatAlertMessage(rule, currentValue, rule.threshold);
    const notificationResults = await notificationService.sendToUsers(
      subscribers.map(s => s.userId),
      message,
      rule.notifyChannels
    );

    // 记录预警
    const record = {
      id: uuidv4(),
      ruleId: rule.id,
      triggeredAt: new Date().toISOString(),
      actualValue: currentValue,
      threshold: rule.threshold,
      status: 'triggered',
      notifiedChannels: rule.notifyChannels,
      notificationResults,
    };

    db.alertRecords.push(record);

    console.log(`🚨 预警已触发 [${rule.name}]: 值=${currentValue}, 阈值=${rule.threshold}`);
    console.log(`   通知渠道: ${rule.notifyChannels.join(', ')}`);

    return record;
  }

  // 获取订阅用户
  async getSubscribers(ruleId) {
    // 实际项目中应从数据库查询
    // 这里返回管理员用户
    return [
      { userId: 'admin-1', role: 'admin' },
    ];
  }

  // 获取预警记录
  getAlertRecords(filters = {}) {
    let records = [...db.alertRecords];

    if (filters.ruleId) {
      records = records.filter(r => r.ruleId === filters.ruleId);
    }
    if (filters.status) {
      records = records.filter(r => r.status === filters.status);
    }

    return records.sort((a, b) => new Date(b.triggeredAt) - new Date(a.triggeredAt));
  }
}

module.exports = new AlertChecker();