// 通知服务 - 支持多渠道通知
const axios = require('axios');

class NotificationService {
  constructor() {
    // 企业微信
    this.weixinCorpId = process.env.WEIXIN_CORP_ID;
    this.weixinAgentId = process.env.WEIXIN_AGENT_ID;
    this.weixinSecret = process.env.WEIXIN_SECRET;
    this.weixinToken = null;
    this.weixinTokenExpiry = null;

    // 钉钉
    this.dingtalkToken = process.env.DINGTALK_TOKEN;

    // 邮件
    this.smtpConfig = {
      host: process.env.SMTP_HOST,
      port: process.env.SMTP_PORT,
      user: process.env.SMTP_USER,
      password: process.env.SMTP_PASSWORD,
    };
  }

  // 获取企业微信 Access Token
  async getWeChatToken() {
    if (this.weixinToken && this.weixinTokenExpiry > Date.now()) {
      return this.weixinToken;
    }

    const url = `https://qyapi.weixin.qq.com/cgi-bin/gettoken`;
    const params = {
      corpid: this.weixinCorpId,
      corpsecret: this.weixinSecret,
    };

    const response = await axios.get(url, { params });
    const { access_token, expires_in } = response.data;

    if (response.data.errcode !== 0) {
      throw new Error(`企业微信 Token 获取失败: ${response.data.errmsg}`);
    }

    this.weixinToken = access_token;
    this.weixinTokenExpiry = Date.now() + (expires_in - 60) * 1000;

    return access_token;
  }

  // 发送企业微信消息
  async sendWeChat(userIds, message) {
    if (!this.weixinCorpId || !this.weixinAgentId) {
      console.log('[通知] 企业微信未配置，跳过');
      return { success: false, reason: 'not_configured' };
    }

    try {
      const token = await this.getWeChatToken();
      const url = `https://qyapi.weixin.qq.com/cgi-bin/message/send`;

      const response = await axios.post(
        url,
        {
          touser: userIds.join('|'),
          msgtype: 'text',
          agentid: this.weixinAgentId,
          text: { content: message },
        },
        { params: { access_token: token } }
      );

      if (response.data.errcode !== 0) {
        throw new Error(response.data.errmsg);
      }

      return { success: true, messageId: response.data.msgid };
    } catch (error) {
      console.error('[通知] 企业微信发送失败:', error.message);
      return { success: false, error: error.message };
    }
  }

  // 发送钉钉消息
  async sendDingTalk(userIds, message) {
    if (!this.dingtalkToken) {
      console.log('[通知] 钉钉未配置，跳过');
      return { success: false, reason: 'not_configured' };
    }

    try {
      const url = `https://oapi.dingtalk.com/robot/send`;
      const response = await axios.post(
        url,
        {
          msgtype: 'text',
          text: { content: message },
          at: {
            atUserIds: userIds,
          },
        },
        { params: { access_token: this.dingtalkToken } }
      );

      if (response.data.errcode !== 0) {
        throw new Error(response.data.errmsg);
      }

      return { success: true };
    } catch (error) {
      console.error('[通知] 钉钉发送失败:', error.message);
      return { success: false, error: error.message };
    }
  }

  // 发送邮件
  async sendEmail(recipients, subject, htmlBody) {
    if (!this.smtpConfig.host) {
      console.log('[通知] 邮件 SMTP 未配置，跳过');
      return { success: false, reason: 'not_configured' };
    }

    // 实际项目中应使用 nodemailer 或邮件服务
    console.log(`[通知] 发送邮件给 ${recipients.join(', ')}: ${subject}`);
    return { success: true };
  }

  // 发送短信（预留接口）
  async sendSMS(phoneNumbers, content) {
    console.log(`[通知] 发送短信给 ${phoneNumbers.join(', ')}: ${content}`);
    return { success: true };
  }

  // 统一发送接口
  async sendToUsers(userIds, message, channels) {
    const results = {};

    for (const channel of channels) {
      const userIdsForChannel = userIds; // 可以根据用户偏好筛选

      switch (channel) {
        case 'wechat':
          results.wechat = await this.sendWeChat(userIdsForChannel, message);
          break;
        case 'dingtalk':
          results.dingtalk = await this.sendDingTalk(userIdsForChannel, message);
          break;
        case 'email':
          results.email = await this.sendEmail(userIdsForChannel, '预警通知', message);
          break;
        case 'sms':
          results.sms = await this.sendSMS(userIdsForChannel, message);
          break;
        default:
          results[channel] = { success: false, reason: 'unknown_channel' };
      }
    }

    return results;
  }

  // 格式化预警消息
  formatAlertMessage(rule, value, threshold) {
    const severityEmoji = {
      low: 'ℹ️',
      medium: '⚠️',
      high: '🔴',
      critical: '🚨',
    };

    const severityZh = {
      low: '低',
      medium: '中',
      high: '高',
      critical: '严重',
    };

    return `
${severityEmoji[rule.severity] || '⚠️'} 【${severityZh[rule.severity] || '中'}级预警】${rule.name}

📊 当前值: ${value}
🎯 阈值: ${rule.condition === 'gt' ? '大于' : rule.condition === 'lt' ? '小于' : rule.condition} ${threshold}
⏰ 时间: ${new Date().toLocaleString()}

请及时处理！
    `.trim();
  }
}

module.exports = new NotificationService();