/**
 * XML数据解析模块
 * 负责XML数据的解析、状态转换检测
 */

const ParameterParser = require('./parser');

class FreseniusXMLParser {
  constructor() {
    this.buffer = '';
    this.recordCount = 0;
    this.lastTSPRGR = null;              // 记录上一个 TSPRGR 值
    this.prewashStartTime = null;        // 预冲开始时间
    this.treatmentStartTime = null;      // 治疗开始时间
    this.treatmentEndTime = null;        // 治疗结束时间
    this.events = [];                    // 事件日志
  }

  /**
   * 解析数据流
   * @param {Buffer} data - 接收到的数据
   */
  parseData(data) {
    this.buffer += data.toString();
    const records = [];

    const regex = /<Rec[^>]*>[\s\S]*?<\/Rec>/g;
    let match;

    while ((match = regex.exec(this.buffer)) !== null) {
      records.push(this.analyzeRecord(match[0]));
    }

    const lastRecEnd = this.buffer.lastIndexOf('</Rec>');
    if (lastRecEnd !== -1) {
      this.buffer = this.buffer.substring(lastRecEnd + 6);
    }

    return records;
  }

  /**
   * 分析单条记录
   * @param {string} xmlStr - XML字符串
   */
  analyzeRecord(xmlStr) {
    this.recordCount++;
    const params = ParameterParser.extractAllParameters(xmlStr);
    const currentTSPRGR = params['TSPRGR'];
    
    // 检查状态转换事件
    const stateTransition = this.checkStateTransition(currentTSPRGR);
    
    const record = {
      recordNo: this.recordCount,
      timestamp: new Date().toLocaleString('zh-CN'),
      crc: ParameterParser.extractAttribute(xmlStr, 'CRC'),
      version: ParameterParser.extractElement(xmlStr, 'Ver'),
      dateTime: ParameterParser.extractElement(xmlStr, 'DtTm'),
      type: ParameterParser.extractElement(xmlStr, 'Type'),
      parameters: params,
      keyData: ParameterParser.extractKeyData(xmlStr),
      tsprgr: currentTSPRGR,
      stateEvent: stateTransition
    };
    
    // 更新最后的 TSPRGR 值
    if (currentTSPRGR) {
      this.lastTSPRGR = currentTSPRGR;
    }
    
    return record;
  }

  /**
   * 检查状态转换并生成事件
   * @param {string} currentTSPRGR - 当前TSPRGR值
   */
  checkStateTransition(currentTSPRGR) {
    const now = new Date().toLocaleString('zh-CN');
    let event = null;

    if (!currentTSPRGR) return null;

    // TSPRGR = 1: 预冲开始
    if (currentTSPRGR === '1' && this.lastTSPRGR !== '1') {
      this.prewashStartTime = now;
      event = {
        type: 'PREWASH_START',
        description: '预冲开始',
        time: now,
        severity: 'info'
      };
      this.events.push(event);
    }

    // TSPRGR = 2: 治疗运行
    if (currentTSPRGR === '2' && this.lastTSPRGR !== '2') {
      this.treatmentStartTime = now;
      event = {
        type: 'TREATMENT_START',
        description: '治疗开始 (参数采集已激活)',
        time: now,
        severity: 'info'
      };
      this.events.push(event);
    }

    // TSPRGR 从 2 到 3: 治疗结束
    if (currentTSPRGR === '3' && this.lastTSPRGR === '2') {
      this.treatmentEndTime = now;
      event = {
        type: 'TREATMENT_END',
        description: '治疗结束',
        time: now,
        severity: 'warning'
      };
      this.events.push(event);
    }

    return event;
  }

  /**
   * 获取事件日志
   */
  getEvents() {
    return this.events;
  }

  /**
   * 获取记录计数
   */
  getRecordCount() {
    return this.recordCount;
  }
}

module.exports = FreseniusXMLParser;